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https://github.com/badvision/lawless-legends.git
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Raycaster with split-expander working now.
This commit is contained in:
Martin Haye
parent
0e6c20cffe
commit
7df3e2ced2
@ -9,29 +9,33 @@
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;****************************************************************************************
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; Select mipmap level 0 (64x64 pixels = 32x32 bytes)
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; On entry, txColumn should be in A-reg
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selectMip0:
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; pTex is already pointing at level 0, no need to adjust its level.
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; However, we do need to move it to the correct column. Currently txColumn
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; is 0..255 pixels, which we need to translate to 0..31 columns; that's
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; a divide by 8. But then we need to multiply by 32 bytes per column,
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; so (1/8)*32 = 4, so we need to multiply by 4 after masking.
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lda #0
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sta tmp
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lda txColumn
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and #$F8 ; retain upper 5 bits
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sta clrAuxZP
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ldy #0
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sty tmp
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and #$F8 ; retain upper 5 bits of txColumn
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asl
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rol tmp ; multiplied by 2
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asl
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rol tmp ; multiplied by 4
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ldy tmp
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mipReady:
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sta clrAuxZP
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clc ; adjust pTex by that much
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adc pTex
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sta pTex
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tax
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tya
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adc pTex+1
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sta pTex+1
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ldy pixNum ; get offset into the blit roll for this column
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sta setAuxZP
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stx pTex
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sta pTex+1
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ldx .blitOffsets,y
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ldy #$FF ; default to copying from top of column (will be 0 after initial INY in unrolled code)
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clv ; so code can use BVC to branch always without BRA
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@ -39,25 +43,25 @@ mipReady:
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.blitOffsets: !byte BLIT_OFF0,BLIT_OFF1,BLIT_OFF2,BLIT_OFF3,BLIT_OFF4,BLIT_OFF5,BLIT_OFF6
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; Select mipmap level 0 (32x32 pixels = 16x16 bytes)
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; On entry, txColumn should be in A-reg
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selectMip1:
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; pTex is pointing at level 0, so we need to move it to level 1.
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; Then we need to move it to the correct column. Currently txColumn
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; is 0..255 pixels, which we need to translate to 0..15 columns; that's
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; a divide by 16. But then we need to multiply by 16 bytes per column,
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; so (1/16)*16 = 1 ==> no multiply needed.
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lda txColumn
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and #$F0 ; retain upper 4 bits
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ldy #>MIP_OFFSET_1 ; adjust to mip level 1
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bne mipReady ; always taken
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; Select mipmap level 2 (16x16 pixels = 8x8 bytes)
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; On entry, txColumn should be in A-reg
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selectMip2:
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; pTex is pointing at level 0, so we need to move it to level 2.
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; Then we need to move it to the correct column. Currently txColumn
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; is 0..255 pixels, which we need to translate to 0..8 columns; that's
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; a divide by 32. But then we need to multiply by 8 bytes per column,
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; so (1/32)*8 = 1/4 ==> overall we need to divide by 4.
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lda txColumn
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and #$E0 ; retain upper 3 bits
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lsr ; div by 2
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lsr ; div by 4
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@ -66,13 +70,13 @@ selectMip2:
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bne mipReady ; always taken
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; Select mipmap level 3 (8x8 pixels = 4x4 bytes)
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; On entry, txColumn should be in A-reg
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selectMip3:
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; pTex is pointing at level 0, so we need to move it to level 3.
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; Then we need to move it to the correct column. Currently txColumn
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; is 0..255 pixels, which we need to translate to 0..3 columns; that's
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; a divide by 64. But then we need to multiply by 4 bytes per column,
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; so (1/64)*4 = 1/16 ==> overall we need to divide by 16.
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lda txColumn
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and #$C0 ; retain upper 2 bits
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lsr ; div by 2
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lsr ; div by 4
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@ -84,13 +88,13 @@ selectMip3:
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bne mipReady ; always taken
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; Select mipmap level 4 (4x4 pixels = 2x2 bytes)
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; On entry, txColumn should be in A-reg
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selectMip4:
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; pTex is pointing at level 0, so we need to move it to level 4.
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; Then we need to move it to the correct column. Currently txColumn
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; is 0..255 pixels, which we need to translate to 0..1 columns; that's
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; a divide by 128. But then we need to multiply by 2 bytes per column,
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; so (1/128)*2 = 1/64 ==> overall we need to divide by 64
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lda txColumn
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and #$80 ; retain the high bit
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beq + ; if not set, result should be zero
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lda #64 ; else result should be 64
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@ -100,10 +104,9 @@ selectMip4:
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bne mipReady ; always taken
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; Select mipmap level 5 (2x2 pixels = 1x1 bytes)
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; On entry, txColumn should be in A-reg
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selectMip5:
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; Mip level 5 is super-easy: it's one byte. Not much choice there.
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lda #<MIP_OFFSET_5
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ldy #>MIP_OFFSET_5
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bne mipReady ; always taken
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@ -34,7 +34,6 @@ start:
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jmp pl_setAvatar ; params: A=tile number
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; Conditional assembly flags
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DOUBLE_BUFFER = 1 ; whether to double-buffer
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DEBUG = 0 ; 1=some logging, 2=lots of logging
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DEBUG_COLUMN = -1
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@ -78,6 +77,7 @@ plasmaStk: !byte 0
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nTextures: !byte 0
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scripts: !word 0 ; pointer to loaded scripts module
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expanderRelocd: !byte 0 ; flag so we only reloc expander once
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shadow_pTex: !word 0 ; backup of pTmp space on aux (because it gets overwritten by expander)
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skyColorEven: !byte $20
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skyColorOdd: !byte $22
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@ -1256,6 +1256,7 @@ drawRay: !zone
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sta pTex+1
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; jump to the unrolled expansion code for the selected height
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!if DEBUG >= 2 { +prStr : !text "Calling expansion code.",0 }
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ldx txColumn
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lda lineCt
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sei ; prevent interrupts while in aux mem
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sta setAuxZP
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@ -1263,7 +1264,8 @@ drawRay: !zone
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bcc +
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lda #254 ; clamp max height
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+ sta expanderJmp+1 ; set vector offset
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lda setLcRW+lcBank2 ; part of expander split and relocated to LC bank 2
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bit setLcRW+lcBank2 ; part of expander split and relocated to LC bank 2
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txa
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jsr callExpander ; was copied from .callIt to $100 at init time
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sta clrAuxZP
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cli ; interrupts ok after we get back from aux
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@ -1394,6 +1396,12 @@ makeClrBlit: !zone
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; Clear the blit
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clearBlit: !zone
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sta setAuxZP
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lda pTex ; save screen addr that gets overwritten by expander
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sta shadow_pTex
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lda pTex+1
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sta shadow_pTex+1
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sta clrAuxZP
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lda byteNum
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and #2
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bne .alt
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@ -1686,7 +1694,7 @@ pl_texControl: !zone {
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graphInit: !zone
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lda #0
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sta frontBuf
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!if DOUBLE_BUFFER { lda #1 }
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lda #1
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sta backBuf
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!if DEBUG >= 2 {
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+prStr : !text "Staying in text mode.",0
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@ -1892,7 +1900,7 @@ castAllRays: !zone
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;-------------------------------------------------------------------------------
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; Render one whole frame
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renderFrame: !zone
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!if DOUBLE_BUFFER { jsr setBackBuf }
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jsr setBackBuf
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jsr castAllRays
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@ -1919,7 +1927,11 @@ renderFrame: !zone
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iny
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sei
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sta setAuxZP
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jsr blitRoll
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lda shadow_pTex ; restore screen addr that gets overwritten by expander
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sta pTex
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lda shadow_pTex+1
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sta pTex+1
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jsr blitRoll ; go do the blitting
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sta clrAuxZP
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cli
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lda #0
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@ -1944,22 +1956,13 @@ pl_flipToPage1: !zone
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;-------------------------------------------------------------------------------
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; Flip back buffer onto the screen
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flip: !zone
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!if DOUBLE_BUFFER {
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ldy backBuf
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lda frontBuf
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sta backBuf
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sty frontBuf
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lda page1,y
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}
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; Hack for real (not emulated) IIc: sometimes displays only lo-bit graphics
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; unless we do this. *HUGE* thanks to Brendan Robert for the fix!
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sta $C07E ; disable double-hi-res
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lda $C05F ; disable double-hi-res
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rts
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;-------------------------------------------------------------------------------
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+ jmp flip
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;-------------------------------------------------------------------------------
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copyScreen: !zone
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; Copy all screen data from page 1 to page 2
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