fp_mode.c
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//===----- lib/arm/fp_mode.c - Floaing-point mode utilities -------*- C -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include <stdint.h>
#include "../fp_mode.h"
#define ARM_TONEAREST 0x0
#define ARM_UPWARD 0x1
#define ARM_DOWNWARD 0x2
#define ARM_TOWARDZERO 0x3
#define ARM_RMODE_MASK (ARM_TONEAREST | ARM_UPWARD | \
ARM_DOWNWARD | ARM_TOWARDZERO)
#define ARM_RMODE_SHIFT 22
#define ARM_INEXACT 0x1000
#ifndef __ARM_FP
// For soft float targets, allow changing rounding mode by overriding the weak
// __arm_fe_default_rmode symbol.
FE_ROUND_MODE __attribute__((weak)) __arm_fe_default_rmode = FE_TONEAREST;
#endif
FE_ROUND_MODE __fe_getround() {
#ifdef __ARM_FP
uint32_t fpscr;
__asm__ __volatile__("vmrs %0, fpscr" : "=r" (fpscr));
fpscr = fpscr >> ARM_RMODE_SHIFT & ARM_RMODE_MASK;
switch (fpscr) {
case ARM_UPWARD:
return FE_UPWARD;
case ARM_DOWNWARD:
return FE_DOWNWARD;
case ARM_TOWARDZERO:
return FE_TOWARDZERO;
case ARM_TONEAREST:
default:
return FE_TONEAREST;
}
#else
return __arm_fe_default_rmode;
#endif
}
int __fe_raise_inexact() {
#ifdef __ARM_FP
uint32_t fpscr;
__asm__ __volatile__("vmrs %0, fpscr" : "=r" (fpscr));
__asm__ __volatile__("vmsr fpscr, %0" : : "ri" (fpscr | ARM_INEXACT));
return 0;
#else
return 0;
#endif
}