diff options
Diffstat (limited to 'REORG.TODO/sysdeps/ieee754/ldbl-128ibm/s_logbl.c')
-rw-r--r-- | REORG.TODO/sysdeps/ieee754/ldbl-128ibm/s_logbl.c | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/ieee754/ldbl-128ibm/s_logbl.c b/REORG.TODO/sysdeps/ieee754/ldbl-128ibm/s_logbl.c new file mode 100644 index 0000000000..3c07c5e8e2 --- /dev/null +++ b/REORG.TODO/sysdeps/ieee754/ldbl-128ibm/s_logbl.c @@ -0,0 +1,63 @@ +/* s_logbl.c -- long double version of s_logb.c. + * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz. + */ + +/* + * ==================================================== + * 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. + * ==================================================== + */ + +/* + * long double logbl(x) + * IEEE 754 logb. Included to pass IEEE test suite. Not recommend. + * Use ilogb instead. + */ + +#include <math.h> +#include <math_private.h> +#include <math_ldbl_opt.h> +#include <fix-int-fp-convert-zero.h> + +long double +__logbl (long double x) +{ + int64_t hx, hxs, rhx; + double xhi, xlo; + + ldbl_unpack (x, &xhi, &xlo); + EXTRACT_WORDS64 (hx, xhi); + hxs = hx; + hx &= 0x7fffffffffffffffLL; /* high |x| */ + if (hx == 0) + return -1.0 / fabs (x); + if (hx >= 0x7ff0000000000000LL) + return x * x; + if (__glibc_unlikely ((rhx = hx >> 52) == 0)) + { + /* POSIX specifies that denormal number is treated as + though it were normalized. */ + rhx -= __builtin_clzll (hx) - 12; + } + else if ((hx & 0x000fffffffffffffLL) == 0) + { + /* If the high part is a power of 2, and the low part is nonzero + with the opposite sign, the low part affects the + exponent. */ + int64_t lx; + EXTRACT_WORDS64 (lx, xlo); + if ((hxs ^ lx) < 0 && (lx & 0x7fffffffffffffffLL) != 0) + rhx--; + } + if (FIX_INT_FP_CONVERT_ZERO && rhx == 1023) + return 0.0L; + return (long double) (rhx - 1023); +} +#ifndef __logbl +long_double_symbol (libm, __logbl, logbl); +#endif |