26 Nov
2017
26 Nov
'17
5:15 a.m.
On Sat, 25 Nov 2017, William Cheswick wrote:
On CDC machines, the return jump (RJ) instruction
generally used to call
subroutines deposited a jump instruction (EQ B0,B0,caller+1) in the
called routine and jumped to the word after it. Clearly, languages like
Pascal didn’t use that.
Ahhh; that brings back fond memories of my Cyber-72 days, and how easily
we CompSci kiddies broke into KRONOS...[*]
One of my favourite machines was the PDP-8; the JSR instruction planted
the return address in the first word and jumped to the second word, with a
return being done (IIRC) by an indirect jump to the first word.
Recursion? What's that?
[*]
Can't remember it now, but (on an LA-36 Duckwriter) it was something like:
COMMON POOL
RELEASE POOL
(intr)
(Could be abbreviated to "COMMO POO" and "REL POO" for those with
a
sick sense of humour, which was most of us.)
and you got system privileges...
--
Dave Horsfall DTM (VK2KFU) "Those who don't understand security will
suffer."