Bug in v7 backup or printf on 11/34
Jack Jansen
jack at vu44.UUCP
Fri Jan 6 05:58:43 AEST 1984
There is a bug in the v7 backup routine. It cannot backup things
like movb .....,(r3)+
This isn't a problem for C programs, but the first few lines of
doprnt.s read something like
sub $128.+12.,sp
....
mov sp,r3
and later on, the 128 bytes following r3 are used as a buffer.
So, if you have the hard luck that you enter doprnt with 'sp'
pointing to an existing location, but sp-128. not, you're in
trouble.
I didn't bother fixing the bug (altough I would be interested in
a fix, of course), I just added a
tst (sp)
instruction after the 'sub' in doprnt.s
Jack Jansen, VU Amsterdam, mcvax!vu44!jack
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