Memory Access Speed Test: DIM vs BG


was8bit 2020-07-12 05:34 (Edited)

Pehaps BG speed is faster because CPU is maxing out and NX is skipping or something....

When you add a VBL right above each LOOP, the # of iterations are identical, which on a game you would use a VBL, so perhaps this test shows no real difference in speed of access..

Timo 2020-07-12 09:45

The difference is the setter:

CELL 0,0,0

CELL uses 4 CPU cycles. One for the command and three for the parameters.

GRID(X,Y)=0 uses 5 CPU cycles... What?!? That's because there is a hidden/optional LET command:
LET GRID(x,y)=0
1 cycle for the command LET
4 cycles for GRID, X, Y and 0

Anyway, this small difference shouldn't be a big thing. Choose more readable code over over-optimization :)

Timo 2020-07-12 09:46

Ok, actually the LET command is not available in NX anymore (it was in LowRes Coder). But it's still an implicit command.

was8bit 2020-07-12 14:33 (Edited)

Ah, many thanks for the tech info, very cool :)

Yea, the difference is very tiny... in original lowres i often used onscreen pixel color as data for the gameplay, and NX backgrounds not only store color data but also actual character data, and i have made some games using this approach...

... i am still exploring variations of different ways to do things ;)

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