Re: [Qemu-devel] [PATCH v9 04/10] softfloat: For Mips only, correct order in pickNaNMulAdd()

[Peter Maydell]

On 10 June 2016 at 10:57, Aleksandar Markovic
 wrote:
> From: Aleksandar Markovic 
>
> Only for Mips platform, and only for cases when snan_bit_is_one is 0,
> correct the order of argument comparisons in pickNaNMulAdd().
>
> For more info, see [1], page 53, section "3.5.3 NaN Propagation".
>
> [1] "MIPS Architecture for Programmers Volume IV-j:
> The MIPS32 SIMD Architecture Module",
> Imagination Technologies LTD, Revision 1.12, February 3, 2016
>
> Reviewed-by: Leon Alrae 
> Signed-off-by: Aleksandar Markovic 

I think the subject line of this commit message would be a little
clearer as
  softfloat: Handle snan_bit_is_one == 0 in MIPS pickNaNMulAdd()

Otherwise:
Reviewed-by: Peter Maydell 

thanks
-- PMM

[Qemu-devel] [PATCH v9 04/10] softfloat: For Mips only, correct order in pickNaNMulAdd()

[Aleksandar Markovic]

From: Aleksandar Markovic 

Only for Mips platform, and only for cases when snan_bit_is_one is 0,
correct the order of argument comparisons in pickNaNMulAdd().

For more info, see [1], page 53, section "3.5.3 NaN Propagation".

[1] "MIPS Architecture for Programmers Volume IV-j:
The MIPS32 SIMD Architecture Module",
Imagination Technologies LTD, Revision 1.12, February 3, 2016

Reviewed-by: Leon Alrae 
Signed-off-by: Aleksandar Markovic 
---
 fpu/softfloat-specialize.h | 41 +
 1 file changed, 29 insertions(+), 12 deletions(-)

diff --git a/fpu/softfloat-specialize.h b/fpu/softfloat-specialize.h
index a1bcb46..4063561 100644
--- a/fpu/softfloat-specialize.h
+++ b/fpu/softfloat-specialize.h
@@ -571,19 +571,36 @@ static int pickNaNMulAdd(flag aIsQNaN, flag aIsSNaN, flag 
bIsQNaN, flag bIsSNaN,
 return 3;
 }
 
-/* Prefer sNaN over qNaN, in the a, b, c order. */
-if (aIsSNaN) {
-return 0;
-} else if (bIsSNaN) {
-return 1;
-} else if (cIsSNaN) {
-return 2;
-} else if (aIsQNaN) {
-return 0;
-} else if (bIsQNaN) {
-return 1;
+if (status->snan_bit_is_one) {
+/* Prefer sNaN over qNaN, in the c, a, b order. */
+if (cIsSNaN) {
+return 2;
+} else if (aIsSNaN) {
+return 0;
+} else if (bIsSNaN) {
+return 1;
+} else if (cIsQNaN) {
+return 2;
+} else if (aIsQNaN) {
+return 0;
+} else {
+return 1;
+}
 } else {
-return 2;
+/* Prefer sNaN over qNaN, in the a, b, c order. */
+if (aIsSNaN) {
+return 0;
+} else if (bIsSNaN) {
+return 1;
+} else if (cIsSNaN) {
+return 2;
+} else if (aIsQNaN) {
+return 0;
+} else if (bIsQNaN) {
+return 1;
+} else {
+return 2;
+}
 }
 }
 #elif defined(TARGET_PPC)
-- 
1.9.1