diff options
author | pommicket <pommicket@gmail.com> | 2022-02-20 13:18:21 -0800 |
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committer | pommicket <pommicket@gmail.com> | 2022-02-20 13:18:21 -0800 |
commit | 9bc8a11afeed3569736b89754012e3ca22ee10f6 (patch) | |
tree | 5f0ec0d5c05f879b1ee86adfa654ed3ef2178d5f /05/musl-0.6.0/src/math/s_modf.c | |
parent | 0f97a589b800bdb71dda05984192f0f66a52edaa (diff) |
conclusion
Diffstat (limited to '05/musl-0.6.0/src/math/s_modf.c')
-rw-r--r-- | 05/musl-0.6.0/src/math/s_modf.c | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/05/musl-0.6.0/src/math/s_modf.c b/05/musl-0.6.0/src/math/s_modf.c new file mode 100644 index 0000000..a5528d6 --- /dev/null +++ b/05/musl-0.6.0/src/math/s_modf.c @@ -0,0 +1,71 @@ +/* @(#)s_modf.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. + * ==================================================== + */ + +/* + * modf(double x, double *iptr) + * return fraction part of x, and return x's integral part in *iptr. + * Method: + * Bit twiddling. + * + * Exception: + * No exception. + */ + +#include <math.h> +#include "math_private.h" + +static const double one = 1.0; + +double +modf(double x, double *iptr) +{ + int32_t i0,i1,j0; + uint32_t i; + EXTRACT_WORDS(i0,i1,x); + j0 = ((i0>>20)&0x7ff)-0x3ff; /* exponent of x */ + if(j0<20) { /* integer part in high x */ + if(j0<0) { /* |x|<1 */ + INSERT_WORDS(*iptr,i0&0x80000000,0); /* *iptr = +-0 */ + return x; + } else { + i = (0x000fffff)>>j0; + if(((i0&i)|i1)==0) { /* x is integral */ + uint32_t high; + *iptr = x; + GET_HIGH_WORD(high,x); + INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */ + return x; + } else { + INSERT_WORDS(*iptr,i0&(~i),0); + return x - *iptr; + } + } + } else if (j0>51) { /* no fraction part */ + uint32_t high; + *iptr = x*one; + GET_HIGH_WORD(high,x); + INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */ + return x; + } else { /* fraction part in low x */ + i = ((uint32_t)(0xffffffff))>>(j0-20); + if((i1&i)==0) { /* x is integral */ + uint32_t high; + *iptr = x; + GET_HIGH_WORD(high,x); + INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */ + return x; + } else { + INSERT_WORDS(*iptr,i0,i1&(~i)); + return x - *iptr; + } + } +} |