>
> In that case, it's as simple as LDA character1 / ORA character2 / STA
> destination, adjust indexes and loop.
Forget adjusting the indexes and looping, and it becomes almost all
ldy char
ldx char+1
lda font1,y
ora font2,x
sta bitmap
lda font+1,y
ora font2+1,y
sta bitmap+6
lda font+2,y...
etc.
The code, fully unwound, is only 264 bytes long. Fonts are up to 512
bytes depending on what's needed. The fonts should be page-aligned so
extra cycles aren't used reading the font data.
> We've been over this before here... look in the archives for a "48 pixel
> highres routine explained" message sometime around April, or if you can't
> find it, let me know and I'll email it, or maybe repost it to the list.
> You need to have six 16-bit pointers to each player image in RAM... after
> that, it's a standard routine with one cycle per line to spare. It
> involves the player vertical delay registers.
I wouldn't mind seeing the code, but if the STELLA 0.7 emulator is right,
I've got a solution that doesn't need vertical delays. Looks great on the
text. Not sure if it'd artifact if all 4 bits of the characters were used
instead of 3.
Please post or email what you've got :)
My code fragment to display one row of graphics is:
DisplayRow:
sta WSYNC
lda BitmapArray,x
sta grp0
lda BitmapArray+1,x
sta grp1
lda BitmapArray+4,x
sta temp
lda BitmapArray+5,x
sta PatchArea+7
lda BitmapArray+2,x
ldy BitmapArray+3,x
ldx temp
jmp PatchArea
; copy this routine into RAM at PatchArea:
PatchToCopy:
sta grp0
sty grp1
stx grp0
lda #0 ; gets modified by sta PatchArea+7
sta grp1
rts
The players are positioned at pixel locations 66 and 74.
There's enough CPU time to render 7 lines of text.
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