screen0v.asm

; PET/CBM EDIT ROM - Screen line LO address table - Screen 1 @ $8000 Video (characters)
; ================   For CODEBASE 0
; Variables: ROWS,COLUMNS
; These tables are used to calculate the starting address of each line on the screen.
; The standard screens are 40x25 and 80x25. Experimental screens can be up to 90x35.
; 32 and 64 are included for future support of non-cbm type screens.
; When ROWS>25 it assumes maximum 35 rows although less are supported as well.

;---------- 32 characters wide (32x32 = 1K RAM)
!IF COLUMNS=32 {
Line_Addr_Lo	!byte $00,$20,$40,$60,$80,$A0,$C0,$E0,$00,$20,$40,$60,$80,$A0,$C0,$E0
		!byte $00,$20,$40,$60,$80,$A0,$C0,$E0,$00,$20,$40,$60,$80,$A0,$C0,$E0
}

;---------- 40 characters wide 
!IF COLUMNS=40 {
Line_Addr_Lo	!byte $00,$28,$50,$78,$a0,$c8,$f0,$18,$40,$68,$90,$b8,$e0,$08,$30,$58
		!byte $80,$a8,$d0,$f8,$20,$48,$70,$98,$c0
}

;---------- 64 characters wide (64x32 = 2K RAM)
!IF COLUMNS=64 {
Line_Addr_Lo	!byte $00,$40,$80,$C0,$00,$40,$80,$C0,$00,$40,$80,$C0,$00,$40,$80,$C0
		!byte $00,$40,$80,$C0,$00,$40,$80,$C0,$00,$40,$80,$C0,$00,$40,$80,$C0
}

;---------- 80 characters wide 
!IF COLUMNS=80 {
Line_Addr_Lo	!byte $00,$50,$a0,$f0,$40,$90,$e0,$30,$80,$d0
		!byte $20,$70,$c0,$10,$60,$b0,$00,$50,$a0,$f0
		!byte $40,$90,$e0,$30,$80
}

;---------- 90 characters wide
!IF COLUMNS=90 {
Line_Addr_Lo	!byte $00,$5a,$b4,$0e,$68,$c2,$1c,$76,$d0,$2a,$84,$de,$38,$92,$ec,$46
		!byte $a0,$fa,$54,$ea,$08,$62,$bc,$16,$70,$ca,$24,$7e,$d8,$32,$8c,$e6
		!byte $40,$9a,$f4
}