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[builtins] Implement rounding mode support for i386/x86_64
Differential Revision: https://reviews.llvm.org/D69870
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Original file line number | Diff line number | Diff line change |
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@@ -239,6 +239,7 @@ set(x86_ARCH_SOURCES | |
floatuntixf.c | ||
mulxc3.c | ||
powixf2.c | ||
i386/fp_mode.c | ||
) | ||
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if (NOT MSVC) | ||
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@@ -0,0 +1,39 @@ | ||
//===----- lib/i386/fp_mode.c - Floaing-point mode utilities -----*- C -*-====// | ||
// | ||
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. | ||
// See https://llvm.org/LICENSE.txt for license information. | ||
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception | ||
// | ||
//===----------------------------------------------------------------------===// | ||
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#include "../fp_mode.h" | ||
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#define X87_TONEAREST 0x0000 | ||
#define X87_DOWNWARD 0x0400 | ||
#define X87_UPWARD 0x0800 | ||
#define X87_TOWARDZERO 0x0c00 | ||
#define X87_RMODE_MASK (X87_TONEAREST | X87_UPWARD | X87_DOWNWARD | X87_TOWARDZERO) | ||
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FE_ROUND_MODE __fe_getround() { | ||
// Assume that the rounding mode state for the fpu agrees with the SSE unit. | ||
unsigned short cw; | ||
__asm__ __volatile__ ("fnstcw %0" : "=m" (cw)); | ||
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switch (cw & X87_RMODE_MASK) { | ||
case X87_TONEAREST: | ||
return FE_TONEAREST; | ||
case X87_DOWNWARD: | ||
return FE_DOWNWARD; | ||
case X87_UPWARD: | ||
return FE_UPWARD; | ||
case X87_TOWARDZERO: | ||
return FE_TOWARDZERO; | ||
} | ||
return FE_TONEAREST; | ||
} | ||
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int __fe_raise_inexact() { | ||
float f = 1.0f, g = 3.0f; | ||
__asm__ __volatile__ ("fdivs %1" : "+t" (f) : "m" (g)); | ||
return 0; | ||
} |
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