1 //===----- lib/arm/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 ARM_TONEAREST 0x0 14 #define ARM_UPWARD 0x1 15 #define ARM_DOWNWARD 0x2 16 #define ARM_TOWARDZERO 0x3 17 #define ARM_RMODE_MASK (ARM_TONEAREST | ARM_UPWARD | \ 18 ARM_DOWNWARD | ARM_TOWARDZERO) 19 #define ARM_RMODE_SHIFT 22 20 21 #define ARM_INEXACT 0x10 22 23 #ifndef __ARM_FP 24 // For soft float targets, allow changing rounding mode by overriding the weak 25 // __arm_fe_default_rmode symbol. 26 CRT_FE_ROUND_MODE __attribute__((weak)) __arm_fe_default_rmode = 27 CRT_FE_TONEAREST; 28 #endif 29 30 CRT_FE_ROUND_MODE __fe_getround(void) { 31 #ifdef __ARM_FP 32 uint32_t fpscr; 33 __asm__ __volatile__("vmrs %0, fpscr" : "=r" (fpscr)); 34 fpscr = fpscr >> ARM_RMODE_SHIFT & ARM_RMODE_MASK; 35 switch (fpscr) { 36 case ARM_UPWARD: 37 return CRT_FE_UPWARD; 38 case ARM_DOWNWARD: 39 return CRT_FE_DOWNWARD; 40 case ARM_TOWARDZERO: 41 return CRT_FE_TOWARDZERO; 42 case ARM_TONEAREST: 43 default: 44 return CRT_FE_TONEAREST; 45 } 46 #else 47 return __arm_fe_default_rmode; 48 #endif 49 } 50 51 int __fe_raise_inexact(void) { 52 #ifdef __ARM_FP 53 uint32_t fpscr; 54 __asm__ __volatile__("vmrs %0, fpscr" : "=r" (fpscr)); 55 __asm__ __volatile__("vmsr fpscr, %0" : : "ri" (fpscr | ARM_INEXACT)); 56 return 0; 57 #else 58 return 0; 59 #endif 60 } 61