diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/alpha/setfpucw.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/alpha/setfpucw.c | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/alpha/setfpucw.c b/sysdeps/unix/sysv/linux/alpha/setfpucw.c new file mode 100644 index 0000000000..43e8536b20 --- /dev/null +++ b/sysdeps/unix/sysv/linux/alpha/setfpucw.c @@ -0,0 +1,65 @@ +#include <fpu_control.h> + +#include <asm/fpu.h> + +extern void __ieee_set_fp_control (unsigned long); +extern unsigned long __ieee_get_fp_control (void); + + +static inline unsigned long +rdfpcr (void) +{ + unsigned long fpcr; + + asm ("trapb; mf_fpcr $f0; trapb; stt $f0,%0" : "m="(fpcr)); + return fpcr; +} + + +static inline void +wrfpcr (unsigned long fpcr) +{ + asm volatile ("ldt $f0,%0; trapb; mt_fpcr $f0; trapb" :: "m"(fpcr)); +} + + +void +__setfpucw (unsigned short fpu_control) +{ + unsigned long fpcr = 0, fpcw = 0; + + if (!fpu_control) + fpu_control = _FPU_DEFAULT; + + /* first, set dynamic rounding mode: */ + + fpcr = rdfpcr(); + fpcr &= ~FPCR_DYN_MASK; + switch (fpu_control & 0xc00) { + case _FPU_RC_NEAREST: fpcr |= FPCR_DYN_NORMAL; break; + case _FPU_RC_DOWN: fpcr |= FPCR_DYN_MINUS; break; + case _FPU_RC_UP: fpcr |= FPCR_DYN_PLUS; break; + case _FPU_RC_ZERO: fpcr |= FPCR_DYN_CHOPPED; break; + } + wrfpcr(fpcr); + + /* now tell kernel about traps that we like to hear about: */ + + fpcw = __ieee_get_fp_control(); + fpcw &= ~IEEE_TRAP_ENABLE_MASK; + + if (!(fpu_control & _FPU_MASK_IM)) + fpcw |= IEEE_TRAP_ENABLE_INV; + if (!(fpu_control & _FPU_MASK_DM)) + fpcw |= IEEE_TRAP_ENABLE_UNF; + if (!(fpu_control & _FPU_MASK_ZM)) + fpcw |= IEEE_TRAP_ENABLE_DZE; + if (!(fpu_control & _FPU_MASK_OM)) + fpcw |= IEEE_TRAP_ENABLE_OVF; + if (!(fpu_control & _FPU_MASK_PM)) + fpcw |= IEEE_TRAP_ENABLE_INE; + + __ieee_set_fp_control(fpcw); + + __fpu_control = fpu_control; /* update global copy */ +} |