Commit d9574a25 authored by Wei Yongjun's avatar Wei Yongjun Committed by Avi Kivity
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KVM: x86 emulator: add bsf/bsr instruction emulation 



Add bsf/bsr instruction emulation (opcode 0x0f 0xbc~0xbd)

Signed-off-by: default avatarWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 8c5eee30

arch/x86/kvm/emulate.c

+26 −2
Original line number Diff line number Diff line
@@ -2379,8 +2379,8 @@ static struct opcode twobyte_table[256] = { 
	/* 0xB8 - 0xBF */

	N, N,

	G(BitOp, group8), D(DstMem | SrcReg | ModRM | BitOp | Lock),

	N, N, D(ByteOp | DstReg | SrcMem | ModRM | Mov),

	    D(DstReg | SrcMem16 | ModRM | Mov),

	D(DstReg | SrcMem | ModRM), D(DstReg | SrcMem | ModRM),

	D(ByteOp | DstReg | SrcMem | ModRM | Mov), D(DstReg | SrcMem16 | ModRM | Mov),

	/* 0xC0 - 0xCF */

	N, N, N, D(DstMem | SrcReg | ModRM | Mov),

	N, N, N, GD(0, &group9),
@@ -3511,6 +3511,30 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt) 
	      btc:		/* btc */

		emulate_2op_SrcV_nobyte("btc", c->src, c->dst, ctxt->eflags);

		break;

	case 0xbc: {		/* bsf */

		u8 zf;

		__asm__ ("bsf %2, %0; setz %1"

			 : "=r"(c->dst.val), "=q"(zf)

			 : "r"(c->src.val));

		ctxt->eflags &= ~X86_EFLAGS_ZF;

		if (zf) {

			ctxt->eflags |= X86_EFLAGS_ZF;

			c->dst.type = OP_NONE;	/* Disable writeback. */

		}

		break;

	}

	case 0xbd: {		/* bsr */

		u8 zf;

		__asm__ ("bsr %2, %0; setz %1"

			 : "=r"(c->dst.val), "=q"(zf)

			 : "r"(c->src.val));

		ctxt->eflags &= ~X86_EFLAGS_ZF;

		if (zf) {

			ctxt->eflags |= X86_EFLAGS_ZF;

			c->dst.type = OP_NONE;	/* Disable writeback. */

		}

		break;

	}

	case 0xbe ... 0xbf:	/* movsx */

		c->dst.bytes = c->op_bytes;

		c->dst.val = (c->d & ByteOp) ? (s8) c->src.val :