From 7f96f96132d5a2e895f4c442e45f821775884894 Mon Sep 17 00:00:00 2001
From: 4am <a2_4am@sent.com>
Date: Tue, 30 Nov 2021 21:28:10 -0500
Subject: [PATCH] Revert "don't clear incremental palettes before stepping"

This reverts commit 215a11fb3d93fa0e3f9c28f02351a2f7d67be04d.
---
 src/fx/fx.shr.fizzle.a | 191 ++++++++++-------------------------------
 1 file changed, 46 insertions(+), 145 deletions(-)

diff --git a/src/fx/fx.shr.fizzle.a b/src/fx/fx.shr.fizzle.a
index 5e80f894e..d22952b84 100644
--- a/src/fx/fx.shr.fizzle.a
+++ b/src/fx/fx.shr.fizzle.a
@@ -1,159 +1,60 @@
 ;license:MIT
-;(c) 2021 by 4am
+;(c) 2019-2020 by qkumba/4am/John Brooks
 
 !cpu 6502
-!to "build/FX/SHR.FIZZLE",plain
+!to "build/SHR.FIZZLE",plain
 *=$A000
 
-color = $F8                          ; byte
-fracv = $F9                          ; byte
-incv =  $FA                          ; byte
-src =   $FC                          ; word
-dst =   $FE                          ; word
+         !source "src/fx/fx.shr.common.a"
 
-         !source "src/fx/macros.a"
+addrs=$80                            ; [128 bytes]
 
-         sta   $C005
-         ldy   #0                    ; copy pixel data
-         sty   src
-         sty   dst
-         lda   #$20
-         sta   src+1
-         ldx   #$7D
--        lda   (src), y
-         sta   (src), y
-         iny
-         bne   -
-         inc   src+1
+         ldx   #(end-start)          ; copy LFSR code to zero page
+-        lda   start-1, x
+         sta   $FF, x
          dex
          bne   -
+         lda   #$A0                  ; create address lookup table
+         tax
+         tay
+-        dey
+         sty   addrs-$21, x
+         dex
+         bne   -
+         ;X=0
 
+         +COPY_SCB_AND_PALETTES
          ;Y=0
--        lda   $9D00, y              ; copy SCB
-         sta   $9D00, y
-         lda   #0
-         sta   $9E00, y              ; clear palettes
-         sta   $9F00, y
-         iny
-         bne   -
 
-         sta   $C004
-         lda   #$9E
-         sta   src+1
-         ldx   #$0F                  ; palette counter ($0F -> $00, not used as index)
-rb_palette_loop
-         ldy   #$00                  ; byte offset within palette (00 -> 1F, used as index)
-rb_color_loop
-         lda   #$00
-         sta   fracv
-         sta   color
-         lda   src
-         sta   dst
-         lda   src+1
-         sec
-         sbc   #$3E
-         sta   dst+1
-         lda   (src), y              ; get final Red or Blue value for this color in this palette
-         asl                         ; Red or Blue value is bits 0-3, shift them into bits 4-7
-         asl
-         asl
-         asl
-         sta   incv
-rb_step_loop
-         lda   fracv
-         clc
-         adc   incv
-         sta   fracv
-         bcc   +
-         inc   color
-+        lda   color
-         sta   (dst), y
-         inc   dst+1
-         inc   dst+1
-         bpl   rb_step_loop
-         iny
-         cpy   #$20
-         bcc   rb_color_loop
-         lda   src
-         clc
-         adc   #$20
-         sta   src
-         bcc   +
-         inc   src+1
-+        dex
-         bpl   rb_palette_loop
+         jmp   loop
 
-         lda   #$9E
-         sta   src+1
-         ldx   #$0F                  ; palette counter ($0F -> $00, not used as index)
-g_palette_loop
-         ldy   #$00                  ; byte offset within palette (00 -> 1E by 2, used as index)
-g_color_loop
-         lda   #$00
-         sta   fracv
-         sta   color
-         lda   src
-         sta   dst
-         lda   src+1
-         sec
-         sbc   #$3E
-         sta   dst+1
-         lda   (src), y              ; get final Green value for this color in this palette
-         and   #$F0                  ; Green value is bits 4-7, mask out other bits
-         sta   incv
-g_step_loop
-         lda   fracv
-         clc
-         adc   incv
-         sta   fracv
-         lda   color
-         bcc   +
-         clc
-         adc   #$10
-         sta   color
-+        ora   (dst), y              ; keep existing Blue value in bits 0-3
-         sta   (dst), y
-         inc   dst+1
-         inc   dst+1
-         bpl   g_step_loop
-         iny
-         iny                         ; high nibble of second color byte is always 0 so skip it
-         cpy   #$20
-         bcc   g_color_loop
-         lda   src
-         clc
-         adc   #$20
-         sta   src
-         bcc   +
-         inc   src+1
-+        dex
-         bpl   g_palette_loop
-
-         ldx   #$62
-         stx   copy1+2
-         inx
-         stx   copy2+2
-         ldx   #$0E
-         ldy   #$00
-copyloop jsr   WaitForVBL
-         sta   $C005
-copy1    lda   $6200, y              ; SMC
-         sta   $9E00, y
-copy2    lda   $6300, y              ; SMC
-         sta   $9F00, y
-         iny
-         bne   copy1
-         sta   $C004
-         inc   copy1+2
-         inc   copy1+2
-         inc   copy2+2
-         inc   copy2+2
-         lda   #$40
-         jsr   WaitForKeyWithTimeout
+start
+!pseudopc 0 {
+         ;X=0
+         ;Y=0
+loop     txa
+loop1    eor   #$60                  ; LFSR form 0x6000 with period 32767
+         tax
+loop2    lda   addrs, x
+         sta   <src+1
+src=*+1
+         lda   $FD00, y              ; SMC high byte
+         sta   (<src), y
+         txa
+         lsr
+         tax
+         tya
+         ror
+         tay
+         bcc   loop2
+         bne   loop
+         bit   $C000
          bmi   exit
-         dex
-         bpl   copyloop
-exit     sta   $C004
-         jmp   UnwaitForVBL
-
-         !source "src/wait.a"
+         txa
+         bne   loop1
+exit     lda   $2000                 ; last lousy byte (because LFSR never hits 0)
+         sta   $2000
+         sta   $C004
+         rts
+}
+end