28 lines
532 B
ArmAsm
28 lines
532 B
ArmAsm
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;;
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;; Official Kernal routine, described in:
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;;
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;; - [RG64] C64 Programmer's Reference Guide - page 290
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;; - [CM64] Compute's Mapping the Commodore 64 - page 215
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;;
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;; CPU registers that has to be preserved (see [RG64]): none
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;;
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plot:
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bcs plot_get
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plot_set:
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sty current_screen_y
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stx current_screen_x
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;; Our implementation has different screen editor, updating any
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;; other variables (see [CM64]) seems to be unnecessary
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;; FALLTROUGH to save one byte on RTS
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plot_get:
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ldy current_screen_y
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ldx current_screen_x
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rts
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