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- #include <float.h>
- #include <math.h>
- #define NANEXP (2047<<20)
- #define NANMASK (2047<<20)
- #define NANSIGN (1<<31)
- double
- NaN(void)
- {
- FPdbleword a;
- a.hi = NANEXP;
- a.lo = 1;
- return a.x;
- }
- int
- isNaN(double d)
- {
- FPdbleword a;
- a.x = d;
- if((a.hi & NANMASK) != NANEXP)
- return 0;
- return !isInf(d, 0);
- }
- double
- Inf(int sign)
- {
- FPdbleword a;
- a.hi = NANEXP;
- a.lo = 0;
- if(sign < 0)
- a.hi |= NANSIGN;
- return a.x;
- }
- int
- isInf(double d, int sign)
- {
- FPdbleword a;
- a.x = d;
- if(a.lo != 0)
- return 0;
- if(a.hi == NANEXP)
- return sign >= 0;
- if(a.hi == (NANEXP|NANSIGN))
- return sign <= 0;
- return 0;
- }
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