Re: [cc65] Modules with self modifying code

Hi,

On Mon, Feb 07, 2011 at 09:04:46PM +0100, Ullrich von Bassewitz wrote:
> > But if it's true, that we have not-so-much valid segment types (in the sense
> > of 6502) then we could have even more one, the writable CODE segment, which
> > would be the place for smc.
>
> Nope. There is a reason why CODE and RODATA are readonly. See my story about
> debugging the memory overwrite bug in elite in one of my last mails. Want to
> know how I found the problem after *weeks* of frustration?

Ehm, it seems you haven't got my point (which can be because of my
not-so-good English): I agree with the usage of segments, that we have
many of them, and not only - let's say - two: for example "RAM" and
"ROM" (for ROMable). That's exactly why I wrote that I like we have
more "fine tuned" segment purposes (and names), that's why I think
it's not so good to place smc into DATA. It would be much more logical
to create one new segment for this, let's say RWCODE. I haven't told
that the "default" CODE segment should be RW, or there is sense to
drop many segments and have fewer. Well, I told this, but as an
example that if smc can't have its own segment, and we want it in
DATA, then it's "fair" not to have RODATA/DATA/CODE separated either
... Of course it does not mean that I would like that, it was an
"anti-example". Basically if the point is about _only_ ROMable and not
"ROMable" code, two segments would be enough, but it's not so nice, of
course! That's exactly I think that "executable and read-write" kind
of segment (smc) is a totally new, which deserves a new segment (DATA
is non-executable/read-write, so it's not a logical choice, imho, even
if know that 6502 hasn't got anything to say something is executable
or not, but if we ignore "executable" and "non-exeutable" behaviour of
segments, then we would be able to ignore the improtance to have
RODATA/CODE separated as well!)

Hopefully I was smart enough this time to express myself well enough :)

[PS: I am waiting from gmail now, since my ISP is blocked, so sorry
about the thread-break I possibly done with this move ...]

-- 
Gábor
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