53 lines
919 B
ArmAsm
53 lines
919 B
ArmAsm
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.include "apple2.inc"
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CROUT := $FD8E
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COUT := $FDED
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INBUF := $200
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.org $4000
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jsr CROUT
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ldx #0
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;; Skip any leading spaces
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jsr skip_spaces
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;; Invoked with "-" ?
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lda INBUF,x
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cmp #'-'|$80
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bne :+
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inx
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:
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;; Skip any more leading spaces
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jsr skip_spaces
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;; Skip command name (i.e. "echo")
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txa
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clc
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adc #cmd_length
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tax
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;; Skip leading spaces before string to echo
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jsr skip_spaces
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;; Echo string
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: lda INBUF,x
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jsr COUT
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cmp #$D | $80
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beq exit
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inx
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jmp :-
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exit: rts
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.proc skip_spaces
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lda INBUF,x
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cmp #' '|$80
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beq :+
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rts
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: inx
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jmp skip_spaces
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.endproc
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cmd_length = .strlen("echo") |