Properly sign extend the result of jrand48() and mrand48().

These functions are supposed to return a value between [_2^31, 2^31).
This doesn't seem to work on 64-bit systems, where we return a value
between [0, 3^32). Patch up the function to use proper casts to int32_t.
While there, fix some other style bugs.

MFC after:	2 weeks
This commit is contained in:
Ed Schouten 2016-12-06 19:08:29 +00:00
parent b02f20f47e
commit 8ab00b8fbc
2 changed files with 9 additions and 2 deletions

View File

@ -14,11 +14,14 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <stdint.h>
#include "rand48.h"
long
jrand48(unsigned short xseed[3])
{
_dorand48(xseed);
return ((long) xseed[2] << 16) + (long) xseed[1];
return ((int32_t)(((uint32_t)xseed[2] << 16) | (uint32_t)xseed[1]));
}

View File

@ -14,6 +14,8 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <stdint.h>
#include "rand48.h"
extern unsigned short _rand48_seed[3];
@ -21,6 +23,8 @@ extern unsigned short _rand48_seed[3];
long
mrand48(void)
{
_dorand48(_rand48_seed);
return ((long) _rand48_seed[2] << 16) + (long) _rand48_seed[1];
return ((int32_t)(((uint32_t)_rand48_seed[2] << 16) |
(uint32_t)_rand48_seed[1]));
}