[PATCH 0/4] Emulator INTn and SCAS fixes

[PATCH 0/4] Emulator INTn and SCAS fixes

[Avi Kivity]

The following patchset makes INTn work and implements SCAS (used by vgabios).
With the patchset, vgabios is able to display its splash screen but gets
confused shortly afterwards.

Based on the non-atomic-injection branch.

Avi Kivity (4):
  KVM: Initialize operand and address sizes before emulating interrupts
  KVM: x86 emulator: fix INTn emulation not pushing EFLAGS and CS
  KVM: x86 emulator: implement SCAS (opcodes AE, AF)
  KVM: x86 emulator: fix REPZ/REPNZ termination condition

 arch/x86/kvm/emulate.c |   60 +++++++++++++++++++++++++++++------------------
 arch/x86/kvm/x86.c     |    2 +
 2 files changed, 39 insertions(+), 23 deletions(-)

[PATCH 1/4] KVM: Initialize operand and address sizes before emulating interrupts

[Avi Kivity]

The emulator needs the operand and address sizes to be valid.

Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/kvm/x86.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6a77fa1..f6a31a1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3965,6 +3965,8 @@ int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq)
 
 	init_emulate_ctxt(vcpu);
 
+	vcpu->arch.emulate_ctxt.decode.op_bytes = 2;
+	vcpu->arch.emulate_ctxt.decode.ad_bytes = 2;
 	ret = emulate_int_real(&vcpu->arch.emulate_ctxt, &emulate_ops, irq);
 
 	if (ret != X86EMUL_CONTINUE)
-- 
1.7.1

[PATCH 2/4] KVM: x86 emulator: fix INTn emulation not pushing EFLAGS and CS

[Avi Kivity]

emulate_push() only schedules a push; it doesn't actually push anything.
Call writeback() to flush out the write.

Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/kvm/emulate.c |   13 ++++++++++++-
 1 files changed, 12 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index f1ec023..0e8f25e 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1228,7 +1228,7 @@ int emulate_int_real(struct x86_emulate_ctxt *ctxt,
 			       struct x86_emulate_ops *ops, int irq)
 {
 	struct decode_cache *c = &ctxt->decode;
-	int rc = X86EMUL_CONTINUE;
+	int rc;
 	struct desc_ptr dt;
 	gva_t cs_addr;
 	gva_t eip_addr;
@@ -1238,14 +1238,25 @@ int emulate_int_real(struct x86_emulate_ctxt *ctxt,
 	/* TODO: Add limit checks */
 	c->src.val = ctxt->eflags;
 	emulate_push(ctxt, ops);
+	rc = writeback(ctxt, ops);
+	if (rc != X86EMUL_CONTINUE)
+		return rc;
 
 	ctxt->eflags &= ~(EFLG_IF | EFLG_TF | EFLG_AC);
 
 	c->src.val = ops->get_segment_selector(VCPU_SREG_CS, ctxt->vcpu);
 	emulate_push(ctxt, ops);
+	rc = writeback(ctxt, ops);
+	if (rc != X86EMUL_CONTINUE)
+		return rc;
 
 	c->src.val = c->eip;
 	emulate_push(ctxt, ops);
+	rc = writeback(ctxt, ops);
+	if (rc != X86EMUL_CONTINUE)
+		return rc;
+
+	c->dst.type = OP_NONE;
 
 	ops->get_idt(&dt, ctxt->vcpu);
 
-- 
1.7.1

[PATCH 3/4] KVM: x86 emulator: implement SCAS (opcodes AE, AF)

[Avi Kivity]

Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/kvm/emulate.c |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 0e8f25e..0c0ada9 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2308,7 +2308,7 @@ static struct opcode opcode_table[256] = {
 	D(DstAcc | SrcImmByte | ByteOp), D(DstAcc | SrcImm),
 	D(ByteOp | SrcAcc | DstDI | Mov | String), D(SrcAcc | DstDI | Mov | String),
 	D(ByteOp | SrcSI | DstAcc | Mov | String), D(SrcSI | DstAcc | Mov | String),
-	D(ByteOp | DstDI | String), D(DstDI | String),
+	D(ByteOp | SrcAcc | DstDI | String), D(SrcAcc | DstDI | String),
 	/* 0xB0 - 0xB7 */
 	X8(D(ByteOp | DstReg | SrcImm | Mov)),
 	/* 0xB8 - 0xBF */
@@ -3068,8 +3068,7 @@ special_insn:
 	case 0xac ... 0xad:	/* lods */
 		goto mov;
 	case 0xae ... 0xaf:	/* scas */
-		DPRINTF("Urk! I don't handle SCAS.\n");
-		goto cannot_emulate;
+		goto cmp;
 	case 0xb0 ... 0xbf: /* mov r, imm */
 		goto mov;
 	case 0xc0 ... 0xc1:
-- 
1.7.1

[PATCH 4/4] KVM: x86 emulator: fix REPZ/REPNZ termination condition

[Avi Kivity]

EFLAGS.ZF needs to be checked after each iteration, not before.

Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/kvm/emulate.c |   42 +++++++++++++++++++++++-------------------
 1 files changed, 23 insertions(+), 19 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 0c0ada9..a2edfb1 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2747,6 +2747,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
 	int rc = X86EMUL_CONTINUE;
 	int saved_dst_type = c->dst.type;
 	int irq; /* Used for int 3, int, and into */
+	ulong old_eip;
 
 	ctxt->decode.mem_read.pos = 0;
 
@@ -2771,28 +2772,10 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
 		ctxt->restart = true;
 		/* All REP prefixes have the same first termination condition */
 		if (address_mask(c, c->regs[VCPU_REGS_RCX]) == 0) {
-		string_done:
 			ctxt->restart = false;
 			ctxt->eip = c->eip;
 			goto done;
 		}
-		/* The second termination condition only applies for REPE
-		 * and REPNE. Test if the repeat string operation prefix is
-		 * REPE/REPZ or REPNE/REPNZ and if it's the case it tests the
-		 * corresponding termination condition according to:
-		 * 	- if REPE/REPZ and ZF = 0 then done
-		 * 	- if REPNE/REPNZ and ZF = 1 then done
-		 */
-		if ((c->b == 0xa6) || (c->b == 0xa7) ||
-		    (c->b == 0xae) || (c->b == 0xaf)) {
-			if ((c->rep_prefix == REPE_PREFIX) &&
-			    ((ctxt->eflags & EFLG_ZF) == 0))
-				goto string_done;
-			if ((c->rep_prefix == REPNE_PREFIX) &&
-			    ((ctxt->eflags & EFLG_ZF) == EFLG_ZF))
-				goto string_done;
-		}
-		c->eip = ctxt->eip;
 	}
 
 	if (c->src.type == OP_MEM) {
@@ -3229,6 +3212,7 @@ special_insn:
 	}
 
 writeback:
+	old_eip = c->eip;
 	rc = writeback(ctxt, ops);
 	if (rc != X86EMUL_CONTINUE)
 		goto done;
@@ -3250,13 +3234,33 @@ writeback:
 	if (c->rep_prefix && (c->d & String)) {
 		struct read_cache *rc = &ctxt->decode.io_read;
 		register_address_increment(c, &c->regs[VCPU_REGS_RCX], -1);
+		/* The second termination condition only applies for REPE
+		 * and REPNE. Test if the repeat string operation prefix is
+		 * REPE/REPZ or REPNE/REPNZ and if it's the case it tests the
+		 * corresponding termination condition according to:
+		 * 	- if REPE/REPZ and ZF = 0 then done
+		 * 	- if REPNE/REPNZ and ZF = 1 then done
+		 */
+		if ((c->b == 0xa6) || (c->b == 0xa7) ||
+		    (c->b == 0xae) || (c->b == 0xaf)) {
+			trace_printk("c->eip %lx ctxt->eip %lx\n",
+				     c->eip, ctxt->eip);
+			if (((c->rep_prefix == REPE_PREFIX) &&
+			     ((ctxt->eflags & EFLG_ZF) == 0))
+			    || ((c->rep_prefix == REPNE_PREFIX) &&
+				((ctxt->eflags & EFLG_ZF) == EFLG_ZF))) {
+				ctxt->restart = false;
+			}
+		}
 		/*
 		 * Re-enter guest when pio read ahead buffer is empty or,
 		 * if it is not used, after each 1024 iteration.
 		 */
 		if ((rc->end == 0 && !(c->regs[VCPU_REGS_RCX] & 0x3ff)) ||
-		    (rc->end != 0 && rc->end == rc->pos))
+		    (rc->end != 0 && rc->end == rc->pos)) {
 			ctxt->restart = false;
+			c->eip = ctxt->eip;
+		}
 	}
 	/*
 	 * reset read cache here in case string instruction is restared
-- 
1.7.1

Re: [PATCH 4/4] KVM: x86 emulator: fix REPZ/REPNZ termination condition

[Gleb Natapov]

On Tue, Aug 17, 2010 at 11:26:43AM +0300, Avi Kivity wrote:
> EFLAGS.ZF needs to be checked after each iteration, not before.
> 
> Signed-off-by: Avi Kivity <avi@redhat.com>
> ---
>  arch/x86/kvm/emulate.c |   42 +++++++++++++++++++++++-------------------
>  1 files changed, 23 insertions(+), 19 deletions(-)
> 
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index 0c0ada9..a2edfb1 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -2747,6 +2747,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
>  	int rc = X86EMUL_CONTINUE;
>  	int saved_dst_type = c->dst.type;
>  	int irq; /* Used for int 3, int, and into */
> +	ulong old_eip;
Is never used.

>  
>  	ctxt->decode.mem_read.pos = 0;
>  
> @@ -2771,28 +2772,10 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
>  		ctxt->restart = true;
>  		/* All REP prefixes have the same first termination condition */
>  		if (address_mask(c, c->regs[VCPU_REGS_RCX]) == 0) {
> -		string_done:
>  			ctxt->restart = false;
>  			ctxt->eip = c->eip;
>  			goto done;
>  		}
> -		/* The second termination condition only applies for REPE
> -		 * and REPNE. Test if the repeat string operation prefix is
> -		 * REPE/REPZ or REPNE/REPNZ and if it's the case it tests the
> -		 * corresponding termination condition according to:
> -		 * 	- if REPE/REPZ and ZF = 0 then done
> -		 * 	- if REPNE/REPNZ and ZF = 1 then done
> -		 */
> -		if ((c->b == 0xa6) || (c->b == 0xa7) ||
> -		    (c->b == 0xae) || (c->b == 0xaf)) {
> -			if ((c->rep_prefix == REPE_PREFIX) &&
> -			    ((ctxt->eflags & EFLG_ZF) == 0))
> -				goto string_done;
> -			if ((c->rep_prefix == REPNE_PREFIX) &&
> -			    ((ctxt->eflags & EFLG_ZF) == EFLG_ZF))
> -				goto string_done;
> -		}
> -		c->eip = ctxt->eip;
>  	}
>  
>  	if (c->src.type == OP_MEM) {
> @@ -3229,6 +3212,7 @@ special_insn:
>  	}
>  
>  writeback:
> +	old_eip = c->eip;
>  	rc = writeback(ctxt, ops);
>  	if (rc != X86EMUL_CONTINUE)
>  		goto done;
> @@ -3250,13 +3234,33 @@ writeback:
>  	if (c->rep_prefix && (c->d & String)) {
>  		struct read_cache *rc = &ctxt->decode.io_read;
>  		register_address_increment(c, &c->regs[VCPU_REGS_RCX], -1);
> +		/* The second termination condition only applies for REPE
> +		 * and REPNE. Test if the repeat string operation prefix is
> +		 * REPE/REPZ or REPNE/REPNZ and if it's the case it tests the
> +		 * corresponding termination condition according to:
> +		 * 	- if REPE/REPZ and ZF = 0 then done
> +		 * 	- if REPNE/REPNZ and ZF = 1 then done
> +		 */
> +		if ((c->b == 0xa6) || (c->b == 0xa7) ||
> +		    (c->b == 0xae) || (c->b == 0xaf)) {
> +			trace_printk("c->eip %lx ctxt->eip %lx\n",
> +				     c->eip, ctxt->eip);
> +			if (((c->rep_prefix == REPE_PREFIX) &&
> +			     ((ctxt->eflags & EFLG_ZF) == 0))
> +			    || ((c->rep_prefix == REPNE_PREFIX) &&
> +				((ctxt->eflags & EFLG_ZF) == EFLG_ZF))) {
> +				ctxt->restart = false;
Why not jump to string_done label here?

> +			}
> +		}
>  		/*
>  		 * Re-enter guest when pio read ahead buffer is empty or,
>  		 * if it is not used, after each 1024 iteration.
>  		 */
>  		if ((rc->end == 0 && !(c->regs[VCPU_REGS_RCX] & 0x3ff)) ||
> -		    (rc->end != 0 && rc->end == rc->pos))
> +		    (rc->end != 0 && rc->end == rc->pos)) {
>  			ctxt->restart = false;
> +			c->eip = ctxt->eip;
We can get here when instruction is completed by above "if", so same
instruction will reexecute once again.


> +		}
>  	}
>  	/*
>  	 * reset read cache here in case string instruction is restared
> -- 
> 1.7.1
> 
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

--
			Gleb.

Re: [PATCH 4/4] KVM: x86 emulator: fix REPZ/REPNZ termination condition

[Avi Kivity]

  On 08/17/2010 12:13 PM, Gleb Natapov wrote:
> On Tue, Aug 17, 2010 at 11:26:43AM +0300, Avi Kivity wrote:
>> EFLAGS.ZF needs to be checked after each iteration, not before.
>>
>> Signed-off-by: Avi Kivity<avi@redhat.com>
>> ---
>>   arch/x86/kvm/emulate.c |   42 +++++++++++++++++++++++-------------------
>>   1 files changed, 23 insertions(+), 19 deletions(-)
>>
>> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
>> index 0c0ada9..a2edfb1 100644
>> --- a/arch/x86/kvm/emulate.c
>> +++ b/arch/x86/kvm/emulate.c
>> @@ -2747,6 +2747,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
>>   	int rc = X86EMUL_CONTINUE;
>>   	int saved_dst_type = c->dst.type;
>>   	int irq; /* Used for int 3, int, and into */
>> +	ulong old_eip;
> Is never used.
>

Whoops.

>> @@ -3250,13 +3234,33 @@ writeback:
>>   	if (c->rep_prefix&&  (c->d&  String)) {
>>   		struct read_cache *rc =&ctxt->decode.io_read;
>>   		register_address_increment(c,&c->regs[VCPU_REGS_RCX], -1);
>> +		/* The second termination condition only applies for REPE
>> +		 * and REPNE. Test if the repeat string operation prefix is
>> +		 * REPE/REPZ or REPNE/REPNZ and if it's the case it tests the
>> +		 * corresponding termination condition according to:
>> +		 * 	- if REPE/REPZ and ZF = 0 then done
>> +		 * 	- if REPNE/REPNZ and ZF = 1 then done
>> +		 */
>> +		if ((c->b == 0xa6) || (c->b == 0xa7) ||
>> +		    (c->b == 0xae) || (c->b == 0xaf)) {
>> +			trace_printk("c->eip %lx ctxt->eip %lx\n",
>> +				     c->eip, ctxt->eip);
>> +			if (((c->rep_prefix == REPE_PREFIX)&&
>> +			     ((ctxt->eflags&  EFLG_ZF) == 0))
>> +			    || ((c->rep_prefix == REPNE_PREFIX)&&
>> +				((ctxt->eflags&  EFLG_ZF) == EFLG_ZF))) {
>> +				ctxt->restart = false;
> Why not jump to string_done label here?

It does a 'goto done;' which skips a couple of things.

>> +			}
>> +		}
>>   		/*
>>   		 * Re-enter guest when pio read ahead buffer is empty or,
>>   		 * if it is not used, after each 1024 iteration.
>>   		 */
>>   		if ((rc->end == 0&&  !(c->regs[VCPU_REGS_RCX]&  0x3ff)) ||
>> -		    (rc->end != 0&&  rc->end == rc->pos))
>> +		    (rc->end != 0&&  rc->end == rc->pos)) {
>>   			ctxt->restart = false;
>> +			c->eip = ctxt->eip;
> We can get here when instruction is completed by above "if", so same
> instruction will reexecute once again.

Not good.  Will redo (and write tests).


-- 
error compiling committee.c: too many arguments to function

Re: [PATCH 4/4] KVM: x86 emulator: fix REPZ/REPNZ termination condition

[Gleb Natapov]

On Tue, Aug 17, 2010 at 12:20:34PM +0300, Avi Kivity wrote:
>  On 08/17/2010 12:13 PM, Gleb Natapov wrote:
> >On Tue, Aug 17, 2010 at 11:26:43AM +0300, Avi Kivity wrote:
> >>EFLAGS.ZF needs to be checked after each iteration, not before.
> >>
> >>Signed-off-by: Avi Kivity<avi@redhat.com>
> >>---
> >>  arch/x86/kvm/emulate.c |   42 +++++++++++++++++++++++-------------------
> >>  1 files changed, 23 insertions(+), 19 deletions(-)
> >>
> >>diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> >>index 0c0ada9..a2edfb1 100644
> >>--- a/arch/x86/kvm/emulate.c
> >>+++ b/arch/x86/kvm/emulate.c
> >>@@ -2747,6 +2747,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
> >>  	int rc = X86EMUL_CONTINUE;
> >>  	int saved_dst_type = c->dst.type;
> >>  	int irq; /* Used for int 3, int, and into */
> >>+	ulong old_eip;
> >Is never used.
> >
> 
> Whoops.
> 
> >>@@ -3250,13 +3234,33 @@ writeback:
> >>  	if (c->rep_prefix&&  (c->d&  String)) {
> >>  		struct read_cache *rc =&ctxt->decode.io_read;
> >>  		register_address_increment(c,&c->regs[VCPU_REGS_RCX], -1);
> >>+		/* The second termination condition only applies for REPE
> >>+		 * and REPNE. Test if the repeat string operation prefix is
> >>+		 * REPE/REPZ or REPNE/REPNZ and if it's the case it tests the
> >>+		 * corresponding termination condition according to:
> >>+		 * 	- if REPE/REPZ and ZF = 0 then done
> >>+		 * 	- if REPNE/REPNZ and ZF = 1 then done
> >>+		 */
> >>+		if ((c->b == 0xa6) || (c->b == 0xa7) ||
> >>+		    (c->b == 0xae) || (c->b == 0xaf)) {
> >>+			trace_printk("c->eip %lx ctxt->eip %lx\n",
> >>+				     c->eip, ctxt->eip);
> >>+			if (((c->rep_prefix == REPE_PREFIX)&&
> >>+			     ((ctxt->eflags&  EFLG_ZF) == 0))
> >>+			    || ((c->rep_prefix == REPNE_PREFIX)&&
> >>+				((ctxt->eflags&  EFLG_ZF) == EFLG_ZF))) {
> >>+				ctxt->restart = false;
> >Why not jump to string_done label here?
> 
> It does a 'goto done;' which skips a couple of things.
> 
The only thing it skips is:
ctxt->decode.mem_read.end = 0;
as far as I can see. And this is ok if instruction is completed.

> >>+			}
> >>+		}
> >>  		/*
> >>  		 * Re-enter guest when pio read ahead buffer is empty or,
> >>  		 * if it is not used, after each 1024 iteration.
> >>  		 */
> >>  		if ((rc->end == 0&&  !(c->regs[VCPU_REGS_RCX]&  0x3ff)) ||
> >>-		    (rc->end != 0&&  rc->end == rc->pos))
> >>+		    (rc->end != 0&&  rc->end == rc->pos)) {
> >>  			ctxt->restart = false;
> >>+			c->eip = ctxt->eip;
> >We can get here when instruction is completed by above "if", so same
> >instruction will reexecute once again.
> 
> Not good.  Will redo (and write tests).
> 
> 
> -- 
> error compiling committee.c: too many arguments to function

--
			Gleb.

Re: [PATCH 4/4] KVM: x86 emulator: fix REPZ/REPNZ termination condition

[Avi Kivity]

  On 08/17/2010 12:27 PM, Gleb Natapov wrote:
> On Tue, Aug 17, 2010 at 12:20:34PM +0300, Avi Kivity wrote:
>>   On 08/17/2010 12:13 PM, Gleb Natapov wrote:
>>> On Tue, Aug 17, 2010 at 11:26:43AM +0300, Avi Kivity wrote:
>>>> EFLAGS.ZF needs to be checked after each iteration, not before.
>>>>
>>>> Signed-off-by: Avi Kivity<avi@redhat.com>
>>>> ---
>>>>   arch/x86/kvm/emulate.c |   42 +++++++++++++++++++++++-------------------
>>>>   1 files changed, 23 insertions(+), 19 deletions(-)
>>>>
>>>> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
>>>> index 0c0ada9..a2edfb1 100644
>>>> --- a/arch/x86/kvm/emulate.c
>>>> +++ b/arch/x86/kvm/emulate.c
>>>> @@ -2747,6 +2747,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
>>>>   	int rc = X86EMUL_CONTINUE;
>>>>   	int saved_dst_type = c->dst.type;
>>>>   	int irq; /* Used for int 3, int, and into */
>>>> +	ulong old_eip;
>>> Is never used.
>>>
>> Whoops.
>>
>>>> @@ -3250,13 +3234,33 @@ writeback:
>>>>   	if (c->rep_prefix&&   (c->d&   String)) {
>>>>   		struct read_cache *rc =&ctxt->decode.io_read;
>>>>   		register_address_increment(c,&c->regs[VCPU_REGS_RCX], -1);
>>>> +		/* The second termination condition only applies for REPE
>>>> +		 * and REPNE. Test if the repeat string operation prefix is
>>>> +		 * REPE/REPZ or REPNE/REPNZ and if it's the case it tests the
>>>> +		 * corresponding termination condition according to:
>>>> +		 * 	- if REPE/REPZ and ZF = 0 then done
>>>> +		 * 	- if REPNE/REPNZ and ZF = 1 then done
>>>> +		 */
>>>> +		if ((c->b == 0xa6) || (c->b == 0xa7) ||
>>>> +		    (c->b == 0xae) || (c->b == 0xaf)) {
>>>> +			trace_printk("c->eip %lx ctxt->eip %lx\n",
>>>> +				     c->eip, ctxt->eip);
>>>> +			if (((c->rep_prefix == REPE_PREFIX)&&
>>>> +			     ((ctxt->eflags&   EFLG_ZF) == 0))
>>>> +			    || ((c->rep_prefix == REPNE_PREFIX)&&
>>>> +				((ctxt->eflags&   EFLG_ZF) == EFLG_ZF))) {
>>>> +				ctxt->restart = false;
>>> Why not jump to string_done label here?
>> It does a 'goto done;' which skips a couple of things.
>>
> The only thing it skips is:
> ctxt->decode.mem_read.end = 0;
> as far as I can see. And this is ok if instruction is completed.

I'd like to avoid this interdependency (and there are enough gotos in 
the emulator already).


-- 
error compiling committee.c: too many arguments to function