tutor7.oph

.include "c64-2.oph"

.data
.org $C000
.text

.macro print
        lda #<_1
        ldx #>_1
        jsr printstr
.macend

.macro greet
        lda #30
        jsr delay
        `print hello1
        `print _1
        `print hello2
.macend

        lda #147
        jsr chrout
        `greet target1
        `greet target2
        `greet target3
        `greet target4
        `greet target5
        `greet target6
        `greet target7
        `greet target8
        `greet target9
        `greet target10

        rts

hello1: .byte "HELLO, ",0
hello2: .byte "!", 13, 0

target1:  .byte "PROGRAMMER", 0
target2:  .byte "ROOM", 0
target3:  .byte "BUILDING", 0
target4:  .byte "NEIGHBORHOOD", 0
target5:  .byte "CITY", 0
target6:  .byte "NATION", 0
target7:  .byte "WORLD", 0
target8:  .byte "SOLAR SYSTEM", 0
target9:  .byte "GALAXY", 0
target10: .byte "UNIVERSE", 0

; DELAY routine.  Takes values from the Accumulator and pauses
; for that many jiffies (1/60th of a second).
.scope
.data
.space _tmp 1
.space _target 1

.text

delay:  sta _tmp        ; save argument (rdtim destroys it)
        jsr rdtim
        clc
        adc _tmp        ; add current time to get target
        sta _target
*       jsr rdtim
        cmp _target
        bmi -           ; Buzz until target reached
        rts
.scend

; PRINTSTR routine.  Accumulator stores the low byte of the address,
; X register stores the high byte.  Destroys the values of $10 and
; $11.

.scope
.data zp
.space _ptr 2
.text
printstr:
        sta _ptr
        stx _ptr+1
        ldy #$00
_lp:    lda (_ptr),y
        beq _done
        jsr chrout
        iny
        bne _lp
_done:  rts
.scend

.checkpc $A000

.data
.checkpc $D000

.data zp
.checkpc $80