mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-05 19:21:05 +00:00
62 lines
2.4 KiB
C
62 lines
2.4 KiB
C
/* Set FP exception mask and rounding mode.
|
|
Copyright (C) 1996-2017 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library. If not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include <fpu_control.h>
|
|
#include <fenv_libc.h>
|
|
|
|
|
|
#define convert_bit(M, F, T) \
|
|
((T) < (F) \
|
|
? ((M) / ((F) / (T))) & (T) \
|
|
: ((M) & (F)) * ((T) / (F)))
|
|
|
|
|
|
void
|
|
__setfpucw (fpu_control_t fpu_control)
|
|
{
|
|
unsigned long fpcr, swcr, fc = (int)fpu_control;
|
|
|
|
/* ??? If this was a real external interface we'd want to read the current
|
|
exception state with __ieee_get_fp_control. But this is an internal
|
|
function only called at process startup, so there's no point in trying
|
|
to preserve exceptions that cannot have been raised yet. Indeed, this
|
|
entire function is likely to be one big nop unless the user overrides
|
|
the default __fpu_control variable. */
|
|
|
|
/* Convert the rounding mode from fpu_control.h format. */
|
|
const unsigned long conv_rnd
|
|
= ( (FE_TOWARDZERO << (_FPU_RC_ZERO >> 8))
|
|
| (FE_DOWNWARD << (_FPU_RC_DOWN >> 8))
|
|
| (FE_TONEAREST << (_FPU_RC_NEAREST >> 8))
|
|
| (FE_UPWARD << (_FPU_RC_UP >> 8)));
|
|
|
|
fpcr = ((conv_rnd >> ((fc >> 8) & 3)) & 3) << FPCR_ROUND_SHIFT;
|
|
|
|
/* Convert the exception mask from fpu_control.h format. */
|
|
swcr = convert_bit (~fc, _FPU_MASK_IM, FE_INVALID >> SWCR_ENABLE_SHIFT);
|
|
swcr |= convert_bit (~fc, _FPU_MASK_DM, FE_UNDERFLOW >> SWCR_ENABLE_SHIFT);
|
|
swcr |= convert_bit (~fc, _FPU_MASK_ZM, FE_DIVBYZERO >> SWCR_ENABLE_SHIFT);
|
|
swcr |= convert_bit (~fc, _FPU_MASK_OM, FE_OVERFLOW >> SWCR_ENABLE_SHIFT);
|
|
swcr |= convert_bit (~fc, _FPU_MASK_PM, FE_INEXACT >> SWCR_ENABLE_SHIFT);
|
|
|
|
/* Install everything. */
|
|
__fpu_control = fc;
|
|
asm volatile ("mt_fpcr %0" : : "f"(fpcr));
|
|
__ieee_set_fp_control(swcr);
|
|
}
|