cpu 6800
        include "motorola.inc"          ; Macros for things like fcc,db, etc.
CRXMIT  EQU $8000 + 3 * 4
RESET   EQU $8000 + 3 * 0

        ORG 0
b40_j:  RMB 1
b40_acc:  RMB 3
b40_tmp:  RMB 3
b40_cb: jmp CRXMIT

        ORG $0100
entry:
        ldx #encoded
        jsr b40print
        jmp reset
encoded: fcb 137, 98, 164, 124, 235, 2, 162, 186, 32, 248, 46, 30, 20, 217, 0

        ORG $0200
b40scl:  ; shift `b40acc << b` in place
        asl b40_acc+2
        rol b40_acc+1
        rol b40_acc
        deca
        bne b40scl
b40done:
        rts

; Call with data pointer in X.
b40print:
        ldab #3
        ldaa 0, x
        staa b40_acc+1
        inx
        ldaa 0, x
        staa b40_acc+2
        inx
        
b40step:
        clr b40_acc
        ldaa #3
        bsr b40scl

        lda b40_acc
        sta b40_tmp
        lda b40_acc+1
        sta b40_tmp+1
        lda b40_acc+2
        sta b40_tmp+2

        ; now b40_tmp = b40_acc = 8 * b40_acc(original)

        ldaa #2
        bsr b40scl
        ; now b40_acc = b40_acc(original) * 32

        ldaa b40_tmp+2
        adda b40_acc+2
        staa b40_acc+2
        ldaa b40_tmp+1
        adca b40_acc+1
        staa b40_acc+1
        ldaa b40_tmp+0
        adca b40_acc+0
        staa b40_acc+0
        ; now b40_acc = b40_acc(original) * 40
        ; and a has the most significant byte of b40_acc

        beq b40done
        cmpa #3
        ble b40sp
        cmpa #12
        ble b40dig

        adda #8         ; alphabetic
b40dig: adda #12        ; digit
b40sp:  adda #31        ; symbol
        jsr b40_cb
        dec b
        bne b40step
        bra b40print