1//===----- lib/aarch64/fp_mode.c - Floaing-point mode utilities ---*- C -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include <stdint.h>
10
11#include "../fp_mode.h"
12
13#define AARCH64_TONEAREST  0x0
14#define AARCH64_UPWARD     0x1
15#define AARCH64_DOWNWARD   0x2
16#define AARCH64_TOWARDZERO 0x3
17#define AARCH64_RMODE_MASK (AARCH64_TONEAREST | AARCH64_UPWARD | \
18                            AARCH64_DOWNWARD | AARCH64_TOWARDZERO)
19#define AARCH64_RMODE_SHIFT 22
20
21#define AARCH64_INEXACT     0x10
22
23#ifndef __ARM_FP
24// For soft float targets, allow changing rounding mode by overriding the weak
25// __aarch64_fe_default_rmode symbol.
26FE_ROUND_MODE __attribute__((weak)) __aarch64_fe_default_rmode = FE_TONEAREST;
27#endif
28
29FE_ROUND_MODE __fe_getround() {
30#ifdef __ARM_FP
31  uint64_t fpcr;
32  __asm__ __volatile__("mrs  %0, fpcr" : "=r" (fpcr));
33  fpcr = fpcr >> AARCH64_RMODE_SHIFT & AARCH64_RMODE_MASK;
34  switch (fpcr) {
35    case AARCH64_UPWARD:
36      return FE_UPWARD;
37    case AARCH64_DOWNWARD:
38      return FE_DOWNWARD;
39    case AARCH64_TOWARDZERO:
40      return FE_TOWARDZERO;
41    case AARCH64_TONEAREST:
42    default:
43      return FE_TONEAREST;
44  }
45#else
46  return __aarch64_fe_default_rmode;
47#endif
48}
49
50int __fe_raise_inexact() {
51#ifdef __ARM_FP
52  uint64_t fpsr;
53  __asm__ __volatile__("mrs  %0, fpsr" : "=r" (fpsr));
54  __asm__ __volatile__("msr  fpsr, %0" : : "ri" (fpsr | AARCH64_INEXACT));
55  return 0;
56#else
57  return 0;
58#endif
59}
60