11 May
2005
11 May
'05
6:22 p.m.
It was thus said that the Great vrs once stated:
Oh, PUSH-JUMP.
-spc (Okay, that makes sense now ... )
What does PUSHJ actually do? I remember
reading about it in Steven Levy's
Hackers, but never got what was so special about it.
PUSHJ does a CALL, using a software implementation of a stack, which allows
the target subroutine to be recursive. JMS stores the return address in the
entry point, so it won't do (without help) for recursive routines.
(Similarly, POPJ is like RET.)