From cd303963aec7291de8aabf9aa04d1423fe7dcac4 Mon Sep 17 00:00:00 2001
From: Mark Wooding <mdw@distorted.org.uk>
Date: Thu, 7 Nov 2019 01:34:06 +0000
Subject: [PATCH] base/regdump.[ch]: Add a feature for printing plain messages.

Introduce a `REGSRC_NONE' which just prints the message, and add a `msg'
macro which invokes this.
---
 base/regdump.c |  6 ++++++
 base/regdump.h | 29 +++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/base/regdump.c b/base/regdump.c
index c591fd5a..89edbcd1 100644
--- a/base/regdump.c
+++ b/base/regdump.c
@@ -213,6 +213,7 @@ static const char *regname(char *buf, uint32 f)
 
   switch (src) {
 
+    case REGSRC_NONE:
     case REGSRC_ABS:
       return (0);
 
@@ -803,6 +804,11 @@ void regdump(const void *base, const char *lbl, uint32 f)
   }
 
   switch (f&REGF_SRCMASK) {
+
+    case REGSRC_NONE:
+      printf(";; %s\n", lbl);
+      return;
+
     case REGSRC_ABS:
       p = base;
       break;
diff --git a/base/regdump.h b/base/regdump.h
index 3ada7eac..e0568202 100644
--- a/base/regdump.h
+++ b/base/regdump.h
@@ -135,6 +135,7 @@ union gp64 { uint64 u64; int64 i64; PTR64 };
 #define   REGSRC_SIMD	0x04000000	/* SIMD vector register */
 #define   REGSRC_STMMX	0x05000000	/* x86-specific: x87/MMX register */
 #define   REGSRC_SEG	0x06000000	/* x86-specific: segment register */
+#define   REGSRC_NONE	0x0f000000	/* just a message */
 /* Where to find the values. */
 
 #define REGF_WDMASK	0xf0000000
@@ -432,6 +433,17 @@ DO8(REGDEF_SIMD)
 	lea	SP, [SP + REGDUMP_SPADJ]
 .endm
 
+.macro	_nilbase
+#  if CPUFAM_X86
+	xor	eax, eax
+	mov	[SP + 0], eax
+#  elif ABI_SYSV
+	xor	edi, edi
+#  elif ABI_WIN
+	xor	ecx, ecx
+#  endif
+.endm
+
 .macro	_regbase
 #  if CPUFAM_X86
 	mov	[SP + 0], BP
@@ -625,6 +637,10 @@ DO16(REGDEF_NEONQ)
 	add	r13, r13, #REGDUMP_GPSIZE
 .endm
 
+.macro	_nilbase
+	mov	r0, #0
+.endm
+
 .macro	_regbase
 	mov	r0, r5
 .endm
@@ -776,6 +792,10 @@ DO32(REGDEF_FP)
 	add	sp, sp, #REGDUMP_GPSIZE
 .endm
 
+.macro	_nilbase
+	mov	x0, #0
+.endm
+
 .macro	_regbase
 	mov	x0, x21
 .endm
@@ -889,6 +909,15 @@ extern void regdump_freshline(void);
 	_rstrregs
 .endm
 
+.macro	msg	lbl
+	_saveregs
+	_nilbase
+	_reglbl	"\lbl"
+	_regfmt	REGSRC_NONE | (1 << REGF_WDSHIFT)
+	callext	F(regdump)
+	_rstrregs
+.endm
+
 .macro	reg	lbl, rn, fmt=0
 	_saveregs
 	_regbase
-- 
2.11.0