Date: 1 Apr 1997 23:36:18 +0200 From: sec@42.org (Stefan `Sec` Zehl) To: freebsd-questions@freebsd.org Subject: Re: 'GET A LIFE' doesn't work Message-ID: <slrn5k2vuh.583.sec@matrix.42.org> References: <199704010048.QAA29694@gabber.c2.net>
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In article <199704010048.QAA29694@gabber.c2.net>, sameer wrote:
> Why doesn't:
>
> echo '[q]sa[ln0=aln256%Pln256/snlbx]sb3135071790101768542287578439snlbxq'|dc
>
> work as expected on freebsd?
I traced it down a little (heavily relying on the Manpage :)
it does nothing more that continually dividing the number
(3135071790101768542287578439)
by 256 and printing the reminders...
# store letter 'q' in register a
[q]sa
# store command "ln0=aln256%Pln256/snlbx" in register b
[ln0=aln256%Pln256/snlbx]sb
# store number "3135071790101768542287578439" in register n
3135071790101768542287578439sn
# load register b on stack and execute as command
lbx
# quit
q
While the command in "b" does:
# load reg. a on stack, compare it with 0, if true execute reg. a (= quit)
ln 0 =a
# load reg. a on stack, do modulo 256 and Print this value
ln 256 % P
# load reg. a on stack, divide (integer) by 256 an store it in reg. n again
ln 256 / sn
# load reg. b on stack and execute as command (recursion)
lbx
So, so far for the difficult part, now why doesn't this work on FreeBSD ?
it's the 'P' command of FreeBSD's dc
on FreeBSD: echo '71Pq'|dc yields "71"
on SunOS: echo '71Pq'|dc yields "G"
from the SunOS manpage:
P Interpret the top of the stack as an ASCII string,
remove and print it.
from the FreeBSD manpage:
P Prints the value on the top of the stack, popping it
off, and does not print a newline after.
so they don't even claim to do the same....
The magic question is now, should this behavior be changed ?
CU,
Sec
--
Fuer die Raupe ist es das Ende der Welt,
Fuer den Rest der Welt ist es ein Schmetterling
Error 0: No error
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