diff options
Diffstat (limited to 'newlib/libm/common/s_lround.c')
-rw-r--r-- | newlib/libm/common/s_lround.c | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/newlib/libm/common/s_lround.c b/newlib/libm/common/s_lround.c new file mode 100644 index 000000000..7bd249f9c --- /dev/null +++ b/newlib/libm/common/s_lround.c @@ -0,0 +1,71 @@ +/* + * ==================================================== + * 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. + * ==================================================== + */ + +#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 */ |