diff options
Diffstat (limited to 'runtime/arith.c')
| -rw-r--r-- | runtime/arith.c | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/runtime/arith.c b/runtime/arith.c index d1d0da29..4c818a76 100644 --- a/runtime/arith.c +++ b/runtime/arith.c @@ -84,26 +84,34 @@ static int64_t _stp_mod64 (const char **error, int64_t x, int64_t y) } -#ifndef _STP_TEST_ -/** Return a random integer between -n and n. +/** Return a random integer between 0 and n - 1. * @param n how far from zero to go. Make it positive but less than a million or so. */ -static int _stp_random_pm (int n) +static unsigned long _stp_random_u (unsigned long n) { static unsigned long seed; static int initialized_p = 0; - + if (unlikely (! initialized_p)) { seed = (unsigned long) jiffies; initialized_p = 1; } - + /* from glibc rand man page */ seed = seed * 1103515245 + 12345; - - return (seed % (2*n+1)-n); + + return (n == 0 ? 0 : seed % n); } -#endif /* _STP_TEST_ */ + + +/** Return a random integer between -n and n. + * @param n how far from zero to go. Make it positive but less than a million or so. + */ +static int _stp_random_pm (unsigned n) +{ + return -(int)n + (int)_stp_random_u (2*n + 1); +} + #if defined (__i386__) || defined (__arm__) |