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342 lines
10 KiB
ArmAsm
342 lines
10 KiB
ArmAsm
********************************
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* *
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* Fast Apple II Graphics *
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* By Andy McFadden *
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* Version 0.3, Aug 2015 *
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* *
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* Pre-computed data and *
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* large internal buffers. *
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* (Included by FDRAW.S) *
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* *
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* Developed with Merlin-16 *
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* *
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********************************
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* Expected layout with alignment:
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*
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* P1 ylooklo, misc tables
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* P2 ylookhi, colorline
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* P3 rastx0l
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* P4 rastx0h
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* P5 rastx1l
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* P6 rastx1h, div7hi, mod7hi
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* P7 div7lo
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* P8 mod7lo
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* P9 rast_unroll, rastunidx
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*
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* Tables should be just under $900 bytes.
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PG_ALIGN
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* Hi-res Y lookup, low part (192 bytes).
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ylooklo HEX 0000000000000000
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HEX 8080808080808080
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HEX 0000000000000000
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HEX 8080808080808080
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HEX 0000000000000000
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HEX 8080808080808080
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HEX 0000000000000000
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HEX 8080808080808080
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HEX 2828282828282828
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HEX a8a8a8a8a8a8a8a8
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HEX 2828282828282828
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HEX a8a8a8a8a8a8a8a8
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HEX 2828282828282828
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HEX a8a8a8a8a8a8a8a8
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HEX 2828282828282828
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HEX a8a8a8a8a8a8a8a8
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HEX 5050505050505050
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HEX d0d0d0d0d0d0d0d0
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HEX 5050505050505050
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HEX d0d0d0d0d0d0d0d0
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HEX 5050505050505050
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HEX d0d0d0d0d0d0d0d0
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HEX 5050505050505050
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HEX d0d0d0d0d0d0d0d0
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* Color masks for odd/even bytes, colors 0-7.
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evencolor dfb $00,$2a,$55,$7f,$80,$aa,$d5,$ff
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oddcolor dfb $00,$55,$2a,$7f,$80,$d5,$aa,$ff
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* XOR mask for colors 0-7 - non-BW flip on odd/even.
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xormask dfb $00,$7f,$7f,$00,$00,$7f,$7f,$00
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* AND mask for the 7 pixel positions, high bit set
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* for the color shift.
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andmask dfb $81,$82,$84,$88,$90,$a0,$c0
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* These are pixel AND masks, used with the modulo 7
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* result. Entry #2 in leftmask means we're touching
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* the rightmost 5 pixels, and entry #2 in rightmask
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* means we're touching the 3 leftmost pixels.
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*
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* The high bit is always set, because we want to
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* keep the color's high bit.
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leftmask dfb $ff,$fe,$fc,$f8,$f0,$e0,$c0
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rightmask dfb $81,$83,$87,$8f,$9f,$bf,$ff
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PG_ALIGN
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* Hi-res Y lookup, high part (192 bytes).
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* OR with $20 or $40.
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ylookhi HEX 0004080c1014181c
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HEX 0004080c1014181c
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HEX 0105090d1115191d
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HEX 0105090d1115191d
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HEX 02060a0e12161a1e
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HEX 02060a0e12161a1e
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HEX 03070b0f13171b1f
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HEX 03070b0f13171b1f
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HEX 0004080c1014181c
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HEX 0004080c1014181c
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HEX 0105090d1115191d
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HEX 0105090d1115191d
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HEX 02060a0e12161a1e
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HEX 02060a0e12161a1e
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HEX 03070b0f13171b1f
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HEX 03070b0f13171b1f
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HEX 0004080c1014181c
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HEX 0004080c1014181c
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HEX 0105090d1115191d
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HEX 0105090d1115191d
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HEX 02060a0e12161a1e
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HEX 02060a0e12161a1e
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HEX 03070b0f13171b1f
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HEX 03070b0f13171b1f
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* Masks for current color (even/odd), e.g. 55 2a 55 2a ...
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* Updated whenever the color changes.
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colorline ds 40
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PG_ALIGN
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rastx0l ds NUM_ROWS
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PG_ALIGN
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rastx0h ds NUM_ROWS
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ds 1 ;repeat mode can overstep
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PG_ALIGN
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rastx1l ds NUM_ROWS
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PG_ALIGN
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rastx1h ds NUM_ROWS
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* Lookup tables for dividing 0-279 by 7. The "hi"
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* parts are 24 bytes each, so they fit inside
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* the previous 192-byte entry. The "lo" parts
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* each fill a page.
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div7hi HEX 2424242525252525
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HEX 2525262626262626
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HEX 2627272727272727
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mod7hi HEX 0405060001020304
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HEX 0506000102030405
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HEX 0600010203040506
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PG_ALIGN
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div7lo HEX 0000000000000001
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HEX 0101010101010202
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HEX 0202020202030303
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HEX 0303030304040404
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HEX 0404040505050505
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HEX 0505060606060606
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HEX 0607070707070707
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HEX 0808080808080809
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HEX 0909090909090a0a
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HEX 0a0a0a0a0a0b0b0b
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HEX 0b0b0b0b0c0c0c0c
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HEX 0c0c0c0d0d0d0d0d
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HEX 0d0d0e0e0e0e0e0e
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HEX 0e0f0f0f0f0f0f0f
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HEX 1010101010101011
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HEX 1111111111111212
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HEX 1212121212131313
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HEX 1313131314141414
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HEX 1414141515151515
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HEX 1515161616161616
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HEX 1617171717171717
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HEX 1818181818181819
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HEX 1919191919191a1a
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HEX 1a1a1a1a1a1b1b1b
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HEX 1b1b1b1b1c1c1c1c
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HEX 1c1c1c1d1d1d1d1d
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HEX 1d1d1e1e1e1e1e1e
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HEX 1e1f1f1f1f1f1f1f
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HEX 2020202020202021
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HEX 2121212121212222
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HEX 2222222222232323
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HEX 2323232324242424
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mod7lo HEX 0001020304050600
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HEX 0102030405060001
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HEX 0203040506000102
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HEX 0304050600010203
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HEX 0405060001020304
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HEX 0506000102030405
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HEX 0600010203040506
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HEX 0001020304050600
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HEX 0102030405060001
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HEX 0203040506000102
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HEX 0304050600010203
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HEX 0405060001020304
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HEX 0506000102030405
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HEX 0600010203040506
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HEX 0001020304050600
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HEX 0102030405060001
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HEX 0203040506000102
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HEX 0304050600010203
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HEX 0405060001020304
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HEX 0506000102030405
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HEX 0600010203040506
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HEX 0001020304050600
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HEX 0102030405060001
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HEX 0203040506000102
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HEX 0304050600010203
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HEX 0405060001020304
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HEX 0506000102030405
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HEX 0600010203040506
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HEX 0001020304050600
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HEX 0102030405060001
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HEX 0203040506000102
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HEX 0304050600010203
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* RastFill unrolled loop. At each step we store the current
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* color value, XOR it to flip the bits if needed, and advance.
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* The caller needs to set the appropriate initial value based
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* on whether the address is odd or even.
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*
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* We can use a 3-cycle "EOR dp" or a 2-cycle "EOR imm". The
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* former is one cycle slower, the latter requires us to
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* self-mod 40 instructions when the color changes.
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*
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* This must be page-aligned so that we can take the value
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* from the rastunidx table and self-mod a JMP without having
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* to do a 16-bit add. We have just enough room for the
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* unrolled loop (40*5+3) and x5 table (41) = 244 bytes, fits
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* on a single page.
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do USE_FAST ;*****
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ds \
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]hbasl equ zptr0 ;must match FillRaster
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rast_unroll equ *
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lst off
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lup BYTES_PER_ROW
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sta (]hbasl),y ;6
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eor #$00 ;2
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iny ;2 10 cycles, 5 bytes
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--^
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jmp rastlinedone
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* Index into rast_unroll. If we need to output N bytes,
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* we want to jump to (rast_unroll + (40 - N) * 5) (where
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* 5 is the number of bytes per iteration).
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rastunidx
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]offset = BYTES_PER_ROW*5
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lup BYTES_PER_ROW+1 ;0-40
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dfb ]offset
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]offset = ]offset-5
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--^
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fin ;*****
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********************************
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*
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* Code used to generate tables above. If you want to
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* decrease load size, use these functions to generate
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* the data into empty memory, then discard the code.
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* (Maybe use a negative DS and overlap with rastx0l?)
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*
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********************************
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DO 0 ;*****
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init_ylook
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]hbasl equ zptr1
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]hbash equ zptr1+1
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* Initialize Y-lookup table. We just call the bascalc
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* function.
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ldx #NUM_ROWS
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ldy #NUM_ROWS-1
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]loop tya
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jsr bascalc
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lda hbasl
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sta ylooklo,y
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lda hbash
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ora #$20 ;remove for $0000 base
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sta ylookhi,y
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dey
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dex
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bne ]loop
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rts
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* Hi-res base address calculation. This is based on the
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* HPOSN routine at $F411.
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*
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* Call with the line in A. The results are placed into
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* zptr1. X and Y are not disturbed.
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*
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* The value is in the $0000-1fff range, so you must OR
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* the desired hi-res page in.
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*
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bascalc
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pha
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and #$c0
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sta ]hbasl
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lsr
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lsr
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ora ]hbasl
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sta ]hbasl
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pla
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sta ]hbash
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asl
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asl
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asl
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rol ]hbash
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asl
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rol ]hbash
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asl
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ror ]hbasl
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lda ]hbash
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and #$1f
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sta ]hbash
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rts
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*
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* Create divide-by-7 tables.
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*
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mkdivtab
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]val equ zloc0
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ldy #0
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sty ]val
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ldx #0
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]loop lda ]val
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sta div7lo,y
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txa
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sta mod7lo,y
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inx
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iny
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beq :lodone
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cpx #7
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bne ]loop
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inc ]val
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ldx #0
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beq ]loop ;always
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:lodone ;safe to ignore ]va update
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]loop lda ]val
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sta div7hi,y
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txa
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sta mod7hi,y
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iny
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cpy #280-256
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beq :hidone
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inx
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cpx #7
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bne ]loop
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inc ]val
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ldx #0
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beq ]loop ;always
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:hidone rts
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FIN ;*****
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