Hello!
Attached patch adds missing FP_EX_DENORM handling to x86 soft-fp
exception generator and improves support code a bit. The FP_EX_DENORM
handling will be needed by gfortran IEEE support.
2013-11-07 Uros Bizjak <[email protected]>
* config/i386/sfp-exceptions.c (__sfp_handle_exceptions): Handle
FP_EX_DENORM. Store result to volatile location after SSE division
to close interrupt window. Remove unneeded fwait after x87
division since interrupt window will be closed by emitted fstp.
Tested on x86_64-pc-linux-gnu {,-m32} and committed to mainline SVN.
The patch will be backported to other release branches due to missing
FP_EX_DENORM.
Uros.
Index: config/i386/sfp-exceptions.c
===================================================================
--- config/i386/sfp-exceptions.c (revision 204522)
+++ config/i386/sfp-exceptions.c (working copy)
@@ -48,20 +48,32 @@
{
float f = 0.0f;
#ifdef __x86_64__
+ volatile float r;
asm volatile ("%vdivss\t{%0, %d0|%d0, %0}" : "+x" (f));
+ r = f; /* Needed to trigger exception. */
#else
asm volatile ("fdiv\t{%y0, %0|%0, %y0}" : "+t" (f));
- asm volatile ("fwait");
+ /* No need for fwait, exception is triggered by emitted fstp. */
#endif
}
+ if (_fex & FP_EX_DENORM)
+ {
+ struct fenv temp;
+ asm volatile ("fnstenv\t%0" : "=m" (temp));
+ temp.__status_word |= FP_EX_DENORM;
+ asm volatile ("fldenv\t%0" : : "m" (temp));
+ asm volatile ("fwait");
+ }
if (_fex & FP_EX_DIVZERO)
{
float f = 1.0f, g = 0.0f;
#ifdef __x86_64__
+ volatile float r;
asm volatile ("%vdivss\t{%1, %d0|%d0, %1}" : "+x" (f) : "xm" (g));
+ r = f; /* Needed to trigger exception. */
#else
asm volatile ("fdivs\t%1" : "+t" (f) : "m" (g));
- asm volatile ("fwait");
+ /* No need for fwait, exception is triggered by emitted fstp. */
#endif
}
if (_fex & FP_EX_OVERFLOW)
