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| author | Keir Fraser <keir.fraser@citrix.com> | 2007-11-25 18:07:33 +0000 |
|---|---|---|
| committer | Keir Fraser <keir.fraser@citrix.com> | 2007-11-25 18:07:33 +0000 |
| commit | 0d0e0d8cc0fc39d679b63e5ce381402d6a0c5940 (patch) | |
| tree | a3740b5000015573fc31020a92d802fa62a9c71f /xen/arch/x86/x86_emulate.c | |
| parent | 4abb21480a434074fa0db3d9e5799a7fc3712a1e (diff) | |
| download | xen-0d0e0d8cc0fc39d679b63e5ce381402d6a0c5940.tar.gz xen-0d0e0d8cc0fc39d679b63e5ce381402d6a0c5940.tar.bz2 xen-0d0e0d8cc0fc39d679b63e5ce381402d6a0c5940.zip | |
x86_emulate: Emulate CMPS and SCAS string-compare instructions.
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
Diffstat (limited to 'xen/arch/x86/x86_emulate.c')
| -rw-r--r-- | xen/arch/x86/x86_emulate.c | 51 |
1 files changed, 48 insertions, 3 deletions
diff --git a/xen/arch/x86/x86_emulate.c b/xen/arch/x86/x86_emulate.c index c6262243ac..b412b50956 100644 --- a/xen/arch/x86/x86_emulate.c +++ b/xen/arch/x86/x86_emulate.c @@ -131,11 +131,13 @@ static uint8_t opcode_table[256] = { /* 0xA0 - 0xA7 */ ByteOp|ImplicitOps|Mov, ImplicitOps|Mov, ByteOp|ImplicitOps|Mov, ImplicitOps|Mov, - ByteOp|ImplicitOps|Mov, ImplicitOps|Mov, 0, 0, + ByteOp|ImplicitOps|Mov, ImplicitOps|Mov, + ByteOp|ImplicitOps, ImplicitOps, /* 0xA8 - 0xAF */ ByteOp|DstReg|SrcImm, DstReg|SrcImm, ByteOp|ImplicitOps|Mov, ImplicitOps|Mov, - ByteOp|ImplicitOps|Mov, ImplicitOps|Mov, 0, 0, + ByteOp|ImplicitOps|Mov, ImplicitOps|Mov, + ByteOp|ImplicitOps, ImplicitOps, /* 0xB0 - 0xB7 */ ByteOp|DstReg|SrcImm|Mov, ByteOp|DstReg|SrcImm|Mov, ByteOp|DstReg|SrcImm|Mov, ByteOp|DstReg|SrcImm|Mov, @@ -828,6 +830,8 @@ x86_emulate( uint8_t b, d, sib, sib_index, sib_base, twobyte = 0, rex_prefix = 0; uint8_t modrm, modrm_mod = 0, modrm_reg = 0, modrm_rm = 0; unsigned int op_bytes, def_op_bytes, ad_bytes, def_ad_bytes; +#define REPE_PREFIX 1 +#define REPNE_PREFIX 2 unsigned int lock_prefix = 0, rep_prefix = 0; int override_seg = -1, rc = X86EMUL_OKAY; struct operand src, dst; @@ -882,8 +886,10 @@ x86_emulate( lock_prefix = 1; break; case 0xf2: /* REPNE/REPNZ */ + rep_prefix = REPNE_PREFIX; + break; case 0xf3: /* REP/REPE/REPZ */ - rep_prefix = 1; + rep_prefix = REPE_PREFIX; break; case 0x40 ... 0x4f: /* REX */ if ( !mode_64bit() ) @@ -2161,6 +2167,27 @@ x86_emulate( _regs.edi, (_regs.eflags & EFLG_DF) ? -dst.bytes : dst.bytes); break; + case 0xa6 ... 0xa7: /* cmps */ { + unsigned long next_eip = _regs.eip; + handle_rep_prefix(); + src.bytes = dst.bytes = (d & ByteOp) ? 1 : op_bytes; + if ( (rc = ops->read(ea.mem.seg, truncate_ea(_regs.esi), + &dst.val, dst.bytes, ctxt)) || + (rc = ops->read(x86_seg_es, truncate_ea(_regs.edi), + &src.val, src.bytes, ctxt)) ) + goto done; + register_address_increment( + _regs.esi, (_regs.eflags & EFLG_DF) ? -dst.bytes : dst.bytes); + register_address_increment( + _regs.edi, (_regs.eflags & EFLG_DF) ? -src.bytes : src.bytes); + /* cmp: dst - src ==> src=*%%edi,dst=*%%esi ==> *%%esi - *%%edi */ + emulate_2op_SrcV("cmp", src, dst, _regs.eflags); + if ( ((rep_prefix == REPE_PREFIX) && !(_regs.eflags & EFLG_ZF)) || + ((rep_prefix == REPNE_PREFIX) && (_regs.eflags & EFLG_ZF)) ) + _regs.eip = next_eip; + break; + } + case 0xaa ... 0xab: /* stos */ handle_rep_prefix(); dst.type = OP_MEM; @@ -2184,6 +2211,24 @@ x86_emulate( _regs.esi, (_regs.eflags & EFLG_DF) ? -dst.bytes : dst.bytes); break; + case 0xae ... 0xaf: /* scas */ { + unsigned long next_eip = _regs.eip; + handle_rep_prefix(); + src.bytes = dst.bytes = (d & ByteOp) ? 1 : op_bytes; + dst.val = _regs.eax; + if ( (rc = ops->read(x86_seg_es, truncate_ea(_regs.edi), + &src.val, src.bytes, ctxt)) != 0 ) + goto done; + register_address_increment( + _regs.edi, (_regs.eflags & EFLG_DF) ? -src.bytes : src.bytes); + /* cmp: dst - src ==> src=*%%edi,dst=%%eax ==> %%eax - *%%edi */ + emulate_2op_SrcV("cmp", src, dst, _regs.eflags); + if ( ((rep_prefix == REPE_PREFIX) && !(_regs.eflags & EFLG_ZF)) || + ((rep_prefix == REPNE_PREFIX) && (_regs.eflags & EFLG_ZF)) ) + _regs.eip = next_eip; + break; + } + case 0xc2: /* ret imm16 (near) */ case 0xc3: /* ret (near) */ { int offset = (b == 0xc2) ? insn_fetch_type(uint16_t) : 0; |