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 FE_ROUND_MODE __attribute__((weak)) __aarch64_fe_default_rmode = FE_TONEAREST; 27 #endif 28 29 FE_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 50 int __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