diff options
| author | das <das@FreeBSD.org> | 2008-01-15 23:31:24 +0000 |
|---|---|---|
| committer | das <das@FreeBSD.org> | 2008-01-15 23:31:24 +0000 |
| commit | 84df07987f7a80e425d1794e682cf78fef24cb51 (patch) | |
| tree | d2f6083b74ada970cac0873b30d999c49fa97a82 /lib/msun/src/s_rintl.c | |
| parent | e5e6d6bdf6f4856c0c717fa6c13976c85772feb5 (diff) | |
| download | FreeBSD-src-84df07987f7a80e425d1794e682cf78fef24cb51.zip FreeBSD-src-84df07987f7a80e425d1794e682cf78fef24cb51.tar.gz | |
Optimize this a bit better.
Submitted by: bde (although these aren't all of his changes)
Diffstat (limited to 'lib/msun/src/s_rintl.c')
| -rw-r--r-- | lib/msun/src/s_rintl.c | 31 |
1 files changed, 18 insertions, 13 deletions
diff --git a/lib/msun/src/s_rintl.c b/lib/msun/src/s_rintl.c index 21dbbf6..43a535a 100644 --- a/lib/msun/src/s_rintl.c +++ b/lib/msun/src/s_rintl.c @@ -32,8 +32,10 @@ __FBSDID("$FreeBSD$"); #include "fpmath.h" -static const long double -shift[2]={ +#define BIAS (LDBL_MAX_EXP - 1) + +static const float +shift[2] = { #if LDBL_MANT_DIG == 64 0x1.0p63, -0x1.0p63 #elif LDBL_MANT_DIG == 113 @@ -51,27 +53,30 @@ rintl(long double x) u.e = x; - if (u.bits.exp >= LDBL_MANT_DIG + LDBL_MAX_EXP - 2) { + if (u.bits.exp >= BIAS + LDBL_MANT_DIG - 1) { /* * The biased exponent is greater than the number of digits * in the mantissa, so x is inf, NaN, or an integer. */ - if (u.bits.exp == 2 * LDBL_MAX_EXP - 1) - return (x + x); /* inf or NaN */ - else - return (x); + return (x); } + sign = u.bits.sign; /* * The following code assumes that intermediate results are * evaluated in long double precision. If they are evaluated in - * greater precision, double rounding will occur, and if they are + * greater precision, double rounding may occur, and if they are * evaluated in less precision (as on i386), results will be * wildly incorrect. */ - sign = u.bits.sign; - u.e = shift[sign] + x; - u.e -= shift[sign]; - u.bits.sign = sign; - return (u.e); + x += shift[sign]; + x -= shift[sign]; + + /* + * If the result is +-0, then it must have the same sign as x, but + * the above calculation doesn't always give this. Fix up the sign. + */ + if (x == 0.0L) + return (sign ? -0.0L : 0.0L); + return (x); } |
