millfork/include/nes_mmc4.mfk

asm inline void set_prg_bank(byte a) {
    STA $A000
    ? RTS
}

// calling with with e.g. $1E will set $0000-$0fff to $E000-$EFFF in chrrom1
asm inline void set_chr_bank0(byte a) {
    STA $B000
    STA $C000
    ? RTS
}

// calling with with e.g. $1E will set $1000-$1fff to $E000-$EFFF in chrrom1
asm inline void set_chr_bank1(byte a) {
    STA $D000
    STA $E000
    ? RTS
}

// TODO: FD/FE latches

asm inline void set_vertical_mirroring() {
    LDA #0
    STA $F000
    ? RTS
}
asm inline void set_horizontal_mirroring() {
    LDA #1
    STA $F000
    ? RTS
}