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Converted Beagle Brothers' unscrunch routine

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This commit is contained in:
Denis Molony 2017-01-11 10:47:15 +11:00
parent 218f612877
commit ee3b38094b
2 changed files with 160 additions and 77 deletions
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55
src/com/bytezone/diskbrowser/applefile/DoubleHiResImage.java
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@ -7,25 +7,46 @@ import com.bytezone.diskbrowser.utilities.HexFormatter;
public class DoubleHiResImage extends HiResImage public class DoubleHiResImage extends HiResImage
{ {
// private static final int BLACK = 0x000000;
// private static final int MAGENTA = 0xFF00FF;
// private static final int BROWN = 0x994C00;
// private static final int ORANGE = 0xFF9933;
// private static final int DARK_GREEN = 0x006600;
// private static final int GRAY = 0xA0A0A0;
// private static final int GREEN = 0x00CC00;
// private static final int YELLOW = 0xFFFF33;
// private static final int DARK_BLUE = 0x0066CC;
// private static final int PURPLE = 0xCC00CC;
// private static final int PINK = 0xFFCCE5;
// private static final int MEDIUM_BLUE = 0x3399FF;
// private static final int LIGHT_BLUE = 0x99CCFF;
// private static final int AQUA = 0x99FFFF;
// private static final int WHITE = 0xFFFFFF;
// private static int[] palette =
// private static int[] palette =
// { BLACK, MAGENTA, BROWN, ORANGE, DARK_GREEN, GRAY, GREEN, YELLOW, DARK_BLUE,
// PURPLE, GRAY, PINK, MEDIUM_BLUE, LIGHT_BLUE, AQUA, WHITE };
private static final int BLACK = 0x000000; private static final int BLACK = 0x000000;
private static final int MAGENTA = 0xFF00FF; private static final int MAGENTA = 0xDD0033;
private static final int BROWN = 0x994C00; private static final int BROWN = 0x885500;
private static final int ORANGE = 0xFF9933; private static final int ORANGE = 0xFF6600;
private static final int DARK_GREEN = 0x006600; private static final int DARK_GREEN = 0x007722;
private static final int GRAY = 0xA0A0A0; private static final int GRAY1 = 0x555555;
private static final int GREEN = 0x00CC00; private static final int GREEN = 0x11DD00;
private static final int YELLOW = 0xFFFF33; private static final int YELLOW = 0xFFFF00;
private static final int DARK_BLUE = 0x0066CC; private static final int DARK_BLUE = 0x000099;
private static final int PURPLE = 0xCC00CC; private static final int PURPLE = 0xDD22DD;
private static final int PINK = 0xFFCCE5; private static final int GRAY2 = 0xAAAAAA;
private static final int MEDIUM_BLUE = 0x3399FF; private static final int PINK = 0xFF9988;
private static final int LIGHT_BLUE = 0x99CCFF; private static final int MEDIUM_BLUE = 0x2222FF;
private static final int AQUA = 0x99FFFF; private static final int LIGHT_BLUE = 0x66AAFF;
private static final int AQUA = 0x44FF99;
private static final int WHITE = 0xFFFFFF; private static final int WHITE = 0xFFFFFF;
private static int[] palette = private static int[] palette =
{ BLACK, MAGENTA, BROWN, ORANGE, DARK_GREEN, GRAY, GREEN, YELLOW, DARK_BLUE, PURPLE, { BLACK, MAGENTA, DARK_BLUE, PURPLE, DARK_GREEN, GRAY1, MEDIUM_BLUE, LIGHT_BLUE,
GRAY, PINK, MEDIUM_BLUE, LIGHT_BLUE, AQUA, WHITE }; BROWN, ORANGE, GRAY2, PINK, GREEN, YELLOW, AQUA, WHITE };
// private static final int BLACK = 0x000000; // private static final int BLACK = 0x000000;
// private static final int MAGENTA = 0x722640; // private static final int MAGENTA = 0x722640;
@ -68,8 +89,8 @@ public class DoubleHiResImage extends HiResImage
packedBuffer = buffer; packedBuffer = buffer;
doubleScrunch = new DoubleScrunch (); doubleScrunch = new DoubleScrunch ();
doubleScrunch.unscrunch (buffer); doubleScrunch.unscrunch (buffer);
auxBuffer = doubleScrunch.auxBuffer; auxBuffer = doubleScrunch.memory[0];
this.buffer = doubleScrunch.primaryBuffer; this.buffer = doubleScrunch.memory[1];
createImage (); createImage ();
} }

182
src/com/bytezone/diskbrowser/applefile/DoubleScrunch.java
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@ -4,10 +4,10 @@ import com.bytezone.diskbrowser.utilities.CPU;
public class DoubleScrunch extends CPU public class DoubleScrunch extends CPU
{ {
private byte mem_71D0; // screen row index (X) private byte mem_71D0; // varies 1/0/1/0 ...
private byte mem_71D2; // screen column index private byte mem_71D2; // column index * 2 (00-4F) increments every C0 bytes
private byte mem_71D3; // byte to repeat private byte mem_71D3; // byte to repeat
private byte mem_71D4; // # of bytes to store private byte mem_71D4; // repetition counter
private int src; // base address of packed buffer private int src; // base address of packed buffer
private int dst; // base address of main/aux memory private int dst; // base address of main/aux memory
@ -20,21 +20,77 @@ public class DoubleScrunch extends CPU
private byte zp_E6; // hi-res page ($20 or $40) private byte zp_E6; // hi-res page ($20 or $40)
final byte[] auxBuffer = new byte[0x2000]; // final byte[] auxBuffer = new byte[0x2000];
final byte[] primaryBuffer = new byte[0x2000]; // final byte[] primaryBuffer = new byte[0x2000];
final byte[][] memory = new byte[2][0x2000];
private byte[] packedBuffer; private byte[] packedBuffer;
private final boolean debug = false; private final boolean debug = false;
private int count;
private final int[] rows = new int[192];
private int ptr;
private int bank;
private int outPtr;
private int column;
public DoubleScrunch () public DoubleScrunch ()
{ {
setDebug (debug); int row = 0;
for (int a = 0x400; a >= 0; a -= 0x400) // reversed!
for (int b = 0; b < 0x78; b += 0x28)
for (int c = 0; c < 0x400; c += 0x80)
for (int d = 0; d < 0x2000; d += 0x800)
rows[row++] = a + b + c + d;
} }
void unscrunch (byte[] buffer) void unscrunch (byte[] buffer)
{ {
packedBuffer = buffer; packedBuffer = buffer;
while (true)
{
int rep = packedBuffer[ptr++] & 0xFF;
if ((rep & 0x80) == 0) // repeat same byte
{
byte val = packedBuffer[ptr++];
while (rep-- > 0)
if (move (val))
return;
}
else // copy bytes
{
rep &= 0x7F;
while (rep-- > 0)
if (move (packedBuffer[ptr++]))
return;
}
}
}
private boolean move (byte val)
{
memory[bank][rows[outPtr++] + column] = val;
if (outPtr % 192 == 0) // screen column for this bank is finished
{
outPtr = 0;
if (++bank > 1) // both banks are finished
{
bank = 0;
if (++column >= 40) // whole screen is finished
return true;
}
}
return false;
}
// no longer needed, it was used to decipher the Beagle Bros routine
void oldUnscrunch (byte[] buffer)
{
packedBuffer = buffer;
src = 0x4000; // packed picture data src = 0x4000; // packed picture data
dst = 0x2000; // main/aux picture data dst = 0x2000; // main/aux picture data
@ -48,9 +104,10 @@ public class DoubleScrunch extends CPU
zp_27 = sta (); zp_27 = sta ();
ldx ((byte) 0x01); ldx ((byte) 0x01);
mem_71D0 = stx (); mem_71D0 = stx (); // X and 71D0 are both set to 1
ldy ((byte) 0x00); ldy ((byte) 0x00);
mem_71D2 = sty (); // line offset = 0 mem_71D2 = sty (); // column index = 0
zp_26 = sty (); // output index = 0 zp_26 = sty (); // output index = 0
while (true) while (true)
@ -60,27 +117,27 @@ public class DoubleScrunch extends CPU
php (); php ();
// prepare address to get next transfer byte (done in copy/repeat routine) // increment address to get next transfer byte (done in copy/repeat routine)
zp_00 = inc (zp_00); zp_00 = inc (zp_00);
if (zero) if (zero)
zp_01 = inc (zp_01); zp_01 = inc (zp_01);
and ((byte) 0x7F); // remove copy/repeat flag and ((byte) 0x7F); // remove copy/repeat flag
mem_71D4 = sta (); // save repetition counter mem_71D4 = sta (); // save repetition counter (RC)
plp (); plp ();
// copy or repeat RC bytes
if (negative ? copyBytes () : repeatBytes ()) if (negative ? copyBytes () : repeatBytes ())
break; break;
// prepare address to get next repetition counter // increment address to get next repetition counter
zp_00 = inc (zp_00); zp_00 = inc (zp_00);
if (zero) if (zero)
zp_01 = inc (zp_01); zp_01 = inc (zp_01);
} }
} }
// $7144 // copy a single byte RC times
// copy a single byte $71D4 times
private boolean repeatBytes () private boolean repeatBytes ()
{ {
// get the byte to store // get the byte to store
@ -93,7 +150,7 @@ public class DoubleScrunch extends CPU
storeByte (); // store it and decrement repetition counter storeByte (); // store it and decrement repetition counter
calculateScreenLine (); calculateScreenColumn ();
if (carry) if (carry)
return true; // completely finished return true; // completely finished
@ -105,8 +162,7 @@ public class DoubleScrunch extends CPU
} }
} }
// $717D // copy the next RC bytes
// copy the next $71D4 bytes
private boolean copyBytes () private boolean copyBytes ()
{ {
while (true) while (true)
@ -117,7 +173,7 @@ public class DoubleScrunch extends CPU
storeByte (); // store it and decrement repetition counter storeByte (); // store it and decrement repetition counter
calculateScreenLine (); calculateScreenColumn ();
if (carry) if (carry)
return true; // completely finished return true; // completely finished
@ -134,33 +190,72 @@ public class DoubleScrunch extends CPU
} }
} }
// store the byte currently in Acc
private void storeByte () private void storeByte ()
{ {
mem_71D4 = dec (mem_71D4); // decrement counter mem_71D4 = dec (mem_71D4); // decrement repetition counter (RC)
ldy (mem_71D2); // line offset ldy (mem_71D2); // column index (times 2)
php (); php ();
sei (); // sei ();
pha (); pha ();
tya (); tya ();
lsr (); // divide by 2 ? lsr (); // divide by 2, put odd/even value in carry (bank)
tay (); tay ();
pla (); pla ();
// switch page
byte[] target = carry ? primaryBuffer : auxBuffer;
// store byte // store byte
sta (target, indirectY (dst, zp_26, zp_27)); if (false)
System.out.printf (
"%04X D0: %02X D2: %02X xReg: %02X bank: %d %02X -> %02X %02X + %02X%n",
count++, mem_71D0, mem_71D2, stx (), carry ? 0 : 1, sta (), zp_27, zp_26,
sty ());
sta (memory[carry ? 1 : 0], indirectY (dst, zp_26, zp_27));
plp (); plp ();
} }
// $70E8 // $71B1
private void calculateScreenColumn ()
{
// increment X by 2 - X varies 01, 03, 05 -> BF, then 00, 02, 04 -> BE
inx ();
inx ();
cpx ((byte) 0xC0); // # screen lines
if (!carry) // X < $C0
return; // continue current phase
// carry is now set, current phase is finished
// change phase
mem_71D0 = dec (mem_71D0); // either 1 -> 0, or 0 -> -1
if (!negative) //
{
assert mem_71D0 == 0;
// start second phase of screen column
ldx ((byte) 0x00); // start X at 0
// mem_71D0 = stx (); // phase 2 (not necessary, was already 0)
clc ();
return; // start phase 2
}
// start a new screen column (and start phase 1)
mem_71D2 = inc (mem_71D2); // increment column index
ldy (mem_71D2);
cpy ((byte) 0x50); // test for end of line (2 x 0x28)
if (carry) // Y >= $50
return; // program finished
ldx ((byte) 0x01); // start X at 1
mem_71D0 = stx (); // start phase 1
clc ();
}
// set locations $26-27 (address of first location in screen line)
private void calculateNextScreenAddress () private void calculateNextScreenAddress ()
{ {
txa (); txa ();
and ((byte) 0xC0); // clear bits 5-0 and ((byte) 0xC0); // get 2 hi bits - 00/40/80
zp_26 = sta (); zp_26 = sta ();
lsr (); lsr ();
@ -188,39 +283,6 @@ public class DoubleScrunch extends CPU
zp_27 = sta (); zp_27 = sta ();
} }
// $71B1
private void calculateScreenLine ()
{
inx ();
inx ();
cpx ((byte) 0xC0);
if (!carry) // BCC $71CE
{
clc ();
return;
}
mem_71D0 = dec (mem_71D0);
if (!negative) // BPL $71C9
{
ldx ((byte) 0);
mem_71D0 = stx ();
clc ();
return;
}
mem_71D2 = inc (mem_71D2); // increment line offset
ldy (mem_71D2);
cpy ((byte) 0x50);
if (carry) // BCS $71CF
return; // program finished
ldx ((byte) 0x01);
// bit ((byte) 0xA2); // ??
mem_71D0 = stx ();
clc ();
}
@Override @Override
protected String debugString () protected String debugString ()
{ {