millfork/include/m6809/stdlib_6809.mfk

// target-independent things

#if not(ARCH_6809)
#warn stdlib_6809 module should be only used on 6809-compatible targets
#endif

import m6809/m6809_math

word nmi_routine_addr   @$FFFC
word reset_routine_addr @$FFFE
word irq_routine_addr   @$FFF8
word swi_routine_addr   @$FFFA
word firq_routine_addr   @$FFF6
word swi2_routine_addr   @$FFF4
word swi3_routine_addr   @$FFF2

macro asm void poke(word const addr, byte register(b) value) {
    ! STB addr
}

macro asm byte peek(word const addr) {
    ! LDB addr
}

macro asm void disable_irq() {
    ORCC #$30
}

macro asm void enable_irq() {
    ANDCC #$CF
}

asm byte hi_nibble_to_hex(byte register(b) value) {
    LSRB
    LSRB
    LSRB
    LSRB
    ? JMP lo_nibble_to_hex
}

asm byte lo_nibble_to_hex(byte register(b) value) {
    ! ANDB #$F
    ADDB #$30
    CMPB #$3A
    BCS _lo_nibble_to_hex_lbl
    ADDB #$7 // carry is set
_lo_nibble_to_hex_lbl:
    ? RTS
}

macro asm void panic() {
    ? JSR _panic
}

noinline asm word call(word register(x) routine) {
    JMP ,X
}