VTI: Bug or not, in my code or not?

Post by **benryves** » Thu 13 Oct, 2005 10:17 am

I don't quite understand this. I wrote a program that drew 3 filled triangles and spun them around. Inside the main loop, I wrote some code to toggle both bits of the link port, like this:

Code: Select all

; ... code
    ld a,(link_port_status)
    xor %00000011
    ld (link_port_status)
    out (bport),a
; more code ...

link_port_status:
    .db 0

With this code in there, my program ran 2 or 3 times faster than the version without the code. It didn't affect anything else, no overflows into other variables controlling the animation. If I didn't output the value to the bport, the speed was unchanged.

Anyone else noticed this? Do I just assume it's a bug in VTI?

CoBB · Post by **CoBB** » Thu 13 Oct, 2005 1:28 pm

I can't think of anything in VTI's code that would result in such behaviour. Does PTI also do the same?

Post by **benryves** » Thu 13 Oct, 2005 1:57 pm

CoBB wrote:I can't think of anything in VTI's code that would result in such behaviour. Does PTI also do the same?

I didn't have a copy of PTI to test with (nor a link cable to test on hardware). I'll give it a shot.

Timendus · Post by **Timendus** » Fri 14 Oct, 2005 12:15 pm

Weird... I don't have a clue either...

http://www.hszk.bme.hu/~pg429/pindurti/pindurti.exe

threefingeredguy · Post by **threefingeredguy** » Fri 14 Oct, 2005 7:55 pm

I though VTI didnt emulate the linkport correctly. Oh well.