diff options
Diffstat (limited to 'src/mame/drivers/snowbros.cpp')
| -rw-r--r-- | src/mame/drivers/snowbros.cpp | 33 |
1 files changed, 26 insertions, 7 deletions
diff --git a/src/mame/drivers/snowbros.cpp b/src/mame/drivers/snowbros.cpp index 3d1f1541797..5388efa6d48 100644 --- a/src/mame/drivers/snowbros.cpp +++ b/src/mame/drivers/snowbros.cpp @@ -520,13 +520,37 @@ void snowbros_state::finalttr_map(address_map &map) } +// Yutnori protection. +// The sequence MEN is sent to the protection device, followed by the code request (4 bytes in all). +// After each byte, a number of NOPs are executed to give the device time to catch up. +// After the 4th byte, the code reads the device to get its response. +READ16_MEMBER(snowbros_state::yutnori_prot_r) +{ + switch(m_yutnori_prot_val) // the 4th byte + { + case 0x33: // C3B6 + return 0xcc; + case 0x60: // 4878 + return 0xf9; + case 0xb8: // D820 + return 0x74; + } + logerror("%s: Unhandled protection sequence found: %02X\n", machine().describe_context(), m_yutnori_prot_val); + return 0; +} + +WRITE16_MEMBER(snowbros_state::yutnori_prot_w) +{ + m_yutnori_prot_val = data; +} + void snowbros_state::yutnori_map(address_map &map) { map(0x000000, 0x03ffff).rom(); // 0x100000 clr.w on startup - // 0x200000 could be the protection device, it makes several writes, then executes an entire subroutine of NOPs.. + map(0x200000, 0x200001).rw(FUNC(snowbros_state::yutnori_prot_r),FUNC(snowbros_state::yutnori_prot_w)); // protection map(0x300000, 0x300001).portr("DSW1"); map(0x300002, 0x300003).portr("DSW2"); @@ -2890,12 +2914,7 @@ void snowbros_state::init_hyperpac() void snowbros_state::init_yutnori() { - // presumably related to the PIC protection - uint16_t *rom = (uint16_t *)memregion("maincpu")->base(); - rom[0x4878 / 2] = 0x4e71; - rom[0xd820 / 2] = 0x4e71; - rom[0xc3b6 / 2] = 0x4e71; - + m_yutnori_prot_val = 0; m_pandora->set_bg_pen(0xf0); } |