At 23.54 29/05/98 +1000, Andrew Davie wrote:
>Further optimization tricks - this time, a pretty simple one.
Here's another, very simple too... never JMP unless you can't really avoid
it. If you know that some status bit is always 0 or 1 at that point, use a
branch instruction instead, to save a byte and some cycles. And what if
the brach is out of range? Easy: spend a couple of hours re-arranging your
time-sensitive code to make that BNE possible. It happened to me, and might
happen to you too... :)
The following one is simple but not obvious, and can turn your clean and
well commented data part of the program into a mess (I learned it from
Jim)..: "merge" the tables! ie:
BitmapShape:
.byte $AA
.byte $23
.byte $00
.byte $00
.byte $01
(..other stuff..)
ZgyzLookupTable:
.byte $00
.byte $00
.byte $01
.byte $01
.byte $02
Why not re-arrange the data in this way:
BitmapShape:
.byte $AA
.byte $23
ZgyzLookupTable:
.byte $00
.byte $00
.byte $01 ; <- end of BitmapShape
.byte $01
.byte $02
Lots of graphics data can be "compacted" in this way. Also, I ended
changing the design of some graphics so that I could compact them better,
and save some more bytes... wicked!
Ciao,
P.
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