diff --git a/presets/c64/c64-sid.cfg b/presets/c64/c64-sid.cfg
index 30b69ac2..a3c23039 100644
--- a/presets/c64/c64-sid.cfg
+++ b/presets/c64/c64-sid.cfg
@@ -5,7 +5,7 @@ SYMBOLS {
     __LOADADDR__:  type = import;
     __EXEHDR__:    type = import;
     __STACKSIZE__: type = weak, value = $0800; # 2k stack
-    __HIMEM__:     type = weak, value = $D000;
+    __HIMEM__:     type = weak, value = $8000;
 }
 MEMORY {
     ZP:       file = "", define = yes, start = $0002,           size = $001A;
@@ -15,6 +15,7 @@ MEMORY {
     SIDFILE:  file = %O, define = yes, start = $1000, size = $1000, fill = yes;
     MAIN:     file = %O, define = yes, start = $2000, size = __HIMEM__ - $2000;
     BSS:      file = "",               start = __ONCE_RUN__,    size = __HIMEM__ - __STACKSIZE__ - __ONCE_RUN__;
+    VICBANK:  file = %O,               start = $8000, size = $4000;
 }
 SEGMENTS {
     ZEROPAGE: load = ZP,       type = zp;
@@ -29,6 +30,7 @@ SEGMENTS {
     INIT:     load = MAIN,     type = rw;
     ONCE:     load = MAIN,     type = ro,  define   = yes;
     BSS:      load = BSS,      type = bss, define   = yes;
+    VICBANK:  load = MAIN,     type = ro,  optional = yes;
 }
 FEATURES {
     CONDES: type    = constructor,
diff --git a/presets/c64/climber.c b/presets/c64/climber.c
index 1cf0c3e2..fc775437 100644
--- a/presets/c64/climber.c
+++ b/presets/c64/climber.c
@@ -5,6 +5,16 @@
 #include <c64.h>
 #include <joystick.h>
 
+//#resource "c64-sid.cfg"
+#define CFGFILE c64-sid.cfg
+
+//#resource "sidmusic1.bin"
+//#link "sidplaysfx.ca65"
+#include "sidplaysfx.h"
+
+//#link "rasterirq.ca65"
+#include "rasterirq.h"
+
 #include "bcd.h"
 //#link "bcd.c"
 
@@ -17,13 +27,6 @@
 #include "sprites.h"
 //#link "sprites.c"
 
-//#resource "c64-sid.cfg"
-#define CFGFILE c64-sid.cfg
-
-//#resource "sidmusic1.bin"
-//#link "sidplaysfx.ca65"
-#include "sidplaysfx.h"
-
 // indices of sound effects
 #define SND_JUMP 0
 #define SND_HIT 2
@@ -755,6 +758,16 @@ void play_scene() {
   blimp_pickup_scene();
 }
 
+// main display list
+void game_displaylist(void) {
+  VIC.bordercolor = 2;
+  sid_update();
+  VIC.bordercolor = 0;
+//  DLIST_NEXT(42);
+//  VIC.bordercolor = 3;
+  DLIST_RESTART(20);
+}
+
 // main program
 void main() {
   byte i;
@@ -767,14 +780,16 @@ void main() {
     sprite_shape(hidbuf, 32+i, SPRITE_DATA[i]);
   }
   sprshad.spr_mcolor = 0xff;
-  sprshad.spr_mcolor0 = 0x0f;
-  sprshad.spr_mcolor1 = 0x00;
+  VIC.spr_mcolor0 = 0x0f;
+  VIC.spr_mcolor1 = 0x00;
   // select character set 2
   VIC.addr = 0x15;
   // start scrolling @ bottom of level
   origin_y = START_ORIGIN_Y;
   // install joystick
   joy_install (joy_static_stddrv);
+  // setup display list
+  DLIST_SETUP(game_displaylist);
   // main game loop
   while (1) {
     make_floors();
diff --git a/presets/c64/hello.dasm b/presets/c64/hello.dasm
index 906aa2c2..899940d3 100644
--- a/presets/c64/hello.dasm
+++ b/presets/c64/hello.dasm
@@ -7,6 +7,7 @@ Start
 	sei		; turn off interrupts
 	ldy #0
         sty $d020	; reset border color
+        
 Loop
         lda Message,y	; load message byte
         beq EOM		; 0 = end of string
diff --git a/presets/c64/rasterirq.ca65 b/presets/c64/rasterirq.ca65
new file mode 100644
index 00000000..ad58d1fb
--- /dev/null
+++ b/presets/c64/rasterirq.ca65
@@ -0,0 +1,86 @@
+
+USE_INTERRUPTOR = 0
+
+.segment "DATA"
+
+StartDlist: .word NullDlist-1
+NextDlist: .word NullDlist-1
+
+.segment "CODE"
+
+.global _dlist_setup
+.global DLIST_IRQ_NEXT
+.global DLIST_IRQ_RESTART
+.if USE_INTERRUPTOR
+.interruptor DLIST_IRQ
+.endif
+
+_dlist_setup:
+  SEI                  ; set interrupt bit, make the CPU ignore interrupt requests
+  
+  sta StartDlist+0     ; save XA as pointer to start of dlist
+  stx StartDlist+1
+  
+  LDA #%01111111       ; switch off interrupt signals from CIA-1
+  STA $DC0D
+
+  AND $D011            ; clear most significant bit of VIC's raster register
+  STA $D011
+
+  LDA $DC0D            ; acknowledge pending interrupts from CIA-1
+  LDA $DD0D            ; acknowledge pending interrupts from CIA-2
+
+  LDA #252             ; set rasterline where interrupt shall occur
+  STA $D012
+
+.if !USE_INTERRUPTOR
+  LDA #<DLIST_IRQ            ; set interrupt vectors, pointing to interrupt service routine below
+  STA $0314
+  LDA #>DLIST_IRQ
+  STA $0315
+.endif
+
+  LDA #%00000001       ; enable raster interrupt signals from VIC
+  STA $D01A
+  cli
+  rts
+
+DLIST_IRQ:
+DLIST_CALL:
+  lda NextDlist+1
+  pha
+  lda NextDlist+0
+  pha
+  rts
+
+DLIST_IRQ_RESTART:
+  sta $d012
+  lda StartDlist+0
+  sta NextDlist+0
+  lda StartDlist+1
+  sta NextDlist+1
+  bne DLIST_ACK
+
+DLIST_IRQ_STOP:
+  lda #0        ; disable raster interrupt signals from VIC
+  sta $D01A
+  bne DLIST_ACK
+        
+DLIST_IRQ_NEXT:
+  sta $d012
+  pla
+  sta NextDlist+0
+  pla
+  sta NextDlist+1
+DLIST_ACK:
+  ASL $D019            ; acknowledge the interrupt by clearing the VIC's interrupt flag
+.if USE_INTERRUPTOR
+  clc
+  rts
+.else
+  JMP $EA31            ; jump into KERNAL's standard interrupt service routine to handle keyboard scan, cursor display etc.
+.endif
+
+NullDlist:
+  lda #252
+  jmp DLIST_IRQ_RESTART
diff --git a/presets/c64/rasterirq.h b/presets/c64/rasterirq.h
new file mode 100644
index 00000000..087300d1
--- /dev/null
+++ b/presets/c64/rasterirq.h
@@ -0,0 +1,19 @@
+#ifndef _RASTERIRQ_H
+#define _RASTERIRQ_H
+
+
+void dlist_setup(void* ptr);
+
+#define DLIST_SETUP(func) \
+  dlist_setup(((char*)func)-1)
+
+#define DLIST_NEXT(line) \
+  __A__ = line; \
+  asm ("jsr DLIST_IRQ_NEXT");
+
+#define DLIST_RESTART(line) \
+  __A__ = line; \
+  asm ("jmp DLIST_IRQ_RESTART");
+
+
+#endif
diff --git a/presets/c64/scroll4.c b/presets/c64/scroll4.c
index 846b0361..7c3c07c7 100644
--- a/presets/c64/scroll4.c
+++ b/presets/c64/scroll4.c
@@ -8,183 +8,92 @@
 #include <stdint.h>
 #include <joystick.h>
 
-typedef uint8_t byte;
-typedef uint16_t word;
-typedef int8_t sbyte;
+#include "common.h"
+//#link "common.c"
 
-#define COLS 40
-#define ROWS 25
+#include "scrolling.h"
+//#link "scrolling.c"
 
-void raster_wait(unsigned char line) {
-  while (VIC.rasterline < line) ;
-}
+#include "sprites.h"
+//#link "sprites.c"
 
-void wait_vblank() {
-  raster_wait(255); // TODO
-}
-
-sbyte scroll_fine_x;
-sbyte scroll_fine_y;
-byte origin_x;
-byte origin_y;
-byte curbuf;
-byte* scrnbuf[2];	// screen buffer(s)
-byte tempbuf[COLS*ROWS];
-
-void draw_cell(byte x, byte y) {
+static void draw_cell(word ofs, byte x, byte y) {
   byte xx = x + origin_x;
   byte yy = y + origin_y;
   byte ch = xx ^ yy;
-  word ofs = x+y*COLS;
-  scrnbuf[curbuf][ofs] = ch; // character
-  tempbuf[ofs] = ch; // color
+  hidbuf[ofs] = ch; // character
+  colorbuf[ofs] = ch; // color
 }
 
 void scroll_draw_column(byte col) {
   byte y;
+  word ofs = col;
   for (y=0; y<ROWS; y++) {
-    draw_cell(col, y);
+    draw_cell(ofs, col, y);
+    ofs += COLS;
   }
 }
 
 void scroll_draw_row(byte row) {
   byte x;
+  word ofs = row * COLS;
   for (x=0; x<COLS; x++) {
-    draw_cell(x, row);
+    draw_cell(ofs, x, row);
+    ++ofs;
   }
 }
 
-void scroll_update_regs() {
-  VIC.ctrl1 = (VIC.ctrl1 & 0xf8) | scroll_fine_y;
-  VIC.ctrl2 = (VIC.ctrl2 & 0xf8) | scroll_fine_x;
-}
-
-void scroll_swap() {
-  // swap hidden and visible buffers
-  curbuf ^= 1;
-  // wait for vblank and update registers
-  wait_vblank();
-  scroll_update_regs();
-  VIC.addr = (VIC.addr & 0xf) | (curbuf ? 0x00 : 0x10);
-}
-
-void scroll_copy() {
-  // copy temp buf to color ram
-  memcpy(COLOR_RAM, tempbuf, COLS*ROWS);
-  // copy visible buffer to hidden buffer
-  memcpy(scrnbuf[curbuf], scrnbuf[curbuf^1], COLS*ROWS);
-}
-
-// TODO: left and up can be faster, b/c we can copy color ram downward
-
-void scroll_left() {
-  memcpy(scrnbuf[curbuf], scrnbuf[curbuf^1]+1, COLS*ROWS-1);
-  ++origin_x;
-  memcpy(tempbuf, COLOR_RAM+1, COLS*ROWS-1);
-  scroll_draw_column(COLS-1);
-  scroll_swap();
-  scroll_copy();
-}
-
-void scroll_up() {
-  memcpy(scrnbuf[curbuf], scrnbuf[curbuf^1]+COLS, COLS*(ROWS-1));
-  ++origin_y;
-  memcpy(tempbuf, COLOR_RAM+COLS, COLS*(ROWS-1));
-  scroll_draw_row(ROWS-1);
-  scroll_swap();
-  scroll_copy();
-}
-
-void scroll_right() {
-  memcpy(scrnbuf[curbuf]+1, scrnbuf[curbuf^1], COLS*ROWS-1);
-  --origin_x;
-  memcpy(tempbuf+1, COLOR_RAM, COLS*ROWS-1);
-  scroll_draw_column(0);
-  scroll_swap();
-  scroll_copy();
-}
-
-void scroll_down() {
-  memcpy(scrnbuf[curbuf]+COLS, scrnbuf[curbuf^1], COLS*(ROWS-1));
-  --origin_y;
-  memcpy(tempbuf+COLS, COLOR_RAM, COLS*(ROWS-1));
-  scroll_draw_row(0);
-  scroll_swap();
-  scroll_copy();
-}
-
-void scroll_horiz(sbyte delta_x) {
-  scroll_fine_x += delta_x;
-  while (scroll_fine_x < 0) {
-    scroll_fine_x += 8;
-    scroll_left();
-  }
-  while (scroll_fine_x >= 8) {
-    scroll_fine_x -= 8;
-    scroll_right();
-  }
-}
-
-void scroll_vert(sbyte delta_y) {
-  scroll_fine_y += delta_y;
-  while (scroll_fine_y < 0) {
-    scroll_fine_y += 8;
-    scroll_up();
-  }
-  while (scroll_fine_y >= 8) {
-    scroll_fine_y -= 8;
-    scroll_down();
-  }
-}
-
-void scroll_setup() {
-  scroll_fine_x = 0;
-  scroll_fine_y = 0;
-  origin_x = 0x80;
-  origin_y = 0x80;
-  curbuf = 0;
-  // get screen buffer addresses
-  scrnbuf[0] = (byte*) 0x8000;
-  scrnbuf[1] = (byte*) 0x8400;
-  // copy existing text to screen 0
-  memcpy(scrnbuf[0], (byte*)0x400, COLS*ROWS);
-  // copy screen 1 to screen 0
-  memcpy(scrnbuf[1], scrnbuf[0], COLS*ROWS);
-  
-  // set VIC bank ($4000-$7FFF)
-  // https://www.c64-wiki.com/wiki/VIC_bank
-  CIA2.pra = 0x01;
-  
-  VIC.ctrl1 = 0x10; // 24 lines
-  VIC.ctrl2 = 0x00; // 38 columns
-}
+/*{w:24,h:21,bpp:1,brev:1}*/
+const char SPRITE1[3*21] = {
+  0x00,0x7F,0x00,0x01,0xFF,0xC0,0x03,0xFF,0xE0,
+  0x03,0xE7,0xE0,0x07,0xD9,0xF0,0x07,0xDF,0xF0,
+  0x07,0xD9,0xF0,0x03,0xE7,0xE0,0x03,0xFF,0xE0,
+  0x03,0xFF,0xE0,0x02,0xFF,0xA0,0x01,0x7F,0x40,
+  0x01,0x3E,0x40,0x00,0x9C,0x80,0x00,0x9C,0x80,
+  0x00,0x49,0x00,0x00,0x49,0x00,0x00,0x3E,0x00,
+  0x00,0x3E,0x00,0x00,0x3E,0x00,0x00,0x1C,0x00
+};
 
 void main(void) {
-  sbyte n =0;
-
+  byte n = 0;
+  
   clrscr();
   printf("\r\n\r\n\r\n                           Hello World!");
   printf("\r\n\r\n\r\n                  This is how we scroll");
   printf("\r\n\r\n\r\n               But color RAM can't move");
   printf("\r\n\r\n\r\n        So we have to use a temp buffer");
   printf("\r\n\r\n\r\n               And copy it just in time");
-  
+
+  // setup scrolling library
   scroll_setup();
 
+  // setup sprite library and copy sprite to VIC bank
+  sprite_clear();
+  sprite_shape(hidbuf, 32, SPRITE1);
+
   // install the joystick driver
   joy_install (joy_static_stddrv);
   
   // infinite loop
   while (1) {
+    static char speed = 1;
     // get joystick bits
     char joy = joy_read(0);
+    // speed up scrolling while button pressed
+    speed = JOY_BTN_1(joy) ? 2 : 1;
     // move sprite based on arrow keys
-    if (JOY_LEFT(joy)) scroll_horiz(-1);
-    if (JOY_UP(joy)) scroll_vert(-1);
-    if (JOY_RIGHT(joy)) scroll_horiz(1);
-    if (JOY_DOWN(joy)) scroll_vert(1);
-    // update regs
+    if (JOY_LEFT(joy)) scroll_horiz(-speed);
+    if (JOY_UP(joy)) scroll_vert(-speed);
+    if (JOY_RIGHT(joy)) scroll_horiz(speed);
+    if (JOY_DOWN(joy)) scroll_vert(speed);
+    // animate sprite in shadow sprite ram
+    sprite_draw(0, n++, 70, 32);
+    // wait for vblank
     wait_vblank();
-    scroll_update_regs();
+    // update scroll registers
+    // and swap screens if we must
+    scroll_update();
+    // then update sprite registers
+    sprite_update(visbuf);
   }
 }
diff --git a/presets/c64/scroll5.c b/presets/c64/scroll5.c
index 8adfd32b..a032114a 100644
--- a/presets/c64/scroll5.c
+++ b/presets/c64/scroll5.c
@@ -17,26 +17,29 @@
 #include "sprites.h"
 //#link "sprites.c"
 
-static void draw_cell(byte x, byte y) {
+static void draw_cell(word ofs, byte x, byte y) {
   byte xx = x + origin_x;
   byte yy = y + origin_y;
   byte ch = xx ^ yy;
-  word ofs = x+y*COLS;
   hidbuf[ofs] = ch; // character
   colorbuf[ofs] = ch; // color
 }
 
 void scroll_draw_column(byte col) {
   byte y;
+  word ofs = col;
   for (y=0; y<ROWS; y++) {
-    draw_cell(col, y);
+    draw_cell(ofs, col, y);
+    ofs += COLS;
   }
 }
 
 void scroll_draw_row(byte row) {
   byte x;
+  word ofs = row * COLS;
   for (x=0; x<COLS; x++) {
-    draw_cell(x, row);
+    draw_cell(ofs, x, row);
+    ++ofs;
   }
 }
 
@@ -51,15 +54,42 @@ const char SPRITE1[3*21] = {
   0x00,0x3E,0x00,0x00,0x3E,0x00,0x00,0x1C,0x00
 };
 
+int playerx = 0;
+int playery = 0;
+int camerax = 0;
+int cameray = 0;
+
+void update_player() {
+  sprite_draw(0, playerx-camerax+160, playery-cameray+140, 32);
+}
+
+void camera_follow(byte moving) {
+  int dx, dy;
+  dx = camerax - playerx;
+  dy = cameray - playery;
+  if (moving && abs(dx) < 32 && abs(dy) < 32) return;
+  dx >>= 4;
+  dy >>= 4;
+  if (dx) {
+    if (dx > 8) dx = 8;
+    else if (dx < -8) dx = -8;
+    camerax -= dx;
+    scroll_horiz(dx);
+  }
+  if (dy) {
+    if (dy > 8) dy = 8;
+    else if (dy < -8) dy = -8;
+    cameray -= dy;
+    scroll_vert(dy);
+  }
+}
+
 void main(void) {
-  byte n = 0;
   
   clrscr();
   printf("\r\n\r\n\r\n                           Hello World!");
-  printf("\r\n\r\n\r\n                  This is how we scroll");
-  printf("\r\n\r\n\r\n               But color RAM can't move");
-  printf("\r\n\r\n\r\n        So we have to use a temp buffer");
-  printf("\r\n\r\n\r\n               And copy it just in time");
+  printf("\r\n\r\n\r\n               Use the joystick to move");
+  printf("\r\n\r\n\r\n             And the camera will follow");
 
   // setup scrolling library
   scroll_setup();
@@ -67,30 +97,39 @@ void main(void) {
   // setup sprite library and copy sprite to VIC bank
   sprite_clear();
   sprite_shape(hidbuf, 32, SPRITE1);
+  sprshad.spr_color[0] = 13;
 
   // install the joystick driver
   joy_install (joy_static_stddrv);
-  
+
   // infinite loop
-  while (1) {
-    static char speed = 1;
+   while (1) {
+    static char speed;
+    static char joy;
+    static bool slowframe = false;
     // get joystick bits
-    char joy = joy_read(0);
+    joy = joy_read(0);
     // speed up scrolling while button pressed
-    speed = JOY_BTN_1(joy) ? 2 : 1;
+    speed = JOY_BTN_1(joy) ? 3 : 1;
+    // if we copied screen memory last frame,
+    // double speed of player for this frame
+    if (slowframe) speed *= 2;
     // move sprite based on arrow keys
-    if (JOY_LEFT(joy)) scroll_horiz(-speed);
-    if (JOY_UP(joy)) scroll_vert(-speed);
-    if (JOY_RIGHT(joy)) scroll_horiz(speed);
-    if (JOY_DOWN(joy)) scroll_vert(speed);
+    if (JOY_LEFT(joy)) playerx -= speed;
+    if (JOY_RIGHT(joy)) playerx += speed;
+    if (JOY_UP(joy)) playery -= speed;
+    if (JOY_DOWN(joy)) playery += speed;
+    // move the camera?
+    camera_follow(joy);
+    slowframe = swap_needed;
     // animate sprite in shadow sprite ram
-    sprite_draw(0, n++, 70, 32);
+    update_player();
     // wait for vblank
     wait_vblank();
+    // then update sprite registers
+    sprite_update(visbuf);
     // update scroll registers
     // and swap screens if we must
     scroll_update();
-    // then update sprite registers
-    sprite_update(visbuf);
   }
 }
diff --git a/presets/c64/scrolling.c b/presets/c64/scrolling.c
index ed133880..45788e80 100644
--- a/presets/c64/scrolling.c
+++ b/presets/c64/scrolling.c
@@ -11,53 +11,124 @@ byte* hidbuf;
 byte* visbuf;
 byte colorbuf[COLS*ROWS];
 byte swap_needed;
+byte copy_needed;
 
 //
 
 void scroll_swap(void) {
   byte* tmp;
-  // set VIC bank address
-  VIC.addr = (VIC.addr & 0xf) | (((word)hidbuf >> 8) << 2);
   // swap hidden and visible buffers
   tmp = hidbuf;
   hidbuf = visbuf;
   visbuf = tmp;
+  // set VIC bank address
+  VIC.addr = (VIC.addr & 0xf) | (((word)visbuf >> 8) << 2);
 }
 
-void scroll_copy(void) {
-  // copy temp buf to color ram
+void copy_color_ram_slow() {
   memcpy(COLOR_RAM, colorbuf, COLS*ROWS);
-  // copy visible buffer to hidden buffer
+}
+
+void copy_color_ram_fast() {
+  // fast copy loop for upper 1/2 of color ram
+  asm("ldy #0");
+  asm("@loop:");
+  asm("lda %v,y", colorbuf);
+  asm("sta $d800,y");
+  asm("lda %v + $100,y", colorbuf);
+  asm("sta $d900,y");
+  asm("iny");
+  asm("bne @loop");
+  // second loop for lower 1/2 of color ram
+  asm("@loop2:");
+  asm("lda %v + $200,y", colorbuf);
+  asm("sta $da00,y");
+  asm("lda %v + $300,y", colorbuf);
+  asm("sta $db00,y");
+  asm("@skip: iny");
+  asm("bne @loop2");
+}
+
+void copy_to_hidden_buffer_slow() {
   memcpy(hidbuf, visbuf, COLS*ROWS);
 }
 
+void copy_to_hidden_buffer_fast() {
+  // self-modifying code
+  asm("ldy %v+1", visbuf);
+  asm("sty @loop+2+6*0");
+  asm("iny");
+  asm("sty @loop+2+6*1");
+  asm("iny");
+  asm("sty @loop+2+6*2");
+  asm("iny");
+  asm("sty @skip-1-3");
+  asm("ldy %v+1", hidbuf);
+  asm("sty @loop+5+6*0");
+  asm("iny");
+  asm("sty @loop+5+6*1");
+  asm("iny");
+  asm("sty @loop+5+6*2");
+  asm("iny");
+  asm("sty @skip-1");
+  // fast copy loop
+  asm("ldy #0");
+  asm("@loop:");
+  asm("lda $8000,y");
+  asm("sta $8000,y");
+  asm("lda $8100,y");
+  asm("sta $8100,y");
+  asm("lda $8200,y");
+  asm("sta $8200,y");
+  asm("cpy #$e8");
+  asm("bcs @skip");
+  asm("lda $8300,y");
+  asm("sta $8300,y");
+  asm("@skip: iny");
+  asm("bne @loop");
+}
+
+void copy_if_needed() {
+  if (copy_needed) {
+    copy_to_hidden_buffer_fast();
+    copy_needed = false;
+  }
+}
+
 void scroll_update(void) {
   VIC.ctrl1 = (VIC.ctrl1 & 0xf8) | scroll_fine_y;
   VIC.ctrl2 = (VIC.ctrl2 & 0xf8) | scroll_fine_x;
   if (swap_needed) {
     scroll_swap();
-    scroll_copy();
-    swap_needed = 0;
+    copy_color_ram_fast();
+    swap_needed = false;
+    copy_needed = true;
+  } else {
+    copy_if_needed();
   }
 }
 
 void scroll_left(void) {
-  memcpy(hidbuf, hidbuf+1, COLS*ROWS-1);
-  memcpy(colorbuf, colorbuf+1, COLS*ROWS-1);
+  copy_if_needed();
+  memmove(hidbuf, hidbuf+1, COLS*ROWS-1);
+  memmove(colorbuf, colorbuf+1, COLS*ROWS-1);
   ++origin_x;
   scroll_draw_column(COLS-1);
   swap_needed = true;
+  VIC.bordercolor = 0;
 }
 
 void scroll_up(void) {
-  memcpy(hidbuf, hidbuf+COLS, COLS*(ROWS-1));
-  memcpy(colorbuf, colorbuf+COLS, COLS*(ROWS-1));
+  copy_if_needed();
+  memmove(hidbuf, hidbuf+COLS, COLS*(ROWS-1));
+  memmove(colorbuf, colorbuf+COLS, COLS*(ROWS-1));
   ++origin_y;
   scroll_draw_row(ROWS-1);
   swap_needed = true;
 }
 
 void scroll_right(void) {
+  copy_if_needed();
   memmove(hidbuf+1, hidbuf, COLS*ROWS-1);
   memmove(colorbuf+1, colorbuf, COLS*ROWS-1);
   --origin_x;
@@ -66,6 +137,7 @@ void scroll_right(void) {
 }
 
 void scroll_down(void) {
+  copy_if_needed();
   memmove(hidbuf+COLS, hidbuf, COLS*(ROWS-1));
   memmove(colorbuf+COLS, colorbuf, COLS*(ROWS-1));
   --origin_y;
@@ -101,19 +173,22 @@ void scroll_setup(void) {
   scroll_fine_x = scroll_fine_y = 0;
   origin_x = origin_y = 0x80;
   swap_needed = true;
+  copy_needed = true;
 
-  // get screen buffer addresses
+  // setup screen buffer addresses
   hidbuf = (byte*) 0x8000;
   visbuf = (byte*) 0x8400;
-  // copy existing text to screen 0
+  
+  // copy existing screen contents to hidden buffer
   memcpy(hidbuf, (byte*)0x400, COLS*ROWS);
-  // copy screen 1 to screen 0
+  // copy also to hidden buffer
   memcpy(visbuf, hidbuf, COLS*ROWS);
   
-  // set VIC bank ($4000-$7FFF)
+  // set VIC bank ($8000-$BFFF)
   // https://www.c64-wiki.com/wiki/VIC_bank
   CIA2.pra = 0x01;
-  
+
+  // set up 24 line / 38 column mode to hide edges
   VIC.ctrl1 &= ~0x08; // 24 lines
   VIC.ctrl2 &= ~0x08; // 38 columns
 }
diff --git a/presets/c64/scrolling.h b/presets/c64/scrolling.h
index 0c9ebff9..a12ec19c 100644
--- a/presets/c64/scrolling.h
+++ b/presets/c64/scrolling.h
@@ -23,7 +23,7 @@ void scroll_setup(void);
 void scroll_horiz(sbyte delta_x);
 void scroll_vert(sbyte delta_y);
 
-// call this after vblank
+// call this right after vblank
 void scroll_update(void);
 
 // caller must implement these two
diff --git a/presets/c64/siddemo.c b/presets/c64/siddemo.c
index 31d0b238..afc86dee 100644
--- a/presets/c64/siddemo.c
+++ b/presets/c64/siddemo.c
@@ -12,7 +12,6 @@
 //#link "sidplaysfx.ca65"
 #include "sidplaysfx.h"
 
-
 void main(void) {
   clrscr();
   cursor(0);
@@ -27,6 +26,6 @@ void main(void) {
       sid_sfx(joy & 3);
     }
     waitvsync();
-    //sid_update();
+    sid_update();
   }
 }
diff --git a/presets/c64/sidplaysfx.ca65 b/presets/c64/sidplaysfx.ca65
index bc114310..7e80f74a 100644
--- a/presets/c64/sidplaysfx.ca65
+++ b/presets/c64/sidplaysfx.ca65
@@ -2,6 +2,10 @@
 ; music and SFX from GoatTracker 2 sample files
 ; http://sourceforge.net/projects/goattracker2
 
+.segment "DATA"
+
+_sid_playing: .byte $00
+
 .segment "SIDFILE"
 
 .incbin "sidmusic1.bin"
@@ -9,13 +13,17 @@
 .segment "LOWCODE"
 
 .global _sid_init, _sid_update, _sid_sfx
-.global _sid_start
+.global _sid_start, _sid_stop, _sid_playing
 
 _sid_init:
         jmp $1000
 
 _sid_update:
+	bit _sid_playing
+        bpl @noplay
 	jmp $1003
+@noplay:
+        rts
 
 _sid_sfx:
 	tax
@@ -24,36 +32,14 @@ _sid_sfx:
         ldx #$0e           ;Channel index in X
         jmp $1006          ;(0, 7 or 14)
 
-SID_IRQ:
-	jsr $1003
-	ASL $D019            ; acknowledge the interrupt by clearing the VIC's interrupt flag
-	JMP $EA31            ; jump into KERNAL's standard interrupt service routine to handle keyboard scan, cursor display etc.
-
 _sid_start:
-        SEI                  ; set interrupt bit, make the CPU ignore interrupt requests
-        LDA #%01111111       ; switch off interrupt signals from CIA-1
-        STA $DC0D
-
-        AND $D011            ; clear most significant bit of VIC's raster register
-        STA $D011
-
-        LDA $DC0D            ; acknowledge pending interrupts from CIA-1
-        LDA $DD0D            ; acknowledge pending interrupts from CIA-2
-
-        LDA #210             ; set rasterline where interrupt shall occur
-        STA $D012
-
-        LDA #<SID_IRQ            ; set interrupt vectors, pointing to interrupt service routine below
-        STA $0314
-        LDA #>SID_IRQ
-        STA $0315
-
-        LDA #%00000001       ; enable raster interrupt signals from VIC
-        STA $D01A
-
-        CLI                  ; clear interrupt flag, allowing the CPU to respond to interrupt requests
-        RTS
-
+	lda #$80
+        bne skipstop
+_sid_stop:
+	lda #$00
+skipstop:
+        sta _sid_playing
+        rts
 
 sfxtbllo:       .byte <arpeggio2
                 .byte <arpeggio1
diff --git a/presets/c64/sprite_collision.c b/presets/c64/sprite_collision.c
index 866ac4f2..7b299c16 100644
--- a/presets/c64/sprite_collision.c
+++ b/presets/c64/sprite_collision.c
@@ -43,7 +43,7 @@ void move_sprites(void) {
   byte i;
   for (i=0; i<8; i++) {
     //VIC.bordercolor = i;
-    sprite_draw(i, (xpos[i]>>7)+0x80, (ypos[i]>>8)+0x80, 32);
+    sprite_draw(i, (xpos[i]>>7)+0x80, (ypos[i]>>8)+0x80, 255);
     // update position
     xpos[i] += xvel[i];
     ypos[i] += yvel[i];
@@ -134,12 +134,12 @@ void main(void) {
 
   // setup sprite library and copy sprite to VIC bank
   sprite_clear();
-  sprite_shape((void*)0x400, 32/2, SPRITEMC);
+  sprite_shape((void*)0x0, 255, SPRITEMC);
   
   // set colors
   sprshad.spr_mcolor = 0xff;
-  sprshad.spr_mcolor0 = 4;
-  sprshad.spr_mcolor1 = 7;
+  VIC.spr_mcolor0 = 4;
+  VIC.spr_mcolor1 = 7;
 
   // set sprite initial positions
   init_sprites();
diff --git a/presets/c64/sprites.c b/presets/c64/sprites.c
index 07eaed11..5c52ed8d 100644
--- a/presets/c64/sprites.c
+++ b/presets/c64/sprites.c
@@ -8,18 +8,16 @@ void sprite_clear(void) {
   memset(&sprshad, 0, sizeof(sprshad));
 }
 
-void sprite_update(char* vicbank) {
-  memcpy(vicbank + 0x3f8, sprshad.spr_shapes, 8);
-  VIC.spr_ena = sprshad.spr_ena;
-  VIC.spr_hi_x = sprshad.spr_hi_x;
+void sprite_update(char* screenmem) {
+  memcpy(screenmem + 0x3f8, sprshad.spr_shapes, 8);
   memcpy(VIC.spr_pos, sprshad.spr_pos, 16);
   memcpy(VIC.spr_color, sprshad.spr_color, 8);
+  VIC.spr_ena = sprshad.spr_ena;
+  VIC.spr_hi_x = sprshad.spr_hi_x;
   VIC.spr_exp_x = sprshad.spr_exp_x;
   VIC.spr_exp_y = sprshad.spr_exp_y;
   VIC.spr_bg_prio = sprshad.spr_bg_prio;
   VIC.spr_mcolor = sprshad.spr_mcolor;
-  VIC.spr_mcolor0 = sprshad.spr_mcolor0;
-  VIC.spr_mcolor1 = sprshad.spr_mcolor1;
 }
 
 void sprite_shape(char* vicbank, byte index, const char* sprite_data) {
diff --git a/presets/c64/sprites.h b/presets/c64/sprites.h
index 90308c88..158b94a7 100644
--- a/presets/c64/sprites.h
+++ b/presets/c64/sprites.h
@@ -6,26 +6,24 @@
 #define DEFAULT_SCREEN ((void*)0x400)
 
 typedef struct {
-  byte spr_ena;        /* Enable sprites */
-  byte spr_hi_x;       /* High bits of X coordinate */
-  byte spr_exp_x;      /* Expand sprites in X dir */
-  byte spr_exp_y;      /* Expand sprites in Y dir */
-  byte spr_bg_prio;    /* Priority to background */
-  byte spr_mcolor;     /* Sprite multicolor bits */
-  byte spr_mcolor0;    /* Color 0 for multicolor sprites */
-  byte spr_mcolor1;    /* Color 1 for multicolor sprites */
-  byte spr_color[8];   /* Colors for the sprites */
   struct {
     byte x;              /* X coordinate */
     byte y;              /* Y coordinate */
   } spr_pos[8];
+  byte spr_hi_x;       /* High bits of X coordinate */
+  byte spr_ena;        /* Enable sprites */
+  byte spr_exp_y;      /* Expand sprites in Y dir */
+  byte spr_bg_prio;    /* Priority to background */
+  byte spr_mcolor;     /* Sprite multicolor bits */
+  byte spr_exp_x;      /* Expand sprites in X dir */
+  byte spr_color[8];   /* Colors for the sprites */
   byte spr_shapes[8];	/* sprite shapes */
 } SpriteShadow;
 
 extern SpriteShadow sprshad;
 
 void sprite_clear(void);
-void sprite_update(char* screenram);
+void sprite_update(char* screenmem);
 void sprite_shape(char* vicbank, byte index, const char* sprite_data);
 void sprite_draw(byte i, word x, byte y, byte shape);
 byte sprite_get_closest_collision(byte i, byte spr_coll);
diff --git a/presets/c64/spritesinborder.c b/presets/c64/spritesinborder.c
new file mode 100644
index 00000000..cb532a0d
--- /dev/null
+++ b/presets/c64/spritesinborder.c
@@ -0,0 +1,69 @@
+  
+#include <stdio.h>
+#include <conio.h>
+#include <c64.h>
+#include <cbm_petscii_charmap.h>
+
+#include "common.h"
+
+//#link "rasterirq.ca65"
+#include "rasterirq.h"
+
+//#link "sprites.c"
+#include "sprites.h"
+
+/*{w:24,h:21,bpp:1,brev:1}*/
+const char spriteshape[3*21] = {
+  0x00,0x7F,0x00,0x01,0xFF,0xC0,0x03,0xFF,0xE0,
+  0x03,0xE7,0xE0,0x07,0xD9,0xF0,0x07,0xDF,0xF0,
+  0x07,0xD9,0xF0,0x03,0xE7,0xE0,0x03,0xFF,0xE0,
+  0x03,0xFF,0xE0,0x02,0xFF,0xA0,0x01,0x7F,0x40,
+  0x01,0x3E,0x40,0x00,0x9C,0x80,0x00,0x9C,0x80,
+  0x00,0x49,0x00,0x00,0x49,0x00,0x00,0x3E,0x00,
+  0x00,0x3E,0x00,0x00,0x3E,0x00,0x00,0x1C,0x00
+};
+
+void dlist_example(void) {
+  static byte i = 0;
+  VIC.bordercolor = 6;
+  VIC.bordercolor = 5;
+  VIC.ctrl1 = 0x18;
+  DLIST_NEXT(150);
+
+//  VIC.ctrl1 = 5 | 0x18;
+
+  VIC.bordercolor = 2;
+  DLIST_NEXT(0xf9);
+
+  VIC.ctrl1 = 0x10;
+  VIC.bordercolor = 3;
+  DLIST_NEXT(0xfc);
+  
+  VIC.ctrl1 = 0x18;
+  VIC.bordercolor = 4;
+  DLIST_RESTART(30);
+}
+
+void main(void) {
+  byte i;
+  
+  clrscr();
+
+  sprite_clear();
+  sprite_shape((void*)0x400, 32/2, spriteshape);
+  
+  // set colors
+  sprshad.spr_exp_x = 0xff;
+  for (i=0; i<8; i++) {
+    sprshad.spr_color[i] = i+3;
+    sprite_draw(i, i*38+24, 248, 32);
+  }
+  // TODO: can't do in IRQ
+
+  DLIST_SETUP(dlist_example);
+  while (1) {
+    sprshad.spr_pos[0].y += 1;
+    sprite_update(DEFAULT_SCREEN);
+    printf("Hello World! ");
+  }
+}
diff --git a/src/worker/tools/cc65.ts b/src/worker/tools/cc65.ts
index 7d29999b..dec05ede 100644
--- a/src/worker/tools/cc65.ts
+++ b/src/worker/tools/cc65.ts
@@ -129,9 +129,9 @@ export function assembleCA65(step: BuildStep): BuildStepResult {
         }
         execMain(step, CA65, args);
         if (errors.length) {
-            // TODO?
             let listings : CodeListingMap = {};
-            listings[step.path] = { lines:[], text:getWorkFileAsString(step.path) };
+            // TODO? change extension to .lst
+            //listings[step.path] = { lines:[], text:getWorkFileAsString(step.path) };
             return { errors, listings };
         }
         objout = FS.readFile(objpath, { encoding: 'binary' });