Re: [PATCH] target/ppc: Fix xvcmp* clearing FI bit

[Daniel Henrique Barboza]

Queued in gitlab.com/danielhb/qemu/tree/ppc-next. Thanks,


Daniel

On 10/5/22 09:15, Víctor Colombo wrote:

Vector instructions in general are not supposed to change the FI bit.
However, xvcmp* instructions are calling gen_helper_float_check_status,
which is leading to a cleared FI flag where it should be kept
unchanged.
As helper_float_check_status only affects inexact, overflow and
underflow, and the xvcmp* instructions don't change these flags, this
issue can be fixed by removing the call to helper_float_check_status.
By doing this, the FI bit in FPSCR will be preserved as expected.

Fixes: 00084a25adf ("target/ppc: introduce separate VSX_CMP macro for xvcmp* 
instructions")
Signed-off-by: Víctor Colombo 
---
  target/ppc/translate/vsx-impl.c.inc | 1 -
  1 file changed, 1 deletion(-)

diff --git a/target/ppc/translate/vsx-impl.c.inc 
b/target/ppc/translate/vsx-impl.c.inc
index 7acdbceec4..e6e5c45ffd 100644
--- a/target/ppc/translate/vsx-impl.c.inc
+++ b/target/ppc/translate/vsx-impl.c.inc
@@ -810,7 +810,6 @@ static void gen_##name(DisasContext *ctx)   
  \
  gen_helper_##name(ignored, cpu_env, xt, xa, xb);  
\
  tcg_temp_free_i32(ignored);   
\
  } 
\
-gen_helper_float_check_status(cpu_env);   \
  tcg_temp_free_ptr(xt);
\
  tcg_temp_free_ptr(xa);
\
  tcg_temp_free_ptr(xb);
\

Re: [PATCH] target/ppc: Fix xvcmp* clearing FI bit

[Richard Henderson]

On 10/5/22 05:15, Víctor Colombo wrote:

Vector instructions in general are not supposed to change the FI bit.
However, xvcmp* instructions are calling gen_helper_float_check_status,
which is leading to a cleared FI flag where it should be kept
unchanged.
As helper_float_check_status only affects inexact, overflow and
underflow, and the xvcmp* instructions don't change these flags, this
issue can be fixed by removing the call to helper_float_check_status.
By doing this, the FI bit in FPSCR will be preserved as expected.

Fixes: 00084a25adf ("target/ppc: introduce separate VSX_CMP macro for xvcmp* 
instructions")
Signed-off-by: Víctor Colombo
---
  target/ppc/translate/vsx-impl.c.inc | 1 -
  1 file changed, 1 deletion(-)


Reviewed-by: Richard Henderson 

r~

[PATCH] target/ppc: Fix xvcmp* clearing FI bit

[Víctor Colombo]

Vector instructions in general are not supposed to change the FI bit.
However, xvcmp* instructions are calling gen_helper_float_check_status,
which is leading to a cleared FI flag where it should be kept
unchanged.
As helper_float_check_status only affects inexact, overflow and
underflow, and the xvcmp* instructions don't change these flags, this
issue can be fixed by removing the call to helper_float_check_status.
By doing this, the FI bit in FPSCR will be preserved as expected.

Fixes: 00084a25adf ("target/ppc: introduce separate VSX_CMP macro for xvcmp* 
instructions")
Signed-off-by: Víctor Colombo 
---
 target/ppc/translate/vsx-impl.c.inc | 1 -
 1 file changed, 1 deletion(-)

diff --git a/target/ppc/translate/vsx-impl.c.inc 
b/target/ppc/translate/vsx-impl.c.inc
index 7acdbceec4..e6e5c45ffd 100644
--- a/target/ppc/translate/vsx-impl.c.inc
+++ b/target/ppc/translate/vsx-impl.c.inc
@@ -810,7 +810,6 @@ static void gen_##name(DisasContext *ctx)   
  \
 gen_helper_##name(ignored, cpu_env, xt, xa, xb);  \
 tcg_temp_free_i32(ignored);   \
 } \
-gen_helper_float_check_status(cpu_env);   \
 tcg_temp_free_ptr(xt);\
 tcg_temp_free_ptr(xa);\
 tcg_temp_free_ptr(xb);\
-- 
2.25.1