From 0b44a0315b47dd8eced9f3b7f31580cf14bbfc01 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Sat, 12 Feb 2011 00:22:29 -0500 Subject: initial check-in, version 0.5.0 --- src/math/s_truncf.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 src/math/s_truncf.c (limited to 'src/math/s_truncf.c') diff --git a/src/math/s_truncf.c b/src/math/s_truncf.c new file mode 100644 index 00000000..c253e62b --- /dev/null +++ b/src/math/s_truncf.c @@ -0,0 +1,50 @@ +/* @(#)s_floor.c 5.1 93/09/24 */ +/* + * ==================================================== + * 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. + * ==================================================== + */ + +/* + * truncf(x) + * Return x rounded toward 0 to integral value + * Method: + * Bit twiddling. + * Exception: + * Inexact flag raised if x not equal to truncf(x). + */ + +#include +#include "math_private.h" + +static const float huge = 1.0e30F; + +float +truncf(float x) +{ + int32_t i0,j0; + uint32_t i; + GET_FLOAT_WORD(i0,x); + j0 = ((i0>>23)&0xff)-0x7f; + if(j0<23) { + if(j0<0) { /* raise inexact if x != 0 */ + if(huge+x>0.0F) /* |x|<1, so return 0*sign(x) */ + i0 &= 0x80000000; + } else { + i = (0x007fffff)>>j0; + if((i0&i)==0) return x; /* x is integral */ + if(huge+x>0.0F) /* raise inexact flag */ + i0 &= (~i); + } + } else { + if(j0==0x80) return x+x; /* inf or NaN */ + else return x; /* x is integral */ + } + SET_FLOAT_WORD(x,i0); + return x; +} -- cgit v1.2.1