@@ -933,15 +933,24 @@ static inline void put_loop_count(
int_regs->ecx = ad_bytes == 4 ? (uint32_t)count : count;
}
-#define get_rep_prefix() ({ \
+#define get_rep_prefix(using_si, using_di) ({ \
unsigned long max_reps = 1; \
if ( rep_prefix() ) \
max_reps = get_loop_count(&_regs, ad_bytes); \
if ( max_reps == 0 ) \
{ \
- /* Skip the instruction if no repetitions are required. */ \
- dst.type = OP_NONE; \
- goto writeback; \
+ /* \
+ * Skip the instruction if no repetitions are required, but \
+ * zero extend involved registers first when using 32-bit \
+ * addressing in 64-bit mode. \
+ */ \
+ if ( mode_64bit() && ad_bytes == 4 ) \
+ { \
+ _regs.ecx = 0; \
+ if ( using_si ) _regs.esi = (uint32_t)_regs.esi; \
+ if ( using_di ) _regs.edi = (uint32_t)_regs.edi; \
+ } \
+ goto no_writeback; \
} \
max_reps; \
})
@@ -2908,7 +2917,7 @@ x86_emulate(
goto imul;
case 0x6c ... 0x6d: /* ins %dx,%es:%edi */ {
- unsigned long nr_reps = get_rep_prefix();
+ unsigned long nr_reps = get_rep_prefix(false, true);
unsigned int port = (uint16_t)_regs.edx;
dst.bytes = !(b & 1) ? 1 : (op_bytes == 8) ? 4 : op_bytes;
dst.mem.seg = x86_seg_es;
@@ -2935,7 +2944,7 @@ x86_emulate(
}
case 0x6e ... 0x6f: /* outs %esi,%dx */ {
- unsigned long nr_reps = get_rep_prefix();
+ unsigned long nr_reps = get_rep_prefix(true, false);
unsigned int port = (uint16_t)_regs.edx;
dst.bytes = !(b & 1) ? 1 : (op_bytes == 8) ? 4 : op_bytes;
ea.mem.off = truncate_ea_and_reps(_regs.esi, nr_reps, dst.bytes);
@@ -3167,7 +3176,8 @@ x86_emulate(
break;
case 0xa4 ... 0xa5: /* movs */ {
- unsigned long nr_reps = get_rep_prefix();
+ unsigned long nr_reps = get_rep_prefix(true, true);
+
dst.bytes = (d & ByteOp) ? 1 : op_bytes;
dst.mem.seg = x86_seg_es;
dst.mem.off = truncate_ea_and_reps(_regs.edi, nr_reps, dst.bytes);
@@ -3197,7 +3207,8 @@ x86_emulate(
case 0xa6 ... 0xa7: /* cmps */ {
unsigned long next_eip = _regs.eip;
- get_rep_prefix();
+
+ get_rep_prefix(true, true);
src.bytes = dst.bytes = (d & ByteOp) ? 1 : op_bytes;
if ( (rc = read_ulong(ea.mem.seg, truncate_ea(_regs.esi),
&dst.val, dst.bytes, ctxt, ops)) ||
@@ -3218,7 +3229,8 @@ x86_emulate(
}
case 0xaa ... 0xab: /* stos */ {
- unsigned long nr_reps = get_rep_prefix();
+ unsigned long nr_reps = get_rep_prefix(false, true);
+
dst.bytes = (d & ByteOp) ? 1 : op_bytes;
dst.mem.seg = x86_seg_es;
dst.mem.off = truncate_ea(_regs.edi);
@@ -3241,8 +3253,8 @@ x86_emulate(
break;
}
- case 0xac ... 0xad: /* lods */ {
- /* unsigned long max_reps = */get_rep_prefix();
+ case 0xac ... 0xad: /* lods */
+ get_rep_prefix(true, false);
dst.type = OP_REG;
dst.bytes = (d & ByteOp) ? 1 : op_bytes;
dst.reg = (unsigned long *)&_regs.eax;
@@ -3253,11 +3265,11 @@ x86_emulate(
_regs.esi, (_regs.eflags & EFLG_DF) ? -dst.bytes : dst.bytes);
put_rep_prefix(1);
break;
- }
case 0xae ... 0xaf: /* scas */ {
unsigned long next_eip = _regs.eip;
- get_rep_prefix();
+
+ get_rep_prefix(false, true);
src.bytes = dst.bytes = (d & ByteOp) ? 1 : op_bytes;
dst.val = _regs.eax;
if ( (rc = read_ulong(x86_seg_es, truncate_ea(_regs.edi),
@@ -5424,7 +5436,6 @@ x86_emulate(
goto cannot_emulate;
}
- writeback:
switch ( dst.type )
{
case OP_REG: