.segment "EXTRA" .export MONRDKEY, MONCOUT, LOAD; SAVE; ISCNTC LOAD: rts SAVE: rts ISCNTC: rts MONRDKEY: lda $BC01 bmi MONRDKEY_SKIP_ECHO sta $BC00 ; echo MONRDKEY_SKIP_ECHO: rts MONCOUT: sta $BC00 rts .segment "RESETVEC" .word $0000 ; NMI vector .word COLD_START ; RESET vector .word $0000 ; IRQ vector