minix/lib/libc/arch/i386/math/fesetround.c

27 lines
561 B
C

#include <errno.h>
#include <fenv.h>
#include "fpu_cw.h"
int fesetround(int round)
{
u16_t cw;
/* read and update FPUCW */
cw = fpu_cw_get() & ~FPUCW_ROUNDING_CONTROL;
switch (round)
{
case FE_TONEAREST: cw |= FPUCW_ROUNDING_CONTROL_NEAREST; break;
case FE_DOWNWARD: cw |= FPUCW_ROUNDING_CONTROL_DOWN; break;
case FE_UPWARD: cw |= FPUCW_ROUNDING_CONTROL_UP; break;
case FE_TOWARDZERO: cw |= FPUCW_ROUNDING_CONTROL_TRUNC; break;
default:
errno = EINVAL;
return -1;
}
/* set FPUCW to the updated value */
fpu_cw_set(cw);
return 0;
}