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author Vas Crabb <vas@vastheman.com>2016-06-15 18:29:26 +1000
committer Vas Crabb <vas@vastheman.com>2016-06-15 18:32:50 +1000
commit241c32eae44675677eef6e121f66878cf5144842 (patch)
tree97cf4df593cdb6970ad292cda6d834122fcc73b1 /src/mame/machine/atarixga.cpp
parentf945016811743c6ebf694fd399d342e1f4144d22 (diff)
clean up (nw)
Diffstat (limited to 'src/mame/machine/atarixga.cpp')
-rw-r--r--src/mame/machine/atarixga.cpp367
1 files changed, 179 insertions, 188 deletions
diff --git a/src/mame/machine/atarixga.cpp b/src/mame/machine/atarixga.cpp
index f2a03af5073..7680a09005a 100644
--- a/src/mame/machine/atarixga.cpp
+++ b/src/mame/machine/atarixga.cpp
@@ -3,7 +3,7 @@
/*************************************************************************
atarixga.cpp
-
+
Atari XGA encryption FPGA
**************************************************************************
@@ -15,7 +15,7 @@
? Road Riot's Revenge
136094-0004A Primal Rage
? T-Mek
-
+
*************************************************************************/
#include "emu.h"
@@ -26,9 +26,9 @@ extern const device_type ATARI_XGA = &device_creator<atari_xga_device>;
atari_xga_device::atari_xga_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
: device_t(mconfig, ATARI_XGA, "Atari XGA", tag, owner, clock, "xga", __FILE__),
- m_mode(FPGA_RESET),
- m_address(0),
- m_ciphertext(0)
+ m_mode(FPGA_RESET),
+ m_address(0),
+ m_ciphertext(0)
{
}
@@ -42,19 +42,19 @@ atari_xga_device::atari_xga_device(const machine_config &mconfig, const char *ta
void atari_xga_device::device_start()
{
- m_ram = std::make_unique<UINT16[]>(RAM_WORDS);
-
- save_pointer(NAME(m_ram.get()), RAM_WORDS * sizeof(UINT16));
- save_item(NAME(m_address));
- save_item(NAME(m_ciphertext));
+ m_ram = std::make_unique<UINT16[]>(RAM_WORDS);
+
+ save_pointer(NAME(m_ram.get()), RAM_WORDS * sizeof(UINT16));
+ save_item(NAME(m_address));
+ save_item(NAME(m_ciphertext));
}
void atari_xga_device::device_reset()
{
- memset(m_ram.get(), 0, RAM_WORDS * sizeof(UINT16));
- m_mode = FPGA_RESET;
- m_address = 0;
- m_ciphertext = 0;
+ memset(m_ram.get(), 0, RAM_WORDS * sizeof(UINT16));
+ m_mode = FPGA_RESET;
+ m_address = 0;
+ m_ciphertext = 0;
}
@@ -71,22 +71,22 @@ void atari_xga_device::device_reset()
/* key 0x10 is special, it has 15 "identical twins". */
static const UINT8 kmap[128] =
{
- 0x6B,0x11,0x1B,0x19,0x4B,0x50,0x17,0x09,
- 0x5D,0x69,0x43,0x33,0x0F,0x0C,0x28,0x3F,
- 0x00,0x20,0x15,0x3C,0x57,0x38,0x00,0x07,
- 0x49,0x25,0x61,0x2F,0x2B,0x4E,0x64,0x00,
- 0x45,0x41,0x6D,0x52,0x31,0x66,0x22,0x59,
- 0x00,0x70,0x6F,0x5B,0x46,0x6E,0x67,0x5A,
- 0x26,0x30,0x2C,0x65,0x21,0x3D,0x58,0x00,
- 0x5E,0x44,0x0D,0x40,0x6C,0x1C,0x51,0x0A,
- 0x35,0x2A,0x13,0x4D,0x63,0x00,0x00,0x3A,
- 0x00,0x48,0x54,0x24,0x60,0x1E,0x2E,0x01,
- 0x56,0x03,0x37,0x00,0x04,0x00,0x05,0x06,
- 0x00,0x55,0x1F,0x02,0x36,0x14,0x00,0x3B,
- 0x5F,0x0E,0x1D,0x0B,0x27,0x2D,0x3E,0x00,
- 0x00,0x5C,0x47,0x68,0x42,0x53,0x32,0x23,
- 0x4A,0x62,0x4F,0x00,0x00,0x16,0x39,0x08,
- 0x6A,0x34,0x10,0x29,0x12,0x1A,0x4C,0x18
+ 0x6B,0x11,0x1B,0x19,0x4B,0x50,0x17,0x09,
+ 0x5D,0x69,0x43,0x33,0x0F,0x0C,0x28,0x3F,
+ 0x00,0x20,0x15,0x3C,0x57,0x38,0x00,0x07,
+ 0x49,0x25,0x61,0x2F,0x2B,0x4E,0x64,0x00,
+ 0x45,0x41,0x6D,0x52,0x31,0x66,0x22,0x59,
+ 0x00,0x70,0x6F,0x5B,0x46,0x6E,0x67,0x5A,
+ 0x26,0x30,0x2C,0x65,0x21,0x3D,0x58,0x00,
+ 0x5E,0x44,0x0D,0x40,0x6C,0x1C,0x51,0x0A,
+ 0x35,0x2A,0x13,0x4D,0x63,0x00,0x00,0x3A,
+ 0x00,0x48,0x54,0x24,0x60,0x1E,0x2E,0x01,
+ 0x56,0x03,0x37,0x00,0x04,0x00,0x05,0x06,
+ 0x00,0x55,0x1F,0x02,0x36,0x14,0x00,0x3B,
+ 0x5F,0x0E,0x1D,0x0B,0x27,0x2D,0x3E,0x00,
+ 0x00,0x5C,0x47,0x68,0x42,0x53,0x32,0x23,
+ 0x4A,0x62,0x4F,0x00,0x00,0x16,0x39,0x08,
+ 0x6A,0x34,0x10,0x29,0x12,0x1A,0x4C,0x18
};
@@ -99,106 +99,101 @@ static const UINT8 kmap[128] =
UINT16 atari_xga_device::ctz(UINT16 x)
{
- UINT16 n = 0;
- if (x == 0) return 16;
- if (!(x & 0x00FF)) n += 8, x >>= 8;
- if (!(x & 0x000F)) n += 4, x >>= 4;
- if (!(x & 0x0003)) n += 2, x >>= 2;
- if (!(x & 0x0001)) n += 1, x >>= 1;
- return n;
+ UINT16 n = 0;
+ if (x == 0) return 16;
+ if (!(x & 0x00FF)) n += 8, x >>= 8;
+ if (!(x & 0x000F)) n += 4, x >>= 4;
+ if (!(x & 0x0003)) n += 2, x >>= 2;
+ if (!(x & 0x0001)) n += 1, x >>= 1;
+ return n;
}
size_t atari_xga_device::popcount(UINT16 x)
{
- size_t count = 0;
- while (x != 0)
- {
- count += 1;
- x &= x - 1;
- }
- return count;
+ size_t count = 0;
+ while (x != 0)
+ {
+ count += 1;
+ x &= x - 1;
+ }
+ return count;
}
UINT16 atari_xga_device::parity(UINT16 x)
{
- return popcount(x) & 1;
+ return popcount(x) & 1;
}
UINT16 atari_xga_device::lfsr1(UINT16 x)
{
- UINT16 bit = parity(x & 0x8016);
- return (x << 1) | bit;
+ const UINT16 bit = parity(x & 0x8016);
+ return (x << 1) | bit;
}
UINT16 atari_xga_device::lfsr2(UINT16 x)
{
- UINT16 bit = parity(x & 0x002D);
- return (x >> 1) | (bit << 15);
+ UINT16 bit = parity(x & 0x002D);
+ return (x >> 1) | (bit << 15);
}
UINT16 atari_xga_device::powers2(UINT8 k, UINT16 x)
{
- static const UINT16 L[16] =
- {
- 0x5E85,0xBD0B,0x2493,0x17A3,
- 0x2F47,0x0005,0x000B,0x0017,
- 0x002F,0x005E,0x00BD,0x017A,
- 0x02F4,0x05E8,0x0BD0,0x17A1
- };
-
- UINT16 t = (x == 16) ? (L[4] ^ L[5]) : L[x];
-
- for (size_t i = 0; i < k; ++i)
- {
- t = lfsr1(t);
- }
-
- return t;
+ static const UINT16 L[16] = {
+ 0x5E85,0xBD0B,0x2493,0x17A3,
+ 0x2F47,0x0005,0x000B,0x0017,
+ 0x002F,0x005E,0x00BD,0x017A,
+ 0x02F4,0x05E8,0x0BD0,0x17A1
+ };
+
+ UINT16 t = (x == 16) ? (L[4] ^ L[5]) : L[x];
+
+ for (size_t i = 0; i < k; ++i)
+ t = lfsr1(t);
+
+ return t;
}
UINT16 atari_xga_device::decipher(UINT8 k, UINT16 c)
{
- UINT16 bit, i, p = 0;
-
- /* Only 128 keys internally, if high bit set,
- then find the 7-bit "twin" by xor 0xA8. */
- if (k & 0x80)
- k ^= 0xA8;
-
- k = kmap[k];
-
- if ((c & (c - 1)) == 0)
- {
- return powers2(k, ctz(c));
- }
-
- for (bit = 0; bit < 5; ++bit)
- {
- if ((c >> bit) & 1)
- {
- p ^= powers2(k, bit);
- }
- }
-
- for (bit = 5; bit < 16; ++bit)
- {
- if ((c >> bit) & 1)
- {
- p ^= powers2(k, bit + 1);
- }
- }
-
- UINT16 x = 0x8010;
- for (i = 0; i < k + 3; ++i)
- {
- if (x == c)
- {
- return (p == 1) ? 0 : lfsr2(p);
- }
- x = lfsr2(x);
- }
-
- return p;
+ UINT16 p = 0;
+
+ /* Only 128 keys internally, if high bit set,
+ then find the 7-bit "twin" by xor 0xA8. */
+ if (k & 0x80)
+ k ^= 0xA8;
+
+ k = kmap[k];
+
+ if ((c & (c - 1)) == 0)
+ return powers2(k, ctz(c));
+
+ for (UINT16 bit = 0; bit < 5; ++bit)
+ {
+ if ((c >> bit) & 1)
+ {
+ p ^= powers2(k, bit);
+ }
+ }
+
+ for (UINT16 bit = 5; bit < 16; ++bit)
+ {
+ if ((c >> bit) & 1)
+ {
+ p ^= powers2(k, bit + 1);
+ }
+ }
+
+ UINT16 x = 0x8010;
+ for (UINT16 i = 0; i < k + 3; ++i)
+ {
+ if (x == c)
+ {
+ return (p == 1) ? 0 : lfsr2(p);
+ }
+ x = lfsr2(x);
+ }
+
+ return p;
}
@@ -211,90 +206,86 @@ UINT16 atari_xga_device::decipher(UINT8 k, UINT16 c)
WRITE32_MEMBER(atari_xga_device::write)
{
- switch (m_mode)
- {
- case FPGA_RESET:
- return;
-
- case FPGA_SETKEY:
- /* Write table to FPGA SRAM. */
- if (ACCESSING_BITS_16_31)
- m_ram[offset << 1] = UINT16 (data >> 16);
- if (ACCESSING_BITS_0_15)
- m_ram[(offset << 1) + 1] = UINT16(data & 0xFFFF);
-
- break;
-
- case FPGA_DECIPHER:
- /* Send Ciphertext to FPGA for decryption. */
- if (ACCESSING_BITS_16_31)
- {
- m_address = offset << 2;
- m_ciphertext = UINT16(data >> 16);
- }
- if (ACCESSING_BITS_0_15)
- {
- m_address = (offset << 2) + 2;
- m_ciphertext = UINT16(data & 0xFFFF);
- }
- break;
- }
+ switch (m_mode)
+ {
+ case FPGA_RESET:
+ return;
+
+ case FPGA_SETKEY:
+ /* Write table to FPGA SRAM. */
+ if (ACCESSING_BITS_16_31)
+ m_ram[offset << 1] = UINT16 (data >> 16);
+ if (ACCESSING_BITS_0_15)
+ m_ram[(offset << 1) + 1] = UINT16(data & 0xFFFF);
+ break;
+
+ case FPGA_DECIPHER:
+ /* Send Ciphertext to FPGA for decryption. */
+ if (ACCESSING_BITS_16_31)
+ {
+ m_address = offset << 2;
+ m_ciphertext = UINT16(data >> 16);
+ }
+ if (ACCESSING_BITS_0_15)
+ {
+ m_address = (offset << 2) + 2;
+ m_ciphertext = UINT16(data & 0xFFFF);
+ }
+ break;
+ }
}
READ32_MEMBER(atari_xga_device::read)
{
- UINT32 plaintext = 0;
-
- switch (offset << 2)
- {
- case 0x0FC0:
- m_mode = FPGA_RESET;
- break;
- case 0x0010:
- m_mode = FPGA_SETKEY;
- break;
- case 0x0020:
- m_mode = FPGA_DECIPHER;
- break;
- }
-
- if (m_mode == FPGA_RESET)
- {
- return 0;
- }
-
- if (m_mode == FPGA_DECIPHER)
- {
- UINT16 address = (offset << 2) - 0x400;
-
- if (ACCESSING_BITS_0_15)
- address += 2;
-
- /* Reply with decrypted plaintext */
- if (address == m_address)
- {
- UINT16 key_offset, key_byte;
-
- /* Algorithm to select key byte based on offset. */
- key_offset = ((((address >> 4) & 1) ^ 1) << 0)
- ^ ((((address >> 2) & 1) ^ 0) << 1)
- ^ ((((address >> 8) & 1) ^ 0) << 2)
- ^ ((((address >> 3) & 1) ^ 1) << 3)
- ^ ((((address >> 1) & 1) ^ 1) << 4)
- ^ ((((address >> 6) & 1) ^ 0) << 5)
- ^ ((((address >> 7) & 1) ^ 0) << 6)
- ^ ((((address >> 5) & 1) ^ 1) << 7)
- ^ ((((address >> 9) & 1) ^ 0) << 8)
- ^ ((((address >> 10) & 1) ^ 0) << 9);
- key_byte = m_ram[key_offset];
-
- /* And now for the full magic. */
- plaintext = decipher(key_byte, m_ciphertext);
-
- if (ACCESSING_BITS_16_31)
- plaintext <<= 16;
- }
- }
-
- return plaintext;
+ switch (offset << 2)
+ {
+ case 0x0FC0:
+ m_mode = FPGA_RESET;
+ break;
+ case 0x0010:
+ m_mode = FPGA_SETKEY;
+ break;
+ case 0x0020:
+ m_mode = FPGA_DECIPHER;
+ break;
+ }
+
+ if (m_mode == FPGA_RESET)
+ return 0;
+
+ UINT32 plaintext = 0;
+ if (m_mode == FPGA_DECIPHER)
+ {
+ UINT16 address = (offset << 2) - 0x400;
+
+ if (ACCESSING_BITS_0_15)
+ address += 2;
+
+ /* Reply with decrypted plaintext */
+ if (address == m_address)
+ {
+ UINT16 key_offset, key_byte;
+
+ /* Algorithm to select key byte based on offset. */
+ key_offset = ((((address >> 4) & 1) ^ 1) << 0)
+ ^ ((((address >> 2) & 1) ^ 0) << 1)
+ ^ ((((address >> 8) & 1) ^ 0) << 2)
+ ^ ((((address >> 3) & 1) ^ 1) << 3)
+ ^ ((((address >> 1) & 1) ^ 1) << 4)
+ ^ ((((address >> 6) & 1) ^ 0) << 5)
+ ^ ((((address >> 7) & 1) ^ 0) << 6)
+ ^ ((((address >> 5) & 1) ^ 1) << 7)
+ ^ ((((address >> 9) & 1) ^ 0) << 8)
+ ^ ((((address >> 10) & 1) ^ 0) << 9);
+ key_byte = m_ram[key_offset];
+
+ /* And now for the full magic. */
+ plaintext = decipher(key_byte, m_ciphertext);
+
+ if (ACCESSING_BITS_16_31)
+ plaintext <<= 16;
+ }
+ }
+
+ return plaintext;
}