diff --git a/.gitignore b/.gitignore
index 15e50eb..d0dad88 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 *.obj
 *.bak
-
+*.dsk
+*.swp
diff --git a/game.exe b/game.exe
new file mode 100755
index 0000000..93502fb
Binary files /dev/null and b/game.exe differ
diff --git a/game.prj b/game.prj
new file mode 100755
index 0000000..b40dde2
Binary files /dev/null and b/game.prj differ
diff --git a/kbd.c b/kbd.c
new file mode 100755
index 0000000..cf246fd
--- /dev/null
+++ b/kbd.c
@@ -0,0 +1,75 @@
+#include <stdio.h>
+#include <dos.h>
+#include "kbd.h"
+
+static void interrupt (*oldKbdISR)() = NULL;
+
+void kbd_cleanup() {
+  if (oldKbdISR != NULL) {
+    setvect(KBD_INT, oldKbdISR);
+    oldKbdISR = NULL;
+  }
+}
+
+volatile unsigned char keybuf[128] = { 0 };
+volatile char kbd_triggered = 0;
+
+static void interrupt kbd_isr() {
+  unsigned char raw;
+  char ctl;
+
+  asm sti;
+  raw = inp(0x60);
+  ctl = inp(0x61) | 0x82;
+  outp(0x61, ctl);
+  outp(0x61, ctl & 0x7f);
+  outp(0x20, 0x20);
+
+  if (raw & 0x80) {
+    keybuf[raw & 0x7f] &= ~KEY_SIGNAL;
+  } else {
+    keybuf[raw] |= KEY_SIGNAL;
+  }
+  kbd_triggered = raw;
+}
+
+unsigned char kbd_wait() {
+  kbd_triggered = 0;
+  while (!kbd_triggered) {}
+  return kbd_triggered;
+}
+
+void kbd_init() {
+  if (oldKbdISR == NULL) {
+    memset(keybuf, 0, 128);
+    oldKbdISR = getvect(KBD_INT);
+    setvect(KBD_INT, kbd_isr);
+    atexit(kbd_cleanup);
+  }
+}
+
+void kbd_debounce() {
+  int i = 0;
+  asm cli;
+  for (i = 0; i < 128; i ++) {
+    unsigned char signal = keybuf[i] & KEY_SIGNAL;
+    unsigned char keystate = keybuf[i] & 0x0f;
+
+    if (!signal) {
+      if (keystate == KEY_RELEASED) {
+	keystate = KEY_OFF;
+      } else if (keystate != KEY_OFF) {
+	keystate = KEY_RELEASED;
+      }
+    } else {
+      if (keystate == KEY_OFF) {
+	keystate = KEY_PRESSED;
+      } else if (keystate == KEY_PRESSED) {
+	keystate = KEY_DOWN;
+      }
+    }
+
+    keybuf[i] = signal | keystate;
+  }
+  asm sti;
+}
\ No newline at end of file
diff --git a/kbd.h b/kbd.h
new file mode 100755
index 0000000..9fefd03
--- /dev/null
+++ b/kbd.h
@@ -0,0 +1,106 @@
+/*** K E Y B O A R D ***/
+#define KBD_INT 0x09
+
+extern volatile unsigned char keybuf[128];
+extern volatile char kbd_triggered;
+
+void kbd_init();
+void kbd_debounce(); // call once per frame
+unsigned char kbd_wait();
+
+#define KEY_OFF 0
+#define KEY_PRESSED 1
+#define KEY_DOWN 2
+#define KEY_RELEASED 3
+#define KEY_SIGNAL 0x80
+
+#define keyIsDown(k) (keybuf[k] & KEY_SIGNAL)
+#define keyWasPressed(k) ((keybuf[k] & 0x0f) == KEY_PRESSED)
+#define keyWasReleased(k) ((keybuf[k] & 0x0f) == KEY_RELEASED)
+
+#define K_ESC   1
+#define K_1     2
+#define K_2	3
+#define K_3	4
+#define K_4	5
+#define K_5	6
+#define K_6	7
+#define K_7	8
+#define K_8	9
+#define K_9	10
+#define K_0	11
+#define K_MINUS	12
+#define K_EQUAL	13
+#define K_BKSP	14
+#define K_TAB	15
+#define K_Q	16
+#define K_W	17
+#define K_E	18
+#define K_R	19
+#define K_T	20
+#define K_Y	21
+#define K_U	22
+#define K_I	23
+#define K_O	24
+#define K_P	25
+#define K_LBRK	26
+#define K_RBRK	27
+#define K_ENTER 28
+#define K_CTRL  29
+#define K_A	30
+#define K_S	31
+#define K_D	32
+#define K_F	33
+#define K_G	34
+#define K_H	35
+#define K_J	36
+#define K_K	37
+#define K_L	38
+#define K_SEMI	39
+#define K_APOS	40
+#define K_TILDE	41
+#define K_LSHFT 42
+#define K_BSLSH 43
+#define K_Z	44
+#define K_X	45
+#define K_C	46
+#define K_V	47
+#define K_B	48
+#define K_N	49
+#define K_M	50
+#define K_COMMA	51
+#define K_DOT	52
+#define K_SLASH	53
+#define K_RSHFT	54
+#define K_PSCRN	55
+#define K_ALT	56
+#define K_SPACE 57
+#define K_CAPS	58
+#define K_F1	59
+#define K_F2	60
+#define K_F3	61
+#define K_F4	62
+#define K_F5	63
+#define K_F6	64
+#define K_F7	65
+#define K_F8	66
+#define K_F9	67
+#define K_F10	68
+#define K_NUMLK	69
+#define K_SCRL	70
+#define K_HOME	71
+#define K_UP    72
+#define K_PGUP	73
+#define K_NDASH	74
+#define K_LEFT  75
+#define K_CENT	76
+#define K_RIGHT 77
+#define K_NPLUS	78
+#define K_END 	79
+#define K_DOWN  80
+#define K_PGDN	81
+#define K_INS	82
+#define K_DEL	83
+#define K_F11	87
+#define K_F12	88
+
diff --git a/mouse.c b/mouse.c
new file mode 100755
index 0000000..78dbafd
--- /dev/null
+++ b/mouse.c
@@ -0,0 +1,55 @@
+#include <dos.h>
+#include "mouse.h";
+
+/*** M O U S E ***/
+Mouse_t MOUSE;
+
+void far mouse_callback() {
+  asm {
+    mov ax, DGROUP
+    mov ds, ax
+    shr cx, 1
+    mov MOUSE.x, cx
+    mov MOUSE.y, dx
+    mov MOUSE.buttons, bx
+  }
+}
+
+void mouse_cleanup() {
+  //uninstall handler
+  asm {
+    mov ax, 0ch
+    mov dx, 0
+    mov es, dx
+    mov cx, 0
+    int 33h
+
+    xor ax, ax
+    int 33h
+  }
+}
+
+void mouse_init() {
+  unsigned seg_mouse_callback = FP_SEG(mouse_callback);
+  unsigned off_mouse_callback = FP_OFF(mouse_callback);
+  unsigned int result;
+  asm {
+    xor ax, ax
+    int 33h
+    mov result, ax
+  }
+  if (result == 0) {
+    printf("Mouse driver not installed\n");
+    exit(1);
+  }
+  atexit(mouse_cleanup);
+
+  asm {
+    mov ax, seg_mouse_callback
+    mov es, ax
+    mov dx, off_mouse_callback
+    mov ax, 0ch
+    mov cx, 1fh
+    int 33h
+  }
+}
diff --git a/mouse.h b/mouse.h
new file mode 100755
index 0000000..6dc02d1
--- /dev/null
+++ b/mouse.h
@@ -0,0 +1,13 @@
+/*** M O U S E ***/
+typedef struct {
+  unsigned int x;
+  unsigned int y;
+  unsigned int buttons;
+} Mouse_t;
+
+extern Mouse_t MOUSE;
+
+void mouse_init();
+
+#define mouse_hide() asm { mov ax, 02h; int 33h }
+#define mouse_show() asm { mov ax, 01h; int 33h }
diff --git a/testbed.c b/testbed.c
index cd56ed1..aed83c2 100755
--- a/testbed.c
+++ b/testbed.c
@@ -2,677 +2,14 @@
 #include <stdlib.h>
 #include <dos.h>
 
-/*** V I D E O ***/
-#define setMode(hexval) asm { mov ax, hexval; int 10h }
-
-#define setVGAMode() setMode(0013h)
-#define setEGAMode() setMode(000Dh)
-#define setTextMode() setMode(0003h)
-
-#define REG_AC   0x03c0
-#define REG_TS   0x03c4
-#define REG_GDC  0x03ce
-#define REG_CRTC 0x03d4
-
-#define PLANE_B 0x00
-#define PLANE_G 0x01
-#define PLANE_R 0x02
-#define PLANE_I 0x03
-#define setPlane(p) outport(REG_TS, 2 | (0x100 << p))
-#define setAllPlanes() outport(REG_TS, 0x0f02)
-
-#define VID ((volatile char far *)MK_FP(0xa000, 0))
-#define WVID ((volatile int far *)MK_FP(0xa000, 0))
-
-void vid_cleanup() {
-  setTextMode();
-}
-
-#define setWriteMode(m) outport(REG_GDC, 0x05 | m << 8)
-void setSplitScreen(unsigned int y) {
-  int val;
-  outport(REG_CRTC, 0x18 | (y << 8));
-  outp(REG_CRTC, 7);
-  val = inp(REG_CRTC + 1);
-  val &= ~0x10;
-  val |= (y & 0x100) >> 4;
-  outp(REG_CRTC + 1, val);
-  outp(REG_CRTC, 9);
-  val = inp(REG_CRTC + 1);
-  val &= ~0x40;
-  outp(REG_CRTC + 1, val);
-}
-
-void unsetSplitScreen() {
-  outport(REG_CRTC, 0xff18);
-  outport(REG_CRTC, 0x1107);
-  outport(REG_CRTC, 0x0f09);
-}
-
-
-#define flipPage(p) outport(REG_CRTC, 0x0c | (p << 8))
-
-void setDisplayOffset(unsigned int offset) {
-  outport(REG_CRTC, 0x0c | (offset & 0xff00));
-  outport(REG_CRTC, 0x0d | (offset << 8));
-}
-
-void setHorizontalPan(int offset) {
-  inp(0x3da); // INPUT_STATUS_1?
-  outp(REG_AC, 0x13 | 0x20);
-  outp(REG_AC, offset);
-}
-
-#define setLogicalWidth(w) outport(REG_CRTC, 0x13 | (w << 8))
- 
-/*** K E Y B O A R D ***/
-#define KBD_INT 0x09
-void interrupt (*oldKbdISR)() = NULL;
-
-void kbd_cleanup() {
-  if (oldKbdISR != NULL) {
-    setvect(KBD_INT, oldKbdISR);
-    oldKbdISR = NULL;
-  }
-}
-
-volatile char keybuf[128];
-volatile char kbd_triggered = 0;
-
-void interrupt kbd_isr() {
-  unsigned char raw;
-  char ctl;
-
-  asm sti;
-  raw = inp(0x60);
-  ctl = inp(0x61) | 0x82;
-  outp(0x61, ctl);
-  outp(0x61, ctl & 0x7f);
-  outp(0x20, 0x20);
-
-  if (raw & 0x80) {
-    keybuf[raw & 0x7f] = 0;
-  } else {
-    keybuf[raw] = 1;
-  }
-  kbd_triggered = raw;
-}
-
-#define K_ESC   1
-#define K_1     2
-#define K_2	3
-#define K_3	4
-#define K_4	5
-#define K_5	6
-#define K_6	7
-#define K_7	8
-#define K_8	9
-#define K_9	10
-#define K_0	11
-#define K_MINUS	12
-#define K_EQUAL	13
-#define K_BKSP	14
-#define K_TAB	15
-#define K_Q	16
-#define K_W	17
-#define K_E	18
-#define K_R	19
-#define K_T	20
-#define K_Y	21
-#define K_U	22
-#define K_I	23
-#define K_O	24
-#define K_P	25
-#define K_LBRK	26
-#define K_RBRK	27
-#define K_ENTER 28
-#define K_CTRL  29
-#define K_A	30
-#define K_S	31
-#define K_D	32
-#define K_F	33
-#define K_G	34
-#define K_H	35
-#define K_J	36
-#define K_K	37
-#define K_L	38
-#define K_SEMI	39
-#define K_APOS	40
-#define K_TILDE	41
-#define K_LSHFT 42
-#define K_BSLSH 43
-#define K_Z	44
-#define K_X	45
-#define K_C	46
-#define K_V	47
-#define K_B	48
-#define K_N	49
-#define K_M	50
-#define K_COMMA	51
-#define K_DOT	52
-#define K_SLASH	53
-#define K_RSHFT	54
-#define K_PSCRN	55
-#define K_ALT	56
-#define K_SPACE 57
-#define K_CAPS	58
-#define K_F1	59
-#define K_F2	60
-#define K_F3	61
-#define K_F4	62
-#define K_F5	63
-#define K_F6	64
-#define K_F7	65
-#define K_F8	66
-#define K_F9	67
-#define K_F10	68
-#define K_NUMLK	69
-#define K_SCRL	70
-#define K_HOME	71
-#define K_UP    72
-#define K_PGUP	73
-#define K_NDASH	74
-#define K_LEFT  75
-#define K_CENT	76
-#define K_RIGHT 77
-#define K_NPLUS	78
-#define K_END 	79
-#define K_DOWN  80
-#define K_PGDN	81
-#define K_INS	82
-#define K_DEL	83
-#define K_F11	87
-#define K_F12	88
-#define keyPressed(k) keybuf[k]
-
-unsigned char kbd_wait() {
-  kbd_triggered = 0;
-  while (!kbd_triggered) {}
-  return kbd_triggered;
-}
-
-void kbd_init() {
-  if (oldKbdISR == NULL) {
-    memset(keybuf, 0, 128);
-    oldKbdISR = getvect(KBD_INT);
-    setvect(KBD_INT, kbd_isr);
-    atexit(kbd_cleanup);
-  }
-}
-
-/*** M O U S E ***/
-struct {
-  unsigned int x;
-  unsigned int y;
-  unsigned int buttons;
-} MOUSE;
-
-void far mouse_callback() {
-  asm {
-    mov ax, DGROUP
-    mov ds, ax
-    shr cx, 1
-    mov MOUSE.x, cx
-    mov MOUSE.y, dx
-    mov MOUSE.buttons, bx
-  }
-}
-
-void mouse_cleanup() {
-  //uninstall handler
-  asm {
-    mov ax, 0ch
-    mov dx, 0
-    mov es, dx
-    mov cx, 0
-    int 33h
-
-    xor ax, ax
-    int 33h
-  }
-}
-
-void mouse_init() {
-  unsigned seg_mouse_callback = FP_SEG(mouse_callback);
-  unsigned off_mouse_callback = FP_OFF(mouse_callback);
-  unsigned int result;
-  asm {
-    xor ax, ax
-    int 33h
-    mov result, ax
-  }
-  if (result == 0) {
-    printf("Mouse driver not installed\n");
-    exit(1);
-  }
-  atexit(mouse_cleanup);
-
-  asm {
-    mov ax, seg_mouse_callback
-    mov es, ax
-    mov dx, off_mouse_callback
-    mov ax, 0ch
-    mov cx, 1fh
-    int 33h
-  }
-}
-
-#define mouse_hide() asm { mov ax, 02h; int 33h }
-#define mouse_show() asm { mov ax, 01h; int 33h }
-
-/*** T I F F ***/
-typedef struct {
-  unsigned int endian;
-  unsigned int version;
-  unsigned long ifdOffset;
-} TifHeader_t;
-
-#define TIF_WIDTH 256
-#define TIF_HEIGHT 257
-#define TIF_BITSPERSAMPLE 258
-#define TIF_COMPRESSION 259
-#define TIF_STRIPOFFSETS 273
-#define TIF_ROWSPERSTRIP 278
-
-typedef struct {
-  unsigned int id;
-  unsigned int dataType;
-  unsigned long dataCount;
-  unsigned long dataOffset;
-} TifTag_t;
-
-typedef struct {
-  unsigned int width;
-  unsigned int height;
-  unsigned long rowsPerStrip;
-  unsigned long stripCount;
-  unsigned long stripOffsets;
-} TifImageMeta_t;
-
-TifImageMeta_t tifLoadMeta(FILE *f) {
-  TifImageMeta_t meta = {0, 0, 0, 0, 0};
-  TifHeader_t header;
-  TifTag_t tag;
-  unsigned int i, tagCount;
-
-  fseek(f, 0, SEEK_SET);
-  fread(&header, 8, 1, f);
-
-  if (header.endian != 0x4949 || header.version != 0x2a) {
-    goto fail;
-  }
-  fseek(f, header.ifdOffset, SEEK_SET);
-  fread(&tagCount, 2, 1, f);
-  for (i = 0; i < tagCount; i ++) {
-    fread(&tag, 12, 1, f);
-    if (tag.id == TIF_WIDTH) {
-      meta.width = tag.dataOffset;
-    } else if (tag.id == TIF_HEIGHT) {
-      meta.height = tag.dataOffset;
-    } else if (tag.id == TIF_BITSPERSAMPLE) {
-      if (tag.dataOffset != 4) goto fail;
-    } else if (tag.id == TIF_COMPRESSION) {
-      if (tag.dataOffset != 1) goto fail;
-    } else if (tag.id == TIF_STRIPOFFSETS) {
-      meta.stripCount = tag.dataCount;
-      meta.stripOffsets = tag.dataOffset;
-    } else if (tag.id == TIF_ROWSPERSTRIP) {
-      meta.rowsPerStrip = tag.dataOffset;
-    }
-  }
-  return meta;
-fail:
-  meta.stripCount = 0;
-  return meta;
-}
-
-#define MAX_WIDTH 320
-
-int tifLoadEGA(FILE *f, TifImageMeta_t meta, unsigned int vidOffset, int maxY, unsigned int w) {
-  int istrip;
-  int irow;
-  int ipixelpair;
-  int y = 0;
-  unsigned long offset;
-  unsigned char rowData[MAX_WIDTH >> 1];
-  volatile unsigned char far *out = &VID[vidOffset];
-  unsigned char b, g, r, i;
-
-  if (meta.width > MAX_WIDTH || (meta.width % 16) != 0) {
-    return 0;
-  }
-  setWriteMode(0);
-
-  for (istrip = 0; istrip < meta.stripCount; istrip ++) {
-    fseek(f, meta.stripOffsets + (istrip << 2), SEEK_SET);
-    fread(&offset, 4, 1, f);
-    fseek(f, offset, SEEK_SET);
-
-    for (irow = 0; irow < meta.rowsPerStrip; irow ++) {
-      int ipixelpairLim = meta.width >> 1;
-      fread(rowData, 1, ipixelpairLim, f);
-      b = g = r = i = 0;
-      for (ipixelpair = 0; ipixelpair < ipixelpairLim; ipixelpair ++) {
-	unsigned char pixelpair = rowData[ipixelpair];
-	int bpair = (pixelpair & 0x01) | (pixelpair & 0x10) >> 3;
-	int gpair = (pixelpair & 0x02) >> 1 | (pixelpair & 0x20) >> 4;
-	int rpair = (pixelpair & 0x04) >> 2 | (pixelpair & 0x40) >> 5;
-	int ipair = (pixelpair & 0x08) >> 3 | (pixelpair & 0x80) >> 6;
-	int shift = (3 - (ipixelpair % 4)) << 1;
-
-	b |= bpair << shift;
-	g |= gpair << shift;
-	r |= rpair << shift;
-	i |= ipair << shift;
-
-	if (shift == 0 || ipixelpair == ipixelpairLim - 1) {
-	  // todo: use write mode 2, this is slooww
-	  setPlane(PLANE_B); *out = b;
-	  setPlane(PLANE_R); *out = r;
-	  setPlane(PLANE_G); *out = g;
-	  setPlane(PLANE_I); *out = i;
-	  out ++;
-	  b = g = r = i = 0;
-	}
-      }
-      y++;
-      if (y == maxY) {
-	return y;
-      }
-      out += (w - meta.width) >> 3;
-    }
-  }
-  return y;
-}
-
-int tifLoad(FILE *f, TifImageMeta_t meta, unsigned int *planeBuf, int maxY, int yRepeat, int planes) {
-  int istrip;
-  int irow;
-  int ipixelpair;
-  int y = 0;
-  unsigned long offset;
-  unsigned char rowData[MAX_WIDTH >> 1];
-  unsigned int planeStride = (meta.width >> 4) * yRepeat;
-  unsigned int *bp = planeBuf;
-  unsigned int *gp = bp + planeStride;
-  unsigned int *rp = gp + planeStride;
-  unsigned int *ip = rp + planeStride;
-  unsigned int *mp = ip + planeStride;
-  unsigned int bv, gv, rv, iv;
-
-  if (meta.width > MAX_WIDTH || (meta.width % 16) != 0 || planes < 4 || planes > 5) {
-    return 0;
-  }
-
-  for (istrip = 0; istrip < meta.stripCount; istrip ++) {
-    fseek(f, meta.stripOffsets + (istrip << 2), SEEK_SET);
-    fread(&offset, 4, 1, f);
-    fseek(f, offset, SEEK_SET);
-
-    for (irow = 0; irow < meta.rowsPerStrip; irow ++) {
-      int ipixelpairLim = meta.width >> 1;
-      fread(rowData, 1, ipixelpairLim, f);
-      bv = gv = rv = iv = 0;
-      for (ipixelpair = 0; ipixelpair < ipixelpairLim; ipixelpair ++) {
-	unsigned char pixelpair = rowData[ipixelpair];
-	int bpair = (pixelpair & 0x01) | (pixelpair & 0x10) >> 3;
-	int gpair = (pixelpair & 0x02) >> 1 | (pixelpair & 0x20) >> 4;
-	int rpair = (pixelpair & 0x04) >> 2 | (pixelpair & 0x40) >> 5;
-	int ipair = (pixelpair & 0x08) >> 3 | (pixelpair & 0x80) >> 6;
-	int shift = (7 - (ipixelpair % 8)) << 1;
-
-	bv |= bpair << shift;
-	gv |= gpair << shift;
-	rv |= rpair << shift;
-	iv |= ipair << shift;
-
-	if (shift == 0 || ipixelpair == ipixelpairLim - 1) {
-	  *bp++ = bv;
-	  *gp++ = gv;
-	  *rp++ = rv;
-	  *ip++ = iv;
-	  if (planes == 5) {
-	    iv = ~(bv & gv & rv & iv);
-	    *mp++ = iv;
-	  }
-	  bv = gv = rv = iv = 0;
-	}
-      }
-      y++;
-      if (y == maxY) {
-	return y;
-      }
-      if (y % yRepeat == 0) {
-	bp += planeStride * (planes - 1);
-	gp += planeStride * (planes - 1);
-	rp += planeStride * (planes - 1);
-	ip += planeStride * (planes - 1);
-	mp += planeStride * (planes - 1);
-      }
-    }
-  }
-  return y;
-}
-
-/*** T I L E S ***/
-
-// Tiles are 16x16 bitmaps, stored as arrays of words.
-// Each tile has 4 or 5 planes (depending on whether it is a tile or sprite)
-// which are stored adjacant to each other; ie. a 16-word array of blue,
-// followed by a 16-word array of green, etc.
-// Tiles in RAM are stored byte-swapped to aid in fast bit-shifting, and must
-// be byte-swapped before being written to video memory.
-
-// Because bit-shifting operations happen on little-endian words:
-// 01234567 89ABCDEF << 3 => 34567XXX BCDEF012
-// which is wrong. So instead we do:
-// 89ABCDEF 01234567 << 3 => BCDEFXXX 3456789A byteswap => 3456789A BCDEFXXX
-
-#define PAGE_TILES_W 21
-#define PAGE_TILES_H 14
-#define PAGE_TILES_COUNT (PAGE_TILES_H * PAGE_TILES_W)
-#define PAGE_STRIDE (PAGE_TILES_W << 1)
-
-void tile_init() {
-  setLogicalWidth(PAGE_STRIDE >> 1);
-}
-
-void blitTile(unsigned int offsetFrom, unsigned int offsetTo) {
-  int y;
-  for (y = 0; y < 16; y ++) {
-    VID[offsetTo] = VID[offsetFrom ++];
-    VID[offsetTo + 1] = VID[offsetFrom ++];
-    offsetTo += PAGE_STRIDE;
-  }
-}
-
-#define D_NOTHING 0x80
-#define D_BGTILE 0x81
-#define isBufIndex(d) (!((d) & 0x80))
-
-#define NUM_BUFFERS 32
-#define nextBufferIndex(i) ((i + 1) % 32)
-#define BUF_WSTRIDE 16
-#define BUF_WSIZE (BUF_WSTRIDE * 4)
-typedef struct {
-  unsigned int w;
-  unsigned int h;
-  int scrollX;
-  int scrollY;
-  unsigned int pageOffset[2];
-  unsigned char dirty[2][PAGE_TILES_COUNT];
-  unsigned int tilesOffset;
-  unsigned int *memTiles;
-  unsigned char *map;
-  unsigned int buffer[NUM_BUFFERS][BUF_WSIZE];
-  unsigned int bufferOffset[NUM_BUFFERS];
-  unsigned char currentPage;
-  unsigned char nextBuffer;
-  unsigned char firstBuffer;
-} TiledScreen_t;
-
-TiledScreen_t screen = { 0, 0, 0, 0, { 0x0600, 0x2B00 }, 0, 0, NULL, NULL,
-  0, 0, 0, 0, 0 };
-
-void loadTiles(unsigned int tilesOffset, unsigned int *memTiles) {
-  screen.tilesOffset = tilesOffset;
-  screen.memTiles = memTiles;
-}
-
-void loadMap(unsigned char *map, unsigned int w, unsigned int h) {
-  screen.map = map;
-  screen.w = w;
-  screen.h = h;
-  memset(screen.dirty, D_BGTILE, PAGE_TILES_COUNT * 2);
-}
-
-int prepareBuffer(int pageX, int pageY) {
-  unsigned char *dirty = &screen.dirty[screen.currentPage][pageX + (pageY * PAGE_TILES_W)];
-  if (!isBufIndex(*dirty)) {
-    unsigned int startX = screen.scrollX >> 4;
-    unsigned int startY = screen.scrollY >> 4;
-    unsigned char tile = screen.map[startX + pageX + ((startY + pageY) * screen.w)];
-    unsigned char ibuffer = screen.nextBuffer;
-    screen.nextBuffer = nextBufferIndex(ibuffer);
-    *dirty = ibuffer;
-    memcpy(screen.buffer[ibuffer], &screen.memTiles[tile * BUF_WSIZE], BUF_WSIZE << 1);
-    screen.bufferOffset[ibuffer] = screen.pageOffset[screen.currentPage]
-      + (pageX << 1) + (pageY * PAGE_STRIDE * 16);
-  }
-  return *dirty;
-}
-
-void drawSpriteToBuf(unsigned int *sprite, int pageX, int pageY, int shift, int yStart) {
-  unsigned int *buf, *mask;
-  unsigned int maskval;
-  int y, h, plane;
-  if (pageX < 0 || pageY < 0 ||
-      pageX >= PAGE_TILES_W || pageY >= PAGE_TILES_H ||
-      shift >= 16 || shift <= -16 ||
-      yStart <= -16 || yStart >= 16) {
-    return;
-  }
-
-  buf = screen.buffer[prepareBuffer(pageX, pageY)];
-  if (yStart < 0) {
-    sprite = &sprite[-yStart];
-    h = yStart + 16;
-  } else {
-    buf = &buf[yStart];
-    h = 16 - yStart;
-  }
-  mask = &sprite[BUF_WSTRIDE * 4];
-  if (shift < 0) {
-    shift = -shift;
-    for (plane = 0; plane < 4; plane ++) {
-      for (y = 0; y < h; y ++) {
-	maskval = mask[y] << shift;
-	buf[y] = (buf[y] & ~maskval) | ((sprite[y] << shift) & maskval);
-      }
-      sprite += BUF_WSTRIDE;
-      buf += BUF_WSTRIDE;
-    }
-  } else {
-    for (plane = 0; plane < 4; plane ++) {
-      for (y = 0; y < h; y ++) {
-	maskval = mask[y] >> shift;
-	buf[y] = (buf[y] & ~maskval) | ((sprite[y] >> shift) & maskval);
-      }
-      sprite += BUF_WSTRIDE;
-      buf += BUF_WSTRIDE;
-    }
-  }
-}
-
-void drawSprite(unsigned int *sprite, int x, int y) {
-  int pageX = (int)(x - (screen.scrollX & 0xfff0)) >> 4;
-  int pageY = (int)(y - (screen.scrollY & 0xfff0)) >> 4;
-  int pageOffsetX = x & 0x0f;
-  int pageOffsetY = y & 0x0f;
-
-  drawSpriteToBuf(sprite, pageX, pageY, pageOffsetX, pageOffsetY);
-  drawSpriteToBuf(sprite, pageX + 1, pageY, pageOffsetX - 16, pageOffsetY);
-  drawSpriteToBuf(sprite, pageX, pageY + 1, pageOffsetX, pageOffsetY - 16);
-  drawSpriteToBuf(sprite, pageX + 1, pageY + 1, pageOffsetX - 16, pageOffsetY - 16);
-}
-
-void scroll(int newX, int newY) {
-  newX = min(max(newX, 0), (screen.w << 4) - 320);
-  newY = min(max(newY, 0), (screen.h << 4) - 200);
-  if ((screen.scrollX & 0xfff0) != (newX & 0xfff0) ||
-      (screen.scrollY & 0xfff0) != (newY & 0xfff0)) {
-    int mapX, mapY;
-    unsigned char page;
-    for (page = 0; page < 2; page ++) {
-      int mapOffsetOld = (screen.scrollX >> 4) + ((screen.scrollY >> 4) * screen.w);
-      int mapOffsetNew = (newX >> 4) + ((newY >> 4) * screen.w);
-      unsigned char *dirty = screen.dirty[page];
-      for (mapY = 0; mapY < PAGE_TILES_H; mapY ++) {
-	for (mapX = 0; mapX < PAGE_TILES_W; mapX ++) {
-	  if (*dirty != D_NOTHING ||
-	    screen.map[mapOffsetOld + mapX] != screen.map[mapOffsetNew + mapX]) {
-	    *dirty = D_BGTILE;
-	  }
-	  dirty ++;
-	}
-	mapOffsetNew += screen.w;
-	mapOffsetOld += screen.w;
-      }
-    }
-  }
-  screen.scrollX = newX;
-  screen.scrollY = newY;
-}
-
-void drawScreen() {
-  unsigned int startX = screen.scrollX >> 4;
-  unsigned int startY = screen.scrollY >> 4;
-  unsigned int offsetX = screen.scrollX - (startX << 4);
-  unsigned int offsetY = screen.scrollY - (startY << 4);
-  unsigned int drawOffset = screen.pageOffset[screen.currentPage];
-  unsigned int scrollOffset = drawOffset + (offsetX >> 3) + (offsetY * PAGE_STRIDE);
-  unsigned char *dirty = screen.dirty[screen.currentPage];
-  unsigned int x, y, di, plane, bmp;
-
-  setAllPlanes();
-  setWriteMode(1);
-
-  di = 0;
-  for (y = startY; y < startY + PAGE_TILES_H; y ++) {
-    for (x = startX; x < startX + PAGE_TILES_W; x ++) {
-      if (dirty[di++] == D_BGTILE) {
-	blitTile(
-	  screen.tilesOffset + (screen.map[x + (y * screen.w)] << 5),
-	  drawOffset);
-      }
-      drawOffset += 2;
-    }
-    drawOffset += PAGE_STRIDE * 15;
-  }
-  setWriteMode(0);
-  for(plane = 0; plane < 4; plane ++) {
-    setPlane(plane);
-    for (di = screen.firstBuffer; di != screen.nextBuffer; di = nextBufferIndex(di)) {
-      drawOffset = screen.bufferOffset[di] >> 1;
-      for (y = 0; y < 16; y ++) {
-	bmp = screen.buffer[di][y + (BUF_WSTRIDE * plane)];
-	WVID[drawOffset] = (bmp << 8) | (bmp >> 8);
-	drawOffset += PAGE_STRIDE >> 1;
-      }
-    }
-  }
-  setAllPlanes();
-  setDisplayOffset(scrollOffset);
-  setHorizontalPan(screen.scrollX & 0x07);
-
-  screen.currentPage ^= 1;
-  screen.firstBuffer = screen.nextBuffer;
-  for (di = 0; di < PAGE_TILES_COUNT; di ++) {
-    dirty[di] = isBufIndex(dirty[di]) ? D_BGTILE : D_NOTHING;
-  }
-}
+#include "video.h"
+#include "kbd.h"
+#include "mouse.h"
+#include "tiff.h"
+#include "tiles.h"
 
 /*** S C R A T C H ***/
+
 #define NUM_TILES 128
 #define NUM_SPRITES 64
 #define OFF_TILES 0x5000
@@ -681,7 +18,6 @@ void drawScreen() {
 unsigned int tiles[NUM_TILES * TILE_STRIDE];
 unsigned int sprites[NUM_SPRITES * SPRITE_STRIDE];
 
-
 unsigned char map[10000];
 
 void fillMap() {
@@ -719,16 +55,15 @@ void drawEntity(Entity_t *entity) {
 }
 
 void playerThink(Entity_t *self) {
-  if (keyPressed(K_LEFT))  { self->x -= 3; self->dir = DIR_W; }
-  if (keyPressed(K_RIGHT)) { self->x += 3; self->dir = DIR_E; }
-  if (keyPressed(K_UP))    { self->y -= 3; self->dir = DIR_N; }
-  if (keyPressed(K_DOWN))  { self->y += 3; self->dir = DIR_S; }
+  if (keyIsDown(K_LEFT))  { self->x -= 3; self->dir = DIR_W; }
+  if (keyIsDown(K_RIGHT)) { self->x += 3; self->dir = DIR_E; }
+  if (keyIsDown(K_UP))    { self->y -= 3; self->dir = DIR_N; }
+  if (keyIsDown(K_DOWN))  { self->y += 3; self->dir = DIR_S; }
 }
 
 typedef struct {
   int dy;
   int y;
-  int debounce;
 } Footer_t;
 
 typedef struct {
@@ -756,6 +91,8 @@ void game_init() {
   setEGAMode();
   atexit(vid_cleanup);
 
+  kbd_init();
+
   tile_init();
   fillMap();
 
@@ -775,8 +112,6 @@ void game_init() {
   tifLoad(f, meta, sprites, NUM_SPRITES * 16, 16, 5);
   fclose(f);
 
-//  setSplitScreen(351);
-
   loadTiles(OFF_TILES, tiles);
   loadMap(map, 100, 100);
   scroll(0, 0);
@@ -784,22 +119,18 @@ void game_init() {
 
 int main() {
   game_init();
-  kbd_init();
 
-  while (!keyPressed(K_ESC)) {
+  while (!keyIsDown(K_ESC)) {
+    kbd_debounce();
     if (game.state == STATE_MAP) {
-      if (keyPressed(K_SPACE)) {
+      if (keyWasPressed(K_SPACE)) {
 	game.state = STATE_DIALOG;
-	game.footer.debounce = 1;
 	game.footer.dy = 1;
       }
       playerThink(&game.player);
       scroll(game.player.x - 152, game.player.y - 92);
     } else if (game.state == STATE_DIALOG) {
-      if (game.footer.debounce && !keyPressed(K_SPACE)) {
-	game.footer.debounce = 0;
-      }
-      if (!game.footer.debounce && keyPressed(K_SPACE)) {
+      if (keyWasPressed(K_SPACE)) {
 	game.footer.dy = -1;
       }
       game.footer.y += game.footer.dy;
diff --git a/tiff.c b/tiff.c
new file mode 100755
index 0000000..72ee169
--- /dev/null
+++ b/tiff.c
@@ -0,0 +1,187 @@
+#include <dos.h>
+#include "tiff.h"
+#include "video.h"
+
+/*** T I F F ***/
+typedef struct {
+  unsigned int endian;
+  unsigned int version;
+  unsigned long ifdOffset;
+} TifHeader_t;
+
+#define TIF_WIDTH 256
+#define TIF_HEIGHT 257
+#define TIF_BITSPERSAMPLE 258
+#define TIF_COMPRESSION 259
+#define TIF_STRIPOFFSETS 273
+#define TIF_ROWSPERSTRIP 278
+
+typedef struct {
+  unsigned int id;
+  unsigned int dataType;
+  unsigned long dataCount;
+  unsigned long dataOffset;
+} TifTag_t;
+
+TifImageMeta_t tifLoadMeta(FILE *f) {
+  TifImageMeta_t meta = {0, 0, 0, 0, 0};
+  TifHeader_t header;
+  TifTag_t tag;
+  unsigned int i, tagCount;
+
+  fseek(f, 0, SEEK_SET);
+  fread(&header, 8, 1, f);
+
+  if (header.endian != 0x4949 || header.version != 0x2a) {
+    goto fail;
+  }
+  fseek(f, header.ifdOffset, SEEK_SET);
+  fread(&tagCount, 2, 1, f);
+  for (i = 0; i < tagCount; i ++) {
+    fread(&tag, 12, 1, f);
+    if (tag.id == TIF_WIDTH) {
+      meta.width = tag.dataOffset;
+    } else if (tag.id == TIF_HEIGHT) {
+      meta.height = tag.dataOffset;
+    } else if (tag.id == TIF_BITSPERSAMPLE) {
+      if (tag.dataOffset != 4) goto fail;
+    } else if (tag.id == TIF_COMPRESSION) {
+      if (tag.dataOffset != 1) goto fail;
+    } else if (tag.id == TIF_STRIPOFFSETS) {
+      meta.stripCount = tag.dataCount;
+      meta.stripOffsets = tag.dataOffset;
+    } else if (tag.id == TIF_ROWSPERSTRIP) {
+      meta.rowsPerStrip = tag.dataOffset;
+    }
+  }
+  return meta;
+fail:
+  meta.stripCount = 0;
+  return meta;
+}
+
+int tifLoadEGA(FILE *f, TifImageMeta_t meta, unsigned int vidOffset, int maxY, unsigned int w) {
+  int istrip;
+  int irow;
+  int ipixelpair;
+  int y = 0;
+  unsigned long offset;
+  unsigned char rowData[MAX_WIDTH >> 1];
+  volatile unsigned char far *out = &VID[vidOffset];
+  unsigned char b, g, r, i;
+
+  if (meta.width > MAX_WIDTH || (meta.width % 16) != 0) {
+    return 0;
+  }
+  setWriteMode(0);
+
+  for (istrip = 0; istrip < meta.stripCount; istrip ++) {
+    fseek(f, meta.stripOffsets + (istrip << 2), SEEK_SET);
+    fread(&offset, 4, 1, f);
+    fseek(f, offset, SEEK_SET);
+
+    for (irow = 0; irow < meta.rowsPerStrip; irow ++) {
+      int ipixelpairLim = meta.width >> 1;
+      fread(rowData, 1, ipixelpairLim, f);
+      b = g = r = i = 0;
+      for (ipixelpair = 0; ipixelpair < ipixelpairLim; ipixelpair ++) {
+	unsigned char pixelpair = rowData[ipixelpair];
+	int bpair = (pixelpair & 0x01) | (pixelpair & 0x10) >> 3;
+	int gpair = (pixelpair & 0x02) >> 1 | (pixelpair & 0x20) >> 4;
+	int rpair = (pixelpair & 0x04) >> 2 | (pixelpair & 0x40) >> 5;
+	int ipair = (pixelpair & 0x08) >> 3 | (pixelpair & 0x80) >> 6;
+	int shift = (3 - (ipixelpair % 4)) << 1;
+
+	b |= bpair << shift;
+	g |= gpair << shift;
+	r |= rpair << shift;
+	i |= ipair << shift;
+
+	if (shift == 0 || ipixelpair == ipixelpairLim - 1) {
+	  // todo: use write mode 2, this is slooww
+	  setPlane(PLANE_B); *out = b;
+	  setPlane(PLANE_R); *out = r;
+	  setPlane(PLANE_G); *out = g;
+	  setPlane(PLANE_I); *out = i;
+	  out ++;
+	  b = g = r = i = 0;
+	}
+      }
+      y++;
+      if (y == maxY) {
+	return y;
+      }
+      out += (w - meta.width) >> 3;
+    }
+  }
+  return y;
+}
+
+int tifLoad(FILE *f, TifImageMeta_t meta, unsigned int *planeBuf, int maxY, int yRepeat, int planes) {
+  int istrip;
+  int irow;
+  int ipixelpair;
+  int y = 0;
+  unsigned long offset;
+  unsigned char rowData[MAX_WIDTH >> 1];
+  unsigned int planeStride = (meta.width >> 4) * yRepeat;
+  unsigned int *bp = planeBuf;
+  unsigned int *gp = bp + planeStride;
+  unsigned int *rp = gp + planeStride;
+  unsigned int *ip = rp + planeStride;
+  unsigned int *mp = ip + planeStride;
+  unsigned int bv, gv, rv, iv;
+
+  if (meta.width > MAX_WIDTH || (meta.width % 16) != 0 || planes < 4 || planes > 5) {
+    return 0;
+  }
+
+  for (istrip = 0; istrip < meta.stripCount; istrip ++) {
+    fseek(f, meta.stripOffsets + (istrip << 2), SEEK_SET);
+    fread(&offset, 4, 1, f);
+    fseek(f, offset, SEEK_SET);
+
+    for (irow = 0; irow < meta.rowsPerStrip; irow ++) {
+      int ipixelpairLim = meta.width >> 1;
+      fread(rowData, 1, ipixelpairLim, f);
+      bv = gv = rv = iv = 0;
+      for (ipixelpair = 0; ipixelpair < ipixelpairLim; ipixelpair ++) {
+	unsigned char pixelpair = rowData[ipixelpair];
+	int bpair = (pixelpair & 0x01) | (pixelpair & 0x10) >> 3;
+	int gpair = (pixelpair & 0x02) >> 1 | (pixelpair & 0x20) >> 4;
+	int rpair = (pixelpair & 0x04) >> 2 | (pixelpair & 0x40) >> 5;
+	int ipair = (pixelpair & 0x08) >> 3 | (pixelpair & 0x80) >> 6;
+	int shift = (7 - (ipixelpair % 8)) << 1;
+
+	bv |= bpair << shift;
+	gv |= gpair << shift;
+	rv |= rpair << shift;
+	iv |= ipair << shift;
+
+	if (shift == 0 || ipixelpair == ipixelpairLim - 1) {
+	  *bp++ = bv;
+	  *gp++ = gv;
+	  *rp++ = rv;
+	  *ip++ = iv;
+	  if (planes == 5) {
+	    iv = ~(bv & gv & rv & iv);
+	    *mp++ = iv;
+	  }
+	  bv = gv = rv = iv = 0;
+	}
+      }
+      y++;
+      if (y == maxY) {
+	return y;
+      }
+      if (y % yRepeat == 0) {
+	bp += planeStride * (planes - 1);
+	gp += planeStride * (planes - 1);
+	rp += planeStride * (planes - 1);
+	ip += planeStride * (planes - 1);
+	mp += planeStride * (planes - 1);
+      }
+    }
+  }
+  return y;
+}
diff --git a/tiff.h b/tiff.h
new file mode 100755
index 0000000..3e1101f
--- /dev/null
+++ b/tiff.h
@@ -0,0 +1,17 @@
+#include <stdio.h>
+
+/*** T I F F ***/
+
+typedef struct {
+  unsigned int width;
+  unsigned int height;
+  unsigned long rowsPerStrip;
+  unsigned long stripCount;
+  unsigned long stripOffsets;
+} TifImageMeta_t;
+
+#define MAX_WIDTH 320
+
+TifImageMeta_t tifLoadMeta(FILE *f);
+int tifLoadEGA(FILE *f, TifImageMeta_t meta, unsigned int vidOffset, int maxY, unsigned int w);
+int tifLoad(FILE *f, TifImageMeta_t meta, unsigned int *planeBuf, int maxY, int yRepeat, int planes);
diff --git a/tiles.c b/tiles.c
new file mode 100755
index 0000000..66ccc6a
--- /dev/null
+++ b/tiles.c
@@ -0,0 +1,222 @@
+#include <dos.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "video.h"
+
+/*** T I L E S ***/
+
+// Tiles are 16x16 bitmaps, stored as arrays of words.
+// Each tile has 4 or 5 planes (depending on whether it is a tile or sprite)
+// which are stored adjacant to each other; ie. a 16-word array of blue,
+// followed by a 16-word array of green, etc.
+// Tiles in RAM are stored byte-swapped to aid in fast bit-shifting, and must
+// be byte-swapped before being written to video memory.
+
+// Because bit-shifting operations happen on little-endian words:
+// 01234567 89ABCDEF << 3 => 34567XXX BCDEF012
+// which is wrong. So instead we do:
+// 89ABCDEF 01234567 << 3 => BCDEFXXX 3456789A byteswap => 3456789A BCDEFXXX
+
+#define PAGE_TILES_W 21
+#define PAGE_TILES_H 14
+#define PAGE_TILES_COUNT (PAGE_TILES_H * PAGE_TILES_W)
+#define PAGE_STRIDE (PAGE_TILES_W << 1)
+
+void tile_init() {
+  setLogicalWidth(PAGE_STRIDE >> 1);
+}
+
+void blitTile(unsigned int offsetFrom, unsigned int offsetTo) {
+  int y;
+  for (y = 0; y < 16; y ++) {
+    VID[offsetTo] = VID[offsetFrom ++];
+    VID[offsetTo + 1] = VID[offsetFrom ++];
+    offsetTo += PAGE_STRIDE;
+  }
+}
+
+#define D_NOTHING 0x80
+#define D_BGTILE 0x81
+#define isBufIndex(d) (!((d) & 0x80))
+
+#define NUM_BUFFERS 32
+#define nextBufferIndex(i) ((i + 1) % 32)
+#define BUF_WSTRIDE 16
+#define BUF_WSIZE (BUF_WSTRIDE * 4)
+typedef struct {
+  unsigned int w;
+  unsigned int h;
+  int scrollX;
+  int scrollY;
+  unsigned int pageOffset[2];
+  unsigned char dirty[2][PAGE_TILES_COUNT];
+  unsigned int tilesOffset;
+  unsigned int *memTiles;
+  unsigned char *map;
+  unsigned int buffer[NUM_BUFFERS][BUF_WSIZE];
+  unsigned int bufferOffset[NUM_BUFFERS];
+  unsigned char currentPage;
+  unsigned char nextBuffer;
+  unsigned char firstBuffer;
+} TiledScreen_t;
+
+TiledScreen_t screen = { 0, 0, 0, 0, { 0x0600, 0x2B00 }, 0, 0, NULL, NULL,
+  0, 0, 0, 0, 0 };
+
+void loadTiles(unsigned int tilesOffset, unsigned int *memTiles) {
+  screen.tilesOffset = tilesOffset;
+  screen.memTiles = memTiles;
+}
+
+void loadMap(unsigned char *map, unsigned int w, unsigned int h) {
+  screen.map = map;
+  screen.w = w;
+  screen.h = h;
+  memset(screen.dirty, D_BGTILE, PAGE_TILES_COUNT * 2);
+}
+
+int prepareBuffer(int pageX, int pageY) {
+  unsigned char *dirty = &screen.dirty[screen.currentPage][pageX + (pageY * PAGE_TILES_W)];
+  if (!isBufIndex(*dirty)) {
+    unsigned int startX = screen.scrollX >> 4;
+    unsigned int startY = screen.scrollY >> 4;
+    unsigned char tile = screen.map[startX + pageX + ((startY + pageY) * screen.w)];
+    unsigned char ibuffer = screen.nextBuffer;
+    screen.nextBuffer = nextBufferIndex(ibuffer);
+    *dirty = ibuffer;
+    memcpy(screen.buffer[ibuffer], &screen.memTiles[tile * BUF_WSIZE], BUF_WSIZE << 1);
+    screen.bufferOffset[ibuffer] = screen.pageOffset[screen.currentPage]
+      + (pageX << 1) + (pageY * PAGE_STRIDE * 16);
+  }
+  return *dirty;
+}
+
+void drawSpriteToBuf(unsigned int *sprite, int pageX, int pageY, int shift, int yStart) {
+  unsigned int *buf, *mask;
+  unsigned int maskval;
+  int y, h, plane;
+  if (pageX < 0 || pageY < 0 ||
+      pageX >= PAGE_TILES_W || pageY >= PAGE_TILES_H ||
+      shift >= 16 || shift <= -16 ||
+      yStart <= -16 || yStart >= 16) {
+    return;
+  }
+
+  buf = screen.buffer[prepareBuffer(pageX, pageY)];
+  if (yStart < 0) {
+    sprite = &sprite[-yStart];
+    h = yStart + 16;
+  } else {
+    buf = &buf[yStart];
+    h = 16 - yStart;
+  }
+  mask = &sprite[BUF_WSTRIDE * 4];
+  if (shift < 0) {
+    shift = -shift;
+    for (plane = 0; plane < 4; plane ++) {
+      for (y = 0; y < h; y ++) {
+	maskval = mask[y] << shift;
+	buf[y] = (buf[y] & ~maskval) | ((sprite[y] << shift) & maskval);
+      }
+      sprite += BUF_WSTRIDE;
+      buf += BUF_WSTRIDE;
+    }
+  } else {
+    for (plane = 0; plane < 4; plane ++) {
+      for (y = 0; y < h; y ++) {
+	maskval = mask[y] >> shift;
+	buf[y] = (buf[y] & ~maskval) | ((sprite[y] >> shift) & maskval);
+      }
+      sprite += BUF_WSTRIDE;
+      buf += BUF_WSTRIDE;
+    }
+  }
+}
+
+void drawSprite(unsigned int *sprite, int x, int y) {
+  int pageX = (int)(x - (screen.scrollX & 0xfff0)) >> 4;
+  int pageY = (int)(y - (screen.scrollY & 0xfff0)) >> 4;
+  int pageOffsetX = x & 0x0f;
+  int pageOffsetY = y & 0x0f;
+
+  drawSpriteToBuf(sprite, pageX, pageY, pageOffsetX, pageOffsetY);
+  drawSpriteToBuf(sprite, pageX + 1, pageY, pageOffsetX - 16, pageOffsetY);
+  drawSpriteToBuf(sprite, pageX, pageY + 1, pageOffsetX, pageOffsetY - 16);
+  drawSpriteToBuf(sprite, pageX + 1, pageY + 1, pageOffsetX - 16, pageOffsetY - 16);
+}
+
+void scroll(int newX, int newY) {
+  newX = min(max(newX, 0), (screen.w << 4) - 320);
+  newY = min(max(newY, 0), (screen.h << 4) - 200);
+  if ((screen.scrollX & 0xfff0) != (newX & 0xfff0) ||
+      (screen.scrollY & 0xfff0) != (newY & 0xfff0)) {
+    int mapX, mapY;
+    unsigned char page;
+    for (page = 0; page < 2; page ++) {
+      int mapOffsetOld = (screen.scrollX >> 4) + ((screen.scrollY >> 4) * screen.w);
+      int mapOffsetNew = (newX >> 4) + ((newY >> 4) * screen.w);
+      unsigned char *dirty = screen.dirty[page];
+      for (mapY = 0; mapY < PAGE_TILES_H; mapY ++) {
+	for (mapX = 0; mapX < PAGE_TILES_W; mapX ++) {
+	  if (*dirty != D_NOTHING ||
+	    screen.map[mapOffsetOld + mapX] != screen.map[mapOffsetNew + mapX]) {
+	    *dirty = D_BGTILE;
+	  }
+	  dirty ++;
+	}
+	mapOffsetNew += screen.w;
+	mapOffsetOld += screen.w;
+      }
+    }
+  }
+  screen.scrollX = newX;
+  screen.scrollY = newY;
+}
+
+void drawScreen() {
+  unsigned int startX = screen.scrollX >> 4;
+  unsigned int startY = screen.scrollY >> 4;
+  unsigned int offsetX = screen.scrollX - (startX << 4);
+  unsigned int offsetY = screen.scrollY - (startY << 4);
+  unsigned int drawOffset = screen.pageOffset[screen.currentPage];
+  unsigned int scrollOffset = drawOffset + (offsetX >> 3) + (offsetY * PAGE_STRIDE);
+  unsigned char *dirty = screen.dirty[screen.currentPage];
+  unsigned int x, y, di, plane, bmp;
+
+  setAllPlanes();
+  setWriteMode(1);
+
+  di = 0;
+  for (y = startY; y < startY + PAGE_TILES_H; y ++) {
+    for (x = startX; x < startX + PAGE_TILES_W; x ++) {
+      if (dirty[di++] == D_BGTILE) {
+	blitTile(
+	  screen.tilesOffset + (screen.map[x + (y * screen.w)] << 5),
+	  drawOffset);
+      }
+      drawOffset += 2;
+    }
+    drawOffset += PAGE_STRIDE * 15;
+  }
+  setWriteMode(0);
+  for(plane = 0; plane < 4; plane ++) {
+    setPlane(plane);
+    for (di = screen.firstBuffer; di != screen.nextBuffer; di = nextBufferIndex(di)) {
+      drawOffset = screen.bufferOffset[di] >> 1;
+      for (y = 0; y < 16; y ++) {
+	bmp = screen.buffer[di][y + (BUF_WSTRIDE * plane)];
+	WVID[drawOffset] = (bmp << 8) | (bmp >> 8);
+	drawOffset += PAGE_STRIDE >> 1;
+      }
+    }
+  }
+  setAllPlanes();
+  setDisplayOffset(scrollOffset);
+  setHorizontalPan(screen.scrollX & 0x07);
+
+  screen.currentPage ^= 1;
+  screen.firstBuffer = screen.nextBuffer;
+  for (di = 0; di < PAGE_TILES_COUNT; di ++) {
+    dirty[di] = isBufIndex(dirty[di]) ? D_BGTILE : D_NOTHING;
+  }
+}
diff --git a/tiles.h b/tiles.h
new file mode 100755
index 0000000..98b83fb
--- /dev/null
+++ b/tiles.h
@@ -0,0 +1,9 @@
+/*** T I L E S ***/
+
+void tile_init();
+
+void loadTiles(unsigned int tilesOffset, unsigned int *memTiles);
+void loadMap(unsigned char *map, unsigned int w, unsigned int h);
+void drawSprite(unsigned int *sprite, int x, int y);
+void scroll(int newX, int newY);
+void drawScreen();
diff --git a/video.c b/video.c
new file mode 100755
index 0000000..39710c4
--- /dev/null
+++ b/video.c
@@ -0,0 +1,39 @@
+#include <dos.h>
+#include "video.h"
+
+void vid_cleanup() {
+  setTextMode();
+}
+
+void setSplitScreen(unsigned int y) {
+  int val;
+  outport(REG_CRTC, 0x18 | (y << 8));
+  outp(REG_CRTC, 7);
+  val = inp(REG_CRTC + 1);
+  val &= ~0x10;
+  val |= (y & 0x100) >> 4;
+  outp(REG_CRTC + 1, val);
+  outp(REG_CRTC, 9);
+  val = inp(REG_CRTC + 1);
+  val &= ~0x40;
+  outp(REG_CRTC + 1, val);
+}
+
+void unsetSplitScreen() {
+  outport(REG_CRTC, 0xff18);
+  outport(REG_CRTC, 0x1107);
+  outport(REG_CRTC, 0x0f09);
+}
+
+
+void setDisplayOffset(unsigned int offset) {
+  outport(REG_CRTC, 0x0c | (offset & 0xff00));
+  outport(REG_CRTC, 0x0d | (offset << 8));
+}
+
+void setHorizontalPan(int offset) {
+  inp(0x3da); // INPUT_STATUS_1?
+  outp(REG_AC, 0x13 | 0x20);
+  outp(REG_AC, offset);
+}
+
diff --git a/video.h b/video.h
new file mode 100755
index 0000000..491a177
--- /dev/null
+++ b/video.h
@@ -0,0 +1,34 @@
+/*** V I D E O ***/
+#define setMode(hexval) asm { mov ax, hexval; int 10h }
+
+#define setVGAMode() setMode(0013h)
+#define setEGAMode() setMode(000Dh)
+#define setTextMode() setMode(0003h)
+
+#define REG_AC   0x03c0
+#define REG_TS   0x03c4
+#define REG_GDC  0x03ce
+#define REG_CRTC 0x03d4
+
+#define PLANE_B 0x00
+#define PLANE_G 0x01
+#define PLANE_R 0x02
+#define PLANE_I 0x03
+#define setPlane(p) outport(REG_TS, 2 | (0x100 << p))
+#define setAllPlanes() outport(REG_TS, 0x0f02)
+
+#define setWriteMode(m) outport(REG_GDC, 0x05 | m << 8)
+
+#define VID ((volatile char far *)MK_FP(0xa000, 0))
+#define WVID ((volatile int far *)MK_FP(0xa000, 0))
+
+#define flipPage(p) outport(REG_CRTC, 0x0c | (p << 8))
+
+#define setLogicalWidth(w) outport(REG_CRTC, 0x13 | (w << 8))
+
+void vid_cleanup();
+void setSplitScreen(unsigned int y);
+void unsetSplitScreen();
+void setDisplayOffset(unsigned int offset);
+void setHorizontalPan(int offset);
+