emulator help

You'll have to count CPU cycles and keep track of the emulated video "beam's" position on the LCD in relation to the CPU clock, otherwise you won't be able to handle raster effects properly. The easiest method is probably to run the CPU and render to the back buffer in synchronization, scanline-per-scanline. And then you can just flip it all to screen when the emulated video chip reaches the vertical blanking period, in 60 Hz or so IIRC.

A more exact method is to track any display IO writes from the CPU and this together with the current CPU cycle to the display emulator. Thus the display can draw all pixels between the previous write and the new one. Horiziontal blanking interrupts complicates this a little though.

ok, thanks m8.

can I ask why? There are several excellent GB emulators available already.

because i want to expand my knowledge of both OOP programming and how computer systems work. ( and its geeky-good fun ( and maybe makes me looks good ( u know... with the ladies :P ) ) )

hmmm it won't...make you look good with the ladies :)

but as for learning GB, I'm prety sure some of the old emulators may be opensource, and were mostly written in C.

Sounds like a fun if not entierly productive project...enjoy

im still having trouble figuring this out :(

im told cpu clock speed is 4.194304MHz ( 4194304 hz ? )
and hsync is 9198 KHz ( 9198000 hz ? :S )
vync is 59.73 Hz

do these figuers seem correct?

The h-sync looks *way* to high. But I suspect that it's supposed to be 9198 Hz, not 9198 KHz.

9198 Hz h-blank / 59.73 Hz v-blank ~= 144 scanlines + 10 lines of vblank.4.194304 MHz CPU freq / 9198 Hz h-blank ~= 456 cycles per scanline.

thanks alot mate, i knew something was wrong