Hi good afternoon.
actually a byte with 255 should be at address b600.
why does this simple program not work with one byte.
Thank you.
greeting
-------------------------
org #0100
xbios equ 0FC5Ah
screen equ 00E9h
roller equ 0B600h
ld a,255
ld hl,roller
ld (hl),a
call xbios
dw screen
ende
jp ende
ret
-----------------------------------
Hello,
Please - think back to the code examples from John Elliott that you were playing with before.
You've written a little prog which is sitting in the SYSTEM memory, i.e. the 4 banks that are active normally.
BUT, the SCREEN ram (is in a different bank, and you're not doing a bank swap as per the earlier progs, so the FF will be set in a byte in the SYSTEM memory map and NOT in the SCREEN RAM.
Maybe if the 3 lines to place the data in RAM were after the 2 lines which (I think) are doing the swap this might help, BUT I don't think you've placed the 3 lines where they'll be available after the bank swap??
Again, refer back to the earlier progs.
Geoff
hello thanks.
actually it should work.
but doesn't do it.
greeting
org #0100
xbios equ 0FC5Ah
screen equ 00E9h
roladr equ 0B600h
start:
ld de,roladr
jr weiter
ret
weiter:
ld bc,routine
call xbios
dw screen
ret
routine:
ld hl,160
jr setzen
setzen:
add hl,de
ld a,255
ld (hl),a
jr ende
ende:
ret