From 2fa288d0599369012465056a06c6ea09ce2a1134 Mon Sep 17 00:00:00 2001
From: Lubomir Rintel <lkundrak@v3.sk>
Date: Sat, 30 Apr 2011 10:11:00 +0200
Subject: Check for incorrect REP/REPNE prefix use

---
 as/asm/each.asm | 39 +++++++++++++++++++++++++++++++++++++++
 as/assemble.c   | 10 ++++++++++
 as/errors.c     |  3 +++
 as/errors.h     |  3 +++
 4 files changed, 55 insertions(+)

(limited to 'as')

diff --git a/as/asm/each.asm b/as/asm/each.asm
index 2145489..371b20e 100644
--- a/as/asm/each.asm
+++ b/as/asm/each.asm
@@ -104,10 +104,49 @@ rcr	[esi*4],1
 rol	[esi*4],1
 ror	[esi*4],1
 rep
+ins
+rep
+outs
+rep
+movs
+rep
+cmps
+rep
+stos
+rep
+scas
+repe
+ins
+repe
+outs
+repe
+movs
+repe
+cmps
 repe
+stos
+repe
+scas
+repz
+ins
+repz
+outs
+repz
+movs
 repz
+cmps
+repz
+stos
+repz
+scas
 repne
+scas
+repne
+cmps
+repnz
+scas
 repnz
+cmps
 ret
 retf
 sahf
diff --git a/as/assemble.c b/as/assemble.c
index 5af954e..10349a1 100644
--- a/as/assemble.c
+++ b/as/assemble.c
@@ -199,6 +199,7 @@ PUBLIC void assemble()
 PRIVATE void asline()
 {
     register struct sym_s *symptr;
+    opcode_t prevop;
 
     postb = popflags = pcrflag =
 #ifdef I80386
@@ -317,9 +318,18 @@ PRIVATE void asline()
 	    mcount = 1;
 	}
     }
+    prevop = opcode;
     opcode = symptr->value_reg_or_op.op.opcode;
 #ifdef I80386
     needcpu((page==0 && ((opcode&0xF0) == 0x60||(opcode&0xF6)==0xC0))?1:0);
+    /* We handle "rep[ne]" refix as separate instruction; check if it's valid */
+    if (prevop == 0xF2 && (opcode&0xF6) != 0xA6)        /* REPNE CMPS/SCAS */
+        error (REPNE_STRING);
+    if (prevop == 0xF3 && !((opcode&0xFC) == 0x6C ||    /* REP INS/OUTS */
+        (opcode&0xFC) == 0xA4 ||                        /* REP MOVS/CMPS */
+        (opcode&0xFC) == 0xAC ||                        /* REP SCAS/LODS */
+        (opcode&0xFE) == 0xAA))                         /* REP STOS */
+        error (REP_STRING);
 #endif
     routine = rout_table[symptr->value_reg_or_op.op.routine];
     getsym();
diff --git a/as/errors.c b/as/errors.c
index 4a78a7f..de9b507 100644
--- a/as/errors.c
+++ b/as/errors.c
@@ -103,6 +103,9 @@ PUBLIC char JUNK_AFTER_OPERANDS[] =  "junk after operands";
 PUBLIC char ALREADY[] =         "already defined";
 PUBLIC char UNSTABLE_LABEL[] =  "label moved in last pass add -O?";
 
+PUBLIC char REPNE_STRING[] =    "CMPS or SCAS expected";
+PUBLIC char REP_STRING[] =      "string instruction expected";
+
 /* Warnings. */
 PUBLIC char CPUCLASH[] =        "instruction illegal for current cpu";
 PUBLIC char SHORTB[] =          "short branch would do";
diff --git a/as/errors.h b/as/errors.h
index ac26b6d..451ac41 100644
--- a/as/errors.h
+++ b/as/errors.h
@@ -103,6 +103,9 @@ EXTERN char JUNK_AFTER_OPERANDS[]; /* "junk after operands" */
 EXTERN char ALREADY[];          /* "already defined" */
 EXTERN char UNSTABLE_LABEL[];   /* "label moved in last pass add -O?" */
 
+EXTERN char REPNE_STRING[];     /* "CMPS or SCAS expected" */
+EXTERN char REP_STRING[];       /* "string instruction expected" */
+
 /* Warnings. */
 EXTERN char CPUCLASH[];         /* "instruction illegal for current cpu" */
 EXTERN char SHORTB[];           /* "short branch would do" */
-- 
cgit v1.2.1