aboutsummaryrefslogtreecommitdiff
path: root/arch/x86
diff options
context:
space:
mode:
authorGuillaume Thouvenin <guillaume.thouvenin@ext.bull.net>2008-09-12 13:50:25 +0200
committerAvi Kivity <avi@qumranet.com>2008-10-15 10:16:14 +0200
commit9c9fddd0e784346a6d0ce82ed20d9ad21f3c8a2c (patch)
treec1bb4964cf454611ff2fafae8a57f464e78a1872 /arch/x86
parentdefed7ed926eca9f178a632df05baa866abe754e (diff)
KVM: x86 emulator: Add DstAcc operand type
Add DstAcc operand type. That means that there are 4 bits now for DstMask. "In the good old days cpus would have only one register that was able to fully participate in arithmetic operations, typically called A for Accumulator. The x86 retains this tradition by having special, shorter encodings for the A register (like the cmp opcode), and even some instructions that only operate on A (like mul). SrcAcc and DstAcc would accommodate these instructions by decoding A into the corresponding 'struct operand'." -- Avi Kivity Signed-off-by: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net> Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kvm/x86_emulate.c50
1 files changed, 34 insertions, 16 deletions
diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c
index 0c120c4c9c0..4390ec8c47a 100644
--- a/arch/x86/kvm/x86_emulate.c
+++ b/arch/x86/kvm/x86_emulate.c
@@ -47,25 +47,26 @@
#define ImplicitOps (1<<1) /* Implicit in opcode. No generic decode. */
#define DstReg (2<<1) /* Register operand. */
#define DstMem (3<<1) /* Memory operand. */
-#define DstMask (3<<1)
+#define DstAcc (4<<1) /* Destination Accumulator */
+#define DstMask (7<<1)
/* Source operand type. */
-#define SrcNone (0<<3) /* No source operand. */
-#define SrcImplicit (0<<3) /* Source operand is implicit in the opcode. */
-#define SrcReg (1<<3) /* Register operand. */
-#define SrcMem (2<<3) /* Memory operand. */
-#define SrcMem16 (3<<3) /* Memory operand (16-bit). */
-#define SrcMem32 (4<<3) /* Memory operand (32-bit). */
-#define SrcImm (5<<3) /* Immediate operand. */
-#define SrcImmByte (6<<3) /* 8-bit sign-extended immediate operand. */
-#define SrcMask (7<<3)
+#define SrcNone (0<<4) /* No source operand. */
+#define SrcImplicit (0<<4) /* Source operand is implicit in the opcode. */
+#define SrcReg (1<<4) /* Register operand. */
+#define SrcMem (2<<4) /* Memory operand. */
+#define SrcMem16 (3<<4) /* Memory operand (16-bit). */
+#define SrcMem32 (4<<4) /* Memory operand (32-bit). */
+#define SrcImm (5<<4) /* Immediate operand. */
+#define SrcImmByte (6<<4) /* 8-bit sign-extended immediate operand. */
+#define SrcMask (7<<4)
/* Generic ModRM decode. */
-#define ModRM (1<<6)
+#define ModRM (1<<7)
/* Destination is only written; never read. */
-#define Mov (1<<7)
-#define BitOp (1<<8)
-#define MemAbs (1<<9) /* Memory operand is absolute displacement */
-#define String (1<<10) /* String instruction (rep capable) */
-#define Stack (1<<11) /* Stack instruction (push/pop) */
+#define Mov (1<<8)
+#define BitOp (1<<9)
+#define MemAbs (1<<10) /* Memory operand is absolute displacement */
+#define String (1<<12) /* String instruction (rep capable) */
+#define Stack (1<<13) /* Stack instruction (push/pop) */
#define Group (1<<14) /* Bits 3:5 of modrm byte extend opcode */
#define GroupDual (1<<15) /* Alternate decoding of mod == 3 */
#define GroupMask 0xff /* Group number stored in bits 0:7 */
@@ -1060,6 +1061,23 @@ done_prefixes:
}
c->dst.type = OP_MEM;
break;
+ case DstAcc:
+ c->dst.type = OP_REG;
+ c->dst.bytes = c->op_bytes;
+ c->dst.ptr = &c->regs[VCPU_REGS_RAX];
+ switch (c->op_bytes) {
+ case 1:
+ c->dst.val = *(u8 *)c->dst.ptr;
+ break;
+ case 2:
+ c->dst.val = *(u16 *)c->dst.ptr;
+ break;
+ case 4:
+ c->dst.val = *(u32 *)c->dst.ptr;
+ break;
+ }
+ c->dst.orig_val = c->dst.val;
+ break;
}
if (c->rip_relative)