1*480093f4SDimitry Andric //===----- lib/i386/fp_mode.c - Floaing-point mode utilities -----*- C -*-====// 2*480093f4SDimitry Andric // 3*480093f4SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*480093f4SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5*480093f4SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*480093f4SDimitry Andric // 7*480093f4SDimitry Andric //===----------------------------------------------------------------------===// 8*480093f4SDimitry Andric 9*480093f4SDimitry Andric #include "../fp_mode.h" 10*480093f4SDimitry Andric 11*480093f4SDimitry Andric #define X87_TONEAREST 0x0000 12*480093f4SDimitry Andric #define X87_DOWNWARD 0x0400 13*480093f4SDimitry Andric #define X87_UPWARD 0x0800 14*480093f4SDimitry Andric #define X87_TOWARDZERO 0x0c00 15*480093f4SDimitry Andric #define X87_RMODE_MASK (X87_TONEAREST | X87_UPWARD | X87_DOWNWARD | X87_TOWARDZERO) 16*480093f4SDimitry Andric 17*480093f4SDimitry Andric FE_ROUND_MODE __fe_getround() { 18*480093f4SDimitry Andric // Assume that the rounding mode state for the fpu agrees with the SSE unit. 19*480093f4SDimitry Andric unsigned short cw; 20*480093f4SDimitry Andric __asm__ __volatile__ ("fnstcw %0" : "=m" (cw)); 21*480093f4SDimitry Andric 22*480093f4SDimitry Andric switch (cw & X87_RMODE_MASK) { 23*480093f4SDimitry Andric case X87_TONEAREST: 24*480093f4SDimitry Andric return FE_TONEAREST; 25*480093f4SDimitry Andric case X87_DOWNWARD: 26*480093f4SDimitry Andric return FE_DOWNWARD; 27*480093f4SDimitry Andric case X87_UPWARD: 28*480093f4SDimitry Andric return FE_UPWARD; 29*480093f4SDimitry Andric case X87_TOWARDZERO: 30*480093f4SDimitry Andric return FE_TOWARDZERO; 31*480093f4SDimitry Andric } 32*480093f4SDimitry Andric return FE_TONEAREST; 33*480093f4SDimitry Andric } 34*480093f4SDimitry Andric 35*480093f4SDimitry Andric int __fe_raise_inexact() { 36*480093f4SDimitry Andric float f = 1.0f, g = 3.0f; 37*480093f4SDimitry Andric __asm__ __volatile__ ("fdivs %1" : "+t" (f) : "m" (g)); 38*480093f4SDimitry Andric return 0; 39*480093f4SDimitry Andric } 40