| 1 | /* sf_nextafter.c -- float version of s_nextafter.c. |
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| 2 | * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. |
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| 3 | */ |
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| 4 | |
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| 5 | /* |
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| 6 | * ==================================================== |
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| 7 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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| 8 | * |
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| 9 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
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| 10 | * Permission to use, copy, modify, and distribute this |
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| 11 | * software is freely granted, provided that this notice |
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| 12 | * is preserved. |
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| 13 | * ==================================================== |
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| 14 | */ |
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| 15 | |
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| 16 | #include "fdlibm.h" |
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| 17 | |
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| 18 | #ifdef __STDC__ |
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| 19 | float nextafterf(float x, float y) |
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| 20 | #else |
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| 21 | float nextafterf(x,y) |
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| 22 | float x,y; |
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| 23 | #endif |
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| 24 | { |
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| 25 | __int32_t hx,hy,ix,iy; |
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| 26 | |
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| 27 | GET_FLOAT_WORD(hx,x); |
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| 28 | GET_FLOAT_WORD(hy,y); |
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| 29 | ix = hx&0x7fffffff; /* |x| */ |
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| 30 | iy = hy&0x7fffffff; /* |y| */ |
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| 31 | |
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| 32 | if(FLT_UWORD_IS_NAN(ix) || |
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| 33 | FLT_UWORD_IS_NAN(iy)) |
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| 34 | return x+y; |
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| 35 | if(x==y) return x; /* x=y, return x */ |
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| 36 | if(FLT_UWORD_IS_ZERO(ix)) { /* x == 0 */ |
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| 37 | SET_FLOAT_WORD(x,(hy&0x80000000)|FLT_UWORD_MIN); |
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| 38 | y = x*x; |
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| 39 | if(y==x) return y; else return x; /* raise underflow flag */ |
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| 40 | } |
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| 41 | if(hx>=0) { /* x > 0 */ |
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| 42 | if(hx>hy) { /* x > y, x -= ulp */ |
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| 43 | hx -= 1; |
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| 44 | } else { /* x < y, x += ulp */ |
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| 45 | hx += 1; |
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| 46 | } |
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| 47 | } else { /* x < 0 */ |
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| 48 | if(hy>=0||hx>hy){ /* x < y, x -= ulp */ |
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| 49 | hx -= 1; |
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| 50 | } else { /* x > y, x += ulp */ |
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| 51 | hx += 1; |
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| 52 | } |
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| 53 | } |
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| 54 | hy = hx&0x7f800000; |
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| 55 | if(hy>FLT_UWORD_MAX) return x+x; /* overflow */ |
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| 56 | if(hy<0x00800000) { /* underflow */ |
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| 57 | y = x*x; |
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| 58 | if(y!=x) { /* raise underflow flag */ |
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| 59 | SET_FLOAT_WORD(y,hx); |
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| 60 | return y; |
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| 61 | } |
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| 62 | } |
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| 63 | SET_FLOAT_WORD(x,hx); |
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| 64 | return x; |
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| 65 | } |
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| 66 | |
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| 67 | #ifdef _DOUBLE_IS_32BITS |
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| 68 | |
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| 69 | #ifdef __STDC__ |
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| 70 | double nextafter(double x, double y) |
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| 71 | #else |
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| 72 | double nextafter(x,y) |
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| 73 | double x,y; |
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| 74 | #endif |
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| 75 | { |
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| 76 | return (double) nextafterf((float) x, (float) x); |
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| 77 | } |
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| 78 | |
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| 79 | #endif /* defined(_DOUBLE_IS_32BITS) */ |
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