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| Rev | Author | Line No. | Line |
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| 3362 | Serge | 1 | |
| 2 | /* |
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| 3 | * ==================================================== |
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| 4 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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| 5 | * |
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| 6 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
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| 7 | * Permission to use, copy, modify, and distribute this |
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| 8 | * software is freely granted, provided that this notice |
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| 9 | * is preserved. |
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| 10 | * ==================================================== |
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| 11 | */ |
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| 12 | |||
| 13 | |||
| 14 | FUNCTION |
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| 15 | < |
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| 16 | |||
| 17 | |||
| 18 | modf |
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| 19 | INDEX |
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| 20 | modff |
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| 21 | |||
| 22 | |||
| 23 | #include |
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| 24 | double modf(double <[val]>, double *<[ipart]>); |
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| 25 | float modff(float <[val]>, float *<[ipart]>); |
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| 26 | |||
| 27 | |||
| 28 | #include |
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| 29 | double modf(<[val]>, <[ipart]>) |
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| 30 | double <[val]>; |
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| 31 | double *<[ipart]>; |
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| 32 | |||
| 33 | |||
| 34 | float <[val]>; |
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| 35 | float *<[ipart]>; |
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| 36 | |||
| 37 | |||
| 38 | < |
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| 39 | and a fractional part, returning the fractional part and |
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| 40 | storing the integer part in <<*<[ipart]>>>. No rounding |
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| 41 | whatsoever is done; the sum of the integer and fractional |
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| 42 | parts is guaranteed to be exactly equal to <[val]>. That |
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| 43 | is, if <[realpart]> = modf(<[val]>, &<[intpart]>); then |
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| 44 | `<<<[realpart]>+<[intpart]>>>' is the same as <[val]>. |
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| 45 | < |
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| 46 | < |
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| 47 | |||
| 48 | |||
| 49 | The fractional part is returned. Each result has the same |
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| 50 | sign as the supplied argument <[val]>. |
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| 51 | |||
| 52 | |||
| 53 | < |
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| 54 | |||
| 55 | |||
| 56 | modf ansi pure |
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| 57 | modff - pure |
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| 58 | |||
| 59 | |||
| 60 | |||
| 61 | |||
| 62 | * modf(double x, double *iptr) |
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| 63 | * return fraction part of x, and return x's integral part in *iptr. |
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| 64 | * Method: |
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| 65 | * Bit twiddling. |
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| 66 | * |
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| 67 | * Exception: |
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| 68 | * No exception. |
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| 69 | */ |
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| 70 | |||
| 71 | |||
| 72 | |||
| 73 | |||
| 74 | |||
| 75 | |||
| 76 | static const double one = 1.0; |
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| 77 | #else |
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| 78 | static double one = 1.0; |
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| 79 | #endif |
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| 80 | |||
| 81 | |||
| 82 | double modf(double x, double *iptr) |
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| 83 | #else |
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| 84 | double modf(x, iptr) |
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| 85 | double x,*iptr; |
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| 86 | #endif |
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| 87 | { |
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| 88 | __int32_t i0,i1,j0; |
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| 89 | __uint32_t i; |
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| 90 | EXTRACT_WORDS(i0,i1,x); |
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| 91 | j0 = ((i0>>20)&0x7ff)-0x3ff; /* exponent of x */ |
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| 92 | if(j0<20) { /* integer part in high x */ |
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| 93 | if(j0<0) { /* |x|<1 */ |
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| 94 | INSERT_WORDS(*iptr,i0&0x80000000,0); /* *iptr = +-0 */ |
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| 95 | return x; |
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| 96 | } else { |
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| 97 | i = (0x000fffff)>>j0; |
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| 98 | if(((i0&i)|i1)==0) { /* x is integral */ |
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| 99 | __uint32_t high; |
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| 100 | *iptr = x; |
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| 101 | GET_HIGH_WORD(high,x); |
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| 102 | INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */ |
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| 103 | return x; |
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| 104 | } else { |
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| 105 | INSERT_WORDS(*iptr,i0&(~i),0); |
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| 106 | return x - *iptr; |
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| 107 | } |
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| 108 | } |
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| 109 | } else if (j0>51) { /* no fraction part */ |
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| 110 | __uint32_t high; |
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| 111 | *iptr = x*one; |
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| 112 | GET_HIGH_WORD(high,x); |
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| 113 | INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */ |
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| 114 | return x; |
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| 115 | } else { /* fraction part in low x */ |
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| 116 | i = ((__uint32_t)(0xffffffff))>>(j0-20); |
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| 117 | if((i1&i)==0) { /* x is integral */ |
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| 118 | __uint32_t high; |
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| 119 | *iptr = x; |
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| 120 | GET_HIGH_WORD(high,x); |
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| 121 | INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */ |
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| 122 | return x; |
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| 123 | } else { |
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| 124 | INSERT_WORDS(*iptr,i0,i1&(~i)); |
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| 125 | return x - *iptr; |
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| 126 | } |
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| 127 | } |
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| 128 | } |
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| 129 | |||
| 130 | |||
| 131 |