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softfloat: Fix float64_to_uint32 

The float64_to_uint32 has several flaws:

 - for numbers between 2**32 and 2**64, the inexact exception flag
   may get incorrectly set.  In this case, only the invalid flag
   should be set.

       test pattern: 425F81378DC0CD1F / 0x1.f81378dc0cd1fp+38

 - for numbers between 2**63 and 2**64, incorrect results may
   be produced:

       test pattern: 43EAAF73F1F0B8BD / 0x1.aaf73f1f0b8bdp+63

This patch re-implements float64_to_uint32 to re-use the
float64_to_uint64 routine (instead of float64_to_int64).  For the
saturation case, we ignore any flags which the conversion routine
has set and raise only the invalid flag.

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

Signed-off-by: Tom Musta <tommusta@gmail.com>
Message-id: 1387397961-4894-5-git-send-email-tommusta@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Tom Musta 2014-01-07 17:17:51 +00:00 committed by Peter Maydell
parent 0a87a3107d
commit 5e7f654fa1
1 changed files with 7 additions and 8 deletions
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15
fpu/softfloat.c
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@ -6650,19 +6650,18 @@ uint_fast16_t float32_to_uint16_round_to_zero(float32 a STATUS_PARAM)
uint32 float64_to_uint32( 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(a STATUS_VAR);
if (v < 0) {
res = 0;
float_raise( float_flag_invalid STATUS_VAR);
} else if (v > 0xffffffff) {
v = float64_to_uint64(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;
}