;; test overflow flag
; https://www.righto.com/2012/12/the-6502-overflow-flag-explained.html

LDA $50
ADD $10 ; CF, OF: 0 0
LDA $50
ADD $50 ; CF, OF: 0 1
LDA $50
ADD $90 ; CF, OF: 0 0
LDA $50
ADD $D0 ; CF, OF: 1 0
LDA $D0
ADD $10 ; CF, OF: 0 0
LDA $D0
ADD $50 ; CF, OF: 1 0
LDA $D0
ADD $90 ; CF, OF: 1 1
LDA $D0
ADD $D0 ; CF, OF: 1 0

LDA $50
SUB $F0   ; CF, OF: 1 0
LDA $50
SUB $B0 ; CF, OF: 1 1
LDA $50
SUB $70 ; CF, OF: 1 0
LDA $50
SUB $30 ; CF, OF: 0 0
LDA $D0
SUB $F0 ; CF, OF: 1 0
LDA $D0
SUB $B0 ; CF, OF: 0 0
LDA $D0
SUB $70 ; CF, OF: 0 1
LDA $D0
SUB $30 ; CF, OF: 0 0