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(random): Use rand differently, and distinguish BSD/USG.

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This commit is contained in:
Richard M. Stallman 1994-07-28 12:50:34 +00:00
parent 8ee9ba64c1
commit f8b53a822c
1 changed files with 9 additions and 2 deletions
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11
src/sysdep.c
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@ -2612,8 +2612,15 @@ random ()
#ifdef HAVE_RAND48
return rand48 ();
#else
/* Arrange to return a range centered on zero. */
return (rand () << 15) + rand () - (1 << 29);
/* The BSD rand returns numbers in the range of 0 to 2e31 - 1,
with unusable least significant bits. The USG rand returns
numbers in the range of 0 to 2e15 - 1, all usable. Let us
build a usable 30 bit number from either. */
#ifdef USG
return (rand () << 15) + rand ();
#else
return (rand () & 0x3fff8000) + (rand () >> 16);
#endif
#endif
}