[PATCH] target/i386: correctly mask SSE4a bit indices in register operands

[PATCH] target/i386: correctly mask SSE4a bit indices in register operands

[Paolo Bonzini]

SSE4a instructions EXTRQ and INSERTQ have two bit index operands, that can be
immediates or taken from an XMM register.  In both cases, the fields are
6-bit wide and the top two bits in the byte are ignored.  translate.c is
doing that correctly for the immediate case, but not for the XMM case, so
fix it.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/ops_sse.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/target/i386/ops_sse.h b/target/i386/ops_sse.h
index c0766de18d..3504bca36a 100644
--- a/target/i386/ops_sse.h
+++ b/target/i386/ops_sse.h
@@ -926,7 +926,7 @@ static inline uint64_t helper_extrq(uint64_t src, int shift, int len)
 
 void helper_extrq_r(CPUX86State *env, ZMMReg *d, ZMMReg *s)
 {
-    d->ZMM_Q(0) = helper_extrq(d->ZMM_Q(0), s->ZMM_B(1), s->ZMM_B(0));
+    d->ZMM_Q(0) = helper_extrq(d->ZMM_Q(0), s->ZMM_B(1) & 63, s->ZMM_B(0) & 63);
 }
 
 void helper_extrq_i(CPUX86State *env, ZMMReg *d, int index, int length)
@@ -948,7 +948,7 @@ static inline uint64_t helper_insertq(uint64_t src, int shift, int len)
 
 void helper_insertq_r(CPUX86State *env, ZMMReg *d, ZMMReg *s)
 {
-    d->ZMM_Q(0) = helper_insertq(s->ZMM_Q(0), s->ZMM_B(9), s->ZMM_B(8));
+    d->ZMM_Q(0) = helper_insertq(s->ZMM_Q(0), s->ZMM_B(9) & 63, s->ZMM_B(8) & 63);
 }
 
 void helper_insertq_i(CPUX86State *env, ZMMReg *d, int index, int length)
-- 
2.37.2

Re: [PATCH] target/i386: correctly mask SSE4a bit indices in register operands

[Richard Henderson]

On 9/18/22 09:18, Paolo Bonzini wrote:
> SSE4a instructions EXTRQ and INSERTQ have two bit index operands, that can be
> immediates or taken from an XMM register.  In both cases, the fields are
> 6-bit wide and the top two bits in the byte are ignored.  translate.c is
> doing that correctly for the immediate case, but not for the XMM case, so
> fix it.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>   target/i386/ops_sse.h | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

But these aren't SSE4a, they're AMD New Media instructions, which was a bit confusing.


r~