105a0b428SJohn Marino /* @(#)s_floor.c 5.1 93/09/24 */
205a0b428SJohn Marino /*
305a0b428SJohn Marino * ====================================================
405a0b428SJohn Marino * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
505a0b428SJohn Marino *
605a0b428SJohn Marino * Developed at SunPro, a Sun Microsystems, Inc. business.
705a0b428SJohn Marino * Permission to use, copy, modify, and distribute this
805a0b428SJohn Marino * software is freely granted, provided that this notice
905a0b428SJohn Marino * is preserved.
1005a0b428SJohn Marino * ====================================================
1105a0b428SJohn Marino */
1205a0b428SJohn Marino
1305a0b428SJohn Marino /*
1405a0b428SJohn Marino * floorl(x)
1505a0b428SJohn Marino * Return x rounded toward -inf to integral value
1605a0b428SJohn Marino * Method:
1705a0b428SJohn Marino * Bit twiddling.
1805a0b428SJohn Marino * Exception:
1905a0b428SJohn Marino * Inexact flag raised if x not equal to floor(x).
2005a0b428SJohn Marino */
2105a0b428SJohn Marino
2205a0b428SJohn Marino #include <math.h>
2305a0b428SJohn Marino
2405a0b428SJohn Marino #include "math_private.h"
2505a0b428SJohn Marino
2605a0b428SJohn Marino static const long double huge = 1.0e4930L;
2705a0b428SJohn Marino
2805a0b428SJohn Marino long double
floorl(long double x)2905a0b428SJohn Marino floorl(long double x)
3005a0b428SJohn Marino {
3105a0b428SJohn Marino int32_t i1,jj0;
3205a0b428SJohn Marino u_int32_t i,j,se,i0,sx;
3305a0b428SJohn Marino GET_LDOUBLE_WORDS(se,i0,i1,x);
3405a0b428SJohn Marino sx = (se>>15)&1;
3505a0b428SJohn Marino jj0 = (se&0x7fff)-0x3fff;
3605a0b428SJohn Marino if(jj0<31) {
3705a0b428SJohn Marino if(jj0<0) { /* raise inexact if x != 0 */
3805a0b428SJohn Marino if(huge+x>0.0) {
3905a0b428SJohn Marino if(sx==0)
4005a0b428SJohn Marino return 0.0L;
4105a0b428SJohn Marino else if(((se&0x7fff)|i0|i1)!=0)
4205a0b428SJohn Marino return -1.0L;
4305a0b428SJohn Marino }
4405a0b428SJohn Marino } else {
4505a0b428SJohn Marino i = (0x7fffffff)>>jj0;
4605a0b428SJohn Marino if(((i0&i)|i1)==0) return x; /* x is integral */
4705a0b428SJohn Marino if(huge+x>0.0) { /* raise inexact flag */
4805a0b428SJohn Marino if(sx) {
4905a0b428SJohn Marino if (jj0>0 && (i0+(0x80000000>>jj0))>i0)
5005a0b428SJohn Marino i0 += (0x80000000)>>jj0;
5105a0b428SJohn Marino else
5205a0b428SJohn Marino {
5305a0b428SJohn Marino i = 0x7fffffff;
5405a0b428SJohn Marino ++se;
5505a0b428SJohn Marino }
5605a0b428SJohn Marino }
5705a0b428SJohn Marino i0 &= (~i); i1=0;
5805a0b428SJohn Marino }
5905a0b428SJohn Marino }
6005a0b428SJohn Marino } else if (jj0>62) {
6105a0b428SJohn Marino if(jj0==0x4000) return x+x; /* inf or NaN */
6205a0b428SJohn Marino else return x; /* x is integral */
6305a0b428SJohn Marino } else {
6405a0b428SJohn Marino i = ((u_int32_t)(0xffffffff))>>(jj0-31);
6505a0b428SJohn Marino if((i1&i)==0) return x; /* x is integral */
6605a0b428SJohn Marino if(huge+x>0.0) { /* raise inexact flag */
6705a0b428SJohn Marino if(sx) {
6805a0b428SJohn Marino if(jj0==31) i0+=1;
6905a0b428SJohn Marino else {
7005a0b428SJohn Marino j = i1+(1<<(63-jj0));
71*74b7c7a8SJohn Marino if(j<(u_int32_t)i1) i0 +=1 ; /* got a carry */
7205a0b428SJohn Marino i1=j;
7305a0b428SJohn Marino }
7405a0b428SJohn Marino }
7505a0b428SJohn Marino i1 &= (~i);
7605a0b428SJohn Marino }
7705a0b428SJohn Marino }
7805a0b428SJohn Marino SET_LDOUBLE_WORDS(x,se,i0,i1);
7905a0b428SJohn Marino return x;
8005a0b428SJohn Marino }
81