LDB #$F0
JNC bankNoCarry
NOT B
bankNoCarry:
LDA $00
AND B,A
OR D,A
STA $00
RET

; Memory copy: A=start, B=offset, length=C, destroys D
copyLoop:
LDD $00,A
ADC B,A
STD $00,A
DEC C
JNZ copyLoop
RET

; Memory copy to screen: A=start, destroys C, D, screen address register
LDD #$80
LDC D
STD $03
screenCopyLoop:

LDD $00,A
STD $02
DEC C
JNZ screenCopyLoop
RET