mirror of
https://github.com/irmen/prog8.git
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111 lines
3.1 KiB
Lua
111 lines
3.1 KiB
Lua
%import c64lib
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;/*****************************************************************************\
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;** plasma test program for cc65. **
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;** **
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;** (w)2001 by groepaz/hitmen **
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;** **
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;** Cleanup and porting by Ullrich von Bassewitz. **
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;** Converted to prog8 by Irmen de Jong **
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;** **
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;\*****************************************************************************/
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main {
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const uword SCREEN1 = $E000
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const uword SCREEN2 = $E400
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const uword CHARSET = $E800
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const ubyte PAGE1 = ((SCREEN1 >> 6) & $F0) | ((CHARSET >> 10) & $0E)
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const ubyte PAGE2 = ((SCREEN2 >> 6) & $F0) | ((CHARSET >> 10) & $0E)
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sub start() {
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c64.COLOR = 1
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c64scr.print("creating charset...\n")
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makechar()
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ubyte block = c64.CIA2PRA
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; ubyte v = c64.VMCSB
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c64.CIA2PRA = (block & $FC) | (lsb(SCREEN1 >> 14) ^ $03)
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repeat {
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doplasma(SCREEN1)
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c64.VMCSB = PAGE1
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doplasma(SCREEN2)
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c64.VMCSB = PAGE2
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}
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; restore screen (if you want)
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;c64.VMCSB = v
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;c64.CIA2PRA = block
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;c64scr.print("done!\n")
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}
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; several variables outside of doplasma to make them retain their value
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ubyte c1A
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ubyte c1B
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ubyte c2A
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ubyte c2B
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sub doplasma(uword screen) {
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ubyte[40] xbuf
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ubyte[25] ybuf
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ubyte c1a = c1A
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ubyte c1b = c1B
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ubyte c2a = c2A
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ubyte c2b = c2B
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ubyte @zp x
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ubyte @zp y
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for y in 24 downto 0 {
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ybuf[y] = sin8u(c1a) + sin8u(c1b)
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c1a += 4
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c1b += 9
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}
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c1A += 3
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c1B -= 5
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for x in 39 downto 0 {
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xbuf[x] = sin8u(c2a) + sin8u(c2b)
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c2a += 3
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c2b += 7
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}
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c2A += 2
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c2B -= 3
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for y in 24 downto 0 {
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for x in 39 downto 0 {
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@(screen) = xbuf[x] + ybuf[y]
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; %asm {{
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; ldy x
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; lda xbuf,y
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; ldy y
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; clc
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; adc ybuf,y
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; ldy #0
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; sta (screen),y
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; }}
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screen++
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}
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}
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}
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sub makechar() {
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ubyte[8] bittab = [ $01, $02, $04, $08, $10, $20, $40, $80 ]
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ubyte c
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for c in 0 to 255 {
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ubyte @zp s = sin8u(c)
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ubyte i
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for i in 0 to 7 {
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ubyte b=0
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ubyte @zp ii
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for ii in 0 to 7 {
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; use 16 bit rng for a bit more randomness instead of the 8-bit rng
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if lsb(rndw()) > s {
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b |= bittab[ii]
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}
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}
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@(CHARSET + i + c*8.w) = b
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}
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}
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}
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}
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