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 0x1000 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 FE_ROUND_MODE __attribute__((weak)) __arm_fe_default_rmode = FE_TONEAREST; 27 #endif 28 29 FE_ROUND_MODE __fe_getround() { 30 #ifdef __ARM_FP 31 uint32_t fpscr; 32 __asm__ __volatile__("vmrs %0, fpscr" : "=r" (fpscr)); 33 fpscr = fpscr >> ARM_RMODE_SHIFT & ARM_RMODE_MASK; 34 switch (fpscr) { 35 case ARM_UPWARD: 36 return FE_UPWARD; 37 case ARM_DOWNWARD: 38 return FE_DOWNWARD; 39 case ARM_TOWARDZERO: 40 return FE_TOWARDZERO; 41 case ARM_TONEAREST: 42 default: 43 return FE_TONEAREST; 44 } 45 #else 46 return __arm_fe_default_rmode; 47 #endif 48 } 49 50 int __fe_raise_inexact() { 51 #ifdef __ARM_FP 52 uint32_t fpscr; 53 __asm__ __volatile__("vmrs %0, fpscr" : "=r" (fpscr)); 54 __asm__ __volatile__("vmsr fpscr, %0" : : "ri" (fpscr | ARM_INEXACT)); 55 return 0; 56 #else 57 return 0; 58 #endif 59 } 60