Add the gx command to dc

This command pushes 1 if extended registers are on, 0 otherwise.

This commit includes the tests, the changes to the manpages, the works.
I still have to run through the release process, but I think this is
pretty safe.

Signed-off-by: Gavin D. Howard <gavin@gavinhoward.com>

26 files changed, 141 insertions, 9 deletions

diff --git a/include/lang.h b/include/lang.h
index 9eee3279..97aeeaa9 100644
--- a/include/lang.h
+++ b/include/lang.h
@@ -277,6 +277,9 @@ typedef enum BcInst
 
 #if DC_ENABLED
 
+	/// dc extended registers command.
+	BC_INST_EXTENDED_REGISTERS,
+
 	/// dc's return; it pops an executing string off of the stack.
 	BC_INST_POP_EXEC,
 
diff --git a/include/lex.h b/include/lex.h
index 060f5bea..ac9b7b6e 100644
--- a/include/lex.h
+++ b/include/lex.h
@@ -409,6 +409,9 @@ typedef enum BcLexType
 
 #if DC_ENABLED
 
+	/// dc extended registers keyword.
+	BC_LEX_EXTENDED_REGISTERS,
+
 	/// A special token for dc to calculate equal without a register.
 	BC_LEX_EQ_NO_REG,
 
diff --git a/include/program.h b/include/program.h
index 93621d4d..ff32d5db 100644
--- a/include/program.h
+++ b/include/program.h
@@ -608,6 +608,7 @@ extern const char bc_program_esc_seqs[];
 		&&lbl_BC_INST_MODEXP,                           \
 		&&lbl_BC_INST_DIVMOD,                           \
 		&&lbl_BC_INST_PRINT_STREAM,                     \
+		&&lbl_BC_INST_EXTENDED_REGISTERS,               \
 		&&lbl_BC_INST_POP_EXEC,                         \
 		&&lbl_BC_INST_EXECUTE,                          \
 		&&lbl_BC_INST_EXEC_COND,                        \
@@ -701,6 +702,7 @@ extern const char bc_program_esc_seqs[];
 		&&lbl_BC_INST_MODEXP,                           \
 		&&lbl_BC_INST_DIVMOD,                           \
 		&&lbl_BC_INST_PRINT_STREAM,                     \
+		&&lbl_BC_INST_EXTENDED_REGISTERS,               \
 		&&lbl_BC_INST_POP_EXEC,                         \
 		&&lbl_BC_INST_EXECUTE,                          \
 		&&lbl_BC_INST_EXEC_COND,                        \
@@ -959,6 +961,7 @@ extern const char bc_program_esc_seqs[];
 		&&lbl_BC_INST_MODEXP,                           \
 		&&lbl_BC_INST_DIVMOD,                           \
 		&&lbl_BC_INST_PRINT_STREAM,                     \
+		&&lbl_BC_INST_EXTENDED_REGISTERS,               \
 		&&lbl_BC_INST_POP_EXEC,                         \
 		&&lbl_BC_INST_EXECUTE,                          \
 		&&lbl_BC_INST_EXEC_COND,                        \
@@ -1027,6 +1030,7 @@ extern const char bc_program_esc_seqs[];
 		&&lbl_BC_INST_MODEXP,                           \
 		&&lbl_BC_INST_DIVMOD,                           \
 		&&lbl_BC_INST_PRINT_STREAM,                     \
+		&&lbl_BC_INST_EXTENDED_REGISTERS,               \
 		&&lbl_BC_INST_POP_EXEC,                         \
 		&&lbl_BC_INST_EXECUTE,                          \
 		&&lbl_BC_INST_EXEC_COND,                        \
diff --git a/manuals/dc.1.md.in b/manuals/dc.1.md.in
index 6e88a643..0750a6d8 100644
--- a/manuals/dc.1.md.in
+++ b/manuals/dc.1.md.in
@@ -1123,6 +1123,11 @@ other character produces a parse error (see the **ERRORS** section).
 :   Pushes the line length set by **DC_LINE_LENGTH** (see the **ENVIRONMENT
     VARIABLES** section) onto the stack.
 
+**gx**
+
+:   Pushes **1** onto the stack if extended register mode is on, **0**
+    otherwise.
+
 **gz**
 
 :   Pushes **0** onto the stack if the leading zero setting has not been enabled
diff --git a/manuals/dc/A.1 b/manuals/dc/A.1
index ba401cb3..277bd48d 100644
--- a/manuals/dc/A.1
+++ b/manuals/dc/A.1
@@ -1251,6 +1251,10 @@ section).
 Pushes the line length set by \f[B]DC_LINE_LENGTH\f[R] (see the
 \f[B]ENVIRONMENT VARIABLES\f[R] section) onto the stack.
 .TP
+\f[B]gx\f[R]
+Pushes \f[B]1\f[R] onto the stack if extended register mode is on,
+\f[B]0\f[R] otherwise.
+.TP
 \f[B]gz\f[R]
 Pushes \f[B]0\f[R] onto the stack if the leading zero setting has not
 been enabled with the \f[B]-z\f[R] or \f[B]--leading-zeroes\f[R] options
diff --git a/manuals/dc/A.1.md b/manuals/dc/A.1.md
index 51a8335f..ece5aba3 100644
--- a/manuals/dc/A.1.md
+++ b/manuals/dc/A.1.md
@@ -1083,6 +1083,11 @@ other character produces a parse error (see the **ERRORS** section).
 :   Pushes the line length set by **DC_LINE_LENGTH** (see the **ENVIRONMENT
     VARIABLES** section) onto the stack.
 
+**gx**
+
+:   Pushes **1** onto the stack if extended register mode is on, **0**
+    otherwise.
+
 **gz**
 
 :   Pushes **0** onto the stack if the leading zero setting has not been enabled
diff --git a/manuals/dc/E.1 b/manuals/dc/E.1
index bcce9f87..0bc1a6dc 100644
--- a/manuals/dc/E.1
+++ b/manuals/dc/E.1
@@ -1036,6 +1036,10 @@ section).
 Pushes the line length set by \f[B]DC_LINE_LENGTH\f[R] (see the
 \f[B]ENVIRONMENT VARIABLES\f[R] section) onto the stack.
 .TP
+\f[B]gx\f[R]
+Pushes \f[B]1\f[R] onto the stack if extended register mode is on,
+\f[B]0\f[R] otherwise.
+.TP
 \f[B]gz\f[R]
 Pushes \f[B]0\f[R] onto the stack if the leading zero setting has not
 been enabled with the \f[B]-z\f[R] or \f[B]--leading-zeroes\f[R] options
diff --git a/manuals/dc/E.1.md b/manuals/dc/E.1.md
index e11381cf..867928b2 100644
--- a/manuals/dc/E.1.md
+++ b/manuals/dc/E.1.md
@@ -914,6 +914,11 @@ other character produces a parse error (see the **ERRORS** section).
 :   Pushes the line length set by **DC_LINE_LENGTH** (see the **ENVIRONMENT
     VARIABLES** section) onto the stack.
 
+**gx**
+
+:   Pushes **1** onto the stack if extended register mode is on, **0**
+    otherwise.
+
 **gz**
 
 :   Pushes **0** onto the stack if the leading zero setting has not been enabled
diff --git a/manuals/dc/EH.1 b/manuals/dc/EH.1
index 4b3ba915..6dadcdc5 100644
--- a/manuals/dc/EH.1
+++ b/manuals/dc/EH.1
@@ -1036,6 +1036,10 @@ section).
 Pushes the line length set by \f[B]DC_LINE_LENGTH\f[R] (see the
 \f[B]ENVIRONMENT VARIABLES\f[R] section) onto the stack.
 .TP
+\f[B]gx\f[R]
+Pushes \f[B]1\f[R] onto the stack if extended register mode is on,
+\f[B]0\f[R] otherwise.
+.TP
 \f[B]gz\f[R]
 Pushes \f[B]0\f[R] onto the stack if the leading zero setting has not
 been enabled with the \f[B]-z\f[R] or \f[B]--leading-zeroes\f[R] options
diff --git a/manuals/dc/EH.1.md b/manuals/dc/EH.1.md
index fd2a28f8..3c04a0cb 100644
--- a/manuals/dc/EH.1.md
+++ b/manuals/dc/EH.1.md
@@ -914,6 +914,11 @@ other character produces a parse error (see the **ERRORS** section).
 :   Pushes the line length set by **DC_LINE_LENGTH** (see the **ENVIRONMENT
     VARIABLES** section) onto the stack.
 
+**gx**
+
+:   Pushes **1** onto the stack if extended register mode is on, **0**
+    otherwise.
+
 **gz**
 
 :   Pushes **0** onto the stack if the leading zero setting has not been enabled
diff --git a/manuals/dc/EHN.1 b/manuals/dc/EHN.1
index 01ca772f..a756a1e8 100644
--- a/manuals/dc/EHN.1
+++ b/manuals/dc/EHN.1
@@ -1036,6 +1036,10 @@ section).
 Pushes the line length set by \f[B]DC_LINE_LENGTH\f[R] (see the
 \f[B]ENVIRONMENT VARIABLES\f[R] section) onto the stack.
 .TP
+\f[B]gx\f[R]
+Pushes \f[B]1\f[R] onto the stack if extended register mode is on,
+\f[B]0\f[R] otherwise.
+.TP
 \f[B]gz\f[R]
 Pushes \f[B]0\f[R] onto the stack if the leading zero setting has not
 been enabled with the \f[B]-z\f[R] or \f[B]--leading-zeroes\f[R] options
diff --git a/manuals/dc/EHN.1.md b/manuals/dc/EHN.1.md
index b24c8790..26638cbd 100644
--- a/manuals/dc/EHN.1.md
+++ b/manuals/dc/EHN.1.md
@@ -914,6 +914,11 @@ other character produces a parse error (see the **ERRORS** section).
 :   Pushes the line length set by **DC_LINE_LENGTH** (see the **ENVIRONMENT
     VARIABLES** section) onto the stack.
 
+**gx**
+
+:   Pushes **1** onto the stack if extended register mode is on, **0**
+    otherwise.
+
 **gz**
 
 :   Pushes **0** onto the stack if the leading zero setting has not been enabled
diff --git a/manuals/dc/EN.1 b/manuals/dc/EN.1
index 555ad7e1..b297bfcb 100644
--- a/manuals/dc/EN.1
+++ b/manuals/dc/EN.1
@@ -1036,6 +1036,10 @@ section).
 Pushes the line length set by \f[B]DC_LINE_LENGTH\f[R] (see the
 \f[B]ENVIRONMENT VARIABLES\f[R] section) onto the stack.
 .TP
+\f[B]gx\f[R]
+Pushes \f[B]1\f[R] onto the stack if extended register mode is on,
+\f[B]0\f[R] otherwise.
+.TP
 \f[B]gz\f[R]
 Pushes \f[B]0\f[R] onto the stack if the leading zero setting has not
 been enabled with the \f[B]-z\f[R] or \f[B]--leading-zeroes\f[R] options
diff --git a/manuals/dc/EN.1.md b/manuals/dc/EN.1.md
index 5025bb0e..97e41e42 100644
--- a/manuals/dc/EN.1.md
+++ b/manuals/dc/EN.1.md
@@ -914,6 +914,11 @@ other character produces a parse error (see the **ERRORS** section).
 :   Pushes the line length set by **DC_LINE_LENGTH** (see the **ENVIRONMENT
     VARIABLES** section) onto the stack.
 
+**gx**
+
+:   Pushes **1** onto the stack if extended register mode is on, **0**
+    otherwise.
+
 **gz**
 
 :   Pushes **0** onto the stack if the leading zero setting has not been enabled
diff --git a/manuals/dc/H.1 b/manuals/dc/H.1
index 94d2e73d..69b030c8 100644
--- a/manuals/dc/H.1
+++ b/manuals/dc/H.1
@@ -1251,6 +1251,10 @@ section).
 Pushes the line length set by \f[B]DC_LINE_LENGTH\f[R] (see the
 \f[B]ENVIRONMENT VARIABLES\f[R] section) onto the stack.
 .TP
+\f[B]gx\f[R]
+Pushes \f[B]1\f[R] onto the stack if extended register mode is on,
+\f[B]0\f[R] otherwise.
+.TP
 \f[B]gz\f[R]
 Pushes \f[B]0\f[R] onto the stack if the leading zero setting has not
 been enabled with the \f[B]-z\f[R] or \f[B]--leading-zeroes\f[R] options
diff --git a/manuals/dc/H.1.md b/manuals/dc/H.1.md
index f9b45468..d56372d6 100644
--- a/manuals/dc/H.1.md
+++ b/manuals/dc/H.1.md
@@ -1083,6 +1083,11 @@ other character produces a parse error (see the **ERRORS** section).
 :   Pushes the line length set by **DC_LINE_LENGTH** (see the **ENVIRONMENT
     VARIABLES** section) onto the stack.
 
+**gx**
+
+:   Pushes **1** onto the stack if extended register mode is on, **0**
+    otherwise.
+
 **gz**
 
 :   Pushes **0** onto the stack if the leading zero setting has not been enabled
diff --git a/manuals/dc/HN.1 b/manuals/dc/HN.1
index ac06c37d..0b92b983 100644
--- a/manuals/dc/HN.1
+++ b/manuals/dc/HN.1
@@ -1251,6 +1251,10 @@ section).
 Pushes the line length set by \f[B]DC_LINE_LENGTH\f[R] (see the
 \f[B]ENVIRONMENT VARIABLES\f[R] section) onto the stack.
 .TP
+\f[B]gx\f[R]
+Pushes \f[B]1\f[R] onto the stack if extended register mode is on,
+\f[B]0\f[R] otherwise.
+.TP
 \f[B]gz\f[R]
 Pushes \f[B]0\f[R] onto the stack if the leading zero setting has not
 been enabled with the \f[B]-z\f[R] or \f[B]--leading-zeroes\f[R] options
diff --git a/manuals/dc/HN.1.md b/manuals/dc/HN.1.md
index 44805105..28a7b379 100644
--- a/manuals/dc/HN.1.md
+++ b/manuals/dc/HN.1.md
@@ -1083,6 +1083,11 @@ other character produces a parse error (see the **ERRORS** section).
 :   Pushes the line length set by **DC_LINE_LENGTH** (see the **ENVIRONMENT
     VARIABLES** section) onto the stack.
 
+**gx**
+
+:   Pushes **1** onto the stack if extended register mode is on, **0**
+    otherwise.
+
 **gz**
 
 :   Pushes **0** onto the stack if the leading zero setting has not been enabled
diff --git a/manuals/dc/N.1 b/manuals/dc/N.1
index fef82c51..1a160a4b 100644
--- a/manuals/dc/N.1
+++ b/manuals/dc/N.1
@@ -1251,6 +1251,10 @@ section).
 Pushes the line length set by \f[B]DC_LINE_LENGTH\f[R] (see the
 \f[B]ENVIRONMENT VARIABLES\f[R] section) onto the stack.
 .TP
+\f[B]gx\f[R]
+Pushes \f[B]1\f[R] onto the stack if extended register mode is on,
+\f[B]0\f[R] otherwise.
+.TP
 \f[B]gz\f[R]
 Pushes \f[B]0\f[R] onto the stack if the leading zero setting has not
 been enabled with the \f[B]-z\f[R] or \f[B]--leading-zeroes\f[R] options
diff --git a/manuals/dc/N.1.md b/manuals/dc/N.1.md
index 3b9dfbeb..f5ef42d6 100644
--- a/manuals/dc/N.1.md
+++ b/manuals/dc/N.1.md
@@ -1083,6 +1083,11 @@ other character produces a parse error (see the **ERRORS** section).
 :   Pushes the line length set by **DC_LINE_LENGTH** (see the **ENVIRONMENT
     VARIABLES** section) onto the stack.
 
+**gx**
+
+:   Pushes **1** onto the stack if extended register mode is on, **0**
+    otherwise.
+
 **gz**
 
 :   Pushes **0** onto the stack if the leading zero setting has not been enabled
diff --git a/src/bc_parse.c b/src/bc_parse.c
index 13e03a49..4cf886ef 100644
--- a/src/bc_parse.c
+++ b/src/bc_parse.c
@@ -1888,6 +1888,7 @@ bc_parse_stmt(BcParse* p)
 		case BC_LEX_KW_AUTO:
 		case BC_LEX_KW_DEFINE:
 #if DC_ENABLED
+		case BC_LEX_EXTENDED_REGISTERS:
 		case BC_LEX_EQ_NO_REG:
 		case BC_LEX_COLON:
 		case BC_LEX_EXECUTE:
@@ -2436,6 +2437,7 @@ bc_parse_expr_err(BcParse* p, uint8_t flags, BcParseNext next)
 			case BC_LEX_KW_STREAM:
 			case BC_LEX_KW_ELSE:
 #if DC_ENABLED
+			case BC_LEX_EXTENDED_REGISTERS:
 			case BC_LEX_EQ_NO_REG:
 			case BC_LEX_COLON:
 			case BC_LEX_EXECUTE:
diff --git a/src/data.c b/src/data.c
index 5eb34bdb..abaf3b8e 100644
--- a/src/data.c
+++ b/src/data.c
@@ -1199,12 +1199,12 @@ const uchar dc_parse_insts[] = {
 #if BC_ENABLED
 	BC_INST_INVALID,
 #endif // BC_ENABLED
-	BC_INST_LEADING_ZERO, BC_INST_PRINT_STREAM, BC_INST_INVALID,
-	BC_INST_REL_EQ,       BC_INST_INVALID,      BC_INST_EXECUTE,
-	BC_INST_PRINT_STACK,  BC_INST_CLEAR_STACK,  BC_INST_INVALID,
-	BC_INST_STACK_LEN,    BC_INST_DUPLICATE,    BC_INST_SWAP,
-	BC_INST_POP,          BC_INST_INVALID,      BC_INST_INVALID,
-	BC_INST_INVALID,
+	BC_INST_LEADING_ZERO,       BC_INST_PRINT_STREAM, BC_INST_INVALID,
+	BC_INST_EXTENDED_REGISTERS, BC_INST_REL_EQ,       BC_INST_INVALID,
+	BC_INST_EXECUTE,            BC_INST_PRINT_STACK,  BC_INST_CLEAR_STACK,
+	BC_INST_INVALID,            BC_INST_STACK_LEN,    BC_INST_DUPLICATE,
+	BC_INST_SWAP,               BC_INST_POP,          BC_INST_INVALID,
+	BC_INST_INVALID, BC_INST_INVALID,
 #if BC_ENABLE_EXTRA_MATH
 	BC_INST_INVALID,
 #endif // BC_ENABLE_EXTRA_MATH
diff --git a/src/dc_lex.c b/src/dc_lex.c
index cf737ea3..963e3f13 100644
--- a/src/dc_lex.c
+++ b/src/dc_lex.c
@@ -278,6 +278,7 @@ dc_lex_token(BcLex* l)
 			c2 = l->buf[l->i];
 
 			if (c2 == 'l') l->t = BC_LEX_KW_LINE_LENGTH;
+			else if (c2 == 'x') l->t = BC_LEX_EXTENDED_REGISTERS;
 			else if (c2 == 'z') l->t = BC_LEX_KW_LEADING_ZERO;
 			else bc_lex_invalidChar(l, c2);
 
diff --git a/src/dc_parse.c b/src/dc_parse.c
index 638ccfb7..2a6f387a 100644
--- a/src/dc_parse.c
+++ b/src/dc_parse.c
@@ -349,6 +349,7 @@ dc_parse_token(BcParse* p, BcLexType t, uint8_t flags)
 		case BC_LEX_KW_LEADING_ZERO:
 		case BC_LEX_KW_STREAM:
 		case BC_LEX_KW_ELSE:
+		case BC_LEX_EXTENDED_REGISTERS:
 		case BC_LEX_EQ_NO_REG:
 		case BC_LEX_EXECUTE:
 		case BC_LEX_PRINT_STACK:
diff --git a/src/program.c b/src/program.c
index 5ede93d5..b6fac12c 100644
--- a/src/program.c
+++ b/src/program.c
@@ -2689,12 +2689,20 @@ bc_program_globalSetting(BcProgram* p, uchar inst)
 	BcBigDig val;
 
 	// Make sure the instruction is valid.
+#if DC_ENABLED
+	assert((inst >= BC_INST_LINE_LENGTH && inst <= BC_INST_LEADING_ZERO) ||
+	       (BC_IS_DC && inst == BC_INST_EXTENDED_REGISTERS));
+#else // DC_ENABLED
 	assert(inst >= BC_INST_LINE_LENGTH && inst <= BC_INST_LEADING_ZERO);
+#endif // DC_ENABLED
 
 	if (inst == BC_INST_LINE_LENGTH) val = (BcBigDig) vm->line_len;
 #if BC_ENABLED
 	else if (inst == BC_INST_GLOBAL_STACKS) val = (BC_G != 0);
 #endif // BC_ENABLED
+#if DC_ENABLED
+	else if (inst == BC_INST_EXTENDED_REGISTERS) val = (DC_X != 0);
+#endif // DC_ENABLED
 	else val = (BC_Z != 0);
 
 	// Push the global.
@@ -3246,6 +3254,9 @@ bc_program_exec(BcProgram* p)
 #if BC_ENABLED
 			BC_PROG_LBL(BC_INST_GLOBAL_STACKS):
 #endif // BC_ENABLED
+#if DC_ENABLED
+			BC_PROG_LBL(BC_INST_EXTENDED_REGISTERS):
+#endif // DC_ENABLE
 			BC_PROG_LBL(BC_INST_LEADING_ZERO):
 			// clang-format on
 			{
diff --git a/tests/other.sh b/tests/other.sh
index de4059b9..04dbf98d 100755
--- a/tests/other.sh
+++ b/tests/other.sh
@@ -273,8 +273,8 @@ else
 
 		printf 'Running dc Easter script...'
 
-		easter_res="$outputdir/dc_outputs/easter.txt"
-		easter_out="$outputdir/dc_outputs/easter_results.txt"
+		easter_out="$outputdir/dc_outputs/easter.txt"
+		easter_res="$outputdir/dc_outputs/easter_results.txt"
 
 		outdir=$(dirname "$easter_out")
 
@@ -287,11 +287,41 @@ else
 		"$testdir/dc/scripts/easter.sh" "$exe" 2021 "$@" 2> /dev/null | cut -c1-12 > "$easter_out"
 		err="$?"
 
-		checktest "$d" "$err" "Easter script" "$easter_res" "$easter_out"
+		checktest "$d" "$err" "Easter script" "$easter_out" "$easter_res"
 
 		printf 'pass\n'
 	fi
 
+	unset DC_ENV_ARGS
+	unset DC_EXPR_EXIT
+
+	printf 'Running dc extended register command tests...'
+
+	ext_reg_out="$outputdir/dc_outputs/ext_reg.txt"
+	ext_reg_res="$outputdir/dc_outputs/ext_reg_results.txt"
+
+	outdir=$(dirname "$ext_reg_out")
+
+	if [ ! -d "$outdir" ]; then
+		mkdir -p "$outdir"
+	fi
+
+	printf '0\n' > "$ext_reg_res"
+
+	"$exe" -e "gxpR" "$@" 2> /dev/null > "$ext_reg_out"
+	err="$?"
+
+	checktest "$d" "$err" "Extended register command" "$ext_reg_out" "$ext_reg_res"
+
+	printf '1\n' > "$ext_reg_res"
+
+	"$exe" -x -e "gxpR" "$@" 2> /dev/null > "$ext_reg_out"
+	err="$?"
+
+	checktest "$d" "$err" "Extended register command" "$ext_reg_out" "$ext_reg_res"
+
+	printf 'pass\n'
+
 fi
 
 out1="$outputdir/${d}_outputs/${d}_other.txt"