17 Oct
2003
17 Oct
'03
9:28 a.m.
Oh no, many HP boot loaders use self modifying code.
Take a look at the source for the H 264X terminal boot rom, it alters an
instruction by
using it as the target for an increment-and-skip-on-zero instuction. HP
took great pains
to squeeze some boot loaders into only 64 words. As a result you have
to reload these
loaders from ROM each time they run.
ben franchuk wrote:
Tony Duell wrote:
Err, self-modifying code? That was the traditional way to do this
sort of thing.
I think the PC is noted more more self-modifying code than the old
machines. The only real self modifying code (on your typical early
machine) is the fact the return address is placed in the first word
of subroutine code.
C requires a stack pointer and a index
register.Offhand I don't
think your hardware supports that.
Certain HP2xxx do have index registers (the ones with the EIG
instructions
IIRC), but guess how FORTRAN compilers handle indexed array accesses -tony