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authorPeter Maydell <peter.maydell@linaro.org>2014-01-07 17:17:49 +0000
committerPeter Maydell <peter.maydell@linaro.org>2014-01-08 19:07:22 +0000
commit34e1c27bc3094ffe484d9855e07ad104bddf579f (patch)
tree3b99b7eb3a70d6e9df561f7df9d2c7c48811e3cf /fpu
parentfb3ea83aa53cead46465c74ddd1872babe9f4a3e (diff)
downloadqemu-arm-34e1c27bc3094ffe484d9855e07ad104bddf579f.tar.gz
softfloat: Only raise Invalid when conversions to int are out of range
We implement a number of float-to-integer conversions using conversion to an integer type with a wider range and then a check against the narrower range we are actually converting to. If we find the result to be out of range we correctly raise the Invalid exception, but we must also suppress other exceptions which might have been raised by the conversion function we called. This won't throw away exceptions we should have preserved, because for the 'core' exception flags the IEEE spec mandates that the only valid combinations of exception that can be raised by a single operation are Inexact + Overflow and Inexact + Underflow. For the non-IEEE softfloat flag for input denormals, we can guarantee that that flag won't have been set for out of range float-to-int conversions because a squashed denormal by definition goes to plus or minus zero, which is always in range after conversion to integer zero. This bug has been fixed for some of the float-to-int conversion routines by previous patches; fix it for the remaining functions as well, so that they all restore the pre-conversion status flags prior to raising Invalid. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Aurelien Jarno <aurelien@aurel32.net> Reviewed-by: Richard Henderson <rth@twiddle.net>
Diffstat (limited to 'fpu')
-rw-r--r--fpu/softfloat.c28
1 files changed, 16 insertions, 12 deletions
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 2364513e0b..6312e0c66f 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -6509,17 +6509,18 @@ uint32 float32_to_uint32( float32 a STATUS_PARAM )
{
int64_t v;
uint32 res;
+ int old_exc_flags = get_float_exception_flags(status);
v = float32_to_int64(a STATUS_VAR);
if (v < 0) {
res = 0;
- float_raise( float_flag_invalid STATUS_VAR);
} else 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;
}
@@ -6527,17 +6528,18 @@ uint32 float32_to_uint32_round_to_zero( float32 a STATUS_PARAM )
{
int64_t v;
uint32 res;
+ int old_exc_flags = get_float_exception_flags(status);
v = float32_to_int64_round_to_zero(a STATUS_VAR);
if (v < 0) {
res = 0;
- float_raise( float_flag_invalid STATUS_VAR);
} else 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;
}
@@ -6585,17 +6587,18 @@ uint_fast16_t float32_to_uint16_round_to_zero(float32 a STATUS_PARAM)
{
int64_t v;
uint_fast16_t res;
+ int old_exc_flags = get_float_exception_flags(status);
v = float32_to_int64_round_to_zero(a STATUS_VAR);
if (v < 0) {
res = 0;
- float_raise( float_flag_invalid STATUS_VAR);
} else if (v > 0xffff) {
res = 0xffff;
- 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;
}
@@ -6679,17 +6682,18 @@ uint_fast16_t float64_to_uint16_round_to_zero(float64 a STATUS_PARAM)
{
int64_t v;
uint_fast16_t 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 > 0xffff) {
res = 0xffff;
- 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;
}