// license:BSD-3-Clause // copyright-holders:smf, Mike Balfour, David Widel #include "emu.h" #include "includes/pacman.h" uint8_t epospm_state::epos_decryption_w(offs_t offset) { if (offset & 0x01) { m_counter = (m_counter - 1) & 0x0F; } else { m_counter = (m_counter + 1) & 0x0F; } switch (m_counter) { case 0x08: case 0x09: case 0x0A: case 0x0B: membank("bank1")->set_entry(m_counter & 3); break; default: logerror("Invalid counter = %02X\n", m_counter); break; } return 0; } static void epos_decrypt_rom(uint8_t *ROM, uint8_t invert, int offset, int *bs) { for (int mem = 0; mem < 0x4000; mem++ ) { ROM[mem + offset] = bitswap<8>(ROM[mem] ^ invert, bs[0], bs[1], bs[2], bs[3], bs[4], bs[5], bs[6], bs[7]); } } /* The Glob protection description: The Glob is designed to run on modified Pacman hardware. It contains two graphics ROMs at 5E and 5F, but contains code ROMs on a daughterboard similar in concept to Ms. Pacman. However, these code ROMs are decrypted through additional circuitry. The daughterboard was encased in epoxy. Here's a description of the protection as best as I can give it. 1) The decrypted D0 bit fed to the CPU is simply an inversion of the D5 bit from the code ROMs. 2) The decrypted D1 bit fed to the CPU is simply an inversion of the D2 bit from the code ROMs. 3) The other 6 data bits are decrypted by a 10H8 PAL. The PAL also takes as input a 4-bit counter. The counter is incremented and decremented as follows: - the Z-80 command IN($xx) where xx is an odd number decrements the counter; an even number increments the counter. Ex: IN($64) would increment the counter, IN($6B) would decrement the counter. 4) The PAL output also contains the two ROM enable lines used to enable the two encrypted code ROMs. As long as the system is working correctly, these ROMs will always be enabled. As it so happens, only four counter values are ever used, which is fortunate because the PAL only contains signals to enable the ROMs for those four counter values. The valid counter values are $8, $9, $A, and $B. The counter's intial value is $A, which is set by jumpers on the daughterboard. Following is a description of the resulting decryptions for these four counter states. COUNTER ENCRYPTED DECRYPTED VALUE VALUE DDDDDDDD DDDDDDDD 76543210 76543210 Counter = 8: abcdefgh EAhBDgFC Counter = 9: abcdefgh FAgeDBFC Counter = A: abcdefgh EHDBagFC Counter = B: abcdefgh GHDEaBFC In the above diagram, capital letters represent inverted bits. Notice that bits D2 and D5 are the same independent of counter state, this is because these bits are not decrypted by the PAL. In the code below, all four of these decryption patterns are used to decrypt the entire code ROMs before execution. This is done for speed, since we can then just bankswitch between the decrypted code sets on each IN($xx) command, as opposed to dynamically decrypting every byte. - Mike Balfour (mab22@po.cwru.edu) */ MACHINE_START_MEMBER(epospm_state, theglobp) { /* Note: D2 is inverted and connected to D1, D5 is inverted and connected to D0. The other six data bits are converted by a PAL10H8 driven by the counter. */ int bs[4][8] = { { 3,7,0,6,4,1,2,5 }, { 1,7,0,3,4,6,2,5 }, { 3,0,4,6,7,1,2,5 }, { 1,0,4,3,7,6,2,5 }, }; /* While the PAL supports up to 16 decryption methods, only four are actually used in the PAL. Therefore, we'll take a little memory overhead and decrypt the ROMs using each method in advance. */ uint8_t *ROM = memregion("maincpu")->base(); epos_decrypt_rom(ROM, 0xfc, 0x10000, bs[0]); epos_decrypt_rom(ROM, 0xf6, 0x14000, bs[1]); epos_decrypt_rom(ROM, 0x7d, 0x18000, bs[2]); epos_decrypt_rom(ROM, 0x77, 0x1c000, bs[3]); membank("bank1")->configure_entries(0, 4, &ROM[0x10000], 0x4000); save_item(NAME(m_counter)); } MACHINE_RESET_MEMBER(epospm_state, theglobp) { m_counter = 0x0A; membank("bank1")->set_entry(m_counter & 3); } /* Same Epos board as usual(theglobp,beastf,street heat). This is fairly easy to decrypt since it has consecutive bytes with the same algorithym. There are 4 different algorithyms. One consists almost entirely of text, one contains the majority of code and the remaining 2 are not used much and are therefore the most difficult. It is however difficult to decrypt to rom. The data for the coin sound is actually program code in a different phase. You need to move the sound tables and add a rom to get it to run without the daughterboard. acitya contains a bug with the insurance in blackjack. It's impossible to collect, so it's likely that acitya is earlier than bwcasino. I don't think this game is a gambling game. For one thing there's no real output hardware on a pacman board and the epos daughterboard doesn't contain any either. David Widel d_widel@hotmail.com */ MACHINE_START_MEMBER(epospm_state, acitya) { /* Note: D2 is inverted and connected to D1, D5 is inverted and connected to D0. The other six data bits are converted by a PAL10H8 driven by the counter. */ int bs[4][8] = { { 1,6,7,3,4,0,2,5 }, { 7,6,1,3,4,0,2,5 }, { 1,0,7,6,4,3,2,5 }, { 7,0,1,6,4,3,2,5 }, }; /* While the PAL supports up to 16 decryption methods, only four are actually used in the PAL. Therefore, we'll take a little memory overhead and decrypt the ROMs using each method in advance. */ uint8_t *ROM = memregion("maincpu")->base(); epos_decrypt_rom(ROM, 0xb5, 0x10000, bs[0]); epos_decrypt_rom(ROM, 0xa7, 0x14000, bs[1]); epos_decrypt_rom(ROM, 0xfc, 0x18000, bs[2]); epos_decrypt_rom(ROM, 0xee, 0x1c000, bs[3]); membank("bank1")->configure_entries(0, 4, &ROM[0x10000], 0x4000); save_item(NAME(m_counter)); } MACHINE_RESET_MEMBER(epospm_state, acitya) { m_counter = 0x0B; membank("bank1")->set_entry(m_counter & 3); } MACHINE_START_MEMBER(epospm_state, eeekkp) { /* Note: D2 is inverted and connected to D1, D5 is inverted and connected to D0. The other six data bits are converted by a PAL10H8 driven by the counter. */ int bs[4][8] = { { 7,6,1,3,0,4,2,5 }, { 7,1,4,3,0,6,2,5 }, { 7,6,1,0,3,4,2,5 }, { 7,1,4,0,3,6,2,5 }, }; /* While the PAL supports up to 16 decryption methods, only four are actually used in the PAL. Therefore, we'll take a little memory overhead and decrypt the ROMs using each method in advance. */ uint8_t *ROM = memregion("maincpu")->base(); epos_decrypt_rom(ROM, 0xfd, 0x10000, bs[0]); epos_decrypt_rom(ROM, 0xbf, 0x14000, bs[1]); epos_decrypt_rom(ROM, 0x75, 0x18000, bs[2]); epos_decrypt_rom(ROM, 0x37, 0x1c000, bs[3]); membank("bank1")->configure_entries(0, 4, &ROM[0x10000], 0x4000); save_item(NAME(m_counter)); } MACHINE_RESET_MEMBER(epospm_state, eeekkp) { m_counter = 0x09; membank("bank1")->set_entry(m_counter & 3); }