# HG changeset patch
# User kfraser@xxxxxxxxxxxxxxxxxxxxx
# Date 1168542088 0
# Node ID ecf6a0a05350eb8518a3c0e49fb04f28241d2f95
# Parent 568ba07641c6998e82ed417417cd0eb9c17e1b8d
[XEN] Add LOOP{,Z,NZ} and CBW/CWD/... emulation.
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
---
xen/arch/x86/x86_emulate.c | 53 +++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 51 insertions(+), 2 deletions(-)
diff -r 568ba07641c6 -r ecf6a0a05350 xen/arch/x86/x86_emulate.c
--- a/xen/arch/x86/x86_emulate.c Thu Jan 11 19:00:35 2007 +0000
+++ b/xen/arch/x86/x86_emulate.c Thu Jan 11 19:01:28 2007 +0000
@@ -109,7 +109,7 @@ static uint8_t opcode_table[256] = {
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
/* 0x98 - 0x9F */
- 0, 0, 0, 0, 0, 0, ImplicitOps, ImplicitOps,
+ ImplicitOps, ImplicitOps, 0, 0, 0, 0, ImplicitOps, ImplicitOps,
/* 0xA0 - 0xA7 */
ByteOp|ImplicitOps|Mov, ImplicitOps|Mov,
ByteOp|ImplicitOps|Mov, ImplicitOps|Mov,
@@ -139,7 +139,7 @@ static uint8_t opcode_table[256] = {
/* 0xD8 - 0xDF */
0, 0, 0, 0, 0, 0, 0, 0,
/* 0xE0 - 0xE7 */
- 0, 0, 0, ImplicitOps, 0, 0, 0, 0,
+ ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps, 0, 0, 0, 0,
/* 0xE8 - 0xEF */
ImplicitOps, ImplicitOps, 0, ImplicitOps, 0, 0, 0, 0,
/* 0xF0 - 0xF7 */
@@ -1339,6 +1339,30 @@ x86_emulate(
dst.val = *dst.reg;
goto xchg;
+ case 0x98: /* cbw/cwde/cdqe */
+ switch ( op_bytes )
+ {
+ case 2: *(int16_t *)&_regs.eax = (int8_t)_regs.eax; break; /* cbw */
+ case 4: _regs.eax = (uint32_t)(int16_t)_regs.eax; break; /* cwde */
+ case 8: _regs.eax = (int32_t)_regs.eax; break; /* cdqe */
+ }
+ break;
+
+ case 0x99: /* cwd/cdq/cqo */
+ switch ( op_bytes )
+ {
+ case 2:
+ *(int16_t *)&_regs.edx = ((int16_t)_regs.eax < 0) ? -1 : 0;
+ break;
+ case 4:
+ _regs.edx = (uint32_t)(((int32_t)_regs.eax < 0) ? -1 : 0);
+ break;
+ case 8:
+ _regs.edx = (_regs.eax < 0) ? -1 : 0;
+ break;
+ }
+ break;
+
case 0x9e: /* sahf */
*(uint8_t *)_regs.eflags = (((uint8_t *)&_regs.eax)[1] & 0xd7) | 0x02;
break;
@@ -1452,6 +1476,31 @@ x86_emulate(
break;
}
+ case 0xe0 ... 0xe2: /* loop{,z,nz} */ {
+ int rel = insn_fetch_type(int8_t);
+ int do_jmp = !(_regs.eflags & EFLG_ZF); /* loopnz */
+ if ( b == 0xe1 )
+ do_jmp = !do_jmp; /* loopz */
+ else if ( b == 0xe2 )
+ do_jmp = 1; /* loop */
+ switch ( ad_bytes )
+ {
+ case 2:
+ do_jmp &= --(*(uint16_t *)&_regs.ecx) != 0;
+ break;
+ case 4:
+ do_jmp &= --(*(uint32_t *)&_regs.ecx) != 0;
+ _regs.ecx = (uint32_t)_regs.ecx; /* zero extend in x86/64 mode */
+ break;
+ default: /* case 8: */
+ do_jmp &= --_regs.ecx != 0;
+ break;
+ }
+ if ( do_jmp )
+ jmp_rel(rel);
+ break;
+ }
+
case 0xe3: /* jcxz/jecxz (short) */ {
int rel = insn_fetch_type(int8_t);
if ( (ad_bytes == 2) ? !(uint16_t)_regs.ecx :
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