It is currently Mon Oct 20, 2014 5:46 pm

All times are UTC [ DST ]




Post new topic Reply to topic  [ 28 posts ]  Go to page Previous  1, 2
Author Message
PostPosted: Tue Apr 08, 2008 7:51 pm 
Offline
User avatar
 Profile

Joined: Tue Mar 25, 2008 4:22 pm
Posts: 129
Yes but the REM statement is still there. I'll probably try it again in BASIC to see if it will work or is the script file anyway, thanks.


Top
 
PostPosted: Tue Oct 14, 2008 6:10 pm 
Offline
 Profile

Joined: Tue Oct 14, 2008 12:43 am
Posts: 18
I don't suppose there are any crunchers that compress executable code, not just basic?

(Someth like this)
http://www.swolff.dk/cruncher/


Top
 
PostPosted: Tue Oct 14, 2008 6:26 pm 
Offline
User avatar
 WWW  Profile

Joined: Wed Jan 09, 2008 10:23 am
Posts: 359
Location: Glasgow, Scotland
Not that I am aware of.

I'm currently working on compression algorithms for storing BBC images though, but that's a different kettle of fish from executable files.

Kind regards,

Francis.


Top
 
PostPosted: Wed Oct 15, 2008 11:26 am 
Offline
User avatar
 Profile

Joined: Fri Jul 25, 2008 2:47 pm
Posts: 190
StuartA wrote:
I don't suppose there are any crunchers that compress executable code, not just basic?

I think it needs to be a bit clearer what you're trying to do. There's saving space for the purposes of moving things around (such as image compression), and then there's optimisation to make code smaller?

I suspect you're looking for the latter, and the answer would be that this could be done along the same lines as you have optimisers in compilers, but they would only be able to work with source code.

Why? Well, code might be self-modifying, relocating, or dependent on executing timing. You can't flag any of these things in the code itself, so you'd need an optimising assembler which could pick up directives aroudn pieces of code.

I can't see that anyone would bother with doing this for the 6502 instruction set.

If I've got the wrong end of the stick, then if you're looking to compress code, then it would have to be a non-lossy algorithm such as what WinZip might use, rather than JPEG. And you'd have to account for adding on new code that decompresses.


Last edited by ParasS on Wed Oct 15, 2008 11:40 am, edited 1 time in total.

Top
 
PostPosted: Wed Oct 15, 2008 11:40 am 
Offline
User avatar
 WWW  Profile

Joined: Wed Jan 09, 2008 10:23 am
Posts: 359
Location: Glasgow, Scotland
I think he's looking for a program to actually compress executable files in a similar manner to e.g. PowerPacker on the Amiga (if you are familiar with that). The compressed files could either have their own decompression routine inbuilt or an external program to decompress and then run the code.

Kind regards,

Francis


Top
 
PostPosted: Wed Oct 15, 2008 11:44 am 
Offline
User avatar
 Profile

Joined: Fri Jul 25, 2008 2:47 pm
Posts: 190
Hey Francis - exactly what I was adding to my post on just now... yes Powerpacker on the Amiga made sense with the amount of RAM and ability of the OS to page, but on the Beeb, it's really quite pointless (in my opinion anyway!).


Top
 
PostPosted: Wed Oct 15, 2008 2:37 pm 
Offline
User avatar
 WWW  Profile

Joined: Wed Jan 09, 2008 10:23 am
Posts: 359
Location: Glasgow, Scotland
I'm not sure I can see the benefit of it either on the Beeb.

Kind regards,

Francis.


Top
 
PostPosted: Fri Oct 17, 2008 2:38 am 
Offline
 Profile

Joined: Tue Oct 14, 2008 12:43 am
Posts: 18
FrancisL wrote:
I'm not sure I can see the benefit of it either on the Beeb.

Kind regards,

Francis.


I suppose it's mainly used to make demos where theres a limit on executable size (4k or 64k for instance), but I do see what you mean as there is a floppy drive on the beeb so prob not as much point. Having said that heres one for 6502 code that can target the other 6502 based computers.

http://hem.bredband.net/magli143/exo/


EDIT: Only just realised - the point of compressing the basic (bytecode(?)) is to make more room for basic progs and that general compression of program code doesn't really help too much in this case. (catching up with BBC Micro still)


Top
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 28 posts ]  Go to page Previous  1, 2

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 0 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron