1 files changed, 94 insertions, 0 deletions
diff --git a/src/libmpg123/getcpuflags.S b/src/libmpg123/getcpuflags.S
new file mode 100644
index 0000000..29ab08d
--- /dev/null
+++ b/src/libmpg123/getcpuflags.S
@@ -0,0 +1,94 @@
+/*
+	getcpucpuflags: get cpuflags for ia32
+
+	copyright ?-2006 by the mpg123 project - free software under the terms of the LGPL 2.1
+	see COPYING and AUTHORS files in distribution or http:#mpg123.org
+	initially written by KIMURA Takuhiro (for 3DNow!)
+	extended for general use by Thomas Orgis
+
+	 extern int getcpuid(struct cpuflags*)
+	or just 
+	 extern int getcpuid(unsigned int*)
+	where there is memory for 4 ints
+	 -> the first set of idflags (basic cpu family info)
+	    and the idflags, stdflags, std2flags, extflags written to the parameter
+	 -> 0x00000000 (CPUID instruction not supported)
+*/
+
+#include "mangle.h"
+
+.text
+	ALIGN4
+
+.globl ASM_NAME(getcpuflags)
+/*	.type ASM_NAME(getcpuflags),@function */
+ASM_NAME(getcpuflags):
+	pushl %ebp
+	movl %esp,%ebp
+	pushl %edx
+	pushl %ecx
+	pushl %ebx
+	pushl %esi
+/* get the int pointer for storing the flags */
+	movl 8(%ebp), %esi
+/* does that one make sense? */
+	movl $0x80000000,%eax
+/* now save the flags and do a check for cpuid availability */
+	pushfl
+	pushfl
+	popl %eax
+	movl %eax,%ebx
+/* set that bit... */
+	xorl $0x00200000,%eax
+	pushl %eax
+	popfl
+/* ...and read back the flags to see if it is understood */
+	pushfl
+	popl %eax
+	popfl
+	cmpl %ebx,%eax
+	je .Lnocpuid
+/* In principle, I would have to check the CPU's identify first to be sure how to interpret the extended flags. */
+/* now get the info, first extended */
+	movl $0x0, 12(%esi) /* clear value */
+/* only if supported... */
+	movl $0x80000000, %eax
+	cpuid
+/* IDT CPUs should not change EAX, generally I hope that non-3DNow cpus do not set a bogus support level here. */
+	cmpl $0x80000001, %eax
+	jb .Lnoextended /* Skip ext check without minimal support level. */
+/* is supported, get flags value */
+	movl $0x80000001,%eax
+	cpuid
+	movl %edx,12(%esi)
+.Lnoextended:
+/* then the other ones, called last to get the id flags in %eax for ret */
+	movl $0x00000001,%eax
+	cpuid
+	movl %eax, (%esi)
+	movl %ecx, 4(%esi)
+	movl %edx, 8(%esi)
+	jmp .Lend
+	ALIGN4
+.Lnocpuid:
+/* error: set everything to zero */
+	movl $0, %eax
+	movl $0, (%esi)
+	movl $0, 4(%esi)
+	movl $0, 8(%esi)
+	movl $0, 12(%esi)
+	ALIGN4
+.Lend:
+/* return value are the id flags, still stored in %eax */
+	popl %esi
+	popl %ebx
+	popl %ecx
+	popl %edx
+	movl %ebp,%esp
+	popl %ebp
+	ret
+
+/* Mark non-executable stack. */
+#if defined(__linux__) && defined(__ELF__)
+.section .note.GNU-stack,"",%progbits
+#endif