diff --git a/cbm_ascii_charmap.h b/cbm_ascii_charmap.h
new file mode 100644
index 0000000..f1381ab
--- /dev/null
+++ b/cbm_ascii_charmap.h
@@ -0,0 +1,262 @@
+// modified CC65 charmap to allow pure ASCII on VIC20
+
+#pragma warn (remap-zero, push, off)
+
+#pragma charmap (0x00, 0x00)
+#pragma charmap (0x01, 0x01)
+#pragma charmap (0x02, 0x02)
+#pragma charmap (0x03, 0x03)
+#pragma charmap (0x04, 0x04)
+#pragma charmap (0x05, 0x05)
+#pragma charmap (0x06, 0x06)
+#pragma charmap (0x07, 0x07)
+#pragma charmap (0x08, 0x08)
+#pragma charmap (0x09, 0x09)
+#pragma charmap (0x0A, 0x0A)
+#pragma charmap (0x0B, 0x0B)
+#pragma charmap (0x0C, 0x0C)
+#pragma charmap (0x0D, 0x0D)
+#pragma charmap (0x0E, 0x0E)
+#pragma charmap (0x0F, 0x0F)
+#pragma charmap (0x10, 0x10)
+#pragma charmap (0x11, 0x11)
+#pragma charmap (0x12, 0x12)
+#pragma charmap (0x13, 0x13)
+#pragma charmap (0x14, 0x14)
+#pragma charmap (0x15, 0x15)
+#pragma charmap (0x16, 0x16)
+#pragma charmap (0x17, 0x17)
+#pragma charmap (0x18, 0x18)
+#pragma charmap (0x19, 0x19)
+#pragma charmap (0x1A, 0x1A)
+#pragma charmap (0x1B, 0x1B)
+#pragma charmap (0x1C, 0x1C)
+#pragma charmap (0x1D, 0x1D)
+#pragma charmap (0x1E, 0x1E)
+#pragma charmap (0x1F, 0x1F)
+#pragma charmap (0x20, 0x20)
+#pragma charmap (0x21, 0x21)
+#pragma charmap (0x22, 0x22)
+#pragma charmap (0x23, 0x23)
+#pragma charmap (0x24, 0x24)
+#pragma charmap (0x25, 0x25)
+#pragma charmap (0x26, 0x26)
+#pragma charmap (0x27, 0x27)
+#pragma charmap (0x28, 0x28)
+#pragma charmap (0x29, 0x29)
+#pragma charmap (0x2A, 0x2A)
+#pragma charmap (0x2B, 0x2B)
+#pragma charmap (0x2C, 0x2C)
+#pragma charmap (0x2D, 0x2D)
+#pragma charmap (0x2E, 0x2E)
+#pragma charmap (0x2F, 0x2F)
+#pragma charmap (0x30, 0x30)
+#pragma charmap (0x31, 0x31)
+#pragma charmap (0x32, 0x32)
+#pragma charmap (0x33, 0x33)
+#pragma charmap (0x34, 0x34)
+#pragma charmap (0x35, 0x35)
+#pragma charmap (0x36, 0x36)
+#pragma charmap (0x37, 0x37)
+#pragma charmap (0x38, 0x38)
+#pragma charmap (0x39, 0x39)
+#pragma charmap (0x3A, 0x3A)
+#pragma charmap (0x3B, 0x3B)
+#pragma charmap (0x3C, 0x3C)
+#pragma charmap (0x3D, 0x3D)
+#pragma charmap (0x3E, 0x3E)
+#pragma charmap (0x3F, 0x3F)
+#pragma charmap (0x40, 0x40)
+#pragma charmap (0x41, 0x41)
+#pragma charmap (0x42, 0x42)
+#pragma charmap (0x43, 0x43)
+#pragma charmap (0x44, 0x44)
+#pragma charmap (0x45, 0x45)
+#pragma charmap (0x46, 0x46)
+#pragma charmap (0x47, 0x47)
+#pragma charmap (0x48, 0x48)
+#pragma charmap (0x49, 0x49)
+#pragma charmap (0x4A, 0x4A)
+#pragma charmap (0x4B, 0x4B)
+#pragma charmap (0x4C, 0x4C)
+#pragma charmap (0x4D, 0x4D)
+#pragma charmap (0x4E, 0x4E)
+#pragma charmap (0x4F, 0x4F)
+#pragma charmap (0x50, 0x50)
+#pragma charmap (0x51, 0x51)
+#pragma charmap (0x52, 0x52)
+#pragma charmap (0x53, 0x53)
+#pragma charmap (0x54, 0x54)
+#pragma charmap (0x55, 0x55)
+#pragma charmap (0x56, 0x56)
+#pragma charmap (0x57, 0x57)
+#pragma charmap (0x58, 0x58)
+#pragma charmap (0x59, 0x59)
+#pragma charmap (0x5A, 0x5A)
+#pragma charmap (0x5B, 0x5B)
+#pragma charmap (0x5C, 0x5C)
+#pragma charmap (0x5D, 0x5D)
+#pragma charmap (0x5E, 0x5E)
+#pragma charmap (0x5F, 0x5F)
+#pragma charmap (0x60, 0x60)
+#pragma charmap (0x61, 0x61)
+#pragma charmap (0x62, 0x62)
+#pragma charmap (0x63, 0x63)
+#pragma charmap (0x64, 0x64)
+#pragma charmap (0x65, 0x65)
+#pragma charmap (0x66, 0x66)
+#pragma charmap (0x67, 0x67)
+#pragma charmap (0x68, 0x68)
+#pragma charmap (0x69, 0x69)
+#pragma charmap (0x6A, 0x6A)
+#pragma charmap (0x6B, 0x6B)
+#pragma charmap (0x6C, 0x6C)
+#pragma charmap (0x6D, 0x6D)
+#pragma charmap (0x6E, 0x6E)
+#pragma charmap (0x6F, 0x6F)
+#pragma charmap (0x70, 0x70)
+#pragma charmap (0x71, 0x71)
+#pragma charmap (0x72, 0x72)
+#pragma charmap (0x73, 0x73)
+#pragma charmap (0x74, 0x74)
+#pragma charmap (0x75, 0x75)
+#pragma charmap (0x76, 0x76)
+#pragma charmap (0x77, 0x77)
+#pragma charmap (0x78, 0x78)
+#pragma charmap (0x79, 0x79)
+#pragma charmap (0x7A, 0x7A)
+#pragma charmap (0x7B, 0x7B)
+#pragma charmap (0x7C, 0x7C)
+#pragma charmap (0x7D, 0x7D)
+#pragma charmap (0x7E, 0x7E)
+#pragma charmap (0x7F, 0x7F)
+#pragma charmap (0x80, 0x80)
+#pragma charmap (0x81, 0x81)
+#pragma charmap (0x82, 0x82)
+#pragma charmap (0x83, 0x83)
+#pragma charmap (0x84, 0x84)
+#pragma charmap (0x85, 0x85)
+#pragma charmap (0x86, 0x86)
+#pragma charmap (0x87, 0x87)
+#pragma charmap (0x88, 0x88)
+#pragma charmap (0x89, 0x89)
+#pragma charmap (0x8A, 0x8A)
+#pragma charmap (0x8B, 0x8B)
+#pragma charmap (0x8C, 0x8C)
+#pragma charmap (0x8D, 0x8D)
+#pragma charmap (0x8E, 0x8E)
+#pragma charmap (0x8F, 0x8F)
+#pragma charmap (0x90, 0x90)
+#pragma charmap (0x91, 0x91)
+#pragma charmap (0x92, 0x92)
+#pragma charmap (0x93, 0x93)
+#pragma charmap (0x94, 0x94)
+#pragma charmap (0x95, 0x95)
+#pragma charmap (0x96, 0x96)
+#pragma charmap (0x97, 0x97)
+#pragma charmap (0x98, 0x98)
+#pragma charmap (0x99, 0x99)
+#pragma charmap (0x9A, 0x9A)
+#pragma charmap (0x9B, 0x9B)
+#pragma charmap (0x9C, 0x9C)
+#pragma charmap (0x9D, 0x9D)
+#pragma charmap (0x9E, 0x9E)
+#pragma charmap (0x9F, 0x9F)
+#pragma charmap (0xA0, 0xA0)
+#pragma charmap (0xA1, 0xA1)
+#pragma charmap (0xA2, 0xA2)
+#pragma charmap (0xA3, 0xA3)
+#pragma charmap (0xA4, 0xA4)
+#pragma charmap (0xA5, 0xA5)
+#pragma charmap (0xA6, 0xA6)
+#pragma charmap (0xA7, 0xA7)
+#pragma charmap (0xA8, 0xA8)
+#pragma charmap (0xA9, 0xA9)
+#pragma charmap (0xAA, 0xAA)
+#pragma charmap (0xAB, 0xAB)
+#pragma charmap (0xAC, 0xAC)
+#pragma charmap (0xAD, 0xAD)
+#pragma charmap (0xAE, 0xAE)
+#pragma charmap (0xAF, 0xAF)
+#pragma charmap (0xB0, 0xB0)
+#pragma charmap (0xB1, 0xB1)
+#pragma charmap (0xB2, 0xB2)
+#pragma charmap (0xB3, 0xB3)
+#pragma charmap (0xB4, 0xB4)
+#pragma charmap (0xB5, 0xB5)
+#pragma charmap (0xB6, 0xB6)
+#pragma charmap (0xB7, 0xB7)
+#pragma charmap (0xB8, 0xB8)
+#pragma charmap (0xB9, 0xB9)
+#pragma charmap (0xBA, 0xBA)
+#pragma charmap (0xBB, 0xBB)
+#pragma charmap (0xBC, 0xBC)
+#pragma charmap (0xBD, 0xBD)
+#pragma charmap (0xBE, 0xBE)
+#pragma charmap (0xBF, 0xBF)
+#pragma charmap (0xC0, 0xC0)
+#pragma charmap (0xC1, 0xC1)
+#pragma charmap (0xC2, 0xC2)
+#pragma charmap (0xC3, 0xC3)
+#pragma charmap (0xC4, 0xC4)
+#pragma charmap (0xC5, 0xC5)
+#pragma charmap (0xC6, 0xC6)
+#pragma charmap (0xC7, 0xC7)
+#pragma charmap (0xC8, 0xC8)
+#pragma charmap (0xC9, 0xC9)
+#pragma charmap (0xCA, 0xCA)
+#pragma charmap (0xCB, 0xCB)
+#pragma charmap (0xCC, 0xCC)
+#pragma charmap (0xCD, 0xCD)
+#pragma charmap (0xCE, 0xCE)
+#pragma charmap (0xCF, 0xCF)
+#pragma charmap (0xD0, 0xD0)
+#pragma charmap (0xD1, 0xD1)
+#pragma charmap (0xD2, 0xD2)
+#pragma charmap (0xD3, 0xD3)
+#pragma charmap (0xD4, 0xD4)
+#pragma charmap (0xD5, 0xD5)
+#pragma charmap (0xD6, 0xD6)
+#pragma charmap (0xD7, 0xD7)
+#pragma charmap (0xD8, 0xD8)
+#pragma charmap (0xD9, 0xD9)
+#pragma charmap (0xDA, 0xDA)
+#pragma charmap (0xDB, 0xDB)
+#pragma charmap (0xDC, 0xDC)
+#pragma charmap (0xDD, 0xDD)
+#pragma charmap (0xDE, 0xDE)
+#pragma charmap (0xDF, 0xDF)
+#pragma charmap (0xE0, 0xE0)
+#pragma charmap (0xE1, 0xE1)
+#pragma charmap (0xE2, 0xE2)
+#pragma charmap (0xE3, 0xE3)
+#pragma charmap (0xE4, 0xE4)
+#pragma charmap (0xE5, 0xE5)
+#pragma charmap (0xE6, 0xE6)
+#pragma charmap (0xE7, 0xE7)
+#pragma charmap (0xE8, 0xE8)
+#pragma charmap (0xE9, 0xE9)
+#pragma charmap (0xEA, 0xEA)
+#pragma charmap (0xEB, 0xEB)
+#pragma charmap (0xEC, 0xEC)
+#pragma charmap (0xED, 0xED)
+#pragma charmap (0xEE, 0xEE)
+#pragma charmap (0xEF, 0xEF)
+#pragma charmap (0xF0, 0xF0)
+#pragma charmap (0xF1, 0xF1)
+#pragma charmap (0xF2, 0xF2)
+#pragma charmap (0xF3, 0xF3)
+#pragma charmap (0xF4, 0xF4)
+#pragma charmap (0xF5, 0xF5)
+#pragma charmap (0xF6, 0xF6)
+#pragma charmap (0xF7, 0xF7)
+#pragma charmap (0xF8, 0xF8)
+#pragma charmap (0xF9, 0xF9)
+#pragma charmap (0xFA, 0xFA)
+#pragma charmap (0xFB, 0xFB)
+#pragma charmap (0xFC, 0xFC)
+#pragma charmap (0xFD, 0xFD)
+#pragma charmap (0xFE, 0xFE)
+#pragma charmap (0xFF, 0xFF)
+
+#pragma warn (remap-zero, pop)
diff --git a/screen1.c b/screen1.c
new file mode 100644
index 0000000..e2cc607
--- /dev/null
+++ b/screen1.c
@@ -0,0 +1,104 @@
+// SCREEN 1 VALUES
+
+// sprite patterns:    $0000
+// pattern table:      $0800   (256*8)
+// sprite attributes:  $1000
+// unused:             $1080
+// name table:         $1400   (32*24)
+// unused:             $1800
+// color table:        $2000   (32)
+// unused              $2020-$3FFF
+
+#define SCREEN1_PATTERN_TABLE   0x0800
+#define SCREEN1_NAME_TABLE      0x1400
+#define SCREEN1_COLOR_TABLE     0x2000
+#define SCREEN1_SPRITE_PATTERNS 0x0000
+#define SCREEN1_SPRITE_ATTRS    0x1000
+#define SCREEN1_SIZE            (32*24)
+
+byte SCREEN1_TABLE[8] = {
+   0x00, 0xc0, 0x05, 0x80, 0x01, 0x20, 0x00, 0x25
+};
+
+// loads the Laser 500 font on the pattern table
+void SCREEN1_LOAD_FONT() {
+
+   static byte *source = FONT;
+   static word i;
+
+   // start writing into VRAM from "space" character
+   set_vram_addr(SCREEN1_PATTERN_TABLE+(32*8));
+   for(i=0;i<768;i++) {
+      POKE(VDP_DATA, *source);
+      source++;
+   }
+
+   source = FONT;
+   set_vram_addr(SCREEN1_PATTERN_TABLE+((128+32)*8));
+   for(i=0;i<768;i++) {
+      POKE(VDP_DATA, ~(*source));
+      source++;
+   }
+
+   // TODO: inverted characters ?
+}
+
+// prints character to TMS (SCREEN 1 MODE)
+void fastcall SCREEN1_PUTCHAR(byte c) {
+   set_vram_addr(tms_cursor);
+   POKE(VDP_DATA, c);
+   tms_cursor++;
+}
+
+// prints 0 terminated string pointed by YA
+void SCREEN1_PUTS(char *s) {
+   byte c;
+
+   while(1) {
+      c = *s;
+      // c = *s & 127;     // TODO: explain why???
+      if(c==0) return;
+      SCREEN1_PUTCHAR(c);
+      s++;
+   }
+}
+
+void SCREEN1_HOME() {
+   tms_cursor = SCREEN1_NAME_TABLE;
+}
+
+void SCREEN1_LOCATEXY(byte x, byte y) {
+   tms_cursor = SCREEN1_NAME_TABLE + ((word)y)*32 + x;
+}
+
+void SCREEN1_INIT() {
+   static byte i;
+   for(i=0;i<8;i++) {
+      write_reg(i, SCREEN1_TABLE[i]);
+   }
+}
+
+void SCREEN1_FILL() {
+   static word i;
+
+   // fills name table with spaces (32)
+   set_vram_addr(SCREEN1_NAME_TABLE);
+   for(i=0;i<SCREEN1_SIZE;i++) {
+      POKE(VDP_DATA, 32);
+      // nops here?
+   }
+
+   // fill pattern table with 0
+   set_vram_addr(SCREEN1_PATTERN_TABLE);
+   for(i=0;i<256*8;i++) {
+      POKE(VDP_DATA, 0);
+      // nops here?
+   }
+
+   // fill color table with $1F
+   set_vram_addr(SCREEN1_COLOR_TABLE);
+   for(i=0;i<32;i++) {
+      POKE(VDP_DATA, 0x1f);
+      // nops here?
+   }
+}
diff --git a/screen2.c b/screen2.c
new file mode 100644
index 0000000..fb20fdf
--- /dev/null
+++ b/screen2.c
@@ -0,0 +1,115 @@
+// SCREEN 2 VALUES
+
+// pattern table:      $0000-$17FF   (256*8*3)
+// sprite patterns:    $1800-$19FF
+// color table:        $2000-$27FF   (256*8*3)
+// name table:         $3800-$3AFF   (32*24 = 256*3 = 768)
+// sprite attributes:  $3B00-$3BFF
+// unused              $3C00-$3FFF
+//
+
+#define SCREEN2_PATTERN_TABLE   0x0000
+#define SCREEN2_NAME_TABLE      0x3800
+#define SCREEN2_COLOR_TABLE     0x2000
+#define SCREEN2_SPRITE_PATTERNS 0x1800
+#define SCREEN2_SPRITE_ATTRS    0x3b00
+#define SCREEN2_SIZE            (32*24)
+
+byte SCREEN2_TABLE[8] = {
+   0x02, 0xc0, 0x0e, 0xff, 0x03, 0x76, 0x03, 0x25
+};
+
+void SCREEN2_INIT() {
+   static byte i;
+   for(i=0;i<8;i++) {
+      write_reg(i, SCREEN2_TABLE[i]);
+   }
+}
+
+void SCREEN2_FILL() {
+   static word i;
+
+   // fills name table x3 with increasing numbers
+   set_vram_addr(SCREEN2_NAME_TABLE);
+   for(i=0;i<SCREEN2_SIZE;i++) {
+      POKE(VDP_DATA, i & 0xFF);
+   }
+
+   // fill pattern table with 0 (clear screen)
+   set_vram_addr(SCREEN2_PATTERN_TABLE);
+   for(i=0;i<768*8;i++) {
+      POKE(VDP_DATA, 0);
+   }
+
+   // fill color table with $1F
+   set_vram_addr(SCREEN2_COLOR_TABLE);
+   for(i=0;i<768*8;i++) {
+      POKE(VDP_DATA, 0x1f);
+   }
+}
+
+void SCREEN2_PUTC(byte ch, byte x, byte y, byte col) {
+   byte *source = &FONT[(ch-32)*8];
+   byte i;
+   word paddr = SCREEN2_PATTERN_TABLE + x*8 + y*256;
+   word caddr = SCREEN2_COLOR_TABLE   + x*8 + y*256;
+
+   set_vram_addr(paddr); for(i=0;i<8;i++) POKE(VDP_DATA, source[i]);
+   set_vram_addr(caddr); for(i=0;i<8;i++) POKE(VDP_DATA, col);
+}
+
+void SCREEN2_PUTS(byte x, byte y, byte col, char *s) {
+   while(*s) {
+      SCREEN2_PUTC(*s++, x++, y, col);
+   }
+}
+
+void SCREEN2_PSET(byte x, byte y) {
+   word paddr = SCREEN2_PATTERN_TABLE + (x & 0b11111000) + (y & 0b11111000)*32 + y%8;
+   byte pattern = 128 >> (x%8);
+   byte data;
+
+   set_vram_read_addr(paddr);
+   data = PEEK(VDP_DATA);
+   set_vram_addr(paddr);
+   POKE(VDP_DATA,data | pattern);
+}
+
+// int vti_abs(int x) {
+//     return x < 0 ? -x : x;
+// }
+//
+// // http://members.chello.at/~easyfilter/bresenham.html
+// void vti_ellipse_rect(int x0, int y0, int x1, int y1)
+// {
+//     long a,b,b1,dx,dy,e2,err;
+//
+//     a = vti_abs(x1-x0);
+//     b = vti_abs(y1-y0);
+//     b1 = b&1; /* values of diameter */
+//     dx = 4*(1-a)*b*b;
+//     dy = 4*(b1+1)*a*a; /* error increment */
+//     err = dx+dy+b1*a*a; /* error of 1.step */
+//
+//     if (x0 > x1) { x0 = x1; x1 += a; } /* if called with swapped points */
+//     if (y0 > y1) y0 = y1; /* .. exchange them */
+//     y0 += (b+1)/2; y1 = y0-b1;   /* starting pixel */
+//     a *= 8*a; b1 = 8*b*b;
+//
+//     do {
+//         SCREEN2_PSET(x1, y0); /*   I. Quadrant */
+//         SCREEN2_PSET(x0, y0); /*  II. Quadrant */
+//         SCREEN2_PSET(x0, y1); /* III. Quadrant */
+//         SCREEN2_PSET(x1, y1); /*  IV. Quadrant */
+//         e2 = 2*err;
+//         if (e2 <= dy) { y0++; y1--; err += dy += a; }  /* y step */
+//         if (e2 >= dx || 2*err > dy) { x0++; x1--; err += dx += b1; } /* x step */
+//     } while (x0 <= x1);
+//
+//     while (y0-y1 < b) {  /* too early stop of flat ellipses a=1 */
+//         SCREEN2_PSET(x0-1, y0); /* -> finish tip of ellipse */
+//         SCREEN2_PSET(x1+1, y0++);
+//         SCREEN2_PSET(x0-1, y1);
+//         SCREEN2_PSET(x1+1, y1--);
+//     }
+// }
diff --git a/test.c b/test.c
index f6fe03c..30f18ae 100644
--- a/test.c
+++ b/test.c
@@ -1,7 +1,7 @@
 #ifdef APPLE1
-   #define WOZMON 0xFF1F         // enters monitor
-   #define ECHO   0xFFEF         // output ascii character in A (A not destroyed)
-   #define PRBYTE 0xFFDC         // print hex byte in A (A destroyed)
+   #define WOZMON   0xFF1F       // enters monitor
+   #define ECHO     0xFFEF       // output ascii character in A (A not destroyed)
+   #define PRBYTE   0xFFDC       // print hex byte in A (A destroyed)
    #define VDP_DATA 0xC000       // TMS9918 data port (VRAM)
    #define VDP_REG  0xC001       // TMS9918 register port (write) or status (read)
 #endif
@@ -10,23 +10,29 @@
    #define ECHO     0xFFD2       // chrout routine in kernal rom
    #define VDP_DATA 0xA000       // TMS9918 data port (VRAM)
    #define VDP_REG  0xA001       // TMS9918 register port (write) or status (read)
+
+   #include "cbm_ascii_charmap.h"  // allow VIC-20 to work with pure ASCII
+
 #endif
 
+// TMS9918 interface flags
 #define WRITE_TO_REG   0b10000000
 #define WRITE_TO_VRAM  0b01000000
 #define READ_FROM_VRAM 0b00000000
 
+// utils
 typedef unsigned char byte;
 typedef unsigned int  word;
 
 #define POKE(a,b) (*((byte *)(a))=(byte)(b))
+#define PEEK(a)   (*((byte *)(a)))
 
 // puts a character on the apple1 screen using the WOZMON routine
 void fastcall woz_putc(byte c) {
    asm("jsr %w", ECHO);
 }
 
-// puts a character on the apple1 screen using the WOZMON routine
+// returns to WOZMON prompt
 void woz_mon() {
    #ifdef APPLE1
       asm("jmp %w", WOZMON);
@@ -44,134 +50,41 @@ void fastcall set_vram_addr(word addr) {
    // nops here ?
 }
 
-// writes a value to a TMS9918 register (0-7)
-void write_reg(byte num, byte val) {
-   POKE(VDP_REG, val);
-   // nops here?
-   POKE(VDP_REG, (num & 0b00001111)|WRITE_TO_REG);
-   // nops here?
+// sets the VRAM address on the TMS9918
+void fastcall set_vram_read_addr(word addr) {
+   asm("sta %w", VDP_REG);         // write address low byte
+   // nops here ?
+   asm("txa");                     // X = addres high byte
+   asm("and #%b", 0b00111111);     // mask address high byte
+   asm("ora #%b", READ_FROM_VRAM); // set "write to vram" flag bits "01" upper bits ("00" for read)
+   asm("sta %w", VDP_REG);         // write flags and address high byte
+   // nops here ?
 }
 
-// SCREEN 1 VALUES
-
-// sprite patterns:    $0000
-// pattern table:      $0800   (256*8)
-// sprite attributes:  $1000
-// unused:             $1080
-// name table:         $1400   (32*24)
-// unused:             $1800
-// color table:        $2000   (32)
-// unused              $2020-$3FFF
-
-#define PATTERN_TABLE   0x0800
-#define NAME_TABLE      0x1400
-#define COLOR_TABLE     0x2000
-#define SPRITE_PATTERNS 0x0000
-#define SPRITE_ATTRS    0x1000
-
-#define SCREEN1_SIZE    (32*24)
-
-byte SCREEN1_TABLE[8] = {
-   0x00, 0xc0, 0x05, 0x80, 0x01, 0x20, 0x00, 0x25
-};
-
-#include "laser500_font.ascii.c"
-
-// loads the Laser 500 font on the pattern table
-void load_font() {
-
-   static byte *source = FONT;
-   static word i;
-
-   // start writing into VRAM from "space" character
-   set_vram_addr(PATTERN_TABLE+(32*8));
-   for(i=0;i<768;i++) {
-      POKE(VDP_DATA, *source);
-      source++;
-   }
-
-   source = FONT;
-   set_vram_addr(PATTERN_TABLE+((128+32)*8));
-   for(i=0;i<768;i++) {
-      POKE(VDP_DATA, ~(*source));
-      source++;
-   }
-
-   // TODO: inverted characters ?
+// writes a value to a TMS9918 register (0-7)
+void write_reg(byte regnum, byte val) {
+   // nops are not required
+   POKE(VDP_REG, val);
+   POKE(VDP_REG, (regnum & 0b00001111)|WRITE_TO_REG);
 }
 
 static word tms_cursor;
 
-// prints character to TMS (SCREEN 1 MODE)
-void fastcall SCREEN1_PUTCHAR(byte c) {
-   set_vram_addr(tms_cursor);
-   POKE(VDP_DATA, c);
-   tms_cursor++;
-}
+#include "laser500_font.ascii.c"
+#include "screen1.c"
+#include "screen2.c"
 
-// prints 0 terminated string pointed by YA
-void SCREEN1_PUTS(char *s) {
-   byte c;
-
-   while(1) {
-      c = *s & 127;     // TODO: explain why???
-      if(c==0) return;
-      SCREEN1_PUTCHAR(c);
-      s++;
-   }
-}
-
-void SCREEN1_HOME() {
-   tms_cursor = NAME_TABLE;
-}
-
-void SCREEN1_LOCATEXY(byte x, byte y) {
-   tms_cursor = NAME_TABLE + ((word)y)*32 + x;
-}
-
-void INIT_SCREEN1() {
-   static byte i;
-   for(i=0;i<8;i++) {
-      write_reg(i, SCREEN1_TABLE[i]);
-   }
-}
-
-void FILL_SCREEN1() {
-   static word i;
-
-   // fills name table with spaces (32)
-   set_vram_addr(NAME_TABLE);
-   for(i=0;i<SCREEN1_SIZE;i++) {
-      POKE(VDP_DATA, 32);
-      // nops here?
-   }
-
-   // fill pattern table with 0
-   set_vram_addr(PATTERN_TABLE);
-   for(i=0;i<256*8;i++) {
-      POKE(VDP_DATA, 0);
-      // nops here?
-   }
-
-   // fill color table with $1F
-   set_vram_addr(COLOR_TABLE);
-   for(i=0;i<32;i++) {
-      POKE(VDP_DATA, 0x1f);
-      // nops here?
-   }
-}
-
-void square_sprites() {
+void screen1_square_sprites() {
    static byte i;
 
    // fills first sprite pattern with 255
-   set_vram_addr(SPRITE_PATTERNS);    // start writing in the sprite patterns
+   set_vram_addr(SCREEN1_SPRITE_PATTERNS);    // start writing in the sprite patterns
    for(i=0;i<8;i++) {
       POKE(VDP_DATA, 255);
    }
 
    // set sprite coordinates
-   set_vram_addr(SPRITE_ATTRS);       // start writing in the sprite attribute
+   set_vram_addr(SCREEN1_SPRITE_ATTRS);       // start writing in the sprite attribute
    for(i=0;i<32;i++) {
       POKE(VDP_DATA,(6+i)*8);   // y coordinate
       POKE(VDP_DATA,(6+i)*8);   // x coordinate
@@ -180,21 +93,63 @@ void square_sprites() {
    }
 }
 
+void screen2_square_sprites() {
+   static byte i;
+
+   // fills first sprite pattern with 255
+   set_vram_addr(SCREEN2_SPRITE_PATTERNS);    // start writing in the sprite patterns
+   for(i=0;i<8;i++) {
+      POKE(VDP_DATA, 0);
+   }
+
+   // set sprite coordinates
+   set_vram_addr(SCREEN2_SPRITE_ATTRS);       // start writing in the sprite attribute
+   for(i=0;i<32;i++) {
+      POKE(VDP_DATA,0);   // y coordinate
+      POKE(VDP_DATA,0);   // x coordinate
+      POKE(VDP_DATA,0);         // name
+      POKE(VDP_DATA,i);         // color
+   }
+}
+
 void main() {
    word i;
 
-   INIT_SCREEN1();
-   FILL_SCREEN1();
-   load_font();
+   if(0) {
+      SCREEN1_INIT();
+      SCREEN1_FILL();
+      SCREEN1_LOAD_FONT();
 
-   SCREEN1_HOME();         SCREEN1_PUTS("*** P-LAB  VIDEO CARD SYSTEM ***");
-   SCREEN1_LOCATEXY(0, 2); SCREEN1_PUTS("16K VRAM BYTES FREE");
-   SCREEN1_LOCATEXY(0, 4); SCREEN1_PUTS("READY.");
+      SCREEN1_HOME();         SCREEN1_PUTS("*** P-LAB  VIDEO CARD SYSTEM ***");
+      SCREEN1_LOCATEXY(0, 2); SCREEN1_PUTS("16K VRAM BYTES FREE");
+      SCREEN1_LOCATEXY(0, 4); SCREEN1_PUTS("READY.");
 
-   SCREEN1_LOCATEXY(0, 10);
-   for(i=0;i<256;i++) SCREEN1_PUTCHAR(i);
+      SCREEN1_LOCATEXY(0, 10);
+      for(i=0;i<256;i++) SCREEN1_PUTCHAR(i);
 
-   square_sprites();
+      screen1_square_sprites();
+   }
+
+   if(1) {
+      SCREEN2_INIT();
+      SCREEN2_FILL();
+      screen2_square_sprites();
+      //SCREEN2_PUTC(65,1,1,0x1F);
+
+      SCREEN2_PUTS(0,0,0x1F,"*** P-LAB  VIDEO CARD SYSTEM ***");
+      SCREEN2_PUTS(0,2,0x1F,"16K VRAM BYTES FREE");
+      SCREEN2_PUTS(0,4,0x1F,"READY.");
+
+      for(i=0;i<16;i++) {
+         SCREEN2_PUTS(5,6+i,((15-i)<<4)+i,"     COLOR     ");
+      }
+
+      for(i=0;i<192;i++) {
+         SCREEN2_PSET(i,i/2);
+         SCREEN2_PSET(i,i);
+         SCREEN2_PSET(i/2,i);
+      }
+   }
 
    woz_putc(42);
    woz_mon();