[Qemu-devel] [PULL 10/28] target-arm: Squash input denormals in FRECPS and FRSQRTS

[Peter Maydell]

The helper functions for FRECPS and FRSQRTS have special case
handling that includes checks for zero inputs, so squash input
denormals if necessary before those checks. This fixes incorrect
output when the FPCR DZ bit is set to enable squashing of input
denormals.

Signed-off-by: Peter Maydell <address@hidden>
Tested-by: Laurent Desnogues <address@hidden>
---
 target-arm/helper-a64.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/target-arm/helper-a64.c b/target-arm/helper-a64.c
index ebd9247..8aa40e9 100644
--- a/target-arm/helper-a64.c
+++ b/target-arm/helper-a64.c
@@ -229,6 +229,9 @@ float32 HELPER(recpsf_f32)(float32 a, float32 b, void 
*fpstp)
 {
     float_status *fpst = fpstp;
 
+    a = float32_squash_input_denormal(a, fpst);
+    b = float32_squash_input_denormal(b, fpst);
+
     a = float32_chs(a);
     if ((float32_is_infinity(a) && float32_is_zero(b)) ||
         (float32_is_infinity(b) && float32_is_zero(a))) {
@@ -241,6 +244,9 @@ float64 HELPER(recpsf_f64)(float64 a, float64 b, void 
*fpstp)
 {
     float_status *fpst = fpstp;
 
+    a = float64_squash_input_denormal(a, fpst);
+    b = float64_squash_input_denormal(b, fpst);
+
     a = float64_chs(a);
     if ((float64_is_infinity(a) && float64_is_zero(b)) ||
         (float64_is_infinity(b) && float64_is_zero(a))) {
@@ -253,6 +259,9 @@ float32 HELPER(rsqrtsf_f32)(float32 a, float32 b, void 
*fpstp)
 {
     float_status *fpst = fpstp;
 
+    a = float32_squash_input_denormal(a, fpst);
+    b = float32_squash_input_denormal(b, fpst);
+
     a = float32_chs(a);
     if ((float32_is_infinity(a) && float32_is_zero(b)) ||
         (float32_is_infinity(b) && float32_is_zero(a))) {
@@ -265,6 +274,9 @@ float64 HELPER(rsqrtsf_f64)(float64 a, float64 b, void 
*fpstp)
 {
     float_status *fpst = fpstp;
 
+    a = float64_squash_input_denormal(a, fpst);
+    b = float64_squash_input_denormal(b, fpst);
+
     a = float64_chs(a);
     if ((float64_is_infinity(a) && float64_is_zero(b)) ||
         (float64_is_infinity(b) && float64_is_zero(a))) {
-- 
1.9.1