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Annotation of researchv10dc/630/3binc/nan.h, revision 1.1.1.1

1.1       root        1: #ident "@(#)/usr/include/nan.h.sl 1.3 4.1 09/02/86 29438 AT&T-SF"
                      2: /* Handling of Not_a_Number's (only in IEEE floating-point standard) */
                      3: #if _IEEE
                      4: typedef union 
                      5: {
                      6:          struct        
                      7:         {
                      8:            unsigned sign     : 1;
                      9:            unsigned exponent :11;
                     10:             unsigned bits:20;
                     11:            unsigned fraction_low:32;
                     12:          } inf_parts;
                     13:         struct 
                     14:         {
                     15:            unsigned sign     : 1;
                     16:             unsigned exponent :11;
                     17:            unsigned qnan_bit : 1;
                     18:            unsigned bits     :19;
                     19:            unsigned fraction_low: 32;
                     20:          } nan_parts;
                     21:          double d;
                     22: 
                     23: } dnan; 
                     24: 
                     25:        /* IsNANorINF checks that exponent of double == 2047 *
                     26:         * i.e. that number is a NaN or an infinity          */
                     27:        
                     28: #define IsNANorINF(X)  (((dnan *)&(X))->nan_parts.exponent == 0x7ff)
                     29: 
                     30:        /* IsINF must be used after IsNANorINF          *
                     31:         * has checked the exponent                     */
                     32: 
                     33: #define IsINF(X)  (((dnan *)&(X))->inf_parts.bits == 0 &&  \
                     34:                     ((dnan *)&(X))->inf_parts.fraction_low == 0)
                     35: 
                     36:        /* IsPosNAN and IsNegNAN can be used            *
                     37:         * to check the sign of infinities too          */
                     38: 
                     39: #define IsPosNAN(X)  (((dnan *)&(X))->nan_parts.sign == 0)
                     40: 
                     41: #define IsNegNAN(X)  (((dnan *)&(X))->nan_parts.sign == 1)
                     42: 
                     43:        /* GETNaNPC gets the leftmost 32 bits           *       
                     44:         * of the fraction part                         */
                     45: 
                     46: #define GETNaNPC(dval)   (((dnan *)&(dval))->inf_parts.bits << 12 | \
                     47:                          ((dnan *)&(dval))->nan_parts.fraction_low>> 20) 
                     48: 
                     49: #define KILLFPE()       (void) kill(getpid(), 8)
                     50: #define NaN(X)  (((dnan *)&(X))->nan_parts.exponent == 0x7ff)
                     51: #define KILLNaN(X)      if (NaN(X)) KILLFPE()
                     52: 
                     53: #else
                     54: 
                     55: typedef double dnan;
                     56: #define IsINF(X)   0
                     57: #define IsPINF(X)  0
                     58: #define IsNegNAN(X)  0
                     59: #define IsPosNAN(X)  0
                     60: #define IsNAN(X)   0
                     61: #define GETNaNPC(X)   0L
                     62: 
                     63: #define NaN(X)  0
                     64: #define KILLNaN(X)
                     65: #endif

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