[Qemu-devel] [PULL 63/76] softfloat: Fix float64_to_uint32_round_to_zero

[Peter Maydell]

From: Tom Musta <address@hidden>

The float64_to_uint32_round_to_zero routine is incorrect.

For example, the following test pattern:

    425F81378DC0CD1F / 0x1.f81378dc0cd1fp+38

will erroneously set the inexact flag.

This patch re-implements the routine to use the float64_to_uint64_round_to_zero
routine.  If saturation occurs we ignore any flags set by the
conversion function and raise only Invalid.

This contribution can be licensed under either the softfloat-2a or -2b
license.

Signed-off-by: Tom Musta <address@hidden>
Message-id: address@hidden
Signed-off-by: Peter Maydell <address@hidden>
Reviewed-by: Richard Henderson <address@hidden>
---
 fpu/softfloat.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index e68a87b..3232ce2 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -6667,19 +6667,18 @@ uint32 float64_to_uint32( float64 a STATUS_PARAM )
 
 uint32 float64_to_uint32_round_to_zero( float64 a STATUS_PARAM )
 {
-    int64_t v;
+    uint64_t v;
     uint32 res;
+    int old_exc_flags = get_float_exception_flags(status);
 
-    v = float64_to_int64_round_to_zero(a STATUS_VAR);
-    if (v < 0) {
-        res = 0;
-        float_raise( float_flag_invalid STATUS_VAR);
-    } else if (v > 0xffffffff) {
+    v = float64_to_uint64_round_to_zero(a STATUS_VAR);
+    if (v > 0xffffffff) {
         res = 0xffffffff;
-        float_raise( float_flag_invalid STATUS_VAR);
     } else {
-        res = v;
+        return v;
     }
+    set_float_exception_flags(old_exc_flags, status);
+    float_raise(float_flag_invalid STATUS_VAR);
     return res;
 }
 
-- 
1.8.5