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This commit is contained in:
Thomas Harte 2024-03-06 15:31:07 -05:00
parent 108a056f1c
commit bbb520fd12
1 changed files with 28 additions and 1 deletions
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29
Machines/Acorn/Archimedes/Archimedes.cpp
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@ -94,6 +94,7 @@ struct Memory {
high_rom_access_time_ = ROMAccessTime((address >> 6) & 3);
low_rom_access_time_ = ROMAccessTime((address >> 4) & 3);
page_size_ = PageSize((address >> 2) & 3);
update_mapping();
logger.info().append("MEMC Control: %08x/%08x -> OS:%d sound:%d video:%d high:%d low:%d size:%d", address, source, os_mode_, sound_dma_enable_, video_dma_enable_, high_rom_access_time_, low_rom_access_time_, page_size_);
@ -126,7 +127,8 @@ struct Memory {
return true;
case Zone::AddressTranslator:
logger.error().append("TODO: Write address translator of %08x to %08x", source, address);
pages_[address & 0x7f] = address;
update_mapping();
break;
default:
@ -166,6 +168,7 @@ struct Memory {
break;
case Zone::HighROM:
// TODO: require A24=A25=0, then A25=1.
has_moved_rom_ = true;
source = high_rom<IntT>(address);
return true;
@ -198,6 +201,11 @@ struct Memory {
return true;
}
Memory() {
// Install initial logical memory map.
update_mapping();
}
private:
bool has_moved_rom_ = false;
std::array<uint8_t, 4*1024*1024> ram_{};
@ -264,11 +272,30 @@ struct Memory {
template <typename IntT, bool is_read>
IntT *logical_ram(uint32_t address, InstructionSet::ARM::Mode) {
// TODO: (1) which logical page is this?
logger.error().append("TODO: Logical RAM mapping at %08x", address);
// 4kb:
// A[6:0] -> PPN[6:0]
// A[11:10] -> LPN[12:11]; A[22:12] -> LPN[10:0]
// 8kb:
// A[0] -> PPN[6]; A[6:1] -> PPN[5:0]
// A[11:10] -> LPN[11:10]; A[22:13] -> LPN[9:0]
// 16kb:
// A[1:0] -> PPN[6:5]; A[6:2] -> PPN[4:0]
// A[11:10] -> LPN[10:9]; A[22:14] -> LPN[8:0]
// 32kb:
// A[1] -> PPN[6]; A[2] -> PPN[5]; A[0] -> PPN[4]; A[6:3] -> PPN[6:3]
// A[11:10] -> LPN[9:8]; A[22:15] -> LPN[7:0]
return nullptr;
}
void update_mapping() {
logger.error().append("TODO: Update logical RAM mapping");
}
};