mirror of
https://github.com/holub/mame
synced 2025-10-04 16:34:53 +03:00
Rewrote the Gaelco video ram encryption, which finally makes sense.
The key observation was that when decryptiong the second word, both encrypted and decrypted bits of the first word are used. Many thanks to Javier Valero for the detailed information that made this possible.
This commit is contained in:
Nicola Salmoria
parent
c5511b65fb
commit
384388cf6f
2
.gitattributes
vendored
2
.gitattributes
vendored
@ -2195,6 +2195,7 @@ src/mame/includes/firetrk.h svneol=native#text/plain
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src/mame/includes/foodf.h svneol=native#text/plain
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src/mame/includes/fromance.h svneol=native#text/plain
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src/mame/includes/gaelco3d.h svneol=native#text/plain
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src/mame/includes/gaelcrpt.h svneol=native#text/plain
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src/mame/includes/galaga.h svneol=native#text/plain
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src/mame/includes/galaxian.h svneol=native#text/plain
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src/mame/includes/galaxold.h svneol=native#text/plain
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@ -2450,6 +2451,7 @@ src/mame/machine/fd1094.h svneol=native#text/plain
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src/mame/machine/fddebug.c svneol=native#text/plain
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src/mame/machine/flstory.c svneol=native#text/plain
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src/mame/machine/gaelco2.c svneol=native#text/plain
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src/mame/machine/gaelcrpt.c svneol=native#text/plain
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src/mame/machine/galaxold.c svneol=native#text/plain
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src/mame/machine/gaplus.c svneol=native#text/plain
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src/mame/machine/harddriv.c svneol=native#text/plain
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@ -11,6 +11,7 @@
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#include "cpu/m68000/m68000.h"
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#include "sound/okim6295.h"
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#include "sound/3812intf.h"
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#include "gaelcrpt.h"
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extern UINT16 *gaelco_vregs;
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extern UINT16 *gaelco_videoram;
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@ -655,395 +656,12 @@ static INPUT_PORTS_START( squash )
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INPUT_PORTS_END
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static int lastpc=0;
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static int lastword=0;
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static int lastoffset=0;
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#define CARRY(bit) {carry[bit] = (dst[bit]>>1); dst[bit]&=1;}
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static int decrypt(int game, int key, int high_word, int low_word)
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{
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static const int swaps[4][16] =
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{
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{ 5,7,9,12,2,14,13,15,3,6,8,11,4,10,0,1 },
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{ 11,2,5,14,8,13,10,4,7,12,0,6,15,9,1,3 },
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{ 7,0,11,12,13,1,6,8,9,5,4,10,14,3,15,2 },
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{ 3,0,2,1,10,15,8,6,9,13,11,7,12,5,4,14 },
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};
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int dst[16],carry[16];
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int i;
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const int *s = swaps[key & 3];
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int flag1 = BIT(high_word, 9) ^ BIT(high_word, 12) ^ 1;
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int flag2 = game ? BIT(high_word, 10) : (BIT(high_word, 9) ^ BIT(high_word, 10));
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if (game)
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flag2 = -flag2;
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for (i = 0; i < 16; i++)
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dst[i] = BIT(low_word, s[15-i]);
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for (i = 0; i < 16; i++)
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carry[i] = 0;
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if (flag1 && flag2)
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{
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dst[13] += game ? 0 : 1; CARRY(13)
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dst[2] += carry[13]; CARRY(2)
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dst[15] += 1 + carry[2]; CARRY(15)
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dst[4] += - carry[15]; CARRY(4)
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dst[6] += 1 - carry[4]; CARRY(6)
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dst[7] += carry[6]; CARRY(7)
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dst[14] += game ? BIT(low_word, 9) : BIT(~low_word, 9); CARRY(14)
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dst[12] += game ? BIT(low_word, 9) : BIT(~low_word, 9); CARRY(12)
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dst[9] += dst[15] + carry[14]; CARRY(9)
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dst[10] += dst[15] + carry[12]; CARRY(10)
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dst[5] += BIT(~low_word, 5) + carry[9]; CARRY(5)
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dst[1] += BIT(~low_word, 5) + carry[10]; CARRY(1)
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dst[3] += 1 + dst[7] - carry[5]; CARRY(3)
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dst[11] += 1 + dst[7] - carry[1]; CARRY(11)
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dst[8] += 1 + dst[6] + carry[3];
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dst[0] += 1 + dst[6] + carry[11];
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}
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else
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{
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dst[13] += BIT(key,2); CARRY(13)
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dst[2] += BIT(key,3) + carry[13]; CARRY(2)
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dst[15] += BIT(key,4) + carry[2]; CARRY(15)
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dst[4] += BIT(key,5) - carry[15]; CARRY(4)
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dst[6] += BIT(key,6) - carry[4]; CARRY(6)
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dst[7] += BIT(key,7) + carry[6]; CARRY(7)
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dst[14] += BIT(key,8); CARRY(14)
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dst[12] += BIT(key,8); CARRY(12)
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dst[9] += BIT(key,9) + carry[14]; CARRY(9)
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dst[10] += BIT(key,9) + carry[12]; CARRY(10)
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dst[5] += BIT(key,10) + carry[9]; CARRY(5)
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dst[1] += BIT(key,10) + carry[10]; CARRY(1)
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dst[3] += BIT(key,11) - flag1*dst[2] - flag2*dst[13] - carry[5]; CARRY(3)
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dst[11] += BIT(key,11) - flag1*dst[2] - flag2*dst[13] - carry[1]; CARRY(11)
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dst[8] += BIT(key,12) + carry[3];
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dst[0] += BIT(key,12) + carry[11];
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}
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low_word = 0;
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for (i = 0; i < 16; i++)
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low_word |= (dst[i] & 1) << i;
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switch (game)
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{
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default:
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case 0:
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return low_word ^ 0xf626;
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case 1:
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return low_word ^ 0x8626;
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}
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}
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static int get_key(int game, int high_word)
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{
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int src[16],dst[16],carry[16];
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int i;
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int flag1 = BIT(high_word, 9) ^ BIT(high_word, 12) ^ 1;
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int flag2 = game ? BIT(high_word, 10) : (BIT(high_word, 9) ^ BIT(high_word, 10));
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int temp;
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for (i = 0; i < 16; i++)
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{
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src[i] = BIT(high_word,i);
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dst[i] = 0;
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carry[i] = 0;
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}
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dst[10] = flag1 ? (src[7] ^ src[12]) : src[5];
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dst[8] = flag2 ? (1 ^ src[6]) : 0;
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dst[5] = (flag1 ^ flag2) ? (1 ^ src[3]) : (1 ^ (src[5] | src[10]) ^ src[11]);
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if (flag1 == 0 && flag2 == 0)
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dst[6] = dst[5] + src[2]; CARRY(6);
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if (flag1 == 1 && flag2 == 0)
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dst[6] = dst[5] + src[8]; CARRY(6);
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if (flag1 == 0 && flag2 == 1)
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dst[6] = dst[5] + src[13]; CARRY(6);
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if (game == 0)
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{
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if (flag1 == 0 && flag2 == 0)
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{
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dst[7] = src[3];
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dst[7] ^= (1^src[12]) & (1^src[5]) & src[0];
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dst[7] ^= src[14] & src[5] & src[0];
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dst[7] ^= ((1^src[12]) ^ src[11]) & (1^src[2]);
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dst[7] ^= src[11] & src[6];
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dst[7] ^= src[12] & src[5] & (1^src[2]);
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dst[7] ^= src[12] & (1^src[11]) & (1^src[5]) & (1^src[6]);
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}
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if (flag1 == 1 && flag2 == 0)
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dst[7] = 1 ^ src[15] ^ carry[6] ^ (src[8] & (1^src[3]));
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if (flag1 == 0 && flag2 == 1)
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dst[7] = 1 ^ src[14] ^ carry[6];
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}
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else
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{
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if (flag1 == 0 && flag2 == 0)
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{
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dst[7] = src[3];
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dst[7] ^= ((1^src[14]) & (1^src[5])) & src[0];
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dst[7] ^= src[6] ^ (src[14] & (1^src[11]));
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dst[7] ^= src[5] & (1^src[6]^src[14]) & (1^src[11]);
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dst[7] ^= (src[11] ^ src[5]) & src[2];
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dst[7] ^= src[14] & (src[11] & (1^src[5]));
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}
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if (flag1 == 1 && flag2 == 0)
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dst[7] = 1 ^ src[15] ^ carry[6] ^ (src[8] & (1^src[3]));
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if (flag1 == 0 && flag2 == 1)
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dst[7] = 1 ^ src[14] ^ carry[6];
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}
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if (game == 0)
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{
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temp = (src[5] | (src[9] & src[10]));
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}
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else
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{
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temp = src[5];
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}
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dst[0] = src[3] ^ (src[6] | ((1^src[11]) & temp));
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if (game == 0)
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{
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dst[1] = src[15]
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^ (temp & src[4] & src[3])
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^ (temp & (src[11] ? (src[6] | src[4]) : (1^src[6])))
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^ (src[13] ?
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(src[6] & (1^temp) & src[4]) ^ ((1^temp) & (1^src[4]) & src[3])
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^ (src[7] & src[8] & (1^src[9]) & temp & (src[6] ^ src[4] ^ src[3]))
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^ ((1^src[11]) & (1^src[6]) & temp & src[7] & src[8] & (1^src[9]))
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^ (src[10] & src[9] & src[8] & (1 ^ src[4] ^ src[3]))
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^ (src[11] & src[10] & src[9] & src[8] & (1^src[6]))
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:
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(src[6] & (1^temp) & (1 ^ src[4] ^ src[8]))
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^ ((1^temp) & (src[4] ? ((1^src[3]) & (1^src[8])) : (src[3] & src[8])))
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^ (src[7] & (1^src[8]) & (1^src[9]) & (1^temp) & (src[6] ^ src[4] ^ src[3]))
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^ (src[10] & src[9] & src[8] & (1 ^ src[4] ^ src[3]) & (1^src[5]))
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^ (src[11] & src[10] & src[9] & src[8] & (1^src[6]) & (1^src[5]))
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)
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;
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}
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else
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{
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dst[1] = src[15]
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^ (temp & src[4] & src[3])
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^ (temp & (src[11] ? (src[6] | src[4]) : (1^src[6])))
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^ (src[13] ?
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(src[6] & (1^temp) & src[4]) ^ ((1^temp) & (1^src[4]) & src[3])
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^ (src[7] & src[8] & src[9] & temp & (src[6] ^ src[4] ^ src[3]))
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^ ((1^src[11]) & (1^src[6]) & temp & src[7] & src[8] & src[9])
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:
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(src[6] & (1^temp) & (1 ^ src[4] ^ src[8]))
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^ ((1^temp) & (src[4] ? ((1^src[3]) & (1^src[8])) : (src[3] & src[8])))
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^ (src[7] & (1^src[8]) & src[9] & (1^temp) & (src[6] ^ src[4] ^ src[3]))
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);
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}
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if (game == 0)
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{
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if (flag1 == 0 && flag2 == 0)
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dst[11] = src[0] ^ (src[5] ? src[14] : src[10]);
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if (flag1 == 1 && flag2 == 0)
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dst[11] = 0;
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if (flag1 == 0 && flag2 == 1)
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dst[11] = 0;
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}
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else
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{
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if (flag1 == 0 && flag2 == 0)
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dst[11] = src[0] ^ (src[5] ? src[10] : (1^src[14])); // note src[10] == 0
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if (flag1 == 1 && flag2 == 0)
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dst[11] = 0;
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if (flag1 == 0 && flag2 == 1)
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dst[11] = 1;
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}
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dst[12] = dst[11];
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if (flag1 == 0 && flag2 == 0)
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dst[12] ^= src[10];
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if (flag1 == 1 && flag2 == 0)
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dst[12] ^= 0;
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if (flag1 == 0 && flag2 == 1)
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dst[12] ^= src[3] ^ (src[11] ? src[6] : (src[6] | src[5]));
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if (game == 0)
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{
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if (flag1 == 0 && flag2 == 0)
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dst[4] = src[6];
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if (flag1 == 1 && flag2 == 0)
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dst[4] = src[0] ^ (src[14] ? (1^src[12]) : src[5]);
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if (flag1 == 0 && flag2 == 1)
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dst[4] = src[7];
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}
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else
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{
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if (flag1 == 0 && flag2 == 0)
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dst[4] = src[6];
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if (flag1 == 1 && flag2 == 0)
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dst[4] = src[0] ^ (src[14] ? ((1^src[12]) | (1^src[5])) : (src[12] | src[5]));
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if (flag1 == 0 && flag2 == 1)
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dst[4] = src[7];
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}
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if (game == 0)
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{
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if (flag1 == 0 && flag2 == 0)
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dst[9] = src[5] ^ (src[12] & (1^src[7])) ^ src[13];
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if (flag1 == 1 && flag2 == 0)
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dst[9] = 1 ^ src[4];
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if (flag1 == 0 && flag2 == 1)
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dst[9] = src[6] ^ ((1^src[11]) & src[5]);
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}
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else
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{
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if (flag1 == 0 && flag2 == 0)
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dst[9] = 1 ^ src[5] ^ ((1^src[12]) & src[7]) ^ src[13];
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if (flag1 == 1 && flag2 == 0)
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dst[9] = 1 ^ src[4];
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if (flag1 == 0 && flag2 == 1)
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dst[9] = src[6] ^ ((1^src[11]) & src[5]);
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}
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if (game == 0)
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{
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if (flag1 == 0 && flag2 == 0)
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dst[3] = src[12];
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if (flag1 == 1 && flag2 == 0)
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dst[3] = src[0] ^ (src[14] ? src[12] : (1^src[5]));
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if (flag1 == 0 && flag2 == 1)
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dst[3] = src[8] ^ ((1^src[13]) & (1^src[12]) & (1^src[5])) ^ (src[12] & (src[13] ? (src[7] & src[5]) : ((1^src[7]) & (1^src[5]))));
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}
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else
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{
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if (flag1 == 0 && flag2 == 0)
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dst[3] = src[12];
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if (flag1 == 1 && flag2 == 0)
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dst[3] = src[0] ^ (src[14] ? (src[5] & src[12]) : ((1^src[5]) & (1^src[12])));
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if (flag1 == 0 && flag2 == 1)
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dst[3] = src[8] ^ ((1^src[13]) & (src[12]) & (1^src[5])) ^ ((1^src[12]) & (src[13] ? (src[7] & src[5]) : ((1^src[7]) & (1^src[5]))));
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}
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if (game == 0)
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{
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if (flag1 == 0 && flag2 == 0)
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dst[2] = src[0];
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if (flag1 == 1 && flag2 == 0)
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dst[2] = src[1]
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^ (src[3] & (1^src[2]))
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^ ((1^src[11]) & src[6] & src[5])
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^ ((1^src[12]) & (1^src[5]) & src[0] & (1^src[14]) & (src[6] ^ src[2] ^ src[3]))
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^ (src[12] & (1^src[6]) & (1^src[5]) & src[3])
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^ (src[2] & (1^src[5]) & (1^src[6]) & (1^src[12]))
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^ (src[2] & src[5] & (1^src[6]) & src[11])
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^ ((1 ^ src[2] ^ src[3]) & (1^src[5]) & src[6] & src[12])
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^ (src[14] & (1^src[12]) & (src[2] ^ src[3] ^ src[6]) & (1^src[5]))
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^ (src[14] & src[12] & src[5] & (1 ^ src[3] ^ src[2] ^ src[11]) & src[0])
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^ (src[14] & src[12] & src[11] & src[6] & src[5] & src[0])
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^ (src[12] & (1^src[5]) & src[3])
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^ (src[12] & (1^src[5]) & src[0] & (1 ^ src[3] ^ src[2] ^ (src[11] & (1^src[6]))))
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^ (src[12] & (1^src[5]) & (1^src[11]) & src[6] & src[2])
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^ (src[12] & (1^src[5]) & src[11] & (src[6] ^ src[2]))
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;
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if (flag1 == 0 && flag2 == 1)
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dst[2] = src[5];
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}
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else
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{
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if (flag1 == 0 && flag2 == 0)
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dst[2] = src[0];
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if (flag1 == 1 && flag2 == 0)
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dst[2] = src[1]
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^ (src[3] & (1^src[2]))
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^ ((1^src[11]) & src[6] & src[5])
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^ ((1^src[12]) & (1^src[5]) & src[0] & (1^src[14]) & (src[6] ^ src[2] ^ src[3]))
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^ (src[12] & (1^src[6]) & (1^src[5]) & src[3])
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^ (src[2] & (1^src[5]) & (1^src[6]) & (1^src[12]))
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^ (src[2] & src[5] & (1^src[6]) & src[11])
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^ ((1 ^ src[2] ^ src[3]) & (1^src[5]) & src[6] & src[12])
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^ (src[14] & (1^src[12]) & (src[2] ^ src[3] ^ src[6]) & (1^src[5]))
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^ (src[14] & src[12] & src[5] & (1 ^ src[3] ^ src[2] ^ src[11]) & src[0])
|
||||
^ (src[14] & src[12] & src[11] & src[6] & src[5] & src[0]);
|
||||
if (flag1 == 0 && flag2 == 1)
|
||||
dst[2] = src[5];
|
||||
}
|
||||
|
||||
if (game == 0)
|
||||
{
|
||||
dst[10] ^= 1;
|
||||
dst[4] ^= 1;
|
||||
dst[2] ^= 1;
|
||||
}
|
||||
else
|
||||
{
|
||||
dst[10] ^= 1;
|
||||
dst[8] ^= 1;
|
||||
dst[4] ^= 1;
|
||||
}
|
||||
|
||||
|
||||
high_word = 0;
|
||||
for (i = 0; i < 16; i++)
|
||||
high_word |= (dst[i] & 1) << i;
|
||||
|
||||
if (flag1 == 1 && flag2 == 1)
|
||||
high_word &= 3;
|
||||
|
||||
return high_word;
|
||||
}
|
||||
|
||||
|
||||
static UINT16 squash_encrypt(int offset, int data, int game)
|
||||
{
|
||||
int thispc = activecpu_get_pc();
|
||||
int savedata = data;
|
||||
|
||||
/* check if 2nd half of 32 bit */
|
||||
if(lastpc == thispc && offset == lastoffset + 1)
|
||||
{
|
||||
lastpc = 0;
|
||||
data = decrypt(game, get_key(game, lastword), lastword, data);
|
||||
}
|
||||
else
|
||||
{
|
||||
/* code as 1st word */
|
||||
lastword = data;
|
||||
lastpc = thispc;
|
||||
lastoffset = offset;
|
||||
|
||||
/* high word returned */
|
||||
data = decrypt(game, 0x0000, 0x0400, lastword);
|
||||
|
||||
logerror("%8x : data1 = %4x > %4x @ %8x\n",activecpu_get_pc(),savedata,data,lastoffset);
|
||||
}
|
||||
return data;
|
||||
}
|
||||
|
||||
static WRITE16_HANDLER( gaelco_vram_encrypted_w )
|
||||
{
|
||||
// mame_printf_debug("gaelco_vram_encrypted_w!!\n");
|
||||
|
||||
data = squash_encrypt(offset,data,0);
|
||||
data = gaelco_decrypt(offset, data, 0x0f, 0x4228);
|
||||
COMBINE_DATA(&gaelco_videoram[offset]);
|
||||
|
||||
tilemap_mark_tile_dirty(gaelco_tilemap[offset >> 11],((offset << 1) & 0x0fff) >> 2);
|
||||
@ -1054,15 +672,15 @@ static WRITE16_HANDLER(gaelco_encrypted_w)
|
||||
{
|
||||
// mame_printf_debug("gaelco_encrypted_w!!\n");
|
||||
|
||||
data = squash_encrypt(offset,data,0);
|
||||
COMBINE_DATA(&gaelco_screen[offset]);
|
||||
data = gaelco_decrypt(offset, data, 0x0f, 0x4228);
|
||||
COMBINE_DATA(&gaelco_screen[offset]);
|
||||
}
|
||||
|
||||
static WRITE16_HANDLER( thoop_vram_encrypted_w )
|
||||
{
|
||||
// mame_printf_debug("gaelco_vram_encrypted_w!!\n");
|
||||
|
||||
data = squash_encrypt(offset,data,1);
|
||||
data = gaelco_decrypt(offset, data, 0x0e, 0x4228);
|
||||
COMBINE_DATA(&gaelco_videoram[offset]);
|
||||
|
||||
tilemap_mark_tile_dirty(gaelco_tilemap[offset >> 11],((offset << 1) & 0x0fff) >> 2);
|
||||
@ -1072,8 +690,8 @@ static WRITE16_HANDLER(thoop_encrypted_w)
|
||||
{
|
||||
// mame_printf_debug("gaelco_encrypted_w!!\n");
|
||||
|
||||
data = squash_encrypt(offset,data,1);
|
||||
COMBINE_DATA(&gaelco_screen[offset]);
|
||||
data = gaelco_decrypt(offset, data, 0x0e, 0x4228);
|
||||
COMBINE_DATA(&gaelco_screen[offset]);
|
||||
}
|
||||
|
||||
|
||||
@ -1336,5 +954,5 @@ ROM_END
|
||||
GAME( 1991, bigkarnk, 0, bigkarnk, bigkarnk, 0, ROT0, "Gaelco", "Big Karnak", 0 )
|
||||
GAME( 1995, biomtoy, 0, maniacsq, biomtoy, 0, ROT0, "Gaelco", "Biomechanical Toy (unprotected)", 0 )
|
||||
GAME( 1996, maniacsp, maniacsq, maniacsq, maniacsq, 0, ROT0, "Gaelco", "Maniac Square (prototype)", 0 )
|
||||
GAME( 1992, squash, 0, squash, squash, 0, ROT0, "Gaelco", "Squash (Ver. 1.0)", 0 )
|
||||
GAME( 1992, thoop, 0, thoop, thoop, 0, ROT0, "Gaelco", "Thunder Hoop (Ver. 1)", 0 )
|
||||
GAME( 1992, squash, 0, squash, squash, 0, ROT0, "Gaelco", "Squash (Ver. 1.0)", 0 )
|
||||
GAME( 1992, thoop, 0, thoop, thoop, 0, ROT0, "Gaelco", "Thunder Hoop (Ver. 1)", 0 )
|
||||
|
||||
2
src/mame/includes/gaelcrpt.h
Normal file
2
src/mame/includes/gaelcrpt.h
Normal file
@ -0,0 +1,2 @@
|
||||
UINT16 gaelco_decrypt(int offset, int data, int param1, int param2);
|
||||
|
||||
151
src/mame/machine/gaelcrpt.c
Normal file
151
src/mame/machine/gaelcrpt.c
Normal file
@ -0,0 +1,151 @@
|
||||
/*
|
||||
|
||||
Gaelco video RAM encryption
|
||||
|
||||
Thanks to Javier Valero for information on the algorithm.
|
||||
|
||||
*/
|
||||
|
||||
#include "driver.h"
|
||||
|
||||
static int decrypt(int const param1, int const param2, int const enc_prev_word, int const dec_prev_word, int const enc_word)
|
||||
{
|
||||
int const swap = (BIT(dec_prev_word, 8) << 1) | BIT(dec_prev_word, 7);
|
||||
int const type = (BIT(dec_prev_word,12) << 1) | BIT(dec_prev_word, 2);
|
||||
int res=0;
|
||||
int k=0;
|
||||
|
||||
switch (swap)
|
||||
{
|
||||
case 0: res = BITSWAP16(enc_word, 1, 2, 0,14,12,15, 4, 8,13, 7, 3, 6,11, 5,10, 9); break;
|
||||
case 1: res = BITSWAP16(enc_word, 14,10, 4,15, 1, 6,12,11, 8, 0, 9,13, 7, 3, 5, 2); break;
|
||||
case 2: res = BITSWAP16(enc_word, 2,13,15, 1,12, 8,14, 4, 6, 0, 9, 5,10, 7, 3,11); break;
|
||||
case 3: res = BITSWAP16(enc_word, 3, 8, 1,13,14, 4,15, 0,10, 2, 7,12, 6,11, 9, 5); break;
|
||||
}
|
||||
|
||||
res ^= param2;
|
||||
|
||||
switch (type)
|
||||
{
|
||||
case 0:
|
||||
k = (0 << 0) |
|
||||
(1 << 1) |
|
||||
(0 << 2) |
|
||||
(1 << 3) |
|
||||
(1 << 4) |
|
||||
(1 << 5);
|
||||
break;
|
||||
|
||||
case 1:
|
||||
k = (BIT(dec_prev_word, 0) << 0) |
|
||||
(BIT(dec_prev_word, 1) << 1) |
|
||||
(BIT(dec_prev_word, 1) << 2) |
|
||||
(BIT(enc_prev_word, 3) << 3) |
|
||||
(BIT(enc_prev_word, 8) << 4) |
|
||||
(BIT(enc_prev_word,15) << 5);
|
||||
break;
|
||||
|
||||
case 2:
|
||||
k = (BIT(enc_prev_word, 5) << 0) |
|
||||
(BIT(dec_prev_word, 5) << 1) |
|
||||
(BIT(enc_prev_word, 7) << 2) |
|
||||
(BIT(enc_prev_word, 3) << 3) |
|
||||
(BIT(enc_prev_word,13) << 4) |
|
||||
(BIT(enc_prev_word,14) << 5);
|
||||
break;
|
||||
|
||||
case 3:
|
||||
k = (BIT(enc_prev_word, 0) << 0) |
|
||||
(BIT(enc_prev_word, 9) << 1) |
|
||||
(BIT(enc_prev_word, 6) << 2) |
|
||||
(BIT(dec_prev_word, 4) << 3) |
|
||||
(BIT(enc_prev_word, 2) << 4) |
|
||||
(BIT(dec_prev_word,11) << 5);
|
||||
break;
|
||||
}
|
||||
|
||||
k ^= param1;
|
||||
|
||||
res = (res & 0xffc0) | ((res + k) & 0x003f);
|
||||
|
||||
res ^= param1;
|
||||
|
||||
switch (type)
|
||||
{
|
||||
case 0:
|
||||
k = (BIT(enc_word, 9) << 0) |
|
||||
(BIT(res,2) << 1) |
|
||||
(BIT(enc_word, 5) << 2) |
|
||||
(BIT(res,5) << 3) |
|
||||
(BIT(res,4) << 4);
|
||||
break;
|
||||
|
||||
case 1:
|
||||
k = (BIT(dec_prev_word, 2) << 0) | // always 1
|
||||
(BIT(enc_prev_word, 4) << 1) |
|
||||
(BIT(dec_prev_word,14) << 2) |
|
||||
(BIT(res, 1) << 3) |
|
||||
(BIT(dec_prev_word,12) << 4); // always 0
|
||||
break;
|
||||
|
||||
case 2:
|
||||
k = (BIT(enc_prev_word, 6) << 0) |
|
||||
(BIT(dec_prev_word, 6) << 1) |
|
||||
(BIT(dec_prev_word,15) << 2) |
|
||||
(BIT(res,0) << 3) |
|
||||
(BIT(dec_prev_word, 7) << 4);
|
||||
break;
|
||||
|
||||
case 3:
|
||||
k = (BIT(dec_prev_word, 2) << 0) | // always 1
|
||||
(BIT(dec_prev_word, 9) << 1) |
|
||||
(BIT(enc_prev_word, 5) << 2) |
|
||||
(BIT(dec_prev_word, 1) << 3) |
|
||||
(BIT(enc_prev_word,10) << 4);
|
||||
|
||||
break;
|
||||
}
|
||||
|
||||
k ^= param1;
|
||||
|
||||
res = (res & 0x003f) |
|
||||
((res + (k << 6)) & 0x07c0) |
|
||||
((res + (k << 11)) & 0xf800);
|
||||
|
||||
res ^= (param1 << 6) | (param1 << 11);
|
||||
|
||||
return BITSWAP16(res, 2,6,0,11,14,12,7,10,5,4,8,3,9,1,13,15);
|
||||
}
|
||||
|
||||
|
||||
|
||||
UINT16 gaelco_decrypt(int offset, int data, int param1, int param2)
|
||||
{
|
||||
static int lastpc, lastoffset, lastencword, lastdecword;
|
||||
|
||||
int thispc = activecpu_get_pc();
|
||||
// int savedata = data;
|
||||
|
||||
/* check if 2nd half of 32 bit */
|
||||
if(lastpc == thispc && offset == lastoffset + 1)
|
||||
{
|
||||
lastpc = 0;
|
||||
data = decrypt(param1, param2, lastencword, lastdecword, data);
|
||||
}
|
||||
else
|
||||
{
|
||||
/* code as 1st word */
|
||||
|
||||
lastpc = thispc;
|
||||
lastoffset = offset;
|
||||
lastencword = data;
|
||||
|
||||
/* high word returned */
|
||||
data = decrypt(param1, param2, 0, 0, data);
|
||||
|
||||
lastdecword = data;
|
||||
|
||||
// logerror("%8x : data1 = %4x > %4x @ %8x\n",activecpu_get_pc(),savedata,data,lastoffset);
|
||||
}
|
||||
return data;
|
||||
}
|
||||
@ -710,7 +710,7 @@ $(MAMEOBJ)/fuuki.a: \
|
||||
$(DRIVERS)/fuukifg3.o $(VIDEO)/fuukifg3.o \
|
||||
|
||||
$(MAMEOBJ)/gaelco.a: \
|
||||
$(DRIVERS)/gaelco.o $(VIDEO)/gaelco.o \
|
||||
$(DRIVERS)/gaelco.o $(VIDEO)/gaelco.o $(MACHINE)/gaelcrpt.o \
|
||||
$(DRIVERS)/gaelco2.o $(MACHINE)/gaelco2.o $(VIDEO)/gaelco2.o \
|
||||
$(DRIVERS)/gaelco3d.o $(VIDEO)/gaelco3d.o \
|
||||
$(DRIVERS)/glass.o $(VIDEO)/glass.o \
|
||||
|
||||
Loading…
Reference in New Issue
Block a user