Re: Crosspost: Did the cpu influence the display?

[A936@hotmail.com]

A936@hotmail.com wrote:
> Here's the 13 bit counter used to iterate through the
> 32x192 pixel bytes (8 pixels per byte):
>
> A BCDE FGHI JKLM
>

Still having my mind on this, here's an organization
that beats Mr. Altwasser's for screen printing
speed:

pixel byte address:

010A BCDE IJKL MFGH

same attribute organization.

Character printing:

; hl = top of character bitmap
; de = address of top pixel byte
;   in 8 pixel high character

LDI x 8

after this de = address of top pixel byte
for next character cell to right (ie all set
up to print next character).

Here's a print at calculation:

; a = row char coord (0-24)
; l = column char coord (0-31)
; exit: hl = address of top pixel byte
;  in char cell

or $40
ld h,a
ld a,l
add a,a
add a,a
add a,a
ld l,a
ret

Mr A, you should have been thinking LDIs
instead of register pairing :-D