1 /* sf_floor.c -- float version of s_floor.c. 2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian (at) cygnus.com. 3 */ 4 5 /* 6 * ==================================================== 7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 8 * 9 * Developed at SunPro, a Sun Microsystems, Inc. business. 10 * Permission to use, copy, modify, and distribute this 11 * software is freely granted, provided that this notice 12 * is preserved. 13 * ==================================================== 14 */ 15 16 /* 17 * floorf(x) 18 * Return x rounded toward -inf to integral value 19 * Method: 20 * Bit twiddling. 21 * Exception: 22 * Inexact flag raised if x not equal to floorf(x). 23 */ 24 25 #include "fdlibm.h" 26 27 #ifdef __STDC__ 28 static const float huge = 1.0e30; 29 #else 30 static float huge = 1.0e30; 31 #endif 32 33 #ifdef __STDC__ 34 float floorf(float x) 35 #else 36 float floorf(x) 37 float x; 38 #endif 39 { 40 __int32_t i0,j0; 41 __uint32_t i,ix; 42 GET_FLOAT_WORD(i0,x); 43 ix = (i0&0x7fffffff); 44 j0 = (ix>>23)-0x7f; 45 if(j0<23) { 46 if(j0<0) { /* raise inexact if x != 0 */ 47 if(huge+x>(float)0.0) {/* return 0*sign(x) if |x|<1 */ 48 if(i0>=0) {i0=0;} 49 else if(!FLT_UWORD_IS_ZERO(ix)) 50 { i0=0xbf800000;} 51 } 52 } else { 53 i = (0x007fffff)>>j0; 54 if((i0&i)==0) return x; /* x is integral */ 55 if(huge+x>(float)0.0) { /* raise inexact flag */ 56 if(i0<0) i0 += (0x00800000)>>j0; 57 i0 &= (~i); 58 } 59 } 60 } else { 61 if(!FLT_UWORD_IS_FINITE(ix)) return x+x; /* inf or NaN */ 62 else return x; /* x is integral */ 63 } 64 SET_FLOAT_WORD(x,i0); 65 return x; 66 } 67 68 #ifdef _DOUBLE_IS_32BITS 69 70 #ifdef __STDC__ 71 double floor(double x) 72 #else 73 double floor(x) 74 double x; 75 #endif 76 { 77 return (double) floorf((float) x); 78 } 79 80 #endif /* defined(_DOUBLE_IS_32BITS) */ 81
