summaryrefslogtreecommitdiff log msg author committer range
path: root/libm/s_floor.c
blob: 91f1879beea5ab7c84ffae8fabe11c3372804298 (plain)
 ```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 ``` ``````/* * ==================================================== * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. * * Developed at SunPro, a Sun Microsystems, Inc. business. * Permission to use, copy, modify, and distribute this * software is freely granted, provided that this notice * is preserved. * ==================================================== */ /* * floor(x) * Return x rounded toward -inf to integral value * Method: * Bit twiddling. * Exception: * Inexact flag raised if x not equal to floor(x). */ #include /* Prevent math.h from defining a colliding inline */ #undef __USE_EXTERN_INLINES #include "math.h" #include "math_private.h" static const double huge = 1.0e300; double floor(double x) { int32_t i0,i1,j0; u_int32_t i,j; EXTRACT_WORDS(i0,i1,x); j0 = ((i0>>20)&0x7ff)-0x3ff; if(j0<20) { if(j0<0) { /* raise inexact if x != 0 */ if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */ if(i0>=0) {i0=i1=0;} else if(((i0&0x7fffffff)|i1)!=0) { i0=0xbff00000;i1=0;} } } else { i = (0x000fffff)>>j0; if(((i0&i)|i1)==0) return x; /* x is integral */ if(huge+x>0.0) { /* raise inexact flag */ if(i0<0) i0 += (0x00100000)>>j0; i0 &= (~i); i1=0; } } } else if (j0>51) { if(j0==0x400) return x+x; /* inf or NaN */ else return x; /* x is integral */ } else { i = ((u_int32_t)(0xffffffff))>>(j0-20); if((i1&i)==0) return x; /* x is integral */ if(huge+x>0.0) { /* raise inexact flag */ if(i0<0) { if(j0==20) i0+=1; else { j = i1+(1<<(52-j0)); if(j