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naomi notes (nw)

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This commit is contained in:
MetalliC 2015-11-14 16:20:55 +02:00
parent 1c0bcf1bb8
commit 904e13184c
1 changed files with 7 additions and 2 deletions
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9
src/mame/machine/naomim2.cpp
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@ -11,6 +11,11 @@ Naomi cartridge type M2/3 mapping
NAOMI_ROM_OFFSET bit29: ROM size/mapping selection, 0 - 4MB ROM mode, 1 - 8MB ROM mode
bit28: Bank selection.
in the case of flash-based 171-7885A ROM boards two of them can be stacked at once
onto main board. each must be configured as Bank 0 or 1 via some (currently unknown) jumper.
this bit selects which one ROM board will be accessed.
note: if ROM is not mounted its area readed as 0xFF
8MB ROM mode:
@ -166,13 +171,13 @@ void naomi_m2_board::board_advance(UINT32 size)
void naomi_m2_board::board_write(offs_t offset, UINT16 data)
{
if(offset & 0x40000000) {
if((offset & 0x0f000000) == 0x02000000) {
if(offset & 0x00020000) {
offset &= RAM_SIZE-1;
ram[offset] = data;
ram[offset+1] = data >> 8;
return;
}
switch(offset & 0x1fffffff) {
switch(offset & 0x1ffff) {
case 0x1fff8: m_cryptdevice->set_addr_low(data); return;
case 0x1fffa: m_cryptdevice->set_addr_high(data); return;
case 0x1fffc: m_cryptdevice->set_subkey(data); return;