KVM: x86 emulator: implement DAS (opcode 2F)
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 81b0f88..83ded7c 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2175,6 +2175,45 @@
return X86EMUL_CONTINUE;
}
+static int em_das(struct x86_emulate_ctxt *ctxt)
+{
+ struct decode_cache *c = &ctxt->decode;
+ u8 al, old_al;
+ bool af, cf, old_cf;
+
+ cf = ctxt->eflags & X86_EFLAGS_CF;
+ al = c->dst.val;
+
+ old_al = al;
+ old_cf = cf;
+ cf = false;
+ af = ctxt->eflags & X86_EFLAGS_AF;
+ if ((al & 0x0f) > 9 || af) {
+ al -= 6;
+ cf = old_cf | (al >= 250);
+ af = true;
+ } else {
+ af = false;
+ }
+ if (old_al > 0x99 || old_cf) {
+ al -= 0x60;
+ cf = true;
+ }
+
+ c->dst.val = al;
+ /* Set PF, ZF, SF */
+ c->src.type = OP_IMM;
+ c->src.val = 0;
+ c->src.bytes = 1;
+ emulate_2op_SrcV("or", c->src, c->dst, ctxt->eflags);
+ ctxt->eflags &= ~(X86_EFLAGS_AF | X86_EFLAGS_CF);
+ if (cf)
+ ctxt->eflags |= X86_EFLAGS_CF;
+ if (af)
+ ctxt->eflags |= X86_EFLAGS_AF;
+ return X86EMUL_CONTINUE;
+}
+
#define D(_y) { .flags = (_y) }
#define N D(0)
#define G(_f, _g) { .flags = ((_f) | Group), .u.group = (_g) }
@@ -2258,7 +2297,8 @@
/* 0x28 - 0x2F */
D(ByteOp | DstMem | SrcReg | ModRM | Lock), D(DstMem | SrcReg | ModRM | Lock),
D(ByteOp | DstReg | SrcMem | ModRM), D(DstReg | SrcMem | ModRM),
- D(ByteOp | DstAcc | SrcImmByte), D(DstAcc | SrcImm), N, N,
+ D(ByteOp | DstAcc | SrcImmByte), D(DstAcc | SrcImm),
+ N, I(ByteOp | DstAcc | No64, em_das),
/* 0x30 - 0x37 */
D(ByteOp | DstMem | SrcReg | ModRM | Lock), D(DstMem | SrcReg | ModRM | Lock),
D(ByteOp | DstReg | SrcMem | ModRM), D(DstReg | SrcMem | ModRM),