From 76ebed5871c20411a6aa0605eeda4aadb0c2afc9 Mon Sep 17 00:00:00 2001
From: Brion Vibber <brion@pobox.com>
Date: Wed, 7 Dec 2022 18:20:24 -0800
Subject: [PATCH] wip 2frame

---
 dither-image.js | 28 +++++++++++-----------
 dither4.s       | 62 ++++++++++++++++++-------------------------------
 2 files changed, 37 insertions(+), 53 deletions(-)

diff --git a/dither-image.js b/dither-image.js
index 1a441c8..b448098 100644
--- a/dither-image.js
+++ b/dither-image.js
@@ -667,7 +667,7 @@ function genAssembly(width, height, nbits, lines, reps) {
             palette3: new Uint8Array(linesEach),
             bitmap: new Uint8Array(stride * linesEach),
         };
-        for (let y = 0; y < lines.length; y++) {
+        for (let y = 0; y < linesEach; y++) {
             let base = linesEach * i;
             console.log(i, y, base);
             frame.palette1[y] = lines[y + base].palette[1];
@@ -694,49 +694,49 @@ function genAssembly(width, height, nbits, lines, reps) {
 .export frame2_palette2
 .export frame2_palette3
 
-.segment buffers
+.segment "BUFFERS"
 
 .align 4096
-frame1_top
-${byte2byte(frame[0].bitmap.slice(0, half))}
+frame1_top:
+${byte2byte(frames[0].bitmap.slice(0, half))}
 
 .align 256
 frame1_palette1:
-${byte2byte(frame[0].palette1)}
+${byte2byte(frames[0].palette1)}
 
 .align 256
 frame1_palette2:
-${byte2byte(frame[0].palette2)}
+${byte2byte(frames[0].palette2)}
 
 .align 256
 frame1_palette3:
-${byte2byte(frame[0].palette3)}
+${byte2byte(frames[0].palette3)}
 
 .align 4096
 frame1_bottom:
-${byte2byte(frame[0].bitmap.slice(half))}
+${byte2byte(frames[0].bitmap.slice(half))}
 
 
 
 .align 4096
-frame2_top
-${byte2byte(frame[1].bitmap.slice(0, half))}
+frame2_top:
+${byte2byte(frames[1].bitmap.slice(0, half))}
 
 .align 256
 frame2_palette1:
-${byte2byte(frame[1].palette1)}
+${byte2byte(frames[1].palette1)}
 
 .align 256
 frame2_palette2:
-${byte2byte(frame[1].palette2)}
+${byte2byte(frames[1].palette2)}
 
 .align 256
 frame2_palette3:
-${byte2byte(frame[1].palette3)}
+${byte2byte(frames[1].palette3)}
 
 .align 4096
 frame2_bottom:
-${byte2byte(frame[1].bitmap.slice(half))}
+${byte2byte(frames[1].bitmap.slice(half))}
 
 `;
 }
diff --git a/dither4.s b/dither4.s
index b75a029..d5acd40 100644
--- a/dither4.s
+++ b/dither4.s
@@ -13,11 +13,6 @@ WSYNC = $D40A
 VCOUNT = $D40B
 NMIEN = $D40E
 
-framebuffer = $a000
-framebuffer2 = $b000
-framebuffer3 = $8000
-framebuffer4 = $9000
-
 temp1l = $80
 temp1h = $81
 temp1 = temp1l
@@ -40,13 +35,20 @@ scanline_max = (lines_per_frame - scanline_offset) / 2
 
 .data
 
-.import palette1
-.import palette2
-.import palette3
-.import bitmap
 .import audio_samples
 .import audio_samples_end
 
+.import frame1_top
+.import frame1_bottom
+.import frame1_palette1
+.import frame1_palette2
+.import frame1_palette3
+.import frame2_top
+.import frame2_bottom
+.import frame2_palette1
+.import frame2_palette2
+.import frame2_palette3
+
 displaylist:
     ; 40 lines overscan
     .repeat 5
@@ -56,12 +58,12 @@ displaylist:
     ; 160 lines graphics
     ; ANTIC mode e (160px 2bpp, 1 scan line per line)
     .byte $4e
-    .addr framebuffer
+    .addr frame1_top
     .repeat height / 2 - 1
         .byte $0e
     .endrep
     .byte $4e
-    .addr framebuffer2
+    .addr frame1_bottom
     .repeat height / 2 - 1
         .byte $0e
     .endrep
@@ -78,12 +80,12 @@ displaylist_part2:
     ; 160 lines graphics
     ; ANTIC mode e (160px 2bpp, 1 scan line per line)
     .byte $4e
-    .addr framebuffer3
+    .addr frame2_top
     .repeat height / 2 - 1
         .byte $0e
     .endrep
     .byte $4e
-    .addr framebuffer4
+    .addr frame2_bottom
     .repeat height / 2 - 1
         .byte $0e
     .endrep
@@ -121,24 +123,6 @@ audio_high_byte:
 .export start
 
 .proc start
-    ; Copy the bitmap into our framebuffer
-    lda #.lobyte(bitmap)
-    sta temp1l
-    lda #.hibyte(bitmap)
-    sta temp1h
-    lda #.lobyte(framebuffer)
-    sta temp2l
-    lda #.hibyte(framebuffer)
-    sta temp2h
-    jsr copy_half_frame
-
-    ; Second half of bitmap has to be separately aligned
-    lda #.lobyte(framebuffer2)
-    sta temp2l
-    lda #.hibyte(framebuffer2)
-    sta temp2h
-    jsr copy_half_frame
-
     ; Set up the audio sample buffer
     lda #.lobyte(audio_samples)
     sta sample_ptrl
@@ -150,7 +134,7 @@ audio_high_byte:
     sta DMACTL
 
     ; Disable VBI and DLI but allow Reset
-    lda #32
+    lda #$20
     sta NMIEN
 
     ; Set up the display list
@@ -186,16 +170,16 @@ each_scanline:
         sta audiotemp ; 3 cyc
     .endmacro
 
-    .macro inner_scanline
+    .macro inner_scanline frame_base
         ; it'll fire on unused lines, but harmlessly
         ldy scanline ; 3 cyc
         inc scanline ; 5 cyc
 
         ; Leisurely memory fetches
-        lda palette1,y ; 5
-        pha            ; ...3?
-        ldx palette2,y ; 5
-        lda palette3,y ; 5
+        lda frame1_palette1,y ; 5 @FIXME alternate
+        pha                   ; ...3?
+        ldx frame1_palette2,y ; 5
+        lda frame1_palette3,y ; 5
         tay
         pla
 
@@ -210,8 +194,8 @@ each_scanline:
 
     .macro audio_play_lo ; 11 cycles
         lda audiotemp ; 3 cyc
-        ;and #$0f ; 2 cyc
-        ;ora #$10 ; 2 cyc
+        and #$0f ; 2 cyc
+        ora #$10 ; 2 cyc
         sta AUDC1 ; 4 cyc
     .endmacro