diff options
Diffstat (limited to 'stdlib')
| -rw-r--r-- | stdlib/drand48-iter.c | 57 | ||||
| -rw-r--r-- | stdlib/drand48_r.c | 9 | ||||
| -rw-r--r-- | stdlib/erand48_r.c | 42 |
3 files changed, 46 insertions, 62 deletions
diff --git a/stdlib/drand48-iter.c b/stdlib/drand48-iter.c index 967c404706..65e78eb3ce 100644 --- a/stdlib/drand48-iter.c +++ b/stdlib/drand48-iter.c @@ -20,7 +20,7 @@ Boston, MA 02111-1307, USA. */ #include <errno.h> #include <stdlib.h> #include <limits.h> - +#include <sys/types.h> /* Global state for non-reentrent functions. */ struct drand48_data __libc_drand48_data; @@ -31,12 +31,7 @@ __drand48_iterate (xsubi, buffer) unsigned short int xsubi[3]; struct drand48_data *buffer; { - /* Be generous for the arguments, detect some errors. */ - if (xsubi == NULL || buffer == NULL) - { - errno = EFAULT; - return -1; - } + u_int64_t X, a, result; /* Initialize buffer, if not yet done. */ if (!buffer->init) @@ -58,42 +53,28 @@ __drand48_iterate (xsubi, buffer) 48 bits. Because we compute the modulus it does not care how many bits really are computed. */ - if (sizeof (long int) >= 6) + if (sizeof (unsigned short int) == 2) { - /* The `long' data type is sufficent. */ - unsigned long int X, a, result; + X = (xsubi[2] << 16 | xsubi[1]) << 16 | xsubi[0]; + a = (buffer->a[2] << 16 | buffer->a[1]) << 16 | buffer->a[0]; -#define ONE_STEP \ - if (sizeof (unsigned short int) == 2) \ - { \ - X = (xsubi[2] << 16 | xsubi[1]) << 16 | xsubi[0]; \ - a = (buffer->a[2] << 16 | buffer->a[1]) << 16 | buffer->a[0]; \ - \ - result = X * a + buffer->c; \ - \ - xsubi[0] = result & 0xffff; \ - result >>= 16; \ - xsubi[1] = result & 0xffff; \ - result >>= 16; \ - xsubi[2] = result & 0xffff; \ - } \ - else \ - { \ - X = xsubi[2] << 16 | xsubi[1] >> 16; \ - a = buffer->a[2] << 16 | buffer->a[1] >> 16; \ - \ - result = X * a + buffer->c; \ - \ - xsubi[0] = result >> 16 & 0xffffffffl; \ - xsubi[1] = result << 16 & 0xffff0000l; \ - } - ONE_STEP; + result = X * a + buffer->c; + + xsubi[0] = result & 0xffff; + result >>= 16; + xsubi[1] = result & 0xffff; + result >>= 16; + xsubi[2] = result & 0xffff; } else { - /* We have to use the `long long' data type. */ - unsigned long long int X, a, result; - ONE_STEP; + X = xsubi[2] << 16 | xsubi[1] >> 16; + a = buffer->a[2] << 16 | buffer->a[1] >> 16; + + result = X * a + buffer->c; + + xsubi[0] = result >> 16 & 0xffffffffl; + xsubi[1] = result << 16 & 0xffff0000l; } return 0; diff --git a/stdlib/drand48_r.c b/stdlib/drand48_r.c index eaba057fa1..3b774863e9 100644 --- a/stdlib/drand48_r.c +++ b/stdlib/drand48_r.c @@ -1,4 +1,4 @@ -/* Copyright (C) 1995 Free Software Foundation, Inc. +/* Copyright (C) 1995, 1996 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, August 1995. @@ -26,12 +26,5 @@ drand48_r (buffer, result) struct drand48_data *buffer; double *result; { - /* be generous for the arguments, detect some errors. */ - if (buffer == NULL) - { - errno = EFAULT; - return -1; - } - return erand48_r (buffer->X, buffer, result); } diff --git a/stdlib/erand48_r.c b/stdlib/erand48_r.c index 86d2f734d9..ab41474aca 100644 --- a/stdlib/erand48_r.c +++ b/stdlib/erand48_r.c @@ -17,9 +17,15 @@ License along with the GNU C Library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ -#include <errno.h> -#include <math.h> #include <stdlib.h> +#include "gmp.h" +#include "gmp-mparam.h" +#include <float.h> + + +/* Function to construct a floating point number from an MP integer + containing the fraction bits, a base 2 exponent, and a sign flag. */ +extern double __mpn_construct_double (mp_srcptr mpn, int exponent, int neg); int erand48_r (xsubi, buffer, result) @@ -27,26 +33,30 @@ erand48_r (xsubi, buffer, result) struct drand48_data *buffer; double *result; { - int i; - - /* Be generous for the arguments, detect some errors. */ - if (result == NULL) - { - errno = EFAULT; - return -1; - } + mp_limb mpn[(3 * sizeof (unsigned short int) + sizeof (mp_limb) - 1) + / sizeof (mp_limb)]; /* Compute next state. */ if (__drand48_iterate (xsubi, buffer) < 0) return -1; - *result = 0.0; - for (i = 4 / sizeof (unsigned short int); i >= 0; --i) - { - double factor = ldexp (1.0, (i - 6) * sizeof (unsigned short int)); + /* Build a 48-bit mpn containing the 48 random bits. */ + +#if BITS_PER_MP_LIMB == 64 + mpn[0] = (xsubi[0] << 32) | (xsubi[1] << 16) | xsubi[2]; +#elif BITS_PER_MP_LIMB == 32 + mpn[0] = (xsubi[1] << 16) | xsubi[2]; + mpn[1] = xsubi[0]; +#else + #error "BITS_PER_MP_LIMB value not handled" +#endif + + /* Shift them up so they are most significant bits of the fraction. */ + __mpn_lshift (mpn, mpn, sizeof mpn / sizeof mpn[0], DBL_MANT_DIG - 48); - *result += factor * (double) xsubi[i]; - } + /* Construct a positive double using those bits for the fractional part, + and a zero exponent so the resulting FP number is [0.0,1.0). */ + *result = __mpn_construct_double (mpn, 0, 0); return 0; } |