gistfile1.txt

.global main
main:

    ; Setup stack pointer
    ldi r16,0x08
    out SPH,r16
    ldi r16,0xff
    out SPL,r16

    ; Configure pin as output
    ldi r16,(1<<PB5)
    out DDRB,r16
    ; Initial pin value
    ldi r16,0
    ldi ZH, hi8(TAB)
    ldi ZL, lo8(TAB)
loop:
    call fetch_char
    call convert_char
    ; ldi r16,1
    ; call beep
    ; call nobeep
    ; ldi r16,0
    ; call beep
    ; call nobeep
    rjmp loop


; Beep related subroutines. These trash r17, r18, r19, r20

beep:
    ldi r17,(1<<PB5)
    out PORTB,r17
    call beep_helper
    ret

nobeep:
    clr r15
    out PORTB,r15
    call beep_helper
    ret

beep_helper:
    cpi r16,1
    breq long_beep
    jmp short_beep

long_beep:
    ldi r18, 82
ld_3:
    ldi r19, 0
ld_2:
    ldi r20, 0
ld_1:
    dec r20
    brne ld_1
    dec r19
    brne ld_2
    dec r18
    brne ld_3
    ret

short_beep:
    ldi r18, 8
sd_3:
    ldi r19, 0
sd_2:
    ldi r20, 0
sd_1:
    dec r20
    brne sd_1
    dec r19
    brne sd_2
    dec r18
    brne sd_3
    ret


# Fetches a char from the Z, increments Z unless the byte is NULL
fetch_char:
    lpm r16,Z
    cpi r16,0
    breq fetch_char_NULL
    adiw r30,1
fetch_char_NULL:
    ret



// Replaces the character in r16 with the morse code representation
convert_char:
    ldi YH, hi8(MORSE)
    ldi YL, lo8(MORSE)
    add YL,r16
    adc YH,0
    ld r17,Y
    ld r16,Y
    ret


TAB:
    .byte 'H'
    .byte 'E'
    .byte 'L'
    .byte 'L'
    .byte 'O'
    .byte 0

MORSE:
    .skip 0x40

    .byte 0x60
    .byte 0x88
    .byte 0xA8
    .byte 0x90
    .byte 0x40
    .byte 0x28
    .byte 0xd0
    .byte 0x08
    .byte 0x20
    .byte 0x78
    .byte 0xB0
    .byte 0x48
    .byte 0xE0
    .byte 0xa0
    .byte 0xf0
    .byte 0x68
    .byte 0xD8
    .byte 0x50
    .byte 0x10
    .byte 0xC0
    .byte 0x30
    .byte 0x18
    .byte 0x70
    .byte 0x98
    .byte 0xB8
    .byte 0xC8