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b85afdfd25
Note: older versions of ML64 are broken and don't understand the register form of movq. See https://stackoverflow.com/questions/24789339/move-quadword-between-xmm-and-general-purpose-register-in-ml64
39 lines
748 B
C
39 lines
748 B
C
/*
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* PROJECT: ReactOS CRT library
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* LICENSE: MIT (https://spdx.org/licenses/MIT)
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* PURPOSE: Portable implementation of fabs
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* COPYRIGHT: Copyright 2021 Timo Kreuzer <timo.kreuzer@reactos.org>
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*/
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#include <math.h>
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#ifdef _MSC_VER
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#pragma function(fabs)
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#endif
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_Check_return_
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double
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__cdecl
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fabs(
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_In_ double x)
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{
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/* Load the value as uint64 */
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unsigned long long u64 = *(unsigned long long*)&x;
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/* Clear the sign bit */
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u64 &= ~(1ULL << 63);
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/* Check for NAN */
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if (u64 > 0x7FF0000000000000ull)
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{
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#ifdef _M_IX86
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/* Set error bit */
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*(unsigned long long*)&x |= 0x0008000000000000ull;
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#endif
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return x;
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}
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/* Convert back to double */
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return *(double*)&u64;
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}
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