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Diffstat (limited to 'stdlib/drand48-iter.c')
-rw-r--r--stdlib/drand48-iter.c57
1 files changed, 19 insertions, 38 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;