* [PATCH] target/i386: fix PHSUB* instructions with dest=src
@ 2022-08-25 15:48 Paolo Bonzini
2022-08-25 15:57 ` Richard Henderson
0 siblings, 1 reply; 2+ messages in thread
From: Paolo Bonzini @ 2022-08-25 15:48 UTC (permalink / raw)
To: qemu-devel
The computation must not overwrite neither the destination
nor the source before the last element has been computed.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
target/i386/ops_sse.h | 49 +++++++++++++++++++++++++------------------
1 file changed, 29 insertions(+), 20 deletions(-)
diff --git a/target/i386/ops_sse.h b/target/i386/ops_sse.h
index 535440f882..2524db4c25 100644
--- a/target/i386/ops_sse.h
+++ b/target/i386/ops_sse.h
@@ -1528,34 +1528,43 @@ void glue(helper_pmaddubsw, SUFFIX)(CPUX86State *env, Reg *d, Reg *s)
void glue(helper_phsubw, SUFFIX)(CPUX86State *env, Reg *d, Reg *s)
{
- d->W(0) = (int16_t)d->W(0) - (int16_t)d->W(1);
- d->W(1) = (int16_t)d->W(2) - (int16_t)d->W(3);
- XMM_ONLY(d->W(2) = (int16_t)d->W(4) - (int16_t)d->W(5));
- XMM_ONLY(d->W(3) = (int16_t)d->W(6) - (int16_t)d->W(7));
- d->W((2 << SHIFT) + 0) = (int16_t)s->W(0) - (int16_t)s->W(1);
- d->W((2 << SHIFT) + 1) = (int16_t)s->W(2) - (int16_t)s->W(3);
- XMM_ONLY(d->W(6) = (int16_t)s->W(4) - (int16_t)s->W(5));
- XMM_ONLY(d->W(7) = (int16_t)s->W(6) - (int16_t)s->W(7));
+ Reg r;
+
+ r.W(0) = (int16_t)d->W(0) - (int16_t)d->W(1);
+ r.W(1) = (int16_t)d->W(2) - (int16_t)d->W(3);
+ XMM_ONLY(r.W(2) = (int16_t)d->W(4) - (int16_t)d->W(5));
+ XMM_ONLY(r.W(3) = (int16_t)d->W(6) - (int16_t)d->W(7));
+ r.W((2 << SHIFT) + 0) = (int16_t)s->W(0) - (int16_t)s->W(1);
+ r.W((2 << SHIFT) + 1) = (int16_t)s->W(2) - (int16_t)s->W(3);
+ XMM_ONLY(r.W(6) = (int16_t)s->W(4) - (int16_t)s->W(5));
+ XMM_ONLY(r.W(7) = (int16_t)s->W(6) - (int16_t)s->W(7));
+ MOVE(*d, r);
}
void glue(helper_phsubd, SUFFIX)(CPUX86State *env, Reg *d, Reg *s)
{
- d->L(0) = (int32_t)d->L(0) - (int32_t)d->L(1);
- XMM_ONLY(d->L(1) = (int32_t)d->L(2) - (int32_t)d->L(3));
- d->L((1 << SHIFT) + 0) = (int32_t)s->L(0) - (int32_t)s->L(1);
- XMM_ONLY(d->L(3) = (int32_t)s->L(2) - (int32_t)s->L(3));
+ Reg r;
+
+ r.L(0) = (int32_t)d->L(0) - (int32_t)d->L(1);
+ XMM_ONLY(r.L(1) = (int32_t)d->L(2) - (int32_t)d->L(3));
+ r.L((1 << SHIFT) + 0) = (int32_t)s->L(0) - (int32_t)s->L(1);
+ XMM_ONLY(r.L(3) = (int32_t)s->L(2) - (int32_t)s->L(3));
+ MOVE(*d, r);
}
void glue(helper_phsubsw, SUFFIX)(CPUX86State *env, Reg *d, Reg *s)
{
- d->W(0) = satsw((int16_t)d->W(0) - (int16_t)d->W(1));
- d->W(1) = satsw((int16_t)d->W(2) - (int16_t)d->W(3));
- XMM_ONLY(d->W(2) = satsw((int16_t)d->W(4) - (int16_t)d->W(5)));
- XMM_ONLY(d->W(3) = satsw((int16_t)d->W(6) - (int16_t)d->W(7)));
- d->W((2 << SHIFT) + 0) = satsw((int16_t)s->W(0) - (int16_t)s->W(1));
- d->W((2 << SHIFT) + 1) = satsw((int16_t)s->W(2) - (int16_t)s->W(3));
- XMM_ONLY(d->W(6) = satsw((int16_t)s->W(4) - (int16_t)s->W(5)));
- XMM_ONLY(d->W(7) = satsw((int16_t)s->W(6) - (int16_t)s->W(7)));
+ Reg r;
+
+ r.W(0) = satsw((int16_t)d->W(0) - (int16_t)d->W(1));
+ r.W(1) = satsw((int16_t)d->W(2) - (int16_t)d->W(3));
+ XMM_ONLY(r.W(2) = satsw((int16_t)d->W(4) - (int16_t)d->W(5)));
+ XMM_ONLY(r.W(3) = satsw((int16_t)d->W(6) - (int16_t)d->W(7)));
+ r.W((2 << SHIFT) + 0) = satsw((int16_t)s->W(0) - (int16_t)s->W(1));
+ r.W((2 << SHIFT) + 1) = satsw((int16_t)s->W(2) - (int16_t)s->W(3));
+ XMM_ONLY(r.W(6) = satsw((int16_t)s->W(4) - (int16_t)s->W(5)));
+ XMM_ONLY(r.W(7) = satsw((int16_t)s->W(6) - (int16_t)s->W(7)));
+ MOVE(*d, r);
}
#define FABSB(_, x) (x > INT8_MAX ? -(int8_t)x : x)
--
2.37.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] target/i386: fix PHSUB* instructions with dest=src
2022-08-25 15:48 [PATCH] target/i386: fix PHSUB* instructions with dest=src Paolo Bonzini
@ 2022-08-25 15:57 ` Richard Henderson
0 siblings, 0 replies; 2+ messages in thread
From: Richard Henderson @ 2022-08-25 15:57 UTC (permalink / raw)
To: Paolo Bonzini, qemu-devel
On 8/25/22 08:48, Paolo Bonzini wrote:
> The computation must not overwrite neither the destination
> nor the source before the last element has been computed.
Too many negatives. Clearer to use use either/or.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
r~
^ permalink raw reply [flat|nested] 2+ messages in thread
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