PDA ramblings...

Ian Molton spyro at f2s.com
Sun Feb 2 06:08:14 PST 2003


On Sun, 2 Feb 2003 13:24:07 +0000
Ian Molton <spyro at f2s.com> wrote:

> 
> so, 0x90049d00 is a table containing useful information about the
> display - the resolution, offset to the font, and, I'm willing to bet,
> the offset to the framebuffer. I will have to reconstruct this table
> by hand-reading the assembly that builds it, and see what it contains.
> 
> This will make a LOT of sense of the string-plotting routines I have
> recently located.

I might have hit gold...

The table contained a couple of pointers into RAM, so I took a peek to
see what was there.

one was 'mov pc,lr' (ie. a dummy function) but the other...

lets just say that this is what it would have been in C...

void drawpoint(int x, int y, unsigned short colour){
    long screenbase = 0x56080000;

    if(x < 0 || y < 0 || x > 240 || y > 320)
        return;

    write_short(colour, (screenbase+x+(240*y))<<1);

    return;
}

Cool!!

this gives (with x = 0 y = 0 a screen base of 0xac100000.

Unfortunately, that didnt work - because, I think, its a physical
address. I think this maps to virtual address 0x9c100000 which I am
about to try...

:-)
-- 
Unsubscribe: send email to listar at linuxfromscratch.org
and put 'unsubscribe lfs-chat' in the subject header of the message



More information about the lfs-chat mailing list