Date: Mon, 20 Dec 2004 19:13:49 -0600 From: "James R. Van Artsalen" <james@jrv.org> To: freebsd-amd64@freebsd.org Subject: /usr/games/random bug? Message-ID: <41C778CD.1080602@jrv.org>
index | next in thread | raw e-mail
5-stable "/usr/games/random -e 99" seems to always return 0, which makes
it very predictable.
5.2.1 does this too. But i386 4.x seems to work as expected (an exit
value between 0 and 98 inclusive).
The source code line in question is
return (int)((denom * random()) / LONG_MAX);
the assembler code is
.p2align 3
.LC17:
.long 0
.long 1006632960
call random
cvtsi2sdq %rax, %xmm0
mulsd 24(%rsp), %xmm0
mulsd .LC17(%rip), %xmm0
cvttsd2si %xmm0, %eax
jmp .L1
I'm not familiar enough with IEEE fp rules or amd64 fp coding to say why
this doesn't work, nor if this source code is even reasonable.
home |
help
Want to link to this message? Use this
URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?41C778CD.1080602>