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. 26 CRT_FE_ROUND_MODE __attribute__((weak)) __aarch64_fe_default_rmode = 27 CRT_FE_TONEAREST; 28 #endif 29 30 CRT_FE_ROUND_MODE __fe_getround(void) { 31 #ifdef __ARM_FP 32 uint64_t fpcr; 33 __asm__ __volatile__("mrs %0, fpcr" : "=r" (fpcr)); 34 fpcr = fpcr >> AARCH64_RMODE_SHIFT & AARCH64_RMODE_MASK; 35 switch (fpcr) { 36 case AARCH64_UPWARD: 37 return CRT_FE_UPWARD; 38 case AARCH64_DOWNWARD: 39 return CRT_FE_DOWNWARD; 40 case AARCH64_TOWARDZERO: 41 return CRT_FE_TOWARDZERO; 42 case AARCH64_TONEAREST: 43 default: 44 return CRT_FE_TONEAREST; 45 } 46 #else 47 return __aarch64_fe_default_rmode; 48 #endif 49 } 50 51 int __fe_raise_inexact(void) { 52 #ifdef __ARM_FP 53 uint64_t fpsr; 54 __asm__ __volatile__("mrs %0, fpsr" : "=r" (fpsr)); 55 __asm__ __volatile__("msr fpsr, %0" : : "ri" (fpsr | AARCH64_INEXACT)); 56 return 0; 57 #else 58 return 0; 59 #endif 60 } 61