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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libm/] [common/] [sf_lrint.c] - Rev 207
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/* @(#)sf_lrint.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. * ==================================================== */ /* * lrintf(x) * Return x rounded to integral value according to the prevailing * rounding mode. * Method: * Using floating addition. * Exception: * Inexact flag raised if x not equal to lrintf(x). */ #include "fdlibm.h" #ifdef __STDC__ static const float #else static float #endif /* Adding a float, x, to 2^23 will cause the result to be rounded based on the fractional part of x, according to the implementation's current rounding mode. 2^23 is the smallest float that can be represented using all 23 significant digits. */ TWO23[2]={ 8.3886080000e+06, /* 0x4b000000 */ -8.3886080000e+06, /* 0xcb000000 */ }; #ifdef __STDC__ long int lrintf(float x) #else long int lrintf(x) float x; #endif { __int32_t j0,sx; __uint32_t i0; float t; volatile float w; long int result; GET_FLOAT_WORD(i0,x); /* Extract sign bit. */ sx = (i0 >> 31); /* Extract exponent field. */ j0 = ((i0 & 0x7f800000) >> 23) - 127; if (j0 < (int)(sizeof (long int) * 8) - 1) { if (j0 < -1) return 0; else if (j0 >= 23) result = (long int) ((i0 & 0x7fffff) | 0x800000) << (j0 - 23); else { w = TWO23[sx] + x; t = w - TWO23[sx]; GET_FLOAT_WORD (i0, t); /* Detect the all-zeros representation of plus and minus zero, which fails the calculation below. */ if ((i0 & ~(1L << 31)) == 0) return 0; j0 = ((i0 >> 23) & 0xff) - 0x7f; i0 &= 0x7fffff; i0 |= 0x800000; result = i0 >> (23 - j0); } } else { return (long int) x; } return sx ? -result : result; } #ifdef _DOUBLE_IS_32BITS #ifdef __STDC__ long int lrint(double x) #else long int lrint(x) double x; #endif { return lrintf((float) x); } #endif /* defined(_DOUBLE_IS_32BITS) */