1480093f4SDimitry Andric //===----- lib/i386/fp_mode.c - Floaing-point mode utilities -----*- C -*-====// 2480093f4SDimitry Andric // 3480093f4SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4480093f4SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5480093f4SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6480093f4SDimitry Andric // 7480093f4SDimitry Andric //===----------------------------------------------------------------------===// 8480093f4SDimitry Andric 9480093f4SDimitry Andric #include "../fp_mode.h" 10480093f4SDimitry Andric 11480093f4SDimitry Andric #define X87_TONEAREST 0x0000 12480093f4SDimitry Andric #define X87_DOWNWARD 0x0400 13480093f4SDimitry Andric #define X87_UPWARD 0x0800 14480093f4SDimitry Andric #define X87_TOWARDZERO 0x0c00 15480093f4SDimitry Andric #define X87_RMODE_MASK (X87_TONEAREST | X87_UPWARD | X87_DOWNWARD | X87_TOWARDZERO) 16480093f4SDimitry Andric 17*fe6060f1SDimitry Andric CRT_FE_ROUND_MODE __fe_getround() { 18480093f4SDimitry Andric // Assume that the rounding mode state for the fpu agrees with the SSE unit. 19480093f4SDimitry Andric unsigned short cw; 20480093f4SDimitry Andric __asm__ __volatile__ ("fnstcw %0" : "=m" (cw)); 21480093f4SDimitry Andric 22480093f4SDimitry Andric switch (cw & X87_RMODE_MASK) { 23480093f4SDimitry Andric case X87_TONEAREST: 24*fe6060f1SDimitry Andric return CRT_FE_TONEAREST; 25480093f4SDimitry Andric case X87_DOWNWARD: 26*fe6060f1SDimitry Andric return CRT_FE_DOWNWARD; 27480093f4SDimitry Andric case X87_UPWARD: 28*fe6060f1SDimitry Andric return CRT_FE_UPWARD; 29480093f4SDimitry Andric case X87_TOWARDZERO: 30*fe6060f1SDimitry Andric return CRT_FE_TOWARDZERO; 31480093f4SDimitry Andric } 32*fe6060f1SDimitry Andric return CRT_FE_TONEAREST; 33480093f4SDimitry Andric } 34480093f4SDimitry Andric 35480093f4SDimitry Andric int __fe_raise_inexact() { 36480093f4SDimitry Andric float f = 1.0f, g = 3.0f; 37480093f4SDimitry Andric __asm__ __volatile__ ("fdivs %1" : "+t" (f) : "m" (g)); 38480093f4SDimitry Andric return 0; 39480093f4SDimitry Andric } 40