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50 lines
875 B
ArmAsm
50 lines
875 B
ArmAsm
; 16B herringbone pattern
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; FIXME: depends on memory init
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; zero page locations
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GBASL = $26
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GBASH = $27
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; ROM calls
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HGR2 = $F3D8
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HGR = $F3E2
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HPOSN = $F411
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XDRAW0 = $F65D
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XDRAW1 = $F661
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RESTORE = $FF3F
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herring:
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; $E7 HGR_SCALE is $00 from memory not initialized
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jsr HGR2 ; Hi-res, full screen ; 3
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; Y=0, A=0 after this call
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; A and Y are 0 here.
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; X is left behind by the boot process?
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jsr HPOSN ; set screen position to X= (y,x) Y=(a)
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; saves X,Y,A to zero page
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; after Y= orig X/7
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; A and X are ??
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tiny_loop:
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; this will be 0 2nd time through loop, arbitrary otherwise
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; lda #1 ; ROT=1
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jsr XDRAW0 ; XDRAW 1 AT X,Y
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; Both A and X are 0 at exit
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; Z flag set on exit
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; Y varies
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inx ; X=1
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txa ; A=1
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tay ; Y=1
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bne tiny_loop ; bra
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; be sure this is at address $0101, easy to set address
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shape_table:
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.byte $04,$00
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