+static void decode_register_operand(struct operand *op,
+ struct decode_cache *c,
+ int inhibit_bytereg)
+{
+ unsigned reg = c->modrm_reg;
+ int highbyte_regs = c->rex_prefix == 0;
+
+ if (!(c->d & ModRM))
+ reg = (c->b & 7) | ((c->rex_prefix & 1) << 3);
+ op->type = OP_REG;
+ if ((c->d & ByteOp) && !inhibit_bytereg) {
+ op->ptr = decode_register(reg, c->regs, highbyte_regs);
+ op->val = *(u8 *)op->ptr;
+ op->bytes = 1;
+ } else {
+ op->ptr = decode_register(reg, c->regs, 0);
+ op->bytes = c->op_bytes;
+ switch (op->bytes) {
+ case 2:
+ op->val = *(u16 *)op->ptr;
+ break;
+ case 4:
+ op->val = *(u32 *)op->ptr;
+ break;
+ case 8:
+ op->val = *(u64 *) op->ptr;
+ break;
+ }
+ }
+ op->orig_val = op->val;
+}
+
+static int decode_modrm(struct x86_emulate_ctxt *ctxt,
+ struct x86_emulate_ops *ops)
+{
+ struct decode_cache *c = &ctxt->decode;
+ u8 sib;
+ int index_reg = 0, base_reg = 0, scale, rip_relative = 0;
+ int rc = 0;
+
+ if (c->rex_prefix) {
+ c->modrm_reg = (c->rex_prefix & 4) << 1; /* REX.R */
+ index_reg = (c->rex_prefix & 2) << 2; /* REX.X */
+ c->modrm_rm = base_reg = (c->rex_prefix & 1) << 3; /* REG.B */
+ }
+
+ c->modrm = insn_fetch(u8, 1, c->eip);
+ c->modrm_mod |= (c->modrm & 0xc0) >> 6;
+ c->modrm_reg |= (c->modrm & 0x38) >> 3;
+ c->modrm_rm |= (c->modrm & 0x07);
+ c->modrm_ea = 0;
+ c->use_modrm_ea = 1;
+
+ if (c->modrm_mod == 3) {
+ c->modrm_val = *(unsigned long *)
+ decode_register(c->modrm_rm, c->regs, c->d & ByteOp);
+ return rc;
+ }
+
+ if (c->ad_bytes == 2) {
+ unsigned bx = c->regs[VCPU_REGS_RBX];
+ unsigned bp = c->regs[VCPU_REGS_RBP];
+ unsigned si = c->regs[VCPU_REGS_RSI];
+ unsigned di = c->regs[VCPU_REGS_RDI];
+
+ /* 16-bit ModR/M decode. */
+ switch (c->modrm_mod) {
+ case 0:
+ if (c->modrm_rm == 6)
+ c->modrm_ea += insn_fetch(u16, 2, c->eip);
+ break;
+ case 1:
+ c->modrm_ea += insn_fetch(s8, 1, c->eip);
+ break;
+ case 2:
+ c->modrm_ea += insn_fetch(u16, 2, c->eip);
+ break;
+ }
+ switch (c->modrm_rm) {
+ case 0:
+ c->modrm_ea += bx + si;
+ break;
+ case 1:
+ c->modrm_ea += bx + di;
+ break;
+ case 2:
+ c->modrm_ea += bp + si;
+ break;
+ case 3:
+ c->modrm_ea += bp + di;
+ break;
+ case 4:
+ c->modrm_ea += si;
+ break;
+ case 5:
+ c->modrm_ea += di;
+ break;
+ case 6:
+ if (c->modrm_mod != 0)
+ c->modrm_ea += bp;
+ break;
+ case 7:
+ c->modrm_ea += bx;
+ break;
+ }
+ if (c->modrm_rm == 2 || c->modrm_rm == 3 ||
+ (c->modrm_rm == 6 && c->modrm_mod != 0))
+ if (!c->override_base)
+ c->override_base = &ctxt->ss_base;
+ c->modrm_ea = (u16)c->modrm_ea;
+ } else {
+ /* 32/64-bit ModR/M decode. */
+ switch (c->modrm_rm) {
+ case 4:
+ case 12:
+ sib = insn_fetch(u8, 1, c->eip);
+ index_reg |= (sib >> 3) & 7;
+ base_reg |= sib & 7;
+ scale = sib >> 6;
+
+ switch (base_reg) {
+ case 5:
+ if (c->modrm_mod != 0)
+ c->modrm_ea += c->regs[base_reg];
+ else
+ c->modrm_ea +=
+ insn_fetch(s32, 4, c->eip);
+ break;
+ default:
+ c->modrm_ea += c->regs[base_reg];
+ }
+ switch (index_reg) {
+ case 4:
+ break;
+ default:
+ c->modrm_ea += c->regs[index_reg] << scale;
+ }
+ break;
+ case 5:
+ if (c->modrm_mod != 0)
+ c->modrm_ea += c->regs[c->modrm_rm];
+ else if (ctxt->mode == X86EMUL_MODE_PROT64)
+ rip_relative = 1;
+ break;
+ default:
+ c->modrm_ea += c->regs[c->modrm_rm];
+ break;
+ }
+ switch (c->modrm_mod) {
+ case 0:
+ if (c->modrm_rm == 5)
+ c->modrm_ea += insn_fetch(s32, 4, c->eip);
+ break;
+ case 1:
+ c->modrm_ea += insn_fetch(s8, 1, c->eip);
+ break;
+ case 2:
+ c->modrm_ea += insn_fetch(s32, 4, c->eip);
+ break;
+ }
+ }
+ if (rip_relative) {
+ c->modrm_ea += c->eip;
+ switch (c->d & SrcMask) {
+ case SrcImmByte:
+ c->modrm_ea += 1;
+ break;
+ case SrcImm:
+ if (c->d & ByteOp)
+ c->modrm_ea += 1;
+ else
+ if (c->op_bytes == 8)
+ c->modrm_ea += 4;
+ else
+ c->modrm_ea += c->op_bytes;
+ }
+ }
+done:
+ return rc;
+}
+
+static int decode_abs(struct x86_emulate_ctxt *ctxt,
+ struct x86_emulate_ops *ops)
+{
+ struct decode_cache *c = &ctxt->decode;
+ int rc = 0;
+
+ switch (c->ad_bytes) {
+ case 2:
+ c->modrm_ea = insn_fetch(u16, 2, c->eip);
+ break;
+ case 4:
+ c->modrm_ea = insn_fetch(u32, 4, c->eip);
+ break;
+ case 8:
+ c->modrm_ea = insn_fetch(u64, 8, c->eip);
+ break;
+ }
+done:
+ return rc;
+}
+