52 lines
1023 B
ArmAsm
52 lines
1023 B
ArmAsm
;; We have the following variables:
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;; cursor_blink_disable
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;; cursor_blink_countdown
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;; cursor_saved_character
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;; cursor_is_visible
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;; colour_under_cursor
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blink_cursor:
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;; Is the cursor enabled?
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bit cursor_blink_disable
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bne no_blink_cursor
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;; Do we need to redraw things?
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dec cursor_blink_countdown
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bpl no_blink_cursor
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;; XXX - Save character colour also!
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;; Check if cursor was visible or not, and toggle
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lda cursor_is_visible
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bne undraw_cursor
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draw_cursor:
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ldy current_screen_x
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lda (current_screen_line_ptr),y
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sta cursor_saved_character
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eor #$80
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sta (current_screen_line_ptr),y
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lda #1
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sta cursor_is_visible
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jmp reset_blink_timer
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undraw_cursor:
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lda cursor_saved_character
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ldy current_screen_x
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sta (current_screen_line_ptr),y
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lda #0
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sta cursor_is_visible
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;; Fall through
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reset_blink_timer:
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;; Rest blink counter
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;; (Compute's Mapping the 64, p39-40)
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lda #20
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sta cursor_blink_countdown
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no_blink_cursor:
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rts
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hide_cursor_if_visible:
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bit cursor_is_visible
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bpl undraw_cursor
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rts
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