===================================================================
@@ -88,7 +88,7 @@
#endif
}
-/* i387 -- see linux <fpu_control.h> header file for details. */
+/* i387 exceptions -- see linux <fpu_control.h> header file for details. */
#define _FPU_MASK_IM 0x01
#define _FPU_MASK_DM 0x02
#define _FPU_MASK_ZM 0x04
@@ -99,7 +99,18 @@
#define _FPU_EX_ALL 0x3f
-void set_fpu (void)
+/* i387 rounding modes. */
+
+#define _FPU_RC_NEAREST 0x0
+#define _FPU_RC_DOWN 0x400
+#define _FPU_RC_UP 0x800
+#define _FPU_RC_ZERO 0xc00
+
+#define _FPU_RC_MASK 0xc00
+
+
+void
+set_fpu (void)
{
int excepts = 0;
unsigned short cw;
@@ -164,3 +175,72 @@
return result;
}
+
+void
+set_fpu_rounding_mode (int round)
+{
+ int round_mode;
+ unsigned short cw;
+
+ switch (round)
+ {
+ case GFC_FPE_TONEAREST:
+ round_mode = _FPU_RC_NEAREST;
+ break;
+ case GFC_FPE_UPWARD:
+ round_mode = _FPU_RC_UP;
+ break;
+ case GFC_FPE_DOWNWARD:
+ round_mode = _FPU_RC_DOWN;
+ break;
+ case GFC_FPE_TOWARDZERO:
+ round_mode = _FPU_RC_ZERO;
+ break;
+ default:
+ return; /* Should be unreachable. */
+ }
+
+ __asm__ __volatile__ ("fnstcw\t%0" : "=m" (cw));
+
+ cw &= ~FPU_RC_MASK;
+ cw |= round_mode;
+
+ __asm__ __volatile__ ("fldcw\t%0" : : "m" (cw));
+
+ if (has_sse())
+ {
+ unsigned int cw_sse;
+
+ __asm__ __volatile__ ("%vstmxcsr\t%0" : "=m" (cw_sse));
+
+ /* The SSE round control bits are shifted by 3 bits. */
+ cw_sse &= ~(FPU_RC_MASK << 3);
+ cw_sse |= round_mode << 3;
+
+ __asm__ __volatile__ ("%vldmxcsr\t%0" : : "m" (cw_sse));
+ }
+}
+
+int
+get_fpu_rounding_mode (void)
+{
+ unsigned short cw;
+
+ __asm__ __volatile__ ("fnstcw\t%0" : "=m" (cw));
+
+ cw &= FPU_RC_MASK;
+
+ switch (cw)
+ {
+ case _FPU_RC_NEAREST:
+ return GFC_FPE_TONEAREST;
+ case _FPU_RC_UP:
+ return GFC_FPE_UPWARD;
+ case _FPU_RC_DOWN:
+ return GFC_FPE_DOWNWARD;
+ case _FPU_RC_ZERO:
+ return GFC_FPE_TOWARDZERO;
+ default:
+ return GFC_FPE_INVALID; /* Should be unreachable. */
+ }
+}