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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libm/] [common/] [s_lround.c] - Rev 298
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/* * ==================================================== * 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. * ==================================================== */ /* FUNCTION <<lround>>, <<lroundf>>, <<llround>>, <<llroundf>>--round to integer, to nearest INDEX lround INDEX lroundf INDEX llround INDEX llroundf ANSI_SYNOPSIS #include <math.h> long int lround(double <[x]>); long int lroundf(float <[x]>); long long int llround(double <[x]>); long long int llroundf(float <[x]>); DESCRIPTION The <<lround>> and <<llround>> functions round their argument to the nearest integer value, rounding halfway cases away from zero, regardless of the current rounding direction. If the rounded value is outside the range of the return type, the numeric result is unspecified (depending upon the floating-point implementation, not the library). A range error may occur if the magnitude of x is too large. RETURNS <[x]> rounded to an integral value as an integer. SEEALSO See the <<round>> functions for the return being the same floating-point type as the argument. <<lrint>>, <<llrint>>. PORTABILITY ANSI C, POSIX */ #include "fdlibm.h" #ifndef _DOUBLE_IS_32BITS #ifdef __STDC__ long int lround(double x) #else long int lround(x) double x; #endif { __int32_t sign, exponent_less_1023; /* Most significant word, least significant word. */ __uint32_t msw, lsw; long int result; EXTRACT_WORDS(msw, lsw, x); /* Extract sign. */ sign = ((msw & 0x80000000) ? -1 : 1); /* Extract exponent field. */ exponent_less_1023 = ((msw & 0x7ff00000) >> 20) - 1023; msw &= 0x000fffff; msw |= 0x00100000; if (exponent_less_1023 < 20) { if (exponent_less_1023 < 0) { if (exponent_less_1023 < -1) return 0; else return sign; } else { msw += 0x80000 >> exponent_less_1023; result = msw >> (20 - exponent_less_1023); } } else if (exponent_less_1023 < (8 * sizeof (long int)) - 1) { if (exponent_less_1023 >= 52) result = ((long int) msw << (exponent_less_1023 - 20)) | (lsw << (exponent_less_1023 - 52)); else { unsigned int tmp = lsw + (0x80000000 >> (exponent_less_1023 - 20)); if (tmp < lsw) ++msw; result = ((long int) msw << (exponent_less_1023 - 20)) | (tmp >> (52 - exponent_less_1023)); } } else /* Result is too large to be represented by a long int. */ return (long int)x; return sign * result; } #endif /* _DOUBLE_IS_32BITS */
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