1 /* @(#)s_floor.c 5.1 93/09/24 */ 2 /* 3 * ==================================================== 4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 5 * 6 * Developed at SunPro, a Sun Microsystems, Inc. business. 7 * Permission to use, copy, modify, and distribute this 8 * software is freely granted, provided that this notice 9 * is preserved. 10 * ==================================================== 11 */ 12 13 /* 14 * floorl(x) 15 * Return x rounded toward -inf to integral value 16 * Method: 17 * Bit twiddling. 18 * Exception: 19 * Inexact flag raised if x not equal to floor(x). 20 */ 21 22 #include <math.h> 23 24 #include "math_private.h" 25 26 static const long double huge = 1.0e4930L; 27 28 long double 29 floorl(long double x) 30 { 31 int32_t i1,jj0; 32 u_int32_t i,j,se,i0,sx; 33 GET_LDOUBLE_WORDS(se,i0,i1,x); 34 sx = (se>>15)&1; 35 jj0 = (se&0x7fff)-0x3fff; 36 if(jj0<31) { 37 if(jj0<0) { /* raise inexact if x != 0 */ 38 if(huge+x>0.0) { 39 if(sx==0) 40 return 0.0L; 41 else if(((se&0x7fff)|i0|i1)!=0) 42 return -1.0L; 43 } 44 } else { 45 i = (0x7fffffff)>>jj0; 46 if(((i0&i)|i1)==0) return x; /* x is integral */ 47 if(huge+x>0.0) { /* raise inexact flag */ 48 if(sx) { 49 if (jj0>0 && (i0+(0x80000000>>jj0))>i0) 50 i0 += (0x80000000)>>jj0; 51 else 52 { 53 i = 0x7fffffff; 54 ++se; 55 } 56 } 57 i0 &= (~i); i1=0; 58 } 59 } 60 } else if (jj0>62) { 61 if(jj0==0x4000) return x+x; /* inf or NaN */ 62 else return x; /* x is integral */ 63 } else { 64 i = ((u_int32_t)(0xffffffff))>>(jj0-31); 65 if((i1&i)==0) return x; /* x is integral */ 66 if(huge+x>0.0) { /* raise inexact flag */ 67 if(sx) { 68 if(jj0==31) i0+=1; 69 else { 70 j = i1+(1<<(63-jj0)); 71 if(j<i1) i0 +=1 ; /* got a carry */ 72 i1=j; 73 } 74 } 75 i1 &= (~i); 76 } 77 } 78 SET_LDOUBLE_WORDS(x,se,i0,i1); 79 return x; 80 } 81 DEF_STD(floorl); 82