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https://github.com/0intro/wmii
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68 lines
1.0 KiB
C
68 lines
1.0 KiB
C
/*
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* 64-bit IEEE not-a-number routines.
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* This is big/little-endian portable assuming that
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* the 64-bit doubles and 64-bit integers have the
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* same byte ordering.
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*/
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#include "plan9.h"
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#include "fmt.h"
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#include "fmtdef.h"
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#if defined (__APPLE__) || (__powerpc__)
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#define _NEEDLL
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#endif
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static uvlong uvnan = ((uvlong)0x7FF00000<<32)|0x00000001;
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static uvlong uvinf = ((uvlong)0x7FF00000<<32)|0x00000000;
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static uvlong uvneginf = ((uvlong)0xFFF00000<<32)|0x00000000;
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double
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__NaN(void)
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{
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uvlong *p;
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/* gcc complains about "return *(double*)&uvnan;" */
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p = &uvnan;
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return *(double*)p;
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}
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int
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__isNaN(double d)
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{
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uvlong x;
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double *p;
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p = &d;
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x = *(uvlong*)p;
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return (ulong)(x>>32)==0x7FF00000 && !__isInf(d, 0);
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}
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double
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__Inf(int sign)
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{
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uvlong *p;
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if(sign < 0)
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p = &uvinf;
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else
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p = &uvneginf;
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return *(double*)p;
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}
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int
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__isInf(double d, int sign)
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{
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uvlong x;
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double *p;
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p = &d;
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x = *(uvlong*)p;
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if(sign == 0)
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return x==uvinf || x==uvneginf;
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else if(sign > 0)
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return x==uvinf;
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else
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return x==uvneginf;
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}
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