31 lines
1.0 KiB
C
31 lines
1.0 KiB
C
/**
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* This file has no copyright assigned and is placed in the Public Domain.
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* This file is part of the mingw-w64 runtime package.
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* No warranty is given; refer to the file DISCLAIMER.PD within this package.
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*/
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#include <fenv.h>
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#include <math.h>
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/* Mask and shift amount for rounding bits on x86/x86_64. */
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#define FE_CW_ROUND_MASK (0x0c00)
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#define FE_CW_ROUND_SHIFT (10)
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long double
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truncl (long double _x)
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{
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#if defined(_ARM_) || defined(__arm__)
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return trunc(_x);
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#else
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long double retval = 0.0L;
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unsigned short saved_cw;
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unsigned short tmp_cw;
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__asm__ __volatile__ ("fnstcw %0;" : "=m" (saved_cw)); /* save FPU control word */
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tmp_cw = (saved_cw & ~FE_CW_ROUND_MASK)
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| (FE_TOWARDZERO << FE_CW_ROUND_SHIFT);
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__asm__ __volatile__ ("fldcw %0;" : : "m" (tmp_cw));
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__asm__ __volatile__ ("frndint;" : "=t" (retval) : "0" (_x)); /* round towards zero */
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__asm__ __volatile__ ("fldcw %0;" : : "m" (saved_cw) ); /* restore saved control word */
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return retval;
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#endif /* defined(_ARM_) || defined(__arm__) */
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}
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