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30 lines
693 B
C
30 lines
693 B
C
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/*
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* isinf(x) returns 1 if x is infinity, else 0;
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* no branching!
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*
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* isinf is a <math.h> macro in the C99 standard. It was previously
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* implemented as a function by newlib and is declared as such in
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* <ieeefp.h>. Newlib supplies it here as a function if the user
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* chooses to use <ieeefp.h> or needs to link older code compiled with the
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* previous <math.h> declaration.
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*/
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#include "fdlibm.h"
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#include <ieeefp.h>
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#ifndef _DOUBLE_IS_32BITS
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int
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_DEFUN (isinf, (x),
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double x)
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{
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__int32_t hx,lx;
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EXTRACT_WORDS(hx,lx,x);
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hx &= 0x7fffffff;
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hx |= (__uint32_t)(lx|(-lx))>>31;
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hx = 0x7ff00000 - hx;
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return 1 - (int)((__uint32_t)(hx|(-hx))>>31);
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}
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#endif /* _DOUBLE_IS_32BITS */
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