5980be9b3c
This work is based in part on code from NetBSD libm, libc and kernel. The library is partly public domain and partly BSD-style licensed.
64 lines
1.5 KiB
C
64 lines
1.5 KiB
C
/* s_floorf.c -- float version of s_floor.c.
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* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
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*/
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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#include <sys/cdefs.h>
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#if defined(LIBM_SCCS) && !defined(lint)
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__RCSID("$NetBSD: s_floorf.c,v 1.8 2008/04/25 22:21:53 christos Exp $");
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#endif
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/*
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* floorf(x)
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* Return x rounded toward -inf to integral value
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* Method:
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* Bit twiddling.
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* Exception:
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* Inexact flag raised if x not equal to floorf(x).
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*/
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#include "math.h"
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#include "math_private.h"
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static const float huge = 1.0e30;
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float
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floorf(float x)
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{
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int32_t i0,jj0;
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uint32_t i;
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GET_FLOAT_WORD(i0,x);
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jj0 = ((i0>>23)&0xff)-0x7f;
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if(jj0<23) {
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if(jj0<0) { /* raise inexact if x != 0 */
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if(huge+x>(float)0.0) {/* return 0*sign(x) if |x|<1 */
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if(i0>=0) {i0=0;}
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else if((i0&0x7fffffff)!=0)
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{ i0=0xbf800000;}
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}
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} else {
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i = (0x007fffff)>>jj0;
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if((i0&i)==0) return x; /* x is integral */
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if(huge+x>(float)0.0) { /* raise inexact flag */
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if(i0<0) i0 += (0x00800000)>>jj0;
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i0 &= (~i);
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}
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}
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} else {
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if(jj0==0x80) return x+x; /* inf or NaN */
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else return x; /* x is integral */
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}
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SET_FLOAT_WORD(x,i0);
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return x;
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}
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