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https://github.com/bobbimanners/emailler.git
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56 lines
1.0 KiB
ArmAsm
56 lines
1.0 KiB
ArmAsm
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.export print_a
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.export print_a_inverse
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.export print_cr
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.export cls
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.export beep
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.exportzp screen_current_row
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.exportzp screen_current_col
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.code
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screen_current_col=$24 ; CH - Horizontal cursor-position (0-39)
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screen_current_row=$25 ; CV - Vertical cursor-position (0-23)
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;
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;use Apple 2 monitor ROM function to display 1 char
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;inputs: A should be set to ASCII char to display
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;outputs: none
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print_a:
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ora #$80 ;turn ASCII into Apple 2 screen codes
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cmp #$8A ;is it a line feed?
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bne @not_line_feed
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; jmp print_cr
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pha
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lda #$0
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sta screen_current_col
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pla
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@not_line_feed:
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jmp $fded
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;use Apple 2 monitor ROM function to move to new line
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;inputs: none
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;outputs: none
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print_cr:
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jmp $fd8e
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;use Apple 2 monitor ROM function to move to clear the screen
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;inputs: none
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;outputs: none
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cls:
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jmp $fc58
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;use Apple 2 monitor ROM function to move to make a 'beep' noise
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;inputs: none
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;outputs: none
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beep:
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jmp $fbdd
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print_a_inverse:
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and #$7F ;turn off top bits
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jsr $fded
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