diff options
Diffstat (limited to 'src/math/floorl.c')
| -rw-r--r-- | src/math/floorl.c | 108 |
1 files changed, 21 insertions, 87 deletions
diff --git a/src/math/floorl.c b/src/math/floorl.c index 3901b060..961f9e89 100644 --- a/src/math/floorl.c +++ b/src/math/floorl.c @@ -1,23 +1,3 @@ -/* origin: FreeBSD /usr/src/lib/msun/src/s_floorl.c */ -/* - * ==================================================== - * 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. - * ==================================================== - */ -/* - * floorl(x) - * Return x rounded toward -inf to integral value - * Method: - * Bit twiddling. - * Exception: - * Inexact flag raised if x not equal to floorl(x). - */ - #include "libm.h" #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024 @@ -26,77 +6,31 @@ long double floorl(long double x) return floor(x); } #elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384 - -#ifdef LDBL_IMPLICIT_NBIT -#define MANH_SIZE (LDBL_MANH_SIZE + 1) -#define INC_MANH(u, c) do { \ - uint64_t o = u.bits.manh; \ - u.bits.manh += (c); \ - if (u.bits.manh < o) \ - u.bits.exp++; \ -} while (0) -#else -#define MANH_SIZE LDBL_MANH_SIZE -#define INC_MANH(u, c) do { \ - uint64_t o = u.bits.manh; \ - u.bits.manh += (c); \ - if (u.bits.manh < o) { \ - u.bits.exp++; \ - u.bits.manh |= 1llu << (LDBL_MANH_SIZE - 1); \ - } \ -} while (0) +#if LDBL_MANT_DIG == 64 +#define TOINT 0x1p63 +#elif LDBL_MANT_DIG == 113 +#define TOINT 0x1p112 #endif - -static const long double huge = 1.0e300; - long double floorl(long double x) { - union IEEEl2bits u = { .e = x }; - int e = u.bits.exp - LDBL_MAX_EXP + 1; + union ldshape u = {x}; + int e = u.i.se & 0x7fff; + long double y; - if (e < MANH_SIZE - 1) { - if (e < 0) { - /* raise inexact if x != 0 */ - if (huge + x > 0.0) - if (u.bits.exp > 0 || - (u.bits.manh | u.bits.manl) != 0) - u.e = u.bits.sign ? -1.0 : 0.0; - } else { - uint64_t m = ((1llu << MANH_SIZE) - 1) >> (e + 1); - if (((u.bits.manh & m) | u.bits.manl) == 0) - return x; /* x is integral */ - if (u.bits.sign) { -#ifdef LDBL_IMPLICIT_NBIT - if (e == 0) - u.bits.exp++; - else -#endif - INC_MANH(u, 1llu << (MANH_SIZE - e - 1)); - } - /* raise inexact flag */ - if (huge + x > 0.0) { - u.bits.manh &= ~m; - u.bits.manl = 0; - } - } - } else if (e < LDBL_MANT_DIG - 1) { - uint64_t m = (uint64_t)-1 >> (64 - LDBL_MANT_DIG + e + 1); - if ((u.bits.manl & m) == 0) - return x; /* x is integral */ - if (u.bits.sign) { - if (e == MANH_SIZE - 1) - INC_MANH(u, 1); - else { - uint64_t o = u.bits.manl; - u.bits.manl += 1llu << (LDBL_MANT_DIG - e - 1); - if (u.bits.manl < o) /* got a carry */ - INC_MANH(u, 1); - } - } - /* raise inexact flag */ - if (huge + x > 0.0) - u.bits.manl &= ~m; + if (e >= 0x3fff+LDBL_MANT_DIG-1 || x == 0) + return x; + /* y = int(x) - x, where int(x) is an integer neighbor of x */ + if (u.i.se >> 15) + y = x - TOINT + TOINT - x; + else + y = x + TOINT - TOINT - x; + /* special case because of non-nearest rounding modes */ + if (e <= 0x3fff-1) { + FORCE_EVAL(y); + return u.i.se >> 15 ? -1 : 0; } - return u.e; + if (y > 0) + return x + y - 1; + return x + y; } #endif |