TinyC, port to HP

From: Bob Shannon <bshannon_at_tiac.net>
Date: Fri Oct 17 16:28:19 2003

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:
>
>>>> 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
>>
>>
>>
>> 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.
>
>> -tony
>>
>
>
>
>
>
Received on Fri Oct 17 2003 - 16:28:19 BST