Clean checkin of the 6.03 codeandroid-wear-o-preview-4android-wear-o-preview-3android-wear-8.1.0_r1android-vts-8.1_r9android-vts-8.1_r8android-vts-8.1_r7android-vts-8.1_r6android-vts-8.1_r5android-vts-8.1_r4android-vts-8.1_r3android-vts-8.1_r14android-vts-8.1_r13android-vts-8.1_r12android-vts-8.1_r11android-vts-8.1_r10android-vts-8.0_r9android-vts-8.0_r8android-vts-8.0_r7android-vts-8.0_r6android-vts-8.0_r2android-vts-8.0_r13android-vts-8.0_r12android-vts-8.0_r11android-vts-8.0_r10android-vts-8.0_r1android-security-8.1.0_r93android-security-8.1.0_r92android-security-8.1.0_r91android-security-8.1.0_r90android-security-8.1.0_r89android-security-8.1.0_r88android-security-8.1.0_r87android-security-8.1.0_r86android-security-8.1.0_r85android-security-8.1.0_r84android-security-8.1.0_r83android-security-8.1.0_r82android-security-8.0.0_r54android-security-8.0.0_r53android-security-8.0.0_r52android-o-preview-4android-o-preview-3android-o-preview-2android-o-mr1-preview-2android-o-mr1-preview-1android-o-mr1-iot-release-smart-display-r9android-o-mr1-iot-release-smart-display-r8android-o-mr1-iot-release-smart-display-r5android-o-mr1-iot-release-smart-display-r40.1Jandroid-o-mr1-iot-release-smart-display-r4android-o-mr1-iot-release-smart-display-r39android-o-mr1-iot-release-smart-display-r30android-o-mr1-iot-release-smart-display-r3android-o-mr1-iot-release-smart-display-r22android-o-mr1-iot-release-smart-display-r14android-o-mr1-iot-release-smart-clock-r6android-o-mr1-iot-release-smart-clock-r2android-o-mr1-iot-release-smart-clock-fsiandroid-o-mr1-iot-release-smart-clock-fcsandroid-o-mr1-iot-release-cube_r2android-o-mr1-iot-release-cube-fsiandroid-o-mr1-iot-release-cube-fcsandroid-o-mr1-iot-release-1.0.8android-o-mr1-iot-release-1.0.7android-o-mr1-iot-release-1.0.5android-o-mr1-iot-release-1.0.4android-o-mr1-iot-release-1.0.3android-o-mr1-iot-release-1.0.2android-o-mr1-iot-release-1.0.14android-o-mr1-iot-release-1.0.13android-o-mr1-iot-release-1.0.12android-o-mr1-iot-release-1.0.10android-o-mr1-iot-release-1.0.1android-o-mr1-iot-release-1.0.0android-o-mr1-iot-preview-8android-o-mr1-iot-preview-7android-o-mr1-iot-preview-6android-o-iot-preview-5android-cts-8.1_r9android-cts-8.1_r8android-cts-8.1_r7android-cts-8.1_r6android-cts-8.1_r5android-cts-8.1_r4android-cts-8.1_r3android-cts-8.1_r25android-cts-8.1_r24android-cts-8.1_r23android-cts-8.1_r22android-cts-8.1_r21android-cts-8.1_r20android-cts-8.1_r2android-cts-8.1_r19android-cts-8.1_r18android-cts-8.1_r17android-cts-8.1_r16android-cts-8.1_r15android-cts-8.1_r14android-cts-8.1_r13android-cts-8.1_r12android-cts-8.1_r11android-cts-8.1_r10android-cts-8.1_r1android-cts-8.0_r9android-cts-8.0_r8android-cts-8.0_r7android-cts-8.0_r6android-cts-8.0_r5android-cts-8.0_r4android-cts-8.0_r3android-cts-8.0_r26android-cts-8.0_r25android-cts-8.0_r24android-cts-8.0_r23android-cts-8.0_r22android-cts-8.0_r21android-cts-8.0_r20android-cts-8.0_r2android-cts-8.0_r19android-cts-8.0_r18android-cts-8.0_r17android-cts-8.0_r16android-cts-8.0_r15android-cts-8.0_r14android-cts-8.0_r13android-cts-8.0_r12android-cts-8.0_r11android-cts-8.0_r10android-cts-8.0_r1android-8.1.0_r9android-8.1.0_r81android-8.1.0_r80android-8.1.0_r8android-8.1.0_r79android-8.1.0_r78android-8.1.0_r77android-8.1.0_r76android-8.1.0_r75android-8.1.0_r74android-8.1.0_r73android-8.1.0_r72android-8.1.0_r71android-8.1.0_r70android-8.1.0_r7android-8.1.0_r69android-8.1.0_r68android-8.1.0_r67android-8.1.0_r66android-8.1.0_r65android-8.1.0_r64android-8.1.0_r63android-8.1.0_r62android-8.1.0_r61android-8.1.0_r60android-8.1.0_r6android-8.1.0_r53android-8.1.0_r52android-8.1.0_r51android-8.1.0_r50android-8.1.0_r5android-8.1.0_r48android-8.1.0_r47android-8.1.0_r46android-8.1.0_r45android-8.1.0_r43android-8.1.0_r42android-8.1.0_r41android-8.1.0_r40android-8.1.0_r4android-8.1.0_r39android-8.1.0_r38android-8.1.0_r37android-8.1.0_r36android-8.1.0_r35android-8.1.0_r33android-8.1.0_r32android-8.1.0_r31android-8.1.0_r30android-8.1.0_r3android-8.1.0_r29android-8.1.0_r28android-8.1.0_r27android-8.1.0_r26android-8.1.0_r25android-8.1.0_r23android-8.1.0_r22android-8.1.0_r21android-8.1.0_r20android-8.1.0_r2android-8.1.0_r19android-8.1.0_r18android-8.1.0_r17android-8.1.0_r16android-8.1.0_r15android-8.1.0_r14android-8.1.0_r13android-8.1.0_r12android-8.1.0_r11android-8.1.0_r10android-8.1.0_r1android-8.0.0_r9android-8.0.0_r7android-8.0.0_r51android-8.0.0_r50android-8.0.0_r49android-8.0.0_r48android-8.0.0_r47android-8.0.0_r46android-8.0.0_r45android-8.0.0_r44android-8.0.0_r43android-8.0.0_r42android-8.0.0_r41android-8.0.0_r40android-8.0.0_r4android-8.0.0_r39android-8.0.0_r38android-8.0.0_r37android-8.0.0_r36android-8.0.0_r35android-8.0.0_r34android-8.0.0_r33android-8.0.0_r32android-8.0.0_r31android-8.0.0_r30android-8.0.0_r3android-8.0.0_r29android-8.0.0_r28android-8.0.0_r27android-8.0.0_r26android-8.0.0_r25android-8.0.0_r24android-8.0.0_r23android-8.0.0_r22android-8.0.0_r21android-8.0.0_r2android-8.0.0_r17android-8.0.0_r16android-8.0.0_r15android-8.0.0_r13android-8.0.0_r12android-8.0.0_r11android-8.0.0_r10android-8.0.0_r1security-oc-releasesecurity-oc-mr1-releaseoreo-vts-releaseoreo-security-releaseoreo-releaseoreo-r6-releaseoreo-r5-releaseoreo-r4-releaseoreo-r3-releaseoreo-r2-releaseoreo-mr1-wear-releaseoreo-mr1-vts-releaseoreo-mr1-security-releaseoreo-mr1-s1-releaseoreo-mr1-releaseoreo-mr1-iot-releaseoreo-mr1-devoreo-mr1-cuttlefish-testingoreo-mr1-cts-releaseoreo-mr1-1.2-iot-releaseoreo-m8-releaseoreo-m7-releaseoreo-m6-s4-releaseoreo-m6-s3-releaseoreo-m6-s2-releaseoreo-m5-releaseoreo-m4-s9-releaseoreo-m4-s8-releaseoreo-m4-s7-releaseoreo-m4-s6-releaseoreo-m4-s5-releaseoreo-m4-s4-releaseoreo-m4-s3-releaseoreo-m4-s2-releaseoreo-m4-s12-releaseoreo-m4-s11-releaseoreo-m4-s10-releaseoreo-m4-s1-releaseoreo-m3-releaseoreo-m2-s5-releaseoreo-m2-s4-releaseoreo-m2-s3-releaseoreo-m2-s2-releaseoreo-m2-s1-releaseoreo-m2-releaseoreo-dr3-releaseoreo-dr2-releaseoreo-dr1-releaseoreo-dr1-devoreo-devoreo-cts-releaseo-preview-4o-preview-3o-preview-2o-mr1-iot-preview-8o-mr1-iot-preview-7o-mr1-iot-preview-6o-iot-preview-5

BUG: 32495852
Change-Id: I5038a3bb41e217380c1188463daec07b1e9b6b48

35 files changed, 2718 insertions, 0 deletions

diff --git a/dos/Makefile b/dos/Makefile
new file mode 100644
index 0000000..b9c337d
--- /dev/null
+++ b/dos/Makefile
@@ -0,0 +1,79 @@
+## -----------------------------------------------------------------------
+##
+##   Copyright 2001-2008 H. Peter Anvin - All Rights Reserved
+##
+##   This program is free software; you can redistribute it and/or modify
+##   it under the terms of the GNU General Public License as published by
+##   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+##   Boston MA 02111-1307, USA; either version 2 of the License, or
+##   (at your option) any later version; incorporated herein by reference.
+##
+## -----------------------------------------------------------------------
+
+##
+## MS-DOS FAT installer
+##
+
+include $(MAKEDIR)/embedded.mk
+
+CFLAGS	+= -D__MSDOS__ -mregparm=3 -DREGPARM=3
+# CFLAGS  += -DDEBUG
+
+LDFLAGS	 = -T $(SRC)/dosexe.ld
+OPTFLAGS = -g
+INCLUDES = -include code16.h -nostdinc -iwithprefix include \
+	   -I$(SRC) -I$(SRC)/.. -I$(SRC)/../libfat \
+	   -I $(SRC)/../libinstaller -I $(SRC)/../libinstaller/getopt \
+	   -I$(objdir)
+
+SRCS     = syslinux.c \
+	   ../libinstaller/fs.c \
+	   ../libinstaller/syslxmod.c \
+	   ../libinstaller/syslxopt.c \
+	   ../libinstaller/setadv.c \
+	   ../libinstaller/getopt/getopt_long.c \
+	   ../libinstaller/bootsect_bin.c \
+	   ../libinstaller/mbr_bin.c \
+           $(wildcard $(SRC)/../libfat/*.c)
+OBJS	 = header.o crt0.o ldlinux.o \
+	   $(patsubst %.c,%.o,$(notdir $(SRCS)))
+LIBOBJS	 = int2526.o conio.o memcpy.o memset.o memmove.o skipatou.o atou.o \
+	   malloc.o free.o getopt_long.o getsetsl.o strchr.o strtoul.o \
+	   strntoumax.o argv.o printf.o __divdi3.o __udivmoddi4.o
+
+VPATH = $(SRC):$(SRC)/../libfat:$(SRC)/../libinstaller:$(SRC)/../libinstaller/getopt:$(OBJ)/../libinstaller
+
+TARGETS = syslinux.com
+
+all: $(TARGETS)
+
+tidy dist:
+	-rm -f *.o *.i *.s *.a .*.d *.tmp *.elf *.lst
+
+clean: tidy
+
+spotless: clean
+	-rm -f *~ $(TARGETS)
+
+installer:
+
+syslinux.elf: $(OBJS) dosexe.ld libcom.a
+	$(LD) $(LDFLAGS) -o $@ $(OBJS) libcom.a
+
+libcom.a: $(LIBOBJS)
+	-rm -f $@
+	$(AR) cq $@ $^
+	$(RANLIB) $@
+
+syslinux.com: syslinux.elf
+	$(OBJCOPY) -O binary $< $@
+	$(UPX) --lzma --ultra-brute $@ || \
+		$(UPX) --ultra-brute $@ || \
+		true
+
+%.com: %.asm
+	$(NASM) $(NASMOPT) -f bin -o $@ -MP -MD .$@.d -l $*.lst $<
+
+ldlinux.o: ldlinux.S $(OBJ)/../core/ldlinux.sys
+
+-include .*.d
diff --git a/dos/__divdi3.c b/dos/__divdi3.c
new file mode 100644
index 0000000..97c7795
--- /dev/null
+++ b/dos/__divdi3.c
@@ -0,0 +1,29 @@
+/*
+ * arch/i386/libgcc/__divdi3.c
+ */
+
+#include <stdint.h>
+#include <stddef.h>
+
+extern uint64_t __udivmoddi4(uint64_t num, uint64_t den, uint64_t * rem);
+
+int64_t __divdi3(int64_t num, int64_t den)
+{
+    int minus = 0;
+    int64_t v;
+
+    if (num < 0) {
+	num = -num;
+	minus = 1;
+    }
+    if (den < 0) {
+	den = -den;
+	minus ^= 1;
+    }
+
+    v = __udivmoddi4(num, den, NULL);
+    if (minus)
+	v = -v;
+
+    return v;
+}
diff --git a/dos/__udivmoddi4.c b/dos/__udivmoddi4.c
new file mode 100644
index 0000000..ca476b7
--- /dev/null
+++ b/dos/__udivmoddi4.c
@@ -0,0 +1,31 @@
+#include <stdint.h>
+
+uint64_t __udivmoddi4(uint64_t num, uint64_t den, uint64_t * rem_p)
+{
+    uint64_t quot = 0, qbit = 1;
+
+    if (den == 0) {
+	asm volatile ("int $0");
+	return 0;		/* If trap returns... */
+    }
+
+    /* Left-justify denominator and count shift */
+    while ((int64_t) den >= 0) {
+	den <<= 1;
+	qbit <<= 1;
+    }
+
+    while (qbit) {
+	if (den <= num) {
+	    num -= den;
+	    quot += qbit;
+	}
+	den >>= 1;
+	qbit >>= 1;
+    }
+
+    if (rem_p)
+	*rem_p = num;
+
+    return quot;
+}
diff --git a/dos/argv.c b/dos/argv.c
new file mode 100644
index 0000000..da28366
--- /dev/null
+++ b/dos/argv.c
@@ -0,0 +1,126 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2004-2008 H. Peter Anvin - All Rights Reserved
+ *   Copyright 2013 Intel Corporation; author: H. Peter Anvin
+ *
+ *   Permission is hereby granted, free of charge, to any person
+ *   obtaining a copy of this software and associated documentation
+ *   files (the "Software"), to deal in the Software without
+ *   restriction, including without limitation the rights to use,
+ *   copy, modify, merge, publish, distribute, sublicense, and/or
+ *   sell copies of the Software, and to permit persons to whom
+ *   the Software is furnished to do so, subject to the following
+ *   conditions:
+ *
+ *   The above copyright notice and this permission notice shall
+ *   be included in all copies or substantial portions of the Software.
+ *
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ *   OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * argv.c
+ *
+ * Parse the MS-DOS command line into argc and argv (argc is return value.)
+ * memptr points to available memory.
+ */
+
+#include <inttypes.h>
+#include <stddef.h>
+#include <stdbool.h>
+#include "mystuff.h"
+
+#define ALIGN_UP(p,t)       ((t *)(((uintptr_t)(p) + (sizeof(t)-1)) & ~(sizeof(t)-1)))
+
+extern char __heap_start[];
+void *__mem_end = &__heap_start;	/* Global variable for use by malloc() */
+
+int __parse_argv(char ***argv)
+{
+    char *mem = __mem_end;
+    const char *str, *p;
+    char *q = mem;
+    char c, *r;
+    char **arg;
+    bool wasspace;
+    int argc;
+    int len;
+    size_t offs;
+    int nulls;
+    uint16_t nstr;
+
+    /* Find and copy argv[0] after the environment block */
+    set_fs(_PSP.environment);
+    offs = 0;
+    nulls = 0;
+    do {
+	if (get_8_fs(offs++) == '\0')
+	    nulls++;
+	else
+	    nulls = 0;
+    } while (nulls < 2);
+
+    nstr = get_16_fs(offs);
+    offs += 2;
+
+    /* Copy the null-terminated filename string */
+    if (nstr >= 1) {
+	while ((c = get_8_fs(offs++)))
+	    *q++ = c;
+    }
+    *q++ = '\0';
+
+    /* Now for the command line tail... */
+
+    len = _PSP.cmdlen;
+    str = _PSP.cmdtail;
+    argc = 1;
+    wasspace = true;
+
+    /* Copy the command tail, turning whitespace runs into nulls */
+    for (p = str;; p++) {
+	if (!len || *p <= ' ') {
+	    if (!wasspace) {
+		wasspace = true;
+		*q++ = '\0';
+	    }
+	} else {
+	    if (wasspace) {
+		argc++;
+		wasspace = false;
+	    }
+	    *q++ = *p;
+	}
+
+	/* This test is AFTER we have processed the end byte;
+	   we treat it as a whitespace character so it terminates
+	   the last argument */
+	if (!len--)
+	    break;
+    }
+
+    /* Now create argv */
+    arg = ALIGN_UP(q, char *);
+    *argv = arg;
+    *arg++ = mem;		/* argv[0] */
+
+    q--;			/* Point q to terminal character */
+    for (r = mem; r < q; r++) {
+	if (*r == '\0') {
+	    *arg++ = r + 1;
+	}
+    }
+
+    *arg++ = NULL;		/* Null pointer at the end */
+    __mem_end = arg;		/* End of memory we used */
+
+    return argc;
+}
diff --git a/dos/atou.c b/dos/atou.c
new file mode 100644
index 0000000..e21736d
--- /dev/null
+++ b/dos/atou.c
@@ -0,0 +1,9 @@
+#include "mystuff.h"
+
+unsigned int atou(const char *s)
+{
+    unsigned int i = 0;
+    while (isdigit(*s))
+	i = i * 10 + (*s++ - '0');
+    return i;
+}
diff --git a/dos/code16.h b/dos/code16.h
new file mode 100644
index 0000000..ca76565
--- /dev/null
+++ b/dos/code16.h
@@ -0,0 +1,6 @@
+/* Must be included first of all */
+#ifdef __ASSEMBLY__
+	.code16
+#else
+__asm__ (".code16gcc");
+#endif
diff --git a/dos/conio.c b/dos/conio.c
new file mode 100644
index 0000000..1400e42
--- /dev/null
+++ b/dos/conio.c
@@ -0,0 +1,42 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2001-2008 H. Peter Anvin - All Rights Reserved
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * conio.c
+ *
+ * Output to the screen
+ */
+
+#include <stdarg.h>
+#include "mystuff.h"
+
+int putchar(int ch)
+{
+    if (ch == '\n')
+	putchar('\r');
+asm("movb $0x02,%%ah ; int $0x21": :"d"(ch));
+    return ch;
+}
+
+/* Note: doesn't put '\n' like the stdc version does */
+int puts(const char *s)
+{
+    int count = 0;
+
+    while (*s) {
+	putchar(*s);
+	count++;
+	s++;
+    }
+
+    return count;
+}
diff --git a/dos/crt0.S b/dos/crt0.S
new file mode 100644
index 0000000..66b52c0
--- /dev/null
+++ b/dos/crt0.S
@@ -0,0 +1,91 @@
+	.code16
+
+#ifndef REGPARM
+# error "This file assumes -mregparm=3 -DREGPARM=3"
+#endif
+
+	.section ".text","ax"
+	.globl _start
+	.type _start,@function
+_start:
+	# Align the stack and make sure the high half is zero
+	andl $0xfffc,%esp
+
+	# DS, ES points to the PSP at this point
+	pushw %es		# Save PSP pointer
+	movw %cs,%ax
+	movw %ax,%ds
+	movw %ax,%es
+
+	# Clear the .bss
+	cld
+	xorl %eax,%eax
+	movw $__bss_start,%di
+	movw $__bss_end+3,%cx
+	subw %di,%cx
+	shrw $2,%cx
+	rep ; stosl
+
+	# Copy the PSP into our own segment
+	popw %fs		# FS -> PSP
+	movw $_PSP,%di
+	xorw %si,%si
+	movw $0x40,%cx
+	fs ; rep ; movsl
+
+	# Verify that this is a supportable DOS version
+	movw $0x3001,%ax
+	int $0x21
+	xchgb %ah,%al
+	movw %ax,dos_version
+	cmpw $0x0314,%ax	# DOS >= 3.20?
+	jae 1f			# If so, okay
+	movw $bad_dos,%dx	# Print error message
+	movb $0x09,%ah
+	int $0x21
+	int $0x20		# Die
+
+1:
+	# Compute argc and argv (assumes REGPARM)
+	pushl %eax		# Make space for argv
+	movl %esp,%eax
+	calll __parse_argv
+	pushl %eax		# argc
+
+	# Initialize malloc
+	calll __init_memory_arena
+
+	# Now call main
+	popl %eax		# argc
+	popl %edx		# argv
+	calll main
+
+	# Here %eax is the exit code, fall through into exit
+
+	.size _start,.-_start
+
+	.globl exit
+	.type exit,@function
+exit:
+	# Exit code already in %eax
+	movb $0x4c,%ah		# Terminate program
+	int $0x21
+1:	hlt
+	jmp 1b
+	.size exit,.-exit
+
+	.section ".rodata","a"
+bad_dos:
+	.ascii "Unsupported DOS version\r\n$"
+	.size bad_dos,.-bad_dos
+
+	.section ".bss","aw"
+	.balign 16
+	.globl _PSP
+_PSP:
+	.space 256
+	.size _PSP, .-_PSP
+
+	/* Purely for sanity */
+	.section ".null","a"
+	.long 0,0,0,0
diff --git a/dos/ctype.h b/dos/ctype.h
new file mode 100644
index 0000000..c0d00c0
--- /dev/null
+++ b/dos/ctype.h
@@ -0,0 +1,3 @@
+static int isspace(int c) {
+  return (c == ' ');
+}
diff --git a/dos/dosexe.ld b/dos/dosexe.ld
new file mode 100644
index 0000000..733f73d
--- /dev/null
+++ b/dos/dosexe.ld
@@ -0,0 +1,141 @@
+/*
+ * Linker script for an MS-DOS EXE binary; this hard-codes a simple
+ * MZ header without relocations.
+ *
+ * For documentation on the MS-DOS MZ EXE format, see:
+ * http://www.delorie.com/djgpp/doc/exe/
+ */
+
+
+/* Script for -z combreloc: combine and sort reloc sections */
+OUTPUT_FORMAT("elf32-i386", "elf32-i386",
+	      "elf32-i386")
+OUTPUT_ARCH(i386)
+EXTERN(_start)
+ENTRY(_start)
+
+SECTIONS
+{
+	. = 0;
+	/* EXE header, from header.S */
+	.header : {
+		*(.header)
+	} =0
+
+	. = ALIGN(16);
+	__header_size = .;
+	__payload_lma = .;
+
+	. = 0x100000000 - syslinux_size;
+	.payload : AT (__payload_lma) {
+		 __payload_start = .;
+		 *(.payload)
+		 __payload_end = .;
+	}
+	__payload_len = ABSOLUTE(__payload_end) - ABSOLUTE(__payload_start);
+	__payload_dwords = __payload_len >> 2;
+
+	__dgroup_lma = __payload_lma + syslinux_size;
+	__payload_sseg = (__payload_lma - __dgroup_lma) >> 4;
+	_exe_text_seg  = (__dgroup_lma - __header_size) >> 4;
+
+/*
+ *	__assert1 = ASSERT((__payload_len == syslinux_ldlinux_size),
+ *	"syslinux_size must equal the size of .payload");
+ */
+	. = 0;
+	__null = .;
+	.null : AT(__dgroup_lma) {
+		*(.null)
+	}
+
+	. = ALIGN(16);
+	__text_vma = .;
+	.text : AT (__text_vma + __dgroup_lma) {
+		*(.text .stub .text.* .gnu.linkonce.t.*)
+		*(.gnu.warning)
+	} =0x90909090
+	_etext = .;
+
+	. = ALIGN(16);
+	__rodata_vma = .;
+	.rodata : AT (__rodata_vma + __dgroup_lma) {
+		*(.rodata .rodata.* .gnu.linkonce.r.*)
+	}
+
+	/* Adjust the address for the data segment.  Avoid mixing code and
+	   data within same 128-byte chunk. */
+	. = ALIGN(128);
+	__data_vma = .;
+	.data : AT (__data_vma + __dgroup_lma) {
+		*(.data .data.* .gnu.linkonce.d.*)
+		SORT(CONSTRUCTORS)
+	}
+	.data1 : { *(.data1) }
+	_edata = .;
+
+	_exe_edata_low    = ((_edata + __dgroup_lma) & 511);
+	_exe_edata_blocks = ((_edata + __dgroup_lma) + 511) >> 9;
+
+	.bss (NOLOAD) : {
+		__bss_start = .;
+		*(.dynbss)
+		*(.bss .bss.* .gnu.linkonce.b.*)
+		*(COMMON)
+		__bss_end = .;
+	}
+
+	. = ALIGN(16);
+	.heap (NOLOAD) : {
+		__heap_start = .;
+		*(.heap)
+		__heap_end = .;
+	}
+
+	. = ALIGN(16);
+	.stack (NOLOAD) : {
+		__stack_start = .;
+		*(.stack)
+		__stack_end = .;
+	}
+	. = ALIGN(16);
+	_end = .;
+
+	_exe_bss_paras = (_end - __bss_start) >> 4;
+
+
+  /* Stabs debugging sections.  */
+  .stab          0 : { *(.stab) }
+  .stabstr       0 : { *(.stabstr) }
+  .stab.excl     0 : { *(.stab.excl) }
+  .stab.exclstr  0 : { *(.stab.exclstr) }
+  .stab.index    0 : { *(.stab.index) }
+  .stab.indexstr 0 : { *(.stab.indexstr) }
+  .comment       0 : { *(.comment) }
+  /* DWARF debug sections.
+     Symbols in the DWARF debugging sections are relative to the beginning
+     of the section so we begin them at 0.  */
+  /* DWARF 1 */
+  .debug          0 : { *(.debug) }
+  .line           0 : { *(.line) }
+  /* GNU DWARF 1 extensions */
+  .debug_srcinfo  0 : { *(.debug_srcinfo) }
+  .debug_sfnames  0 : { *(.debug_sfnames) }
+  /* DWARF 1.1 and DWARF 2 */
+  .debug_aranges  0 : { *(.debug_aranges) }
+  .debug_pubnames 0 : { *(.debug_pubnames) }
+  /* DWARF 2 */
+  .debug_info     0 : { *(.debug_info .gnu.linkonce.wi.*) }
+  .debug_abbrev   0 : { *(.debug_abbrev) }
+  .debug_line     0 : { *(.debug_line) }
+  .debug_frame    0 : { *(.debug_frame) }
+  .debug_str      0 : { *(.debug_str) }
+  .debug_loc      0 : { *(.debug_loc) }
+  .debug_macinfo  0 : { *(.debug_macinfo) }
+  /* SGI/MIPS DWARF 2 extensions */
+  .debug_weaknames 0 : { *(.debug_weaknames) }
+  .debug_funcnames 0 : { *(.debug_funcnames) }
+  .debug_typenames 0 : { *(.debug_typenames) }
+  .debug_varnames  0 : { *(.debug_varnames) }
+  /DISCARD/ : { *(.note.GNU-stack) }
+}
diff --git a/dos/errno.h b/dos/errno.h
new file mode 100644
index 0000000..da733bf
--- /dev/null
+++ b/dos/errno.h
@@ -0,0 +1,42 @@
+#ifndef ERRNO_H
+#define ERRNO_H
+
+#define	EPERM		 1	/* Operation not permitted */
+#define	ENOENT		 2	/* No such file or directory */
+#define	ESRCH		 3	/* No such process */
+#define	EINTR		 4	/* Interrupted system call */
+#define	EIO		 5	/* I/O error */
+#define	ENXIO		 6	/* No such device or address */
+#define	E2BIG		 7	/* Argument list too long */
+#define	ENOEXEC		 8	/* Exec format error */
+#define	EBADF		 9	/* Bad file number */
+#define	ECHILD		10	/* No child processes */
+#define	EAGAIN		11	/* Try again */
+#define	ENOMEM		12	/* Out of memory */
+#define	EACCES		13	/* Permission denied */
+#define	EFAULT		14	/* Bad address */
+#define	ENOTBLK		15	/* Block device required */
+#define	EBUSY		16	/* Device or resource busy */
+#define	EEXIST		17	/* File exists */
+#define	EXDEV		18	/* Cross-device link */
+#define	ENODEV		19	/* No such device */
+#define	ENOTDIR		20	/* Not a directory */
+#define	EISDIR		21	/* Is a directory */
+#define	EINVAL		22	/* Invalid argument */
+#define	ENFILE		23	/* File table overflow */
+#define	EMFILE		24	/* Too many open files */
+#define	ENOTTY		25	/* Not a typewriter */
+#define	ETXTBSY		26	/* Text file busy */
+#define	EFBIG		27	/* File too large */
+#define	ENOSPC		28	/* No space left on device */
+#define	ESPIPE		29	/* Illegal seek */
+#define	EROFS		30	/* Read-only file system */
+#define	EMLINK		31	/* Too many links */
+#define	EPIPE		32	/* Broken pipe */
+#define	EDOM		33	/* Math argument out of domain of func */
+#define	ERANGE		34	/* Math result not representable */
+
+int errno;
+void perror(const char *);
+
+#endif /* ERRNO_H */
diff --git a/dos/free.c b/dos/free.c
new file mode 100644
index 0000000..b0b72ef
--- /dev/null
+++ b/dos/free.c
@@ -0,0 +1,73 @@
+/*
+ * free.c
+ *
+ * Very simple linked-list based malloc()/free().
+ */
+
+#include <stdlib.h>
+#include "malloc.h"
+
+static struct free_arena_header *__free_block(struct free_arena_header *ah)
+{
+    struct free_arena_header *pah, *nah;
+
+    pah = ah->a.prev;
+    nah = ah->a.next;
+    if (pah->a.type == ARENA_TYPE_FREE &&
+	(char *)pah + pah->a.size == (char *)ah) {
+	/* Coalesce into the previous block */
+	pah->a.size += ah->a.size;
+	pah->a.next = nah;
+	nah->a.prev = pah;
+
+#ifdef DEBUG_MALLOC
+	ah->a.type = ARENA_TYPE_DEAD;
+#endif
+
+	ah = pah;
+	pah = ah->a.prev;
+    } else {
+	/* Need to add this block to the free chain */
+	ah->a.type = ARENA_TYPE_FREE;
+
+	ah->next_free = __malloc_head.next_free;
+	ah->prev_free = &__malloc_head;
+	__malloc_head.next_free = ah;
+	ah->next_free->prev_free = ah;
+    }
+
+    /* In either of the previous cases, we might be able to merge
+       with the subsequent block... */
+    if (nah->a.type == ARENA_TYPE_FREE &&
+	(char *)ah + ah->a.size == (char *)nah) {
+	ah->a.size += nah->a.size;
+
+	/* Remove the old block from the chains */
+	nah->next_free->prev_free = nah->prev_free;
+	nah->prev_free->next_free = nah->next_free;
+	ah->a.next = nah->a.next;
+	nah->a.next->a.prev = ah;
+
+#ifdef DEBUG_MALLOC
+	nah->a.type = ARENA_TYPE_DEAD;
+#endif
+    }
+
+    /* Return the block that contains the called block */
+    return ah;
+}
+
+void free(void *ptr)
+{
+    struct free_arena_header *ah;
+
+    if (!ptr)
+	return;
+
+    ah = (struct free_arena_header *)
+	((struct arena_header *)ptr - 1);
+
+    __free_block(ah);
+
+    /* Here we could insert code to return memory to the system. */
+}
diff --git a/dos/getsetsl.c b/dos/getsetsl.c
new file mode 100644
index 0000000..c6e6ae7
--- /dev/null
+++ b/dos/getsetsl.c
@@ -0,0 +1,144 @@
+/*
+ * Special handling for the MS-DOS derivative: syslinux_ldlinux
+ * is a "far" object...
+ */
+
+#define _XOPEN_SOURCE 500	/* Required on glibc 2.x */
+#define _BSD_SOURCE
+/* glibc 2.20 deprecates _BSD_SOURCE in favour of _DEFAULT_SOURCE */
+#define _DEFAULT_SOURCE 1
+#include <inttypes.h>
+#include <string.h>
+#include <stddef.h>
+#include <stdlib.h>
+
+#include "syslxint.h"
+#include "mystuff.h"
+
+static inline void *set_fs_sl(const void *p)
+{
+    uint16_t seg;
+
+    seg = ds() + ((size_t) p >> 4);
+    set_fs(seg);
+    return (void *)((size_t) p & 0xf);
+}
+
+#if 0				/* unused */
+uint8_t get_8_sl(const uint8_t * p)
+{
+    uint8_t v;
+
+    p = set_fs_sl(p);
+    asm volatile("movb %%fs:%1,%0":"=q" (v):"m"(*p));
+    return v;
+}
+#endif
+
+uint16_t get_16_sl(const uint16_t * p)
+{
+    uint16_t v;
+
+    p = set_fs_sl(p);
+    asm volatile("movw %%fs:%1,%0":"=r" (v):"m"(*p));
+    return v;
+}
+
+uint32_t get_32_sl(const uint32_t * p)
+{
+    uint32_t v;
+
+    p = set_fs_sl(p);
+    asm volatile("movl %%fs:%1,%0":"=r" (v):"m"(*p));
+    return v;
+}
+
+#if 0				/* unused */
+uint64_t get_64_sl(const uint64_t * p)
+{
+    uint32_t v0, v1;
+    const uint32_t *pp = (const uint32_t *)set_fs_sl(p);
+
+    asm volatile("movl %%fs:%1,%0" : "=r" (v0) : "m" (pp[0]));
+    asm volatile("movl %%fs:%1,%0" : "=r" (v1) : "m" (pp[1]));
+    return v0 + ((uint64_t)v1 << 32);
+}
+#endif
+
+#if 0				/* unused */
+void set_8_sl(uint8_t * p, uint8_t v)
+{
+    p = set_fs_sl(p);
+    asm volatile("movb %1,%%fs:%0":"=m" (*p):"qi"(v));
+}
+#endif
+
+void set_16_sl(uint16_t * p, uint16_t v)
+{
+    p = set_fs_sl(p);
+    asm volatile("movw %1,%%fs:%0":"=m" (*p):"ri"(v));
+}
+
+void set_32_sl(uint32_t * p, uint32_t v)
+{
+    p = set_fs_sl(p);
+    asm volatile("movl %1,%%fs:%0":"=m" (*p):"ri"(v));
+}
+
+void set_64_sl(uint64_t * p, uint64_t v)
+{
+    uint32_t *pp = (uint32_t *)set_fs_sl(p);
+    asm volatile("movl %1,%%fs:%0" : "=m" (pp[0]) : "ri"((uint32_t)v));
+    asm volatile("movl %1,%%fs:%0" : "=m" (pp[1]) : "ri"((uint32_t)(v >> 32)));
+}
+
+void memcpy_to_sl(void *dst, const void *src, size_t len)
+{
+    uint16_t seg;
+    uint16_t off;
+
+    seg = ds() + ((size_t)dst >> 4);
+    off = (size_t)dst & 15;
+
+    asm volatile("pushw %%es ; "
+		 "movw %3,%%es ; "
+		 "rep ; movsb ; "
+		 "popw %%es"
+		 : "+D" (off), "+S" (src), "+c" (len)
+		 : "r" (seg)
+		 : "memory");
+}
+
+void memcpy_from_sl(void *dst, const void *src, size_t len)
+{
+    uint16_t seg;
+    uint16_t off;
+
+    seg = ds() + ((size_t)src >> 4);
+    off = (size_t)src & 15;
+
+    asm volatile("pushw %%ds ; "
+		 "movw %3,%%ds ; "
+		 "rep ; movsb ; "
+		 "popw %%ds"
+		 : "+D" (dst), "+S" (off), "+c" (len)
+		 : "r" (seg)
+		 : "memory");
+}
+
+void memset_sl(void *dst, int c, size_t len)
+{
+    uint16_t seg;
+    uint16_t off;
+
+    seg = ds() + ((size_t)dst >> 4);
+    off = (size_t)dst & 15;
+
+    asm volatile("pushw %%es ; "
+		 "movw %3,%%es ; "
+		 "rep ; stosb ; "
+		 "popw %%es"
+		 : "+D" (off), "+c" (len)
+		 : "a" (c), "r" (seg)
+		 : "memory");
+}
diff --git a/dos/header.S b/dos/header.S
new file mode 100644
index 0000000..8367078
--- /dev/null
+++ b/dos/header.S
@@ -0,0 +1,54 @@
+STACK_SIZE	= 8192
+HEAP_SIZE	= 16384
+
+		.section ".header","a"
+		.balign	512
+__header_start:
+		.short	0x5a4d
+		.short	_exe_edata_low
+		.short	_exe_edata_blocks
+		.short	0		/* Relocation count */
+		.short	(__header_end - __header_start) >> 4
+		.short	_exe_bss_paras
+		.short	_exe_bss_paras
+		.short	_exe_text_seg	/* SP */
+		.short	__stack_end
+		.short	0		/* Checksum */
+		.short	_start
+		.short	_exe_text_seg	/* CS */
+		.short	__reloc
+		.short	0		/* Overlay number */
+/*
+ * Don't put these fields in unless we actually have an NE or PE image;
+ * some tools might get confused and assume __reloc = 64 automatically
+ * means an NE/PE image or a Windows image of some sort.
+ */
+#if 0
+		.short	0		/* Unknown/pad? */
+		.short	0		/* Unknown/pad? */
+		.short	0		/* Unknown/pad? */
+		.short	0		/* Unknown/pad? */
+		.short	0		/* Unknown/pad? */
+		.short	0		/* Unknown/pad? */
+		.short	0		/* Unknown/pad? */
+		.short	0		/* Unknown/pad? */
+		.short	0		/* Unknown/pad? */
+		.short	0		/* Unknown/pad? */
+		.short	0		/* Unknown/pad? */
+		.short	0		/* Unknown/pad? */
+		.short	0		/* Unknown/pad? */
+		.short	0		/* Unknown/pad? */
+		.short	0		/* Unknown/pad? */
+		.short	0		/* Unknown/pad? */
+		.long	0		/* Pointer to Windows PE header */
+#endif
+		.balign 4
+__reloc:
+		.balign	512
+__header_end:
+
+		.section ".heap","aw"
+		.space	HEAP_SIZE
+
+		.section ".stack","aw"
+		.space	STACK_SIZE
diff --git a/dos/int2526.S b/dos/int2526.S
new file mode 100644
index 0000000..53e63f8
--- /dev/null
+++ b/dos/int2526.S
@@ -0,0 +1,78 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 1998-2008 H. Peter Anvin - All Rights Reserved
+ *   Copyright 2009 Intel Corporation; author: H. Peter Anvin
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * int 0x25 and 0x26 direct sector access
+ *
+ * Use assembly wrapper functions for these system calls, since unlike
+ * int 0x21 calls they are "dirty" and can destroy unrelated registers.
+ *
+ * NOTE: these all assume the data buffer is in the data segment, i.e.
+ * %ds == %es == dio.bufseg.
+ *
+ * Usage: int int25_read_sector(drive, dio)
+ * Usage: int int26_write_sector(drive, dio)
+ */
+
+	.code16gcc
+	.text
+
+	.globl	int25_read_sector
+	.type	int25_read_sector, @function
+int25_read_sector:
+	pushl	%ebp
+	pushl	%edi
+	pushl	%esi
+	pushl	%ebx
+
+	decw	%ax		/* AL = drive number (0 = A:) */
+	movw	%dx, %bx	/* BX = dio structure */
+	movw	6(%bx), %dx	/* DX = data buffer */
+	movw	$-1, %cx
+	int	$0x25
+	jc	1f
+	xorw	%ax, %ax	/* Error code: 0 = no error */
+1:
+	popfw
+	movzwl	%ax, %eax
+	popl	%ebx
+	popl	%esi
+	popl	%edi
+	popl	%ebp
+	retl
+	.size	int25_read_sector, .-int25_read_sector
+
+	.globl	int26_write_sector
+	.type	int26_write_sector, @function
+int26_write_sector:
+	pushl	%ebp
+	pushl	%edi
+	pushl	%esi
+	pushl	%ebx
+
+	decw	%ax		/* AL = drive number (0 = A:) */
+	movw	%dx, %bx	/* BX = dio structure */
+	movw	6(%bx), %dx	/* DX = data buffer */
+	movw	$-1, %cx
+	int	$0x26
+	jc	1f
+	xorw	%ax, %ax	/* Error code: 0 = no error */
+1:
+	popfw
+	movzwl	%ax, %eax
+	popl	%ebx
+	popl	%esi
+	popl	%edi
+	popl	%ebp
+	retl
+	.size	int26_write_sector, .-int26_write_sector
diff --git a/dos/inttypes.h b/dos/inttypes.h
new file mode 100644
index 0000000..9a6118b
--- /dev/null
+++ b/dos/inttypes.h
@@ -0,0 +1 @@
+#include <stdint.h>
diff --git a/dos/ldlinux.S b/dos/ldlinux.S
new file mode 100644
index 0000000..9145bd7
--- /dev/null
+++ b/dos/ldlinux.S
@@ -0,0 +1,31 @@
+/*
+ * Wrap ldlinux.sys and ldlinux.c32; this needs special handling for DOS.
+ */
+
+	.section ".payload","aw"
+	.balign	16
+	.globl	syslinux_ldlinux, syslinux_ldlinux_size
+syslinux_ldlinux:
+	.incbin "../core/ldlinux.sys"
+	.space ((syslinux_ldlinux - .) & 511)
+syslinux_ldlinux_size	= . - syslinux_ldlinux
+	.size	syslinux_ldlinux, .-syslinux_ldlinux
+	.globl	syslinux_ldlinuxc32, syslinux_ldlinuxc32_size
+syslinux_ldlinuxc32:
+	.incbin "../com32/elflink/ldlinux/ldlinux.c32"
+	.space ((syslinux_ldlinuxc32 - .) & 511)
+syslinux_ldlinuxc32_size = . - syslinux_ldlinuxc32
+	.size	syslinux_ldlinuxc32, .-syslinux_ldlinuxc32
+	.globl syslinux_size
+syslinux_size	= . - syslinux_ldlinux
+
+	.section ".rodata","a"
+	.balign	4
+	.globl	syslinux_ldlinux_len
+syslinux_ldlinux_len:
+	.long	syslinux_ldlinux_size
+	.size	syslinux_ldlinux_len, .-syslinux_ldlinux_len
+	.globl	syslinux_ldlinuxc32_len
+syslinux_ldlinuxc32_len:
+	.long	syslinux_ldlinuxc32_size
+	.size	syslinux_ldlinuxc32_len, .-syslinux_ldlinuxc32_len
diff --git a/dos/malloc.c b/dos/malloc.c
new file mode 100644
index 0000000..55c78c4
--- /dev/null
+++ b/dos/malloc.c
@@ -0,0 +1,111 @@
+/*
+ * malloc.c
+ *
+ * Very simple linked-list based malloc()/free().
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include "malloc.h"
+
+struct free_arena_header __malloc_head = {
+    {
+     ARENA_TYPE_HEAD,
+     0,
+     &__malloc_head,
+     &__malloc_head,
+     },
+    &__malloc_head,
+    &__malloc_head
+};
+
+extern void *__mem_end;		/* In argv.c */
+
+void __init_memory_arena(void)
+{
+    extern char __heap_end[];
+    struct free_arena_header *fp;
+
+    fp = (struct free_arena_header *)__mem_end;
+    fp->a.type = ARENA_TYPE_FREE;
+    fp->a.size = __heap_end - (char *)__mem_end;
+
+    /* Insert into chains */
+    fp->a.next = fp->a.prev = &__malloc_head;
+    fp->next_free = fp->prev_free = &__malloc_head;
+    __malloc_head.a.next = __malloc_head.a.prev = fp;
+    __malloc_head.next_free = __malloc_head.prev_free = fp;
+}
+
+static void *__malloc_from_block(struct free_arena_header *fp, size_t size)
+{
+    size_t fsize;
+    struct free_arena_header *nfp, *na;
+
+    fsize = fp->a.size;
+
+    /* We need the 2* to account for the larger requirements of a free block */
+    if (fsize >= size + 2 * sizeof(struct arena_header)) {
+	/* Bigger block than required -- split block */
+	nfp = (struct free_arena_header *)((char *)fp + size);
+	na = fp->a.next;
+
+	nfp->a.type = ARENA_TYPE_FREE;
+	nfp->a.size = fsize - size;
+	fp->a.type = ARENA_TYPE_USED;
+	fp->a.size = size;
+
+	/* Insert into all-block chain */
+	nfp->a.prev = fp;
+	nfp->a.next = na;
+	na->a.prev = nfp;
+	fp->a.next = nfp;
+
+	/* Replace current block on free chain */
+	nfp->next_free = fp->next_free;
+	nfp->prev_free = fp->prev_free;
+	fp->next_free->prev_free = nfp;
+	fp->prev_free->next_free = nfp;
+    } else {
+	/* Allocate the whole block */
+	fp->a.type = ARENA_TYPE_USED;
+
+	/* Remove from free chain */
+	fp->next_free->prev_free = fp->prev_free;
+	fp->prev_free->next_free = fp->next_free;
+    }
+
+    return (void *)(&fp->a + 1);
+}
+
+void *malloc(size_t size)
+{
+    struct free_arena_header *fp;
+
+    if (size == 0)
+	return NULL;
+
+    /* Add the obligatory arena header, and round up */
+    size = (size + 2 * sizeof(struct arena_header) - 1) & ~ARENA_SIZE_MASK;
+
+    for (fp = __malloc_head.next_free; fp->a.type != ARENA_TYPE_HEAD;
+	 fp = fp->next_free) {
+	if (fp->a.size >= size) {
+	    /* Found fit -- allocate out of this block */
+	    return __malloc_from_block(fp, size);
+	}
+    }
+
+    /* Nothing found... need to request a block from the kernel */
+    return NULL;		/* No kernel to get stuff from */
+}
+
+void *calloc(size_t nmemb, size_t size)
+{
+    void *p;
+    size *= nmemb;
+    p = malloc(size);
+    if (p)
+	memset(p, 0, size);
+    return p;
+}
diff --git a/dos/malloc.h b/dos/malloc.h
new file mode 100644
index 0000000..67bf217
--- /dev/null
+++ b/dos/malloc.h
@@ -0,0 +1,54 @@
+/*
+ * malloc.h
+ *
+ * Internals for the memory allocator
+ */
+
+#include <stdint.h>
+#include <stddef.h>
+
+/*
+ * This is the minimum chunk size we will ask the kernel for; this should
+ * be a multiple of the page size on all architectures.
+ */
+#define MALLOC_CHUNK_SIZE	65536
+#define MALLOC_CHUNK_MASK       (MALLOC_CHUNK_SIZE-1)
+
+/*
+ * This structure should be a power of two.  This becomes the
+ * alignment unit.
+ */
+struct free_arena_header;
+
+struct arena_header {
+    size_t type;
+    size_t size;		/* Also gives the location of the next entry */
+    struct free_arena_header *next, *prev;
+};
+
+#ifdef DEBUG_MALLOC
+#define ARENA_TYPE_USED 0x64e69c70
+#define ARENA_TYPE_FREE 0x012d610a
+#define ARENA_TYPE_HEAD 0x971676b5
+#define ARENA_TYPE_DEAD 0xeeeeeeee
+#else
+#define ARENA_TYPE_USED 0
+#define ARENA_TYPE_FREE 1
+#define ARENA_TYPE_HEAD 2
+#endif
+
+#define ARENA_SIZE_MASK (sizeof(struct arena_header)-1)
+
+#define ARENA_ALIGN_UP(p)	((char *)(((uintptr_t)(p) + ARENA_SIZE_MASK) & ~ARENA_SIZE_MASK))
+#define ARENA_ALIGN_DOWN(p)	((char *)((uintptr_t)(p) & ~ARENA_SIZE_MASK))
+
+/*
+ * This structure should be no more than twice the size of the
+ * previous structure.
+ */
+struct free_arena_header {
+    struct arena_header a;
+    struct free_arena_header *next_free, *prev_free;
+};
+
+extern struct free_arena_header __malloc_head;
diff --git a/dos/memcpy.S b/dos/memcpy.S
new file mode 100644
index 0000000..76eef73
--- /dev/null
+++ b/dos/memcpy.S
@@ -0,0 +1,23 @@
+#
+# memcpy.S
+#
+# Simple 16-bit memcpy() implementation
+#
+
+	.text
+	.code16gcc
+	.globl memcpy
+	.type memcpy, @function
+memcpy:
+	cld
+	pushw %di
+	pushw %si
+	movw %ax,%di
+	movw %dx,%si
+	# The third argument is already in cx
+	rep ; movsb
+	popw %si
+	popw %di
+	ret
+
+	.size memcpy,.-memcpy
diff --git a/dos/memmove.S b/dos/memmove.S
new file mode 100644
index 0000000..1ab2cb2
--- /dev/null
+++ b/dos/memmove.S
@@ -0,0 +1,36 @@
+#
+# memmove.S
+#
+# Simple 16-bit memmove() implementation
+#
+
+	.text
+	.code16gcc
+	.globl memmove
+	.type memmove, @function
+memmove:
+	pushw %di
+	pushw %si
+	movw %ax,%di
+	movw %dx,%si
+	cmpw %si,%di
+	ja 1f
+	# The third argument is already in cx
+	cld
+	rep ; movsb
+2:
+	popw %si
+	popw %di
+	ret
+
+1:	/* si <= di, need reverse copy */
+	add %cx,%di
+	add %cx,%si
+	dec %di
+	dec %si
+	std
+	rep ; movsb
+	cld
+	jmp 2b
+
+	.size memmove,.-memmove
diff --git a/dos/memset.S b/dos/memset.S
new file mode 100644
index 0000000..86e12ab
--- /dev/null
+++ b/dos/memset.S
@@ -0,0 +1,21 @@
+#
+# memset.S
+#
+# Minimal 16-bit memset() implementation
+#
+
+	.text
+	.code16gcc
+	.globl memset
+	.type memset, @function
+memset:
+	cld
+	pushw %di
+	movw %ax,%di
+	movb %dl,%al
+	# The third argument is already in %cx
+	rep ; stosb
+	popw %di
+	retl
+
+	.size memset,.-memset
diff --git a/dos/mystuff.h b/dos/mystuff.h
new file mode 100644
index 0000000..2d9574d
--- /dev/null
+++ b/dos/mystuff.h
@@ -0,0 +1,79 @@
+#ifndef MYSTUFF_H
+#define MYSTUFF_H
+
+#include <inttypes.h>
+#include <stddef.h>
+
+unsigned int skip_atou(const char **s);
+unsigned int atou(const char *s);
+
+static inline int isdigit(int ch)
+{
+    return (ch >= '0') && (ch <= '9');
+}
+
+struct diskio {
+    uint32_t startsector;
+    uint16_t sectors;
+    uint16_t bufoffs, bufseg;
+} __attribute__ ((packed));
+int int25_read_sector(unsigned char drive, struct diskio *dio);
+int int26_write_sector(unsigned char drive, struct diskio *dio);
+
+struct psp {
+    uint16_t	int20;
+    uint16_t	nextpara;
+    uint8_t	resv1;
+    uint8_t	dispatcher[5];
+    uint32_t	termvector;
+    uint32_t	ctrlcvector;
+    uint32_t	criterrvector;
+    uint16_t	resv2[11];
+    uint16_t	environment;
+    uint16_t	resv3[23];
+    uint8_t	fcb[2][16];
+    uint32_t	resv4;
+    uint8_t	cmdlen;
+    char	cmdtail[127];
+} __attribute__((packed));
+
+extern struct psp _PSP;
+
+static inline __attribute__((const))
+uint16_t ds(void)
+{
+    uint16_t v;
+    asm("movw %%ds,%0":"=rm"(v));
+    return v;
+}
+
+static inline void set_fs(uint16_t seg)
+{
+    asm volatile("movw %0,%%fs"::"rm" (seg));
+}
+
+static inline uint8_t get_8_fs(size_t offs)
+{
+    uint8_t v;
+    asm volatile("movb %%fs:%1,%0"
+		 : "=q" (v) : "m" (*(const uint8_t *)offs));
+    return v;
+}
+
+static inline uint16_t get_16_fs(size_t offs)
+{
+    uint16_t v;
+    asm volatile("movw %%fs:%1,%0"
+		 : "=r" (v) : "m" (*(const uint16_t *)offs));
+    return v;
+}
+
+static inline uint32_t get_32_fs(size_t offs)
+{
+    uint32_t v;
+    asm volatile("movl %%fs:%1,%0"
+		 : "=r" (v) : "m" (*(const uint32_t *)offs));
+    return v;
+}
+
+#endif /* MYSTUFF_H */
diff --git a/dos/perror.c b/dos/perror.c
new file mode 100644
index 0000000..99ab2f8
--- /dev/null
+++ b/dos/perror.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+#include <errno.h>
+
+void perror(const char *msg)
+{
+    printf("%s: error %s\n", msg, errno);
+}
diff --git a/dos/printf.c b/dos/printf.c
new file mode 100644
index 0000000..4bef266
--- /dev/null
+++ b/dos/printf.c
@@ -0,0 +1,308 @@
+/*
+ * Oh, it's a waste of space, but oh-so-yummy for debugging.  It's just
+ * initialization code anyway, so it doesn't take up space when we're
+ * actually running.  This version of printf() does not include 64-bit
+ * support.  "Live with it."
+ *
+ * Most of this code was shamelessly snarfed from the Linux kernel, then
+ * modified.  It's therefore GPL.
+ *
+ * printf() isn't actually needed to build syslinux.com, but during
+ * debugging it's handy.
+ */
+
+#include <stdarg.h>
+#include <stdio.h>
+#include "mystuff.h"
+
+static int strnlen(const char *s, int maxlen)
+{
+    const char *es = s;
+    while (*es && maxlen) {
+	es++;
+	maxlen--;
+    }
+
+    return (es - s);
+}
+
+#define ZEROPAD	1		/* pad with zero */
+#define SIGN	2		/* unsigned/signed long */
+#define PLUS	4		/* show plus */
+#define SPACE	8		/* space if plus */
+#define LEFT	16		/* left justified */
+#define SPECIAL	32		/* 0x */
+#define LARGE	64		/* use 'ABCDEF' instead of 'abcdef' */
+
+#define do_div(n,base) ({ \
+int __res; \
+__res = ((unsigned long) n) % (unsigned) base; \
+n = ((unsigned long) n) / (unsigned) base; \
+__res; })
+
+static char *number(char *str, long num, int base, int size, int precision,
+		    int type)
+{
+    char c, sign, tmp[66];
+    const char *digits = "0123456789abcdefghijklmnopqrstuvwxyz";
+    int i;
+
+    if (type & LARGE)
+	digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+    if (type & LEFT)
+	type &= ~ZEROPAD;
+    if (base < 2 || base > 36)
+	return 0;
+    c = (type & ZEROPAD) ? '0' : ' ';
+    sign = 0;
+    if (type & SIGN) {
+	if (num < 0) {
+	    sign = '-';
+	    num = -num;
+	    size--;
+	} else if (type & PLUS) {
+	    sign = '+';
+	    size--;
+	} else if (type & SPACE) {
+	    sign = ' ';
+	    size--;
+	}
+    }
+    if (type & SPECIAL) {
+	if (base == 16)
+	    size -= 2;
+	else if (base == 8)
+	    size--;
+    }
+    i = 0;
+    if (num == 0)
+	tmp[i++] = '0';
+    else
+	while (num != 0)
+	    tmp[i++] = digits[do_div(num, base)];
+    if (i > precision)
+	precision = i;
+    size -= precision;
+    if (!(type & (ZEROPAD + LEFT)))
+	while (size-- > 0)
+	    *str++ = ' ';
+    if (sign)
+	*str++ = sign;
+    if (type & SPECIAL) {
+	if (base == 8)
+	    *str++ = '0';
+	else if (base == 16) {
+	    *str++ = '0';
+	    *str++ = digits[33];
+	}
+    }
+    if (!(type & LEFT))
+	while (size-- > 0)
+	    *str++ = c;
+    while (i < precision--)
+	*str++ = '0';
+    while (i-- > 0)
+	*str++ = tmp[i];
+    while (size-- > 0)
+	*str++ = ' ';
+    return str;
+}
+
+/* Forward decl. needed for IP address printing stuff... */
+int sprintf(char *buf, const char *fmt, ...);
+
+int vsprintf(char *buf, const char *fmt, va_list args)
+{
+    int len;
+    unsigned long num;
+    int i, base;
+    char *str;
+    const char *s;
+
+    int flags;			/* flags to number() */
+
+    int field_width;		/* width of output field */
+    int precision;		/* min. # of digits for integers; max
+				   number of chars for from string */
+    int qualifier;		/* 'h', 'l', or 'L' for integer fields */
+
+    for (str = buf; *fmt; ++fmt) {
+	if (*fmt != '%') {
+	    *str++ = *fmt;
+	    continue;
+	}
+
+	/* process flags */
+	flags = 0;
+repeat:
+	++fmt;			/* this also skips first '%' */
+	switch (*fmt) {
+	case '-':
+	    flags |= LEFT;
+	    goto repeat;
+	case '+':
+	    flags |= PLUS;
+	    goto repeat;
+	case ' ':
+	    flags |= SPACE;
+	    goto repeat;
+	case '#':
+	    flags |= SPECIAL;
+	    goto repeat;
+	case '0':
+	    flags |= ZEROPAD;
+	    goto repeat;
+	}
+
+	/* get field width */
+	field_width = -1;
+	if (isdigit(*fmt))
+	    field_width = skip_atou(&fmt);
+	else if (*fmt == '*') {
+	    ++fmt;
+	    /* it's the next argument */
+	    field_width = va_arg(args, int);
+	    if (field_width < 0) {
+		field_width = -field_width;
+		flags |= LEFT;
+	    }
+	}
+
+	/* get the precision */
+	precision = -1;
+	if (*fmt == '.') {
+	    ++fmt;
+	    if (isdigit(*fmt))
+		precision = skip_atou(&fmt);
+	    else if (*fmt == '*') {
+		++fmt;
+		/* it's the next argument */
+		precision = va_arg(args, int);
+	    }
+	    if (precision < 0)
+		precision = 0;
+	}
+
+	/* get the conversion qualifier */
+	qualifier = -1;
+	if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L') {
+	    qualifier = *fmt;
+	    ++fmt;
+	}
+
+	/* default base */
+	base = 10;
+
+	switch (*fmt) {
+	case 'c':
+	    if (!(flags & LEFT))
+		while (--field_width > 0)
+		    *str++ = ' ';
+	    *str++ = (unsigned char)va_arg(args, int);
+	    while (--field_width > 0)
+		*str++ = ' ';
+	    continue;
+
+	case 's':
+	    s = va_arg(args, char *);
+	    len = strnlen(s, precision);
+
+	    if (!(flags & LEFT))
+		while (len < field_width--)
+		    *str++ = ' ';
+	    for (i = 0; i < len; ++i)
+		*str++ = *s++;
+	    while (len < field_width--)
+		*str++ = ' ';
+	    continue;
+
+	case 'p':
+	    if (field_width == -1) {
+		field_width = 2 * sizeof(void *);
+		flags |= ZEROPAD;
+	    }
+	    str = number(str,
+			 (unsigned long)va_arg(args, void *), 16,
+			 field_width, precision, flags);
+	    continue;
+
+	case 'n':
+	    if (qualifier == 'l') {
+		long *ip = va_arg(args, long *);
+		*ip = (str - buf);
+	    } else {
+		int *ip = va_arg(args, int *);
+		*ip = (str - buf);
+	    }
+	    continue;
+
+	case '%':
+	    *str++ = '%';
+	    continue;
+
+	    /* integer number formats - set up the flags and "break" */
+	case 'o':
+	    base = 8;
+	    break;
+
+	case 'X':
+	    flags |= LARGE;
+	case 'x':
+	    base = 16;
+	    break;
+
+	case 'd':
+	case 'i':
+	    flags |= SIGN;
+	case 'u':
+	    break;
+
+	default:
+	    *str++ = '%';
+	    if (*fmt)
+		*str++ = *fmt;
+	    else
+		--fmt;
+	    continue;
+	}
+	if (qualifier == 'l')
+	    num = va_arg(args, unsigned long);
+	else if (qualifier == 'h') {
+	    num = (unsigned short)va_arg(args, int);
+	    if (flags & SIGN)
+		num = (short)num;
+	} else if (flags & SIGN)
+	    num = va_arg(args, int);
+	else
+	    num = va_arg(args, unsigned int);
+	str = number(str, num, base, field_width, precision, flags);
+    }
+    *str = '\0';
+    return str - buf;
+}
+
+int sprintf(char *buf, const char *fmt, ...)
+{
+    va_list args;
+    int i;
+
+    va_start(args, fmt);
+    i = vsprintf(buf, fmt, args);
+    va_end(args);
+    return i;
+}
+
+int printf(const char *fmt, ...)
+{
+    char printf_buf[1024];
+    va_list args;
+    int printed;
+
+    va_start(args, fmt);
+    printed = vsprintf(printf_buf, fmt, args);
+    va_end(args);
+
+    puts(printf_buf);
+
+    return printed;
+}
diff --git a/dos/skipatou.c b/dos/skipatou.c
new file mode 100644
index 0000000..655ab56
--- /dev/null
+++ b/dos/skipatou.c
@@ -0,0 +1,10 @@
+#include "mystuff.h"
+
+unsigned int skip_atou(const char **s)
+{
+    int i = 0;
+
+    while (isdigit(**s))
+	i = i * 10 + *((*s)++) - '0';
+    return i;
+}
diff --git a/dos/stdint.h b/dos/stdint.h
new file mode 100644
index 0000000..a8391bf
--- /dev/null
+++ b/dos/stdint.h
@@ -0,0 +1,142 @@
+/*
+ * stdint.h
+ */
+
+#ifndef _STDINT_H
+#define _STDINT_H
+
+/* Exact types */
+
+typedef signed char int8_t;
+typedef signed short int16_t;
+typedef signed int int32_t;
+typedef signed long long int64_t;
+
+typedef unsigned char uint8_t;
+typedef unsigned short uint16_t;
+typedef unsigned int uint32_t;
+typedef unsigned long long uint64_t;
+
+/* Small types */
+
+typedef signed char int_least8_t;
+typedef signed short int_least16_t;
+typedef signed int int_least32_t;
+typedef signed long long int_least64_t;
+
+typedef unsigned char uint_least8_t;
+typedef unsigned short uint_least16_t;
+typedef unsigned int uint_least32_t;
+typedef unsigned long long uint_least64_t;
+
+/* Fast types */
+
+typedef signed char int_fast8_t;
+typedef signed short int_fast16_t;
+typedef signed int int_fast32_t;
+typedef signed long long int_fast64_t;
+
+typedef unsigned char uint_fast8_t;
+typedef unsigned short uint_fast16_t;
+typedef unsigned int uint_fast32_t;
+typedef unsigned long long uint_fast64_t;
+
+/* Pointer types */
+
+typedef int32_t intptr_t;
+typedef uint32_t uintptr_t;
+
+/* Maximal types */
+
+typedef int64_t intmax_t;
+typedef uint64_t uintmax_t;
+
+/*
+ * To be strictly correct...
+ */
+#if !defined(__cplusplus) || defined(__STDC_LIMIT_MACROS)
+
+# define INT8_MIN               (-128)
+# define INT16_MIN              (-32767-1)
+# define INT32_MIN              (-2147483647-1)
+# define INT64_MIN              (-9223372036854775807LL-1)
+
+# define INT8_MAX               (127)
+# define INT16_MAX              (32767)
+# define INT32_MAX              (2147483647)
+# define INT64_MAX              (9223372036854775807LL)
+
+# define UINT8_MAX              (255U)
+# define UINT16_MAX             (65535U)
+# define UINT32_MAX             (4294967295U)
+# define UINT64_MAX             (18446744073709551615ULL)
+
+# define INT_LEAST8_MIN               (-128)
+# define INT_LEAST16_MIN              (-32767-1)
+# define INT_LEAST32_MIN              (-2147483647-1)
+# define INT_LEAST64_MIN              (-9223372036854775807LL-1)
+
+# define INT_LEAST8_MAX               (127)
+# define INT_LEAST16_MAX              (32767)
+# define INT_LEAST32_MAX              (2147483647)
+# define INT_LEAST64_MAX              (9223372036854775807LL)
+
+# define UINT_LEAST8_MAX              (255U)
+# define UINT_LEAST16_MAX             (65535U)
+# define UINT_LEAST32_MAX             (4294967295U)
+# define UINT_LEAST64_MAX             (18446744073709551615ULL)
+
+# define INT_FAST8_MIN               (-128)
+# define INT_FAST16_MIN              (-32767-1)
+# define INT_FAST32_MIN              (-2147483647-1)
+# define INT_FAST64_MIN              (-9223372036854775807LL-1)
+
+# define INT_FAST8_MAX               (127)
+# define INT_FAST16_MAX              (32767)
+# define INT_FAST32_MAX              (2147483647)
+# define INT_FAST64_MAX              (9223372036854775807LL)
+
+# define UINT_FAST8_MAX              (255U)
+# define UINT_FAST16_MAX             (65535U)
+# define UINT_FAST32_MAX             (4294967295U)
+# define UINT_FAST64_MAX             (18446744073709551615ULL)
+
+# define INTPTR_MIN		(-2147483647-1)
+# define INTPTR_MAX		(2147483647)
+# define UINTPTR_MAX		(4294967295U)
+
+# define INTMAX_MIN		(-9223372036854775807LL-1)
+# define INTMAX_MAX		(9223372036854775807LL)
+# define UINTMAX_MAX		(18446744073709551615ULL)
+
+/* ptrdiff_t limit */
+# define PTRDIFF_MIN		(-2147483647-1)
+# define PTRDIFF_MAX		(2147483647)
+
+/* sig_atomic_t limit */
+# define SIG_ATOMIC_MIN         (-2147483647-1)
+# define SIG_ATOMIC_MAX         (2147483647)
+
+/* size_t limit */
+# define SIZE_MAX		(4294967295U)
+
+#endif /* STDC_LIMIT_MACROS */
+
+#if !defined(__cplusplus) || defined(__STDC_CONSTANT_MACROS)
+
+# define INT8_C(n)	n
+# define INT16_C(n)	n
+# define INT32_C(n)	n
+# define INT64_C(n)	n ## LL
+
+# define UINT8_C(n)	n ## U
+# define UINT16_C(n)	n ## U
+# define UINT32_C(n)	n ## U
+# define UINT64_C(n)	n ## ULL
+
+# define INTMAX_C(n)	n ## LL
+# define UINTMAX_C(n)	n ## ULL
+
+#endif /* STDC_CONSTANT_MACROS */
+
+#endif /* _STDINT_H */
diff --git a/dos/stdio.h b/dos/stdio.h
new file mode 100644
index 0000000..c7ca25c
--- /dev/null
+++ b/dos/stdio.h
@@ -0,0 +1,23 @@
+#ifndef STDIO_H
+#define STDIO_H
+
+#include <stdarg.h>
+#include <stdlib.h>
+
+typedef unsigned int off_t;
+
+int putchar(int);
+int puts(const char *);
+int sprintf(char *buf, const char *fmt, ...);
+int vsprintf(char *buf, const char *fmt, va_list args);
+int printf(const char *fmt, ...);
+
+#define stdin	0
+#define stdout	1
+#define stderr	2
+
+#define EOF (-1)
+
+#define fprintf(x, y, ...) printf(y, ## __VA_ARGS__)
+
+#endif /* STDIO_H */
diff --git a/dos/stdlib.h b/dos/stdlib.h
new file mode 100644
index 0000000..d982670
--- /dev/null
+++ b/dos/stdlib.h
@@ -0,0 +1,23 @@
+#ifndef STDLIB_H
+#define STDLIB_H
+
+typedef int ssize_t;
+/* size_t is defined elsewhere */
+#if __SIZEOF_POINTER__ == 4
+typedef unsigned int size_t;
+#elif __SIZEOF_POINTER__ == 8
+typedef unsigned long size_t;
+#else
+#error "unsupported architecture"
+#endif
+
+void __attribute__ ((noreturn)) exit(int);
+
+void *malloc(size_t);
+void *calloc(size_t, size_t);
+void free(void *);
+
+extern unsigned long int strtoul(const char *nptr,
+                                  char **endptr, int base);
+
+#endif
diff --git a/dos/strchr.c b/dos/strchr.c
new file mode 100644
index 0000000..8315311
--- /dev/null
+++ b/dos/strchr.c
@@ -0,0 +1,17 @@
+/*
+ * strchr.c
+ */
+
+#include <string.h>
+#include "mystuff.h"
+
+char *strchr(const char *s, int c)
+{
+    while (*s != (char)c) {
+	if (!*s)
+	    return NULL;
+	s++;
+    }
+
+    return (char *)s;
+}
diff --git a/dos/string.h b/dos/string.h
new file mode 100644
index 0000000..f648de2
--- /dev/null
+++ b/dos/string.h
@@ -0,0 +1,26 @@
+/*
+ * string.h
+ */
+
+#ifndef _STRING_H
+#define _STRING_H
+
+/* Standard routines */
+#define memcpy(a,b,c)	__builtin_memcpy(a,b,c)
+#define memmove(a,b,c)	__builtin_memmove(a,b,c)
+#define memset(a,b,c)	__builtin_memset(a,b,c)
+#define strcpy(a,b)	__builtin_strcpy(a,b)
+#define strlen(a)	__builtin_strlen(a)
+
+/* This only returns true or false */
+static inline int memcmp(const void *__m1, const void *__m2, unsigned int __n)
+{
+    _Bool rv;
+    asm volatile ("cld ; repe ; cmpsb ; setne %0":"=abd" (rv), "+D"(__m1),
+		  "+S"(__m2), "+c"(__n));
+    return rv;
+}
+
+extern char *strchr(const char *s, int c);
+
+#endif /* _STRING_H */
diff --git a/dos/strntoumax.c b/dos/strntoumax.c
new file mode 100644
index 0000000..d8bc73b
--- /dev/null
+++ b/dos/strntoumax.c
@@ -0,0 +1,73 @@
+/*
+ * strntoumax.c
+ *
+ * The strntoumax() function and associated
+ */
+
+#include <stddef.h>
+#include <stdint.h>
+#include <ctype.h>
+
+static inline int digitval(int ch)
+{
+    if (ch >= '0' && ch <= '9') {
+	return ch - '0';
+    } else if (ch >= 'A' && ch <= 'Z') {
+	return ch - 'A' + 10;
+    } else if (ch >= 'a' && ch <= 'z') {
+	return ch - 'a' + 10;
+    } else {
+	return -1;
+    }
+}
+
+uintmax_t strntoumax(const char *nptr, char **endptr, int base, size_t n)
+{
+    int minus = 0;
+    uintmax_t v = 0;
+    int d;
+
+    while (n && isspace((unsigned char)*nptr)) {
+	nptr++;
+	n--;
+    }
+
+    /* Single optional + or - */
+    if (n && *nptr == '-') {
+	minus = 1;
+	nptr++;
+	n--;
+    } else if (n && *nptr == '+') {
+	nptr++;
+    }
+
+    if (base == 0) {
+	if (n >= 2 && nptr[0] == '0' && (nptr[1] == 'x' || nptr[1] == 'X')) {
+	    n -= 2;
+	    nptr += 2;
+	    base = 16;
+	} else if (n >= 1 && nptr[0] == '0') {
+	    n--;
+	    nptr++;
+	    base = 8;
+	} else {
+	    base = 10;
+	}
+    } else if (base == 16) {
+	if (n >= 2 && nptr[0] == '0' && (nptr[1] == 'x' || nptr[1] == 'X')) {
+	    n -= 2;
+	    nptr += 2;
+	}
+    }
+
+    while (n && (d = digitval(*nptr)) >= 0 && d < base) {
+	v = v * base + d;
+	n--;
+	nptr++;
+    }
+
+    if (endptr)
+	*endptr = (char *)nptr;
+
+    return minus ? -v : v;
+}
diff --git a/dos/strtoul.c b/dos/strtoul.c
new file mode 100644
index 0000000..3be9430
--- /dev/null
+++ b/dos/strtoul.c
@@ -0,0 +1,15 @@
+/*
+ * strtoul.c
+ *
+ * strtoul() function
+ */
+
+#include <stddef.h>
+#include <inttypes.h>
+
+extern uintmax_t strntoumax(const char *nptr, char **endptr, int base, size_t n);
+
+unsigned long strtoul(const char *nptr, char **endptr, int base)
+{
+    return (unsigned long) strntoumax(nptr, endptr, base, ~(size_t) 0);
+}
diff --git a/dos/sysexits.h b/dos/sysexits.h
new file mode 100644
index 0000000..483d3ba
--- /dev/null
+++ b/dos/sysexits.h
@@ -0,0 +1 @@
+#define EX_USAGE 0x40
diff --git a/dos/syslinux.c b/dos/syslinux.c
new file mode 100644
index 0000000..3c45f34
--- /dev/null
+++ b/dos/syslinux.c
@@ -0,0 +1,769 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 1998-2008 H. Peter Anvin - All Rights Reserved
+ *   Copyright 2009-2010 Intel Corporation; author: H. Peter Anvin
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * syslinux.c - Linux installer program for SYSLINUX
+ *
+ * Hacked up for DOS.
+ */
+
+#include <errno.h>
+#include <getopt.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include "mystuff.h"
+
+#include "syslinux.h"
+#include "libfat.h"
+#include "setadv.h"
+#include "sysexits.h"
+#include "syslxopt.h"
+#include "syslxint.h"
+#include "syslxfs.h"
+
+char *program = "syslinux.com";		/* Name of program */
+uint16_t dos_version;
+
+#ifdef DEBUG
+# define dprintf printf
+void pause(void)
+{
+    uint16_t ax;
+
+    asm volatile("int $0x16" : "=a" (ax) : "a" (0));
+}
+#else
+# define dprintf(...) ((void)0)
+# define pause() ((void)0)
+#endif
+
+void unlock_device(int);
+
+void __attribute__ ((noreturn)) die(const char *msg)
+{
+    unlock_device(0);
+    puts("syslinux: ");
+    puts(msg);
+    putchar('\n');
+    exit(1);
+}
+
+void warning(const char *msg)
+{
+    puts("syslinux: warning: ");
+    puts(msg);
+    putchar('\n');
+}
+
+/*
+ * read/write wrapper functions
+ */
+int creat(const char *filename, int mode)
+{
+    uint16_t rv;
+    uint8_t err;
+
+    dprintf("creat(\"%s\", 0x%x)\n", filename, mode);
+
+    rv = 0x3C00;
+    asm volatile ("int $0x21 ; setc %0"
+		  : "=bcdm" (err), "+a" (rv)
+		  : "c" (mode), "d" (filename));
+    if (err) {
+	dprintf("rv = %d\n", rv);
+	die("cannot open ldlinux.sys");
+    }
+
+    return rv;
+}
+
+void close(int fd)
+{
+    uint16_t rv = 0x3E00;
+
+    dprintf("close(%d)\n", fd);
+
+    asm volatile ("int $0x21":"+a" (rv)
+		  :"b"(fd));
+
+    /* The only error MS-DOS returns for close is EBADF,
+       and we really don't care... */
+}
+
+int rename(const char *oldname, const char *newname)
+{
+    uint16_t rv = 0x5600;	/* Also support 43FFh? */
+    uint8_t err;
+
+    dprintf("rename(\"%s\", \"%s\")\n", oldname, newname);
+
+    asm volatile ("int $0x21 ; setc %0":"=bcdm" (err), "+a"(rv)
+		  :"d"(oldname), "D"(newname));
+
+    if (err) {
+	dprintf("rv = %d\n", rv);
+	warning("cannot move ldlinux.sys");
+	return rv;
+    }
+
+    return 0;
+}
+
+ssize_t write_file_sl(int fd, const unsigned char _slimg *buf,
+		      const unsigned int len)
+{
+    uint32_t filepos = 0;
+    uint16_t rv;
+    uint8_t err;
+
+    while (filepos < len) {
+	uint16_t seg = ((size_t)buf >> 4) + ds();
+	uint16_t offset = (size_t)buf & 15;
+	uint32_t chunk = len - filepos;
+	if (chunk > 32768 - offset)
+	    chunk = 32768 - offset;
+	asm volatile ("pushw %%ds ; "
+		      "movw %6,%%ds ; "
+		      "int $0x21 ; "
+		      "popw %%ds ; " "setc %0":"=bcdm" (err), "=a"(rv)
+		      :"a"(0x4000), "b"(fd), "c"(chunk), "d" (offset),
+		       "SD" (seg));
+	if (err || rv == 0)
+	    die("file write error");
+	filepos += rv;
+	buf += rv;
+    }
+
+    return filepos;
+}
+
+ssize_t write_file(int fd, const void *buf, size_t count)
+{
+    uint16_t rv;
+    ssize_t done = 0;
+    uint8_t err;
+
+    dprintf("write_file(%d,%p,%u)\n", fd, buf, count);
+
+    while (count) {
+	asm volatile ("int $0x21 ; setc %0":"=bcdm" (err), "=a"(rv)
+		      :"a"(0x4000), "b"(fd), "c"(count), "d"(buf));
+	if (err || rv == 0)
+	    die("file write error");
+
+	done += rv;
+	count -= rv;
+    }
+
+    return done;
+}
+
+void write_device(int drive, const void *buf, size_t nsecs, unsigned int sector)
+{
+    uint16_t errnum = 0x0001;
+    struct diskio dio;
+
+    dprintf("write_device(%d,%p,%u,%u)\n", drive, buf, nsecs, sector);
+
+    dio.startsector = sector;
+    dio.sectors = nsecs;
+    dio.bufoffs = (uintptr_t) buf;
+    dio.bufseg = ds();
+
+    if (dos_version >= 0x070a) {
+	/* Try FAT32-aware system call first */
+	asm volatile("int $0x21 ; jc 1f ; xorw %0,%0\n"
+		     "1:"
+		     : "=a" (errnum)
+		     : "a" (0x7305), "b" (&dio), "c" (-1), "d" (drive),
+		       "S" (1), "m" (dio)
+		     : "memory");
+	dprintf(" rv(7305) = %04x", errnum);
+    }
+
+    /* If not supported, try the legacy system call (int2526.S) */
+    if (errnum == 0x0001)
+	errnum = int26_write_sector(drive, &dio);
+
+    if (errnum) {
+	dprintf("rv = %04x\n", errnum);
+	die("sector write error");
+    }
+}
+
+void read_device(int drive, void *buf, size_t nsecs, unsigned int sector)
+{
+    uint16_t errnum = 0x0001;
+    struct diskio dio;
+
+    dprintf("read_device(%d,%p,%u,%u)\n", drive, buf, nsecs, sector);
+
+    dio.startsector = sector;
+    dio.sectors = nsecs;
+    dio.bufoffs = (uintptr_t) buf;
+    dio.bufseg = ds();
+
+    if (dos_version >= 0x070a) {
+	/* Try FAT32-aware system call first */
+	asm volatile("int $0x21 ; jc 1f ; xorw %0,%0\n"
+		     "1:"
+		     : "=a" (errnum)
+		     : "a" (0x7305), "b" (&dio), "c" (-1), "d" (drive),
+		       "S" (0), "m" (dio));
+	dprintf(" rv(7305) = %04x", errnum);
+    }
+
+    /* If not supported, try the legacy system call (int2526.S) */
+    if (errnum == 0x0001)
+	errnum = int25_read_sector(drive, &dio);
+
+    if (errnum) {
+	dprintf("rv = %04x\n", errnum);
+	die("sector read error");
+    }
+}
+
+/* Both traditional DOS and FAT32 DOS return this structure, but
+   FAT32 return a lot more data, so make sure we have plenty of space */
+struct deviceparams {
+    uint8_t specfunc;
+    uint8_t devtype;
+    uint16_t devattr;
+    uint16_t cylinders;
+    uint8_t mediatype;
+    uint16_t bytespersec;
+    uint8_t secperclust;
+    uint16_t ressectors;
+    uint8_t fats;
+    uint16_t rootdirents;
+    uint16_t sectors;
+    uint8_t media;
+    uint16_t fatsecs;
+    uint16_t secpertrack;
+    uint16_t heads;
+    uint32_t hiddensecs;
+    uint32_t hugesectors;
+    uint8_t lotsofpadding[224];
+} __attribute__ ((packed));
+
+uint32_t get_partition_offset(int drive)
+{
+    uint8_t err;
+    uint16_t rv;
+    struct deviceparams dp;
+
+    dp.specfunc = 1;		/* Get current information */
+
+    rv = 0x440d;
+    asm volatile ("int $0x21 ; setc %0"
+		  :"=abcdm" (err), "+a"(rv), "=m"(dp)
+		  :"b" (drive), "c" (0x0860), "d" (&dp));
+
+    if (!err)
+	return dp.hiddensecs;
+
+    rv = 0x440d;
+    asm volatile ("int $0x21 ; setc %0"
+		  : "=abcdm" (err), "+a" (rv), "=m" (dp)
+		  : "b" (drive), "c" (0x4860), "d" (&dp));
+
+    if (!err)
+	return dp.hiddensecs;
+
+    die("could not find partition start offset");
+}
+
+struct rwblock {
+    uint8_t special;
+    uint16_t head;
+    uint16_t cylinder;
+    uint16_t firstsector;
+    uint16_t sectors;
+    uint16_t bufferoffset;
+    uint16_t bufferseg;
+} __attribute__ ((packed));
+
+static struct rwblock mbr = {
+    .special = 0,
+    .head = 0,
+    .cylinder = 0,
+    .firstsector = 0,		/* MS-DOS, unlike the BIOS, zero-base sectors */
+    .sectors = 1,
+    .bufferoffset = 0,
+    .bufferseg = 0
+};
+
+void write_mbr(int drive, const void *buf)
+{
+    uint16_t rv;
+    uint8_t err;
+
+    dprintf("write_mbr(%d,%p)", drive, buf);
+
+    mbr.bufferoffset = (uintptr_t) buf;
+    mbr.bufferseg = ds();
+
+    rv = 0x440d;
+    asm volatile ("int $0x21 ; setc %0" : "=bcdm" (err), "+a"(rv)
+		  :"c"(0x0841), "d"(&mbr), "b"(drive), "m"(mbr));
+
+    dprintf(" rv(0841) = %04x", rv);
+    if (!err) {
+	dprintf("\n");
+	return;
+    }
+
+    rv = 0x440d;
+    asm volatile ("int $0x21 ; setc %0" : "=bcdm" (err), "+a"(rv)
+		  :"c"(0x4841), "d"(&mbr), "b"(drive), "m"(mbr));
+
+    dprintf(" rv(4841) = %04x\n", rv);
+    if (err)
+	die("mbr write error");
+}
+
+void read_mbr(int drive, const void *buf)
+{
+    uint16_t rv;
+    uint8_t err;
+
+    dprintf("read_mbr(%d,%p)", drive, buf);
+
+    mbr.bufferoffset = (uintptr_t) buf;
+    mbr.bufferseg = ds();
+
+    rv = 0x440d;
+    asm volatile ("int $0x21 ; setc %0":"=abcdm" (err), "+a"(rv)
+		  :"c"(0x0861), "d"(&mbr), "b"(drive), "m"(mbr));
+
+    dprintf(" rv(0861) = %04x", rv);
+    if (!err) {
+	dprintf("\n");
+	return;
+    }
+
+    rv = 0x440d;
+    asm volatile ("int $0x21 ; setc %0":"=abcdm" (err), "+a"(rv)
+		  :"c"(0x4861), "d"(&mbr), "b"(drive), "m"(mbr));
+
+    dprintf(" rv(4841) = %04x\n", rv);
+    if (err)
+	die("mbr read error");
+
+    dprintf("Bytes: %02x %02x %02x %02x %02x %02x %02x %02x\n",
+	    ((const uint8_t *)buf)[0],
+	    ((const uint8_t *)buf)[1],
+	    ((const uint8_t *)buf)[2],
+	    ((const uint8_t *)buf)[3],
+	    ((const uint8_t *)buf)[4],
+	    ((const uint8_t *)buf)[5],
+	    ((const uint8_t *)buf)[6],
+	    ((const uint8_t *)buf)[7]);
+}
+
+/* This call can legitimately fail, and we don't care, so ignore error return */
+void set_attributes(const char *file, int attributes)
+{
+    uint16_t rv = 0x4301;
+
+    dprintf("set_attributes(\"%s\", 0x%02x)\n", file, attributes);
+
+    asm volatile ("int $0x21":"+a" (rv)
+		  :"c"(attributes), "d"(file));
+}
+
+/*
+ * Version of the read_device function suitable for libfat
+ */
+int libfat_xpread(intptr_t pp, void *buf, size_t secsize,
+		  libfat_sector_t sector)
+{
+    read_device(pp, buf, 1, sector);
+    return secsize;
+}
+
+static inline void get_dos_version(void)
+{
+    dprintf("DOS version %d.%d\n", (dos_version >> 8), dos_version & 0xff);
+}
+
+/* The locking interface relies on static variables.  A massive hack :( */
+static uint8_t lock_level, lock_drive;
+
+static inline void set_lock_device(uint8_t device)
+{
+    lock_level  = 0;
+    lock_drive = device;
+}
+
+static int do_lock(uint8_t level)
+{
+    uint16_t level_arg = lock_drive + (level << 8);
+    uint16_t rv;
+    uint8_t err;
+#if 0
+    /* DOS 7.10 = Win95 OSR2 = first version with FAT32 */
+    uint16_t lock_call = (dos_version >= 0x070a) ? 0x484A : 0x084A;
+#else
+    uint16_t lock_call = 0x084A; /* MSDN says this is OK for all filesystems */
+#endif
+
+    dprintf("Trying lock %04x... ", level_arg);
+    asm volatile ("int $0x21 ; setc %0"
+		  : "=bcdm" (err), "=a" (rv)
+		  : "a" (0x440d), "b" (level_arg),
+		    "c" (lock_call), "d" (0x0001));
+    dprintf("%s %04x\n", err ? "err" : "ok", rv);
+
+    return err ? rv : 0;
+}
+
+void lock_device(int level)
+{
+    static int hard_lock = 0;
+    int err;
+
+    if (dos_version < 0x0700)
+	return;			/* Win9x/NT only */
+
+    if (!hard_lock) {
+	/* Assume hierarchial "soft" locking supported */
+
+	while (lock_level < level) {
+	    int new_level = lock_level + 1;
+	    err = do_lock(new_level);
+	    if (err) {
+		if (err == 0x0001) {
+		    /* Try hard locking next */
+		    hard_lock = 1;
+		}
+		goto soft_fail;
+	    }
+
+	    lock_level = new_level;
+	}
+	return;
+    }
+
+soft_fail:
+    if (hard_lock) {
+	/* Hard locking, only level 4 supported */
+	/* This is needed for Win9x in DOS mode */
+
+	err = do_lock(4);
+	if (err) {
+	    if (err == 0x0001) {
+		/* Assume locking is not needed */
+		return;
+	    }
+	    goto hard_fail;
+	}
+
+	lock_level = 4;
+	return;
+    }
+
+hard_fail:
+    die("could not lock device");
+}
+
+void unlock_device(int level)
+{
+    uint16_t rv;
+    uint8_t err;
+    uint16_t unlock_call;
+
+    if (dos_version < 0x0700)
+	return;			/* Win9x/NT only */
+
+#if 0
+    /* DOS 7.10 = Win95 OSR2 = first version with FAT32 */
+    unlock_call = (dos_version >= 0x070a) ? 0x486A : 0x086A;
+#else
+    unlock_call = 0x086A;	/* MSDN says this is OK for all filesystems */
+#endif
+
+    if (lock_level == 4 && level > 0)
+	return;			/* Only drop the hard lock at the end */
+
+    while (lock_level > level) {
+	uint8_t new_level = (lock_level == 4) ? 0 : lock_level - 1;
+	uint16_t level_arg = (new_level << 8) + lock_drive;
+	rv = 0x440d;
+	dprintf("Trying unlock %04x... ", new_level);
+	asm volatile ("int $0x21 ; setc %0"
+		      : "=bcdm" (err), "+a" (rv)
+		      : "b" (level_arg), "c" (unlock_call));
+	dprintf("%s %04x\n", err ? "err" : "ok", rv);
+	lock_level = new_level;
+    }
+}
+
+/*
+ * This function does any desired MBR manipulation; called with the device lock held.
+ */
+struct mbr_entry {
+    uint8_t active;		/* Active flag */
+    uint8_t bhead;		/* Begin head */
+    uint8_t bsector;		/* Begin sector */
+    uint8_t bcylinder;		/* Begin cylinder */
+    uint8_t filesystem;		/* Filesystem value */
+    uint8_t ehead;		/* End head */
+    uint8_t esector;		/* End sector */
+    uint8_t ecylinder;		/* End cylinder */
+    uint32_t startlba;		/* Start sector LBA */
+    uint32_t sectors;		/* Length in sectors */
+} __attribute__ ((packed));
+
+static void adjust_mbr(int device, int writembr, int set_active)
+{
+    static unsigned char sectbuf[SECTOR_SIZE];
+    int i;
+
+    if (!writembr && !set_active)
+	return;			/* Nothing to do */
+
+    read_mbr(device, sectbuf);
+
+    if (writembr) {
+	memcpy(sectbuf, syslinux_mbr, syslinux_mbr_len);
+	*(uint16_t *) (sectbuf + 510) = 0xaa55;
+    }
+
+    if (set_active) {
+	uint32_t offset = get_partition_offset(device);
+	struct mbr_entry *me = (struct mbr_entry *)(sectbuf + 446);
+	int found = 0;
+
+	dprintf("Searching for partition offset: %08x\n", offset);
+
+	for (i = 0; i < 4; i++) {
+	    if (me->startlba == offset) {
+		me->active = 0x80;
+		found++;
+	    } else {
+		me->active = 0;
+	    }
+	    me++;
+	}
+
+	if (found < 1) {
+	    die("partition not found (-a is not implemented for logical partitions)");
+	} else if (found > 1) {
+	    die("multiple aliased partitions found");
+	}
+    }
+
+    write_mbr(device, sectbuf);
+}
+
+static void move_file(int dev_fd, char *pathname, char *filename)
+{
+    char new_name[160];
+    char *cp = new_name + 3;
+    const char *sd;
+    int slash = 1;
+
+    new_name[0] = dev_fd | 0x40;
+    new_name[1] = ':';
+    new_name[2] = '\\';
+
+    for (sd = opt.directory; *sd; sd++) {
+	char c = *sd;
+
+	if (c == '/' || c == '\\') {
+	    if (slash)
+		continue;
+	    c = '\\';
+	    slash = 1;
+	} else {
+	    slash = 0;
+	}
+
+	*cp++ = c;
+    }
+
+    /* Skip if subdirectory == root */
+    if (cp > new_name + 3) {
+	if (!slash)
+	    *cp++ = '\\';
+
+	memcpy(cp, filename, 12);
+
+	set_attributes(pathname, 0);
+	if (rename(pathname, new_name))
+	    set_attributes(pathname, 0x07);
+	else
+	    set_attributes(new_name, 0x07);
+    }
+}
+
+int main(int argc, char *argv[])
+{
+    static unsigned char sectbuf[SECTOR_SIZE];
+    int dev_fd, fd;
+    static char ldlinux_name[] = "@:\\ldlinux.sys";
+    static char ldlinuxc32_name[] = "@:\\ldlinux.c32";
+    struct libfat_filesystem *fs;
+    libfat_sector_t s, *secp;
+    libfat_sector_t *sectors;
+    int ldlinux_sectors;
+    int32_t ldlinux_cluster;
+    int nsectors;
+    const char *errmsg;
+    int i;
+    int patch_sectors;
+    unsigned char *dp;
+
+    dprintf("argv = %p\n", argv);
+    for (i = 0; i <= argc; i++)
+	dprintf("argv[%d] = %p = \"%s\"\n", i, argv[i], argv[i]);
+
+    get_dos_version();
+
+    argv[0] = program;
+    parse_options(argc, argv, MODE_SYSLINUX_DOSWIN);
+
+    if (!opt.device)
+	usage(EX_USAGE, MODE_SYSLINUX_DOSWIN);
+    if (opt.sectors || opt.heads || opt.reset_adv || opt.set_once
+	|| (opt.update_only > 0) || opt.menu_save || opt.offset) {
+	fprintf(stderr,
+		"At least one specified option not yet implemented"
+		" for this installer.\n");
+	exit(1);
+    }
+
+    /*
+     * Create an ADV in memory... this should be smarter.
+     */
+    syslinux_reset_adv(syslinux_adv);
+
+    /*
+     * Figure out which drive we're talking to
+     */
+    dev_fd = (opt.device[0] & ~0x20) - 0x40;
+    if (dev_fd < 1 || dev_fd > 26 || opt.device[1] != ':' || opt.device[2])
+	usage(EX_USAGE, MODE_SYSLINUX_DOSWIN);
+
+    set_lock_device(dev_fd);
+
+    lock_device(2);		/* Make sure we can lock the device */
+    read_device(dev_fd, sectbuf, 1, 0);
+    unlock_device(1);
+
+    /*
+     * Check to see that what we got was indeed an MS-DOS boot sector/superblock
+     */
+    if ((errmsg = syslinux_check_bootsect(sectbuf, NULL))) {
+	unlock_device(0);
+	puts(errmsg);
+	putchar('\n');
+	exit(1);
+    }
+
+    ldlinux_name[0] = dev_fd | 0x40;
+    ldlinuxc32_name[0] = dev_fd | 0x40;
+
+    set_attributes(ldlinux_name, 0);
+    fd = creat(ldlinux_name, 0);	/* SYSTEM HIDDEN READONLY */
+    write_file_sl(fd, syslinux_ldlinux, syslinux_ldlinux_len);
+    write_file(fd, syslinux_adv, 2 * ADV_SIZE);
+    close(fd);
+    set_attributes(ldlinux_name, 0x07);	/* SYSTEM HIDDEN READONLY */
+
+    set_attributes(ldlinuxc32_name, 0);
+    fd = creat(ldlinuxc32_name, 0);		/* SYSTEM HIDDEN READONLY */
+    write_file_sl(fd, syslinux_ldlinuxc32, syslinux_ldlinuxc32_len);
+    close(fd);
+    set_attributes(ldlinuxc32_name, 0x07);	/* SYSTEM HIDDEN READONLY */
+
+    /*
+     * Now, use libfat to create a block map.  This probably
+     * should be changed to use ioctl(...,FIBMAP,...) since
+     * this is supposed to be a simple, privileged version
+     * of the installer.
+     */
+    ldlinux_sectors = (syslinux_ldlinux_len + 2 * ADV_SIZE
+		       + SECTOR_SIZE - 1) >> SECTOR_SHIFT;
+    sectors = calloc(ldlinux_sectors, sizeof *sectors);
+    lock_device(2);
+    fs = libfat_open(libfat_xpread, dev_fd);
+    ldlinux_cluster = libfat_searchdir(fs, 0, "LDLINUX SYS", NULL);
+    secp = sectors;
+    nsectors = 0;
+    s = libfat_clustertosector(fs, ldlinux_cluster);
+    while (s && nsectors < ldlinux_sectors) {
+	*secp++ = s;
+	nsectors++;
+	s = libfat_nextsector(fs, s);
+    }
+    libfat_close(fs);
+
+    /*
+     * If requested, move ldlinux.sys
+     */
+    if (opt.directory) {
+	move_file(dev_fd, ldlinux_name, "ldlinux.sys");
+	move_file(dev_fd, ldlinuxc32_name, "ldlinux.c32");
+    }
+
+    /*
+     * Patch ldlinux.sys and the boot sector
+     */
+    i = syslinux_patch(sectors, nsectors, opt.stupid_mode, opt.raid_mode, opt.directory, NULL);
+    patch_sectors = (i + SECTOR_SIZE - 1) >> SECTOR_SHIFT;
+
+    /*
+     * Overwrite the now-patched ldlinux.sys
+     */
+    /* lock_device(3); -- doesn't seem to be needed */
+    dp = syslinux_ldlinux;
+    for (i = 0; i < patch_sectors; i++) {
+	memcpy_from_sl(sectbuf, dp, SECTOR_SIZE);
+	dp += SECTOR_SIZE;
+	write_device(dev_fd, sectbuf, 1, sectors[i]);
+    }
+
+    /*
+     * Muck with the MBR, if desired, while we hold the lock
+     */
+    adjust_mbr(dev_fd, opt.install_mbr, opt.activate_partition);
+
+    /*
+     * To finish up, write the boot sector
+     */
+
+    /* Read the superblock again since it might have changed while mounted */
+    read_device(dev_fd, sectbuf, 1, 0);
+
+    /* Copy the syslinux code into the boot sector */
+    syslinux_make_bootsect(sectbuf, VFAT);
+
+    /* Write new boot sector */
+    if (opt.bootsecfile) {
+	unlock_device(0);
+	fd = creat(opt.bootsecfile, 0x20);	/* ARCHIVE */
+	write_file(fd, sectbuf, SECTOR_SIZE);
+	close(fd);
+    } else {
+	write_device(dev_fd, sectbuf, 1, 0);
+	unlock_device(0);
+    }
+
+    /* Done! */
+
+    return 0;
+}