// license:BSD-3-Clause // copyright-holders:Nicola Salmoria, Andreas Naive, Charles MacDonald /*************************************************************************** Hitachi FD1089FD1094 encryption emulation **************************************************************************** Copyright Nicola Salmoria, Andreas Naive, and Charles MacDonald. All rights reserved. **************************************************************************** The FD1094 is a custom CPU based on the 68000, which runs encrypted code. The decryption key is stored in 8KB of battery-backed RAM; when the battery dies, the CPU can no longer decrypt the program code and the game stops working (though the CPU itself still works - it just uses a wrong decryption key). Being a 68000, the encryption works on 16-bit words. Only words fetched from program space are decrypted; words fetched from data space are not affected. The decryption can logically be split in two parts. The first part consists of a series of conditional XORs and bitswaps, controlled by the decryption key, which will be described in the next paragraph. The second part does a replacement of several values with FFFF. This last step is done to prevent usage of any PC-relative opcode, which would easily allow an intruder to dump decrypted values from program space. The FFFF replacement may affect either ~300 values or ~5000, depending on the decryption key. The main part of the decryption can itself be subdivided in five consecutive steps. The first one is executed only if bit 15 of the encrypted value is 1; the second one only if bit 14 of the _current_ value is 1; the third one only if bit 13 of the current value is 1; the fourth one is executed whenever one of the first three has been executed; the fifth one is always executed. Every step can be thought as consisting of a serie of operations, with some steps avoiding some of them: a unconditional bitswap, some conditional XORs, a unconditional XOR and some conditional bitswaps. In the end, the decryption of a value at a given address is controlled by 32 boolean variables; 8 of them change at every address (repeating after 0x2000 words), and constitute the main key which is stored in the battery-backed RAM; the other 24 don't change with the address, and depend solely on bytes 1, 2, and 3 of the battery-backed RAM, modified by the "state" which the CPU is in. The CPU can be in one of 256 possible states. The 8 bits of the state modify the 24 bits of the global key in a fixed way, which isn't affected by the battery-backed RAM. On reset, the CPU goes in state 0x00. The state can then be modified by the program, executing the instruction CMPI.L #$00xxFFFF, D0 where xx is the state. When an interrupt happens, the CPU enters "irq mode", forcing a specific state, which is stored in byte 0 of the battery-backed RAM. Irq mode can also be selected by the program with the instruction CMPI.L #$0200FFFF, D0 When RTE is executed, the CPU leaves irq mode, restoring the previous state. This can also be done by the program with the instruction CMPI.L #$0300FFFF, D0 Since bytes 0-3 of the battery-backed RAM are used to store the irq state and the global key, they have a double use: this one, and the normal 8-bit key that changes at every address. To prevent that double use, the CPU fetches the 8-bit key from a different place when decrypting words 0-3, but this only happens after wrapping around at least once; when decrypting the first four words of memory, which correspond to the initial SP and initial PC vectors, the 8-bit key is taken from bytes 0-3 of RAM. Instead, when fetching the vectors, the global key is handled differently, to prevent double use of those bytes. But this special handling of the global key doesn't apply to normal operations: reading words 1-3 from program space results in bytes 1-3 of RAM being used both for the 8-bit key and for the 24-bit global key. There is still uncertainty about the assignment of two global key bits. key[1] ------ key_0b invert; \ bits 7,5 always 1 for now (but 0 in a bad CPU) global_xor0; / key_5b invert; bit 6 key_2b invert; bit 4 key_1b invert; bit 3 always 1 for now (but 0 in a bad CPU) global_xor1; bit 2 key_0c invert; bit 1 global_swap2; bit 0 key[2] ------ key_1a invert; bit 7 always 1 for now (but 0 in a bad CPU) key_6b invert; bit 6 always 1 for now (but 0 in a bad CPU) global_swap0a; bit 5 key_7a invert; bit 4 key_4a invert; bit 3 global_swap0b; bit 2 key_6a invert; bit 1 key_3a invert; bit 0 key[3] ------ key_2a invert; bit 7 always 1 for now (but 0 in a bad CPU) global_swap3; bit 6 always 1 for now (but 0 in a bad CPU) key_5a_invert; bit 5 global_swap1; bit 4 key_3b invert; bit 3 global_swap4; bit 2 key_0a invert; bit 1 key_4b invert; bit 0 Analysis of the data contained in the 8k key data indicates some regularities. To begin with, in all the keys seen so far, bit 7 ($80) in key values at addresses $0004-$0FFF is always set to 1. Similarly, bit 6 ($40) in key values at addresses $1000-$1FFF is always set to 1. Even more interesting, however, is that analyzing the low 6 bits of the key data reveals that a simple linear congruential generator has been used consistently to generate the key bits. The LCG is of the form: temp = A * val; val' = temp + (temp << 16); and it appears to be calculated to at least 22 bits. In all cases seen so far, the value of 'A' is fixed at $29. To generate the low 6 bits of the key, the result of the LCG is shifted right 16 bits and inverted. The following pseudo-code will generate 7 of the 8 bits of the key data successfully for all known keys, given the values of the 'shift' and 'B' parameters, as well as an initial 'seed' for the generator: void genkey(UINT32 seed, UINT8 *output) { int bytenum; for (bytenum = 4; bytenum < 8192; bytenum++) { UINT8 byteval; seed = seed * 0x29; seed += seed << 16; byteval = (~seed >> 16) & 0x3f; byteval |= (bytenum < 0x1000) ? 0x80 : 0x40; output[bytenum] = byteval; } } This only leaves one bit per key value (and the global key) left to determine. It is worth pointing out that this remaining bit is the same bit that controls how many opcodes to blank to $FFFF: 0 means a smaller subset (~300), while 1 indicates a much larger subset (~5000). Looking at the correlations between where the key has this bit set to 0, and the presence of opcodes that would be blanked as a result, seems to imply that the key is generated based on the plaintext. That is, this final bit is set to 1 by default (hence blanking more aggressively), and cleared to 0 if any plaintext words affected by the byte in question would be incorrectly blanked. When the keys were generated, the LCG seed wasn't input directly. Instead, another value was entered, which in most cases was derived from the current date/time. The LCG seed is obtained from that value via a multiplication. The current date/time was also used in most cases to select the three bytes of the global key. Interestingly, the global key must be inverted and read in decimal representation to see this, while the seed must be read in hexadecimal representation. For some reason, bit 3 of the first byte of the global key was always set to 1 regardless of the value input into the key generator program, so e.g. the input "88 01 23" would become "80 01 23". The very first byte of internal RAM, which indicates the IRQ state, doesn't seem to follow the same procedure. The IRQ state was probably decided at an earlier time, not during the final key generation. summary: -------- +----------------------------------------------------- 317- part # | +--------------------------------------------- IRQ state (hex) | | +--------------------------------------- global key (inverted, dec) | | | +------------------------------ main key seed (hex) (LCG seed = seed * 0x2F1E21) | | | | +--------------------- game | | | | | +------------ year | | | | | | +- inferred key generation date | | | | | | | -------- -- -------- ------ -------- ---- ----------------------------- 0041 12 87 06 19 895963 bullet 1987 87/06/19 (atypical) 0045 34 97 02 39 384694 suprleag 1987 (atypical) 0046 E3 87 10 07 012563 hwchampj 1987 87/10/07 (atypical) 0049 F1 87 10 28 8932F7 shinobi2 1987 87/10/28 (atypical) 0050 F1 87 10 28 8932F7 shinobi1 1987 87/10/28 (atypical) 0053 00 00 00 00 020000 sonicbom 1987 atypical 0056 CD 80 01 23 032ABC thndrbld 1987 88/01/23 (atypical) 0059 45 80 03 30 343210 aceattac 1988 88/03/30 (atypical) 0060 45 80 03 30 343210 aceattaca 1988 88/03/30 (atypical) 0065 FC 80 06 06 880606 altbeastj1 1988 88/06/06 0068 20 80 06 10 880610 altbeastj3 1988 88/06/10 0069 20 80 06 10 880610 altbeast5 1998 88/06/10 0070 59 80 08 06 880806 passshtj 1988 88/08/06 0074 47 80 08 06 880806 passshta 1988 88/08/06 0071 20 80 08 09 880809 passsht 1988 88/08/09 0079 98 80 09 05 880906 exctleag 1988 88/09/05-88/09/06 (atypical) 0080 96 80 08 26 880826 passsht 1988 88/08/26 0058-02C FF 80 10 07 881007 sspirtfc 1988 88/10/07 0084 0E 80 10 31 881031 wb31 1988 88/10/31 0085 26 80 11 08 881108 wb32 1988 88/11/08 0087 69 80 11 08 881108 wb34 1988 88/11/08 0089 52 80 11 29 881129 wb33 1988 88/11/29 0058-03B 71 80 11 25 881125 ggroundj 1988 88/11/25 0058-03C 04 80 11 27 881127 gground 1988 88/11/27 0090 AB 80 01 27 247333 wrestwar1 1989 atypical 0091 68 80 11 27 881127 tetris1 1988 88/11/27 0092 10 80 11 28 881128 tetris2 1988 88/11/28 0093 25 80 11 29 881129 tetris 1988 88/11/29 0093A 35 02 09 17 900209 tetris3 1988 90/02/09 0096 21 80 11 21 881121 ddux 1988 88/11/21 0102 AB 80 02 03 04588A wrestwar2 1989 atypical 0058-04B 27 03 27 14 032714 crkdownj 1989 89/03/27 14:xx 0058-04C 19 03 27 05 032705 crkdown 1989 89/03/27 05:xx 0058-04D DC 03 27 06 032706 crkdownu 1989 89/03/27 06:xx 0110 19 81 03 29 032916 goldnaxe1 1989 89/03/29 16:xx 0115 12 04 05 11 040511 bayroutej 1989 89/04/05 11:xx 0116 11 03 30 09 033009 bayroute 1989 89/03/30 09:xx 0118 22 81 03 07 030719 toutrun 1989 89/03/07 19:xx toutrun2 22 81 03 07 031113 toutrun2 1989 89/03/11 13:xx (atypical) 0120 0D 81 03 29 032916 goldnaxe3 1989 89/03/29 16:xx 0121 35 81 03 29 032916 goldnaxej 1989 89/03/29 16:xx 0122 03 81 04 04 890404 goldnaxeu 1989 89/04/04 0058-05B 92 81 06 09 890609 sgmastj 1989 89/06/09 0058-05C 30 81 06 13 890613 sgmastc 1989 89/06/13 0058-05D 50 81 06 09 890609 sgmast 1989 89/06/09 0124A 80 06 21 11 890621 smgpj 1989 89/06/21 11:xx 0125A DE 06 15 16 890615 smgpu 1989 89/06/15 16:xx 0126 54 05 28 01 890528 smgp5 1989 89/05/28 01:xx 0126A 74 06 16 15 890616 smgp 1989 89/06/16 15:xx 0127A 5F 81 07 06 890706 fpoint 1989 89/07/06 0127A 5F 81 07 06 890706 fpoint1 1989 89/07/06 0128 55 00 28 20 890828 eswatj 1989 89/08/28 20:xx 0129 0A 00 28 20 890828 eswatu 1989 89/08/28 20:xx 0130 EC 00 28 19 890828 eswat 1989 89/08/28 19:xx 0134 DE 81 11 30 891130 loffirej 1989 89/11/30 0135 98 81 11 31 891131 loffireu 1989 89/11/31 0136 12 81 11 29 891129 loffire 1989 89/11/29 0139 49 03 25 15 891125 bloxeed 1990 89/11/25 15:xx 0142 91 01 24 17 900124 mvpj 1989 90/01/24 17:xx 0143 20 02 02 18 900202 mvp 1989 90/02/02 18:xx 0144 2E 02 23 18 022318 rachero 1989 90/02/23 18:xx 0058-06B 88 03 15 09 900315 roughrac 1990 90/03/15 09:xx 0146 10 04 26 17 900426 astormj 1990 90/04/26 17:xx 0147 2D 04 14 14 900414 astormu 1990 90/04/14 14:xx 0148 50 04 26 15 900426 astorm3 1990 90/04/26 15:xx 0153 FC 04 10 14 900410 pontoon 1990 90/04/10 14:xx 0154 ED 05 01 13 900501 astorm 1990 90/05/01 13:xx 0157 20 07 20 10 900720 mwalkj 1990 90/07/20 10:xx 0158 DE 07 15 15 900715 mwalku 1990 90/07/15 15:xx 0159 39 07 20 10 900720 mwalk 1990 90/07/20 10:xx 0162 8F 01 14 15 900914 gprider1 1990 90/09/14 15:xx 0163 99 01 13 15 900913 gprider 1990 90/09/13 15:xx 5023 EF 04 18 05 900917 ryukyu 1990 90/09/17 12:18? (atypical) 0165 56 82 11 25 901125 lghostu 1990 90/11/25 0166 A2 82 11 24 901124 lghost 1990 90/11/24 0169B 48 06 35 32 901205 abcop 1990 90/12/05 14:35? (atypical) 0058-08B 4E 04 17 15 910206 qsww 1991 91/02/06 12:17? (atypical) 0175 91 83 03 22 910322 cltchitrj 1991 91/03/22 0176 FC 83 03 14 910314 cltchitr 1991 91/03/14 0179B 73 06 55 17 910318 cottonj 1991 91/03/18 14:55? (atypical) 0180 73 03 53 00 910403 cottonu 1991 91/04/03 11:53? (atypical) 0181A 73 06 55 17 910318 cotton 1991 91/03/18 14:55? (atypical) 0058-09D 91 83 06 26 910618 dcclubfd 1991 91/06/18-91/06/26 (atypical) 0182 07 07 12 14 921401 ddcrewj2 1991 92/07/12 14:01? (atypical) 0184 07 07 12 16 921622 ddcrew2 1991 92/07/12 16:22? (atypical) 0185 91 07 06 16 910704 ddcrewj 1991 91/07/04-91/07/06 16:xx (atypical) 0186 5F 83 07 01 912030 ddcrewu 1991 91/07/01 20:30? (atypical) 0187 91 84 07 42 910744 ddcrew1 1991 92/07/xx 07:44? (atypical) 0190 07 07 17 16 921716 ddcrew 1992 92/07/07 17:16? (atypical) 0194 4A 07 10 13 920623 desertbrj 1992 92/06/23 07:10? (atypical) 0196 4A 20 12 22 920623 desertbr 1992 92/06/23 20:12? (atypical) 0197A 3F 84 06 19 920612 wwallyja 1992 92/06/12-92/06/19 (atypical) 0197B 3F 84 06 19 920612 wwallyj 1992 92/06/12-92/06/19 (atypical) ---- Bad CPUs that gave some more information about the global key: global01 global02 global03 -------- -------- -------- ..... .. .. unknown 11111111 11110110 10111110 (Shinobi 16A, part no. unreadable, could be dead) unknown 10101011 11111000 11010101 (unknown ddcrewa key) dead 00001111 00001111 00001111 (Alien Storm CPU with no battery) bad 11100000 10101011 10111001 (flaky 317-0049) ---- Notes: We start in state 0. Vectors are fetched: SP.HI @ $000000 -> mainkey = key[0], globalkey = { $00, $00, $00 }, less aggressive blanking SP.LO @ $000002 -> mainkey = key[1], globalkey = { $00, $00, $00 }, less aggressive blanking PC.HI @ $000004 -> mainkey = key[2], globalkey = { key[1], $00, $00 } PC.LO @ $000006 -> mainkey = key[3], globalkey = { key[1], key[2], $00 } driver FD1094 SP plain SP enc PC plain PC enc States Used (majority one marked with asterisk, if known) -------- -------- -------- -------- -------- -------- --------------------- aceattac 317-0059 00000000 A711AF59 00000414 AF59AACD 00 12 17 31 45 90 FC* aceattaca 317-0060 00000000 A711AF59 00000400 AF59EADD 00 17 31 45 90 FC* altbeast5 317-0069 FFFFFF00 B2F7F299 00000400 CCDDEF58 00 0F 18 20 93* A7 D8 altbeastj1 317-0065 FFFFFF00 C9C5F299 00000400 CCDDECDD 00 09 12 67* 99 FC altbeastj3 317-0068 FFFFFF00 B2F7F299 00000400 CCDDEF58 00 0F 18 20 93* A7 D8 astorm 317-0154 FFFFFF00 B297F23F 00000400 BD5999DD 00 1F 48* 5F 66 ED astorm3 317-0148 FFFFFF00 ED9FF23F 00000400 FC58B9DC 00 06 36 50 CC D9* astormj 317-0146 FFFFFF00 ED8CF23F 00000400 FC58BC59 00 10 29* 44 CE DF astormu 317-0147 FFFFFF00 B297F23F 00000400 55334533 00 19 2D 46 58* DF bayroute 317-0116 00504000 5EB40000 00001000 5533A184 00 04* 11 18 bayroutej 317-0115 00504000 56150000 00001000 85948DCF 00 05* 12 16 bloxeed 317-0139 00000000 5D92A711 00001D38 BD59FFE8 00 49 53 55 56* DF bullet 317-0041 00000000 57355D96 00001882 8DDC8CF4 00 12 21 69* FE cltchitr 317-0176 00000000 A711A711 00000416 AF59EBCD 00 01* 80 FC cltchitrj 317-0175 00000000 5F94A711 00000416 AF59AFFB 00 03 19* 91 cotton 317-0181a 00204000 5DB20000 00000716 CCDD0716 00 0E* 73 cottonj 317-0179b 00204000 5DB20000 00000720 CCDD0720 00 0E* 73 cottonu 317-0180 00204000 5DB20000 00000716 A1840716 00 0E* 73 ddcrew 317-0190 00000000 AF595D92 00000408 BD59FD7F 00 07 16* 17 ddcrew1 317-0187 00000000 5F945D96 00000408 8DDCE758 00 04 07* 13 91 ddcrew2 317-0184 00000000 AF595D92 00000408 5533FD7F 00 07 12* 16 22 ddcrewj 317-0185 00000000 5F945D92 00000408 5533FD7F 00 06 07* 09 91 ddcrewu 317-0186 00000000 AF59A711 00000408 8DDCC381 00 01 07 5F 91* ddux 317-0096 00000000 5F94AF59 00000406 AF5987A0 00 21 28 70* D9 desertbr 317-0196 00000000 55335D92 00001838 5533F46A 00 3C 4A 82 DA* desertbrj 317-0194 00000000 55335D92 00001838 BD59E720 00 3C 4A 82 DA* eswat 317-0130 00000000 A711AF59 00000400 5533BC59 00 05 0C EC FA* eswatj 317-0128 00000000 A711AF59 00000400 55334735 00 55 63 CB* D5 eswatu 317-0129 00000000 5537AF59 00000400 55334735 00 0A 12 C3* CC exctleag 317-0079 00000000 5537AF59 00000410 83018384 00 02 39 4B 85 98 E5* fpoint 317-0127a 00000000 AF59AF59 00001A40 8DDC9960 00 15* 35 5F 82 DB fpoint1 317-0127a 00000000 AF59AF59 00001A40 8DDC9960 00 15* 35 5F 82 DB goldnaxe1 317-0110 FFFFFF00 ED62F2B9 00000400 AF59A785 00 19 2E 31 48* 5D goldnaxe3 317-0120 FFFFFF00 ED62F2B9 00000400 AF59A785 00 0A 0D 44 C7 EF* goldnaxej 317-0121 FFFFFF00 C9D6F2B9 00000400 AF59A785 00 12* 35 58 7A 9E goldnaxeu 317-0122 FFFFFF00 E53AF2B9 00000400 A184A196 00 03 51* 72 99 F6 hwchampj 317-0046 00000000 5D925D96 000008AC AF59AA41 00 8B* E3 lghost 317-0166 00000000 5F94A711 00000404 EE588241 00 A2 DC E0* lghostu 317-0165 00000000 AF59A711 00000404 EE58C340 00 56 C4 DE* mvp 317-0143 00000000 5F94A711 00000416 BD59DC5B 00 19* 20 88 98 mwalk 317-0159 FFFFFF00 C9C7F23F 00000400 5533BD7F 00 39 51* AA CC mwalkj 317-0157 FFFFFF00 B2F7F23F 00000400 5533BD7F 00 20 88 99 CF* mwalku 317-0158 FFFFFF00 C572F23F 00000400 8DDC8DDD 00 49* 90 C0 DE passsht 317-0080 00000000 AF59AF59 00003202 C2003923 00 11 52* 96 EE passshta 317-0074 00000000 AF59AF59 000031E4 C2003F8C 00 12* 47 83 A7 passshtj 317-0070 00000000 5D92AF59 000031E4 C2003F8C 00 12 59 83* FE pontoon 317-0153 00000000 A7115D92 00000E0C FC585979 00 19 70 DC* FC ryukyu 317-5023 00203800 AF49D30B 0000042E FC5863B5 00 DC* EF shinobi2 317-0049 FFFFFF00 C9C5F25F 00000400 AF598395 00 53 88 98 9B 9C* F1 sonicbom 317-0053 00000000 5735AF59 00001000 FC587133 00* suprleag 317-0045 00000000 A711AF59 0000108E BD59CE5B 00 12* 34 56 AB CD tetris1 317-0091 00000000 5D92AF59 00000410 AF59AE58 99 25 42 5B 68 FC tetris2 317-0092 00000000 5735AF59 00000410 AF598685 00 10 52 74 97* FC wb32 317-0085 FFFFFF7E B2F78997 00000500 AF590500 00 10 13 26 77 wb33 317-0089 FFFFFF7E E5C78997 00000500 AF590500 00 23 40 52 71* wb34 317-0087 FFFFFF7E B2978997 00000500 AF590500 00 11* 64 69 82 wrestwar1 317-0090 00000000 5D96AF59 00000414 8301AE18 00 12* A7 AB CC F9 FC wrestwar2 317-0102 00000000 5D96AF59 00000414 EE588E5B 00 12* A7 AB CC F9 FC wwallyj 317-0197b 00000000 AF595D96 00000416 CCDDCE5B 00 16* 32 3F 43 wwallyja 317-0197a 00000000 AF595D96 00000416 CCDDCE5B 00 16* 32 3F 43 *****************************************************************************/ #include "emu.h" #include "fd1094.h" //************************************************************************** // CONSTANTS //************************************************************************** // device type definition const device_type FD1094 = &device_creator; /* 317-0162 CPU also needs to mask: 0x107a, 0x127a, 0x147a, 0x167a, 0x187a, 0x1a7a, 0x1c7a, 0x1e7a, this only happens with 317-0162 so far; I assume it is a fault in the CPU. */ const UINT16 fd1094_device::s_masked_opcodes[] = { 0x013a,0x033a,0x053a,0x073a,0x083a,0x093a,0x0b3a,0x0d3a,0x0f3a, 0x103a, 0x10ba,0x10fa, 0x113a,0x117a,0x11ba,0x11fa, 0x123a, 0x12ba,0x12fa, 0x133a,0x137a,0x13ba,0x13fa, 0x143a, 0x14ba,0x14fa, 0x153a,0x157a,0x15ba, 0x163a, 0x16ba,0x16fa, 0x173a,0x177a,0x17ba, 0x183a, 0x18ba,0x18fa, 0x193a,0x197a,0x19ba, 0x1a3a, 0x1aba,0x1afa, 0x1b3a,0x1b7a,0x1bba, 0x1c3a, 0x1cba,0x1cfa, 0x1d3a,0x1d7a,0x1dba, 0x1e3a, 0x1eba,0x1efa, 0x1f3a,0x1f7a,0x1fba, 0x203a,0x207a,0x20ba,0x20fa, 0x213a,0x217a,0x21ba,0x21fa, 0x223a,0x227a,0x22ba,0x22fa, 0x233a,0x237a,0x23ba,0x23fa, 0x243a,0x247a,0x24ba,0x24fa, 0x253a,0x257a,0x25ba, 0x263a,0x267a,0x26ba,0x26fa, 0x273a,0x277a,0x27ba, 0x283a,0x287a,0x28ba,0x28fa, 0x293a,0x297a,0x29ba, 0x2a3a,0x2a7a,0x2aba,0x2afa, 0x2b3a,0x2b7a,0x2bba, 0x2c3a,0x2c7a,0x2cba,0x2cfa, 0x2d3a,0x2d7a,0x2dba, 0x2e3a,0x2e7a,0x2eba,0x2efa, 0x2f3a,0x2f7a,0x2fba, 0x303a,0x307a,0x30ba,0x30fa, 0x313a,0x317a,0x31ba,0x31fa, 0x323a,0x327a,0x32ba,0x32fa, 0x333a,0x337a,0x33ba,0x33fa, 0x343a,0x347a,0x34ba,0x34fa, 0x353a,0x357a,0x35ba, 0x363a,0x367a,0x36ba,0x36fa, 0x373a,0x377a,0x37ba, 0x383a,0x387a,0x38ba,0x38fa, 0x393a,0x397a,0x39ba, 0x3a3a,0x3a7a,0x3aba,0x3afa, 0x3b3a,0x3b7a,0x3bba, 0x3c3a,0x3c7a,0x3cba,0x3cfa, 0x3d3a,0x3d7a,0x3dba, 0x3e3a,0x3e7a,0x3eba,0x3efa, 0x3f3a,0x3f7a,0x3fba, 0x41ba,0x43ba,0x44fa,0x45ba,0x46fa,0x47ba,0x49ba,0x4bba,0x4cba,0x4cfa,0x4dba,0x4fba, 0x803a,0x807a,0x80ba,0x80fa, 0x81fa, 0x823a,0x827a,0x82ba,0x82fa, 0x83fa, 0x843a,0x847a,0x84ba,0x84fa, 0x85fa, 0x863a,0x867a,0x86ba,0x86fa, 0x87fa, 0x883a,0x887a,0x88ba,0x88fa, 0x89fa, 0x8a3a,0x8a7a,0x8aba,0x8afa, 0x8bfa, 0x8c3a,0x8c7a,0x8cba,0x8cfa, 0x8dfa, 0x8e3a,0x8e7a,0x8eba,0x8efa, 0x8ffa, 0x903a,0x907a,0x90ba,0x90fa, 0x91fa, 0x923a,0x927a,0x92ba,0x92fa, 0x93fa, 0x943a,0x947a,0x94ba,0x94fa, 0x95fa, 0x963a,0x967a,0x96ba,0x96fa, 0x97fa, 0x983a,0x987a,0x98ba,0x98fa, 0x99fa, 0x9a3a,0x9a7a,0x9aba,0x9afa, 0x9bfa, 0x9c3a,0x9c7a,0x9cba,0x9cfa, 0x9dfa, 0x9e3a,0x9e7a,0x9eba,0x9efa, 0x9ffa, 0xb03a,0xb07a,0xb0ba,0xb0fa, 0xb1fa, 0xb23a,0xb27a,0xb2ba,0xb2fa, 0xb3fa, 0xb43a,0xb47a,0xb4ba,0xb4fa, 0xb5fa, 0xb63a,0xb67a,0xb6ba,0xb6fa, 0xb7fa, 0xb83a,0xb87a,0xb8ba,0xb8fa, 0xb9fa, 0xba3a,0xba7a,0xbaba,0xbafa, 0xbbfa, 0xbc3a,0xbc7a,0xbcba,0xbcfa, 0xbdfa, 0xbe3a,0xbe7a,0xbeba,0xbefa, 0xbffa, 0xc03a,0xc07a,0xc0ba,0xc0fa, 0xc1fa, 0xc23a,0xc27a,0xc2ba,0xc2fa, 0xc3fa, 0xc43a,0xc47a,0xc4ba,0xc4fa, 0xc5fa, 0xc63a,0xc67a,0xc6ba,0xc6fa, 0xc7fa, 0xc83a,0xc87a,0xc8ba,0xc8fa, 0xc9fa, 0xca3a,0xca7a,0xcaba,0xcafa, 0xcbfa, 0xcc3a,0xcc7a,0xccba,0xccfa, 0xcdfa, 0xce3a,0xce7a,0xceba,0xcefa, 0xcffa, 0xd03a,0xd07a,0xd0ba,0xd0fa, 0xd1fa, 0xd23a,0xd27a,0xd2ba,0xd2fa, 0xd3fa, 0xd43a,0xd47a,0xd4ba,0xd4fa, 0xd5fa, 0xd63a,0xd67a,0xd6ba,0xd6fa, 0xd7fa, 0xd83a,0xd87a,0xd8ba,0xd8fa, 0xd9fa, 0xda3a,0xda7a,0xdaba,0xdafa, 0xdbfa, 0xdc3a,0xdc7a,0xdcba,0xdcfa, 0xddfa, 0xde3a,0xde7a,0xdeba,0xdefa, 0xdffa }; //************************************************************************** // DECRYPTION CACHE HELPER //************************************************************************** //------------------------------------------------- // fd1094_decryption_cache - constructor //------------------------------------------------- fd1094_decryption_cache::fd1094_decryption_cache(fd1094_device &fd1094) : m_fd1094(fd1094), m_baseaddress(0), m_size(0), m_rgnoffset(0) { reset(); } //------------------------------------------------- // reset - reset the cache //------------------------------------------------- void fd1094_decryption_cache::reset() { // reset all allocated cache buffers for (auto & elem : m_decrypted_opcodes) elem.clear(); } //------------------------------------------------- // configure - configure the address and size // of the region we are caching //------------------------------------------------- void fd1094_decryption_cache::configure(offs_t baseaddress, UINT32 size, offs_t rgnoffset) { // if something important changes, throw away what we have if (m_baseaddress != baseaddress || m_size != size || m_rgnoffset != rgnoffset) { m_baseaddress = baseaddress; m_size = size; m_rgnoffset = rgnoffset; reset(); } } //------------------------------------------------- // decrypted_opcodes - return a pointer to the // decrypted opcodes for the given state //------------------------------------------------- UINT16 *fd1094_decryption_cache::decrypted_opcodes(UINT8 state) { // if we have already decrypted this state, use it if (!m_decrypted_opcodes[state].empty()) return &m_decrypted_opcodes[state][0]; // otherwise, allocate and decrypt m_decrypted_opcodes[state].resize(0x200000/2); memset(&m_decrypted_opcodes[state][0], 0, 0x200000); m_fd1094.decrypt(m_baseaddress, m_size, m_rgnoffset, &m_decrypted_opcodes[state][0], state); return &m_decrypted_opcodes[state][0]; } //************************************************************************** // CORE IMPLEMENTATION //************************************************************************** //------------------------------------------------- // fd1094_device - constructor //------------------------------------------------- fd1094_device::fd1094_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) : m68000_device(mconfig, tag, owner, clock, "fd1094", __FILE__), m_decrypted_opcodes_bank(*this, "^fd1094_decrypted_opcodes"), m_state(0x00), m_irqmode(false), m_cache(*this), m_srcbase(nullptr), m_srcbytes(0), m_key(nullptr) { // override the name after the m68000 initializes m_name.assign("FD1094"); // add the decrypted opcodes map // m_address_map[AS_DECRYPTED_OPCODES] = ADDRESS_MAP_NAME(decrypted_opcodes_map); // create the initial masked opcode table memset(m_masked_opcodes_lookup, 0, sizeof(m_masked_opcodes_lookup)); for (auto opcode : s_masked_opcodes) { m_masked_opcodes_lookup[0][opcode >> 4] |= 1 << ((opcode >> 1) & 7); m_masked_opcodes_lookup[1][opcode >> 4] |= 1 << ((opcode >> 1) & 7); } // add some more opcodes for the more aggressive table for (int opcode = 0; opcode < 65536; opcode += 2) if ((opcode & 0xff80) == 0x4e80 || (opcode & 0xf0f8) == 0x50c8 || (opcode & 0xf000) == 0x6000) m_masked_opcodes_lookup[1][opcode >> 4] |= 1 << ((opcode >> 1) & 7); m_state_change = state_change_delegate(FUNC(fd1094_device::default_state_change), this); } //------------------------------------------------- // change_state - set the current state of the // chip //------------------------------------------------- void fd1094_device::change_state(int newstate) { // adjust state and IRQ mode switch (newstate & 0x300) { case 0x0000: // 0x00xx: select state xx m_state = newstate & 0xff; break; case STATE_RESET: // 0x01xx: select state xx and exit irq mode m_state = newstate & 0xff; m_irqmode = false; break; case STATE_IRQ: // 0x02xx: enter irq mode m_irqmode = true; break; case STATE_RTE: // 0x03xx: exit irq mode m_irqmode = false; break; } // notify of the state change m_state_change(state()); // force a flush of the prefetch cache on any state change set_state_int(M68K_PREF_ADDR, 0x0010); } //************************************************************************** // DEVICE OVERRIDES //************************************************************************** //------------------------------------------------- // device_start - one-time device initialization //------------------------------------------------- void fd1094_device::device_start() { // find the key m_key = memregion("key")->base(); if (m_key == nullptr) throw emu_fatalerror("FD1094 key region not found!"); // get a pointer to the ROM region if (region() != nullptr) { m_srcbase = reinterpret_cast(region()->base()); m_srcbytes = region()->bytes(); } // if no ROM region, see if there's a memory share with our name else { memory_share *share = owner()->memshare(tag()); if (share != nullptr) { m_srcbase = reinterpret_cast(share->ptr()); m_srcbytes = share->bytes(); } } // if we got nothing, error if (m_srcbase == nullptr) throw emu_fatalerror("FD1094 found no data to decrypt!"); // determine length and configure our cache m_cache.configure(0x000000, m_srcbytes, 0x000000); change_state(STATE_RESET); // start the base device m68000_device::device_start(); // register for the state changing callbacks we need in the m68000 set_cmpild_callback(write32_delegate(FUNC(fd1094_device::cmp_callback),this)); set_rte_callback(write_line_delegate(FUNC(fd1094_device::rte_callback),this)); static_set_irq_acknowledge_callback(*this, device_irq_acknowledge_delegate(FUNC(fd1094_device::irq_callback), this)); // save state save_item(NAME(m_state)); save_item(NAME(m_irqmode)); } //------------------------------------------------- // device_reset - one-time device initialization //------------------------------------------------- void fd1094_device::device_reset() { // flush the cache and switch to the reset state m_cache.reset(); change_state(STATE_RESET); fprintf(stderr, "reset done\n"); // reset the parent m68000_device::device_reset(); } //------------------------------------------------- // device_postload - post restore initialization //------------------------------------------------- void fd1094_device::device_postload() { // refresh the state m_state_change(state()); } //************************************************************************** // INTERNAL HELPERS //************************************************************************** //------------------------------------------------- // decrypt_one - decrypt a single opcode given // the address, data, and keys; note that the // address provided is the word address // (physical address / 2) //------------------------------------------------- UINT16 fd1094_device::decrypt_one(offs_t address, UINT16 val, const UINT8 *main_key, UINT8 state, bool vector_fetch) { // extract and adjust the global key UINT8 gkey1 = main_key[1]; UINT8 gkey2 = main_key[2]; UINT8 gkey3 = main_key[3]; if (state & 0x0001) { gkey1 ^= 0x04; // global_xor1 gkey2 ^= 0x80; // key_1a invert gkey3 ^= 0x80; // key_2a invert } if (state & 0x0002) { gkey1 ^= 0x01; // global_swap2 gkey2 ^= 0x10; // key_7a invert gkey3 ^= 0x01; // key_4b invert } if (state & 0x0004) { gkey1 ^= 0x80; // key_0b invert gkey2 ^= 0x40; // key_6b invert gkey3 ^= 0x04; // global_swap4 } if (state & 0x0008) { gkey1 ^= 0x20; // global_xor0 gkey2 ^= 0x02; // key_6a invert gkey3 ^= 0x20; // key_5a invert } if (state & 0x0010) { gkey1 ^= 0x02; // key_0c invert gkey1 ^= 0x40; // key_5b invert gkey2 ^= 0x08; // key_4a invert } if (state & 0x0020) { gkey1 ^= 0x08; // key_1b invert gkey3 ^= 0x08; // key_3b invert gkey3 ^= 0x10; // global_swap1 } if (state & 0x0040) { gkey1 ^= 0x10; // key_2b invert gkey2 ^= 0x20; // global_swap0a gkey2 ^= 0x04; // global_swap0b } if (state & 0x0080) { gkey2 ^= 0x01; // key_3a invert gkey3 ^= 0x02; // key_0a invert gkey3 ^= 0x40; // global_swap3 } // for address xx0000-xx0006 (but only if >= 000008), use key xx2000-xx2006 UINT8 mainkey; if ((address & 0x0ffc) == 0 && address >= 4) mainkey = main_key[(address & 0x1fff) | 0x1000]; else mainkey = main_key[address & 0x1fff]; UINT8 key_F; if (address & 0x1000) key_F = BIT(mainkey,7); else key_F = BIT(mainkey,6); // the CPU has been verified to produce different results when fetching opcodes // from 0000-0006 than when fetching the inital SP and PC on reset. if (vector_fetch) { if (address <= 3) gkey3 = 0x00; // supposed to always be the case if (address <= 2) gkey2 = 0x00; if (address <= 1) gkey1 = 0x00; if (address <= 1) key_F = 0; } UINT8 global_xor0 = 1^BIT(gkey1,5); UINT8 global_xor1 = 1^BIT(gkey1,2); UINT8 global_swap2 = 1^BIT(gkey1,0); UINT8 global_swap0a = 1^BIT(gkey2,5); UINT8 global_swap0b = 1^BIT(gkey2,2); UINT8 global_swap3 = 1^BIT(gkey3,6); UINT8 global_swap1 = 1^BIT(gkey3,4); UINT8 global_swap4 = 1^BIT(gkey3,2); UINT8 key_0a = BIT(mainkey,0) ^ BIT(gkey3,1); UINT8 key_0b = BIT(mainkey,0) ^ BIT(gkey1,7); UINT8 key_0c = BIT(mainkey,0) ^ BIT(gkey1,1); UINT8 key_1a = BIT(mainkey,1) ^ BIT(gkey2,7); UINT8 key_1b = BIT(mainkey,1) ^ BIT(gkey1,3); UINT8 key_2a = BIT(mainkey,2) ^ BIT(gkey3,7); UINT8 key_2b = BIT(mainkey,2) ^ BIT(gkey1,4); UINT8 key_3a = BIT(mainkey,3) ^ BIT(gkey2,0); UINT8 key_3b = BIT(mainkey,3) ^ BIT(gkey3,3); UINT8 key_4a = BIT(mainkey,4) ^ BIT(gkey2,3); UINT8 key_4b = BIT(mainkey,4) ^ BIT(gkey3,0); UINT8 key_5a = BIT(mainkey,5) ^ BIT(gkey3,5); UINT8 key_5b = BIT(mainkey,5) ^ BIT(gkey1,6); UINT8 key_6a = BIT(mainkey,6) ^ BIT(gkey2,1); UINT8 key_6b = BIT(mainkey,6) ^ BIT(gkey2,6); UINT8 key_7a = BIT(mainkey,7) ^ BIT(gkey2,4); if (val & 0x8000) // block invariant: val & 0x8000 != 0 { val = BITSWAP16(val, 15, 9,10,13, 3,12, 0,14, 6, 5, 2,11, 8, 1, 4, 7); if (!global_xor1) if (~val & 0x0800) val ^= 0x3002; // 1,12,13 if (~val & 0x0020) val ^= 0x0044; // 2,6 if (!key_1b) if (~val & 0x0400) val ^= 0x0890; // 4,7,11 if (!global_swap2) if (!key_0c) val ^= 0x0308; // 3,8,9 val ^= 0x6561; if (!key_2b) val = BITSWAP16(val,15,10,13,12,11,14,9,8,7,6,0,4,3,2,1,5); // 0-5, 10-14 } if (val & 0x4000) // block invariant: val & 0x4000 != 0 { val = BITSWAP16(val, 13,14, 7, 0, 8, 6, 4, 2, 1,15, 3,11,12,10, 5, 9); if (!global_xor0) if (val & 0x0010) val ^= 0x0468; // 3,5,6,10 if (!key_3a) if (val & 0x0100) val ^= 0x0081; // 0,7 if (!key_6a) if (val & 0x0004) val ^= 0x0100; // 8 if (!key_5b) if (!key_0b) val ^= 0x3012; // 1,4,12,13 val ^= 0x3523; if (!global_swap0b) val = BITSWAP16(val, 2,14,13,12, 9,10,11, 8, 7, 6, 5, 4, 3,15, 1, 0); // 2-15, 9-11 } if (val & 0x2000) // block invariant: val & 0x2000 != 0 { val = BITSWAP16(val, 10, 2,13, 7, 8, 0, 3,14, 6,15, 1,11, 9, 4, 5,12); if (!key_4a) if (val & 0x0800) val ^= 0x010c; // 2,3,8 if (!key_1a) if (val & 0x0080) val ^= 0x1000; // 12 if (!key_7a) if (val & 0x0400) val ^= 0x0a21; // 0,5,9,11 if (!key_4b) if (!key_0a) val ^= 0x0080; // 7 if (!global_swap0a) if (!key_6b) val ^= 0xc000; // 14,15 val ^= 0x99a5; if (!key_5b) val = BITSWAP16(val,15,14,13,12,11, 1, 9, 8, 7,10, 5, 6, 3, 2, 4, 0); // 1,4,6,10 } if (val & 0xe000) // block invariant: val & 0xe000 != 0 { val = BITSWAP16(val,15,13,14, 5, 6, 0, 9,10, 4,11, 1, 2,12, 3, 7, 8); val ^= 0x17ff; if (!global_swap4) val = BITSWAP16(val, 15,14,13, 6,11,10, 9, 5, 7,12, 8, 4, 3, 2, 1, 0); // 5-8, 6-12 if (!global_swap3) val = BITSWAP16(val, 13,15,14,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0); // 15-14-13 if (!global_swap2) val = BITSWAP16(val, 15,14,13,12,11, 2, 9, 8,10, 6, 5, 4, 3, 0, 1, 7); // 10-2-0-7 if (!key_3b) val = BITSWAP16(val, 15,14,13,12,11,10, 4, 8, 7, 6, 5, 9, 1, 2, 3, 0); // 9-4, 3-1 if (!key_2a) val = BITSWAP16(val, 13,14,15,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0); // 13-15 if (!global_swap1) val = BITSWAP16(val, 15,14,13,12, 9, 8,11,10, 7, 6, 5, 4, 3, 2, 1, 0); // 11...8 if (!key_5a) val = BITSWAP16(val, 15,14,13,12,11,10, 9, 8, 4, 5, 7, 6, 3, 2, 1, 0); // 7...4 if (!global_swap0a) val = BITSWAP16(val, 15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 0, 3, 2, 1); // 3...0 } val = BITSWAP16(val, 12,15,14,13,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0); if ((val & 0xb080) == 0x8000) val ^= 0x4000; if ((val & 0xf000) == 0xc000) val ^= 0x0080; if ((val & 0xb100) == 0x0000) val ^= 0x4000; // mask out opcodes doing PC-relative addressing, replace them with FFFF if ((m_masked_opcodes_lookup[key_F][val >> 4] >> ((val >> 1) & 7)) & 1) val = 0xffff; return val; } //------------------------------------------------- // decrypt - decrypt a buffers' worth of opcodes //------------------------------------------------- void fd1094_device::decrypt(offs_t baseaddr, UINT32 size, const UINT16 *srcptr, UINT16 *opcodesptr, UINT8 state) { for (offs_t offset = 0; offset < size; offset += 2) opcodesptr[offset / 2] = decrypt_one((baseaddr + offset) / 2, srcptr[offset / 2], m_key, state, (baseaddr + offset) < 8); } //------------------------------------------------- // default_state_change - handle state changes // for standard cases //------------------------------------------------- void fd1094_device::default_state_change(UINT8 state) { m_decrypted_opcodes_bank->set_base(m_cache.decrypted_opcodes(state)); } //************************************************************************** // STATIC CALLBACKS //************************************************************************** //------------------------------------------------- // cmp_callback - callback for CMP.L instructions // (state change) //------------------------------------------------- WRITE32_MEMBER(fd1094_device::cmp_callback) { if (offset == 0 && (data & 0x0000ffff) == 0x0000ffff) change_state(data >> 16); } //------------------------------------------------- // irq_callback - callback when the FD1094 enters // interrupt code //------------------------------------------------- IRQ_CALLBACK_MEMBER( fd1094_device::irq_callback ) { change_state(STATE_IRQ); return (0x60 + irqline * 4) / 4; // vector address } //------------------------------------------------- // rte_callback - callback when an RTE instruction // is encountered //------------------------------------------------- WRITE_LINE_MEMBER(fd1094_device::rte_callback) { change_state(STATE_RTE); }