base:opening_the_top_bottom_borders
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— | base:opening_the_top_bottom_borders [2015-04-17 04:33] (current) – created - external edit 127.0.0.1 | ||
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+ | ==== Opening the top and bottom borders ==== | ||
+ | This is a clever trick for you to try on the C64. Demos in the 1980's and 1990's and probably still today use the opened borders technique. I am going to show you how to do a simple border opening technique in ACME crossassembler format. | ||
+ | < | ||
+ | ;Opening the top + bottom borders | ||
+ | ;inside an IRQ interrupt player | ||
+ | !to " | ||
+ | |||
+ | * = $0810 ;SYS 2064 to run it | ||
+ | sei | ||
+ | lda #$02 | ||
+ | sta $d020 | ||
+ | lda #$00 | ||
+ | sta $d021 | ||
+ | lda #<irq1 | ||
+ | sta $314 | ||
+ | lda #>irq1 | ||
+ | sta $315 | ||
+ | lda #$7f | ||
+ | sta $dc0d | ||
+ | lda #$1b | ||
+ | sta $d011 | ||
+ | lda #$01 | ||
+ | sta $d01a | ||
+ | cli | ||
+ | jmp * | ||
+ | irq1: inc $d019 | ||
+ | lda #$00 | ||
+ | sta $d012 | ||
+ | lda #$00 | ||
+ | sta $d011 | ||
+ | lda #<irq2 | ||
+ | sta $314 | ||
+ | lda #>irq2 | ||
+ | sta $315 | ||
+ | jmp $ea7e | ||
+ | irq2: inc $d019 | ||
+ | lda #$fa | ||
+ | sta $d012 | ||
+ | lda #$1b ;If you want to display a bitmap pic, use #$3b instead | ||
+ | sta $d011 | ||
+ | lda #<irq1 | ||
+ | sta $314 | ||
+ | lda #>irq1 | ||
+ | sta $315 | ||
+ | jmp $ea7e | ||
+ | </ |
base/opening_the_top_bottom_borders.txt · Last modified: 2015-04-17 04:33 by 127.0.0.1