Thingamajig/examples/ascii.asm

        ;ASCII code printer

        ;Print a prompt
        load    r0, #3e
        store   ffff, r0
        load    r0, #20
        store   ffff, r0

        ;Read a character to r0 and load it to r2
        load    r0, ffff
        xor     r2, r2
        xor     r2, r0

        ;Print a newline
        cleq    r0, r0, newln

        ;Convert and print the high nibble
        ;Convert
        ror     r0, 4
        cleq    r0, r0, n2hex
        ;Print
        store   ffff, r0

        ;Re-load the character to r0
        xor     r0, r0
        xor     r0, r2

        ;Convert and print the low nibble
        ;Convert
        cleq    r0, r0, n2hex
        ;Print
        store   ffff, r0

        ;Print a newline
        cleq    r0, r0, newln

        ;Halt
        halt

        ;***

        ;Print a newline
newln:  load    r1, #d
        store   ffff, r1
        load    r1, #a
        store   ffff, r1
        ret

        ;***

        ;Get the hexadecimal digit of a nibble

        ;Extract the low nibble
n2hex:  load    r1, #f
        and     r0, r1

        ;Locate the nibble in the table
        load    r1, #0
        breq    r0, r1, dgt0
        load    r1, #1
        breq    r0, r1, dgt1
        load    r1, #2
        breq    r0, r1, dgt2
        load    r1, #3
        breq    r0, r1, dgt3
        load    r1, #4
        breq    r0, r1, dgt4
        load    r1, #5
        breq    r0, r1, dgt5
        load    r1, #6
        breq    r0, r1, dgt6
        load    r1, #7
        breq    r0, r1, dgt7
        load    r1, #8
        breq    r0, r1, dgt8
        load    r1, #9
        breq    r0, r1, dgt9
        load    r1, #a
        breq    r0, r1, dgta
        load    r1, #b
        breq    r0, r1, dgtb
        load    r1, #c
        breq    r0, r1, dgtc
        load    r1, #d
        breq    r0, r1, dgtd
        load    r1, #e
        breq    r0, r1, dgte
        load    r1, #f
        breq    r0, r1, dgtf

        ;Load the hexadecimal digit of the nibble
dgt0:   load    r0, #30
        breq    r0, r0, n2hend
dgt1:   load    r0, #31
        breq    r0, r0, n2hend
dgt2:   load    r0, #32
        breq    r0, r0, n2hend
dgt3:   load    r0, #33
        breq    r0, r0, n2hend
dgt4:   load    r0, #34
        breq    r0, r0, n2hend
dgt5:   load    r0, #35
        breq    r0, r0, n2hend
dgt6:   load    r0, #36
        breq    r0, r0, n2hend
dgt7:   load    r0, #37
        breq    r0, r0, n2hend
dgt8:   load    r0, #38
        breq    r0, r0, n2hend
dgt9:   load    r0, #39
        breq    r0, r0, n2hend
dgta:   load    r0, #41
        breq    r0, r0, n2hend
dgtb:   load    r0, #42
        breq    r0, r0, n2hend
dgtc:   load    r0, #43
        breq    r0, r0, n2hend
dgtd:   load    r0, #44
        breq    r0, r0, n2hend
dgte:   load    r0, #45
        breq    r0, r0, n2hend
dgtf:   load    r0, #46
        breq    r0, r0, n2hend

        ;Return
n2hend: ret