6502/CLK
1
0
Fork 0
mirror of https://github.com/TomHarte/CLK.git synced 2024-07-05 10:28:58 +00:00
Code Issues Projects Releases Wiki Activity

Give Nick some RAM to inspect and just enough sense to know when it should reload its line parameter table.

Browse Source
This commit is contained in:
Thomas Harte 2021-06-15 17:43:13 -04:00
parent 440b11708b
commit a1e4389f63
3 changed files with 33 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
Machines/Enterprise/Enterprise.cpp
View File

@ -63,7 +63,8 @@ class ConcreteMachine:
public MachineTypes::TimedMachine {
public:
ConcreteMachine([[maybe_unused]] const Analyser::Static::Enterprise::Target &target, const ROMMachine::ROMFetcher &rom_fetcher) :
z80_(*this) {
z80_(*this),
nick_(ram_.end() - 65536) {
// Request a clock of 4Mhz; this'll be mapped upwards for Nick and Dave elsewhere.
set_clock_rate(4'000'000);
@ -189,11 +190,9 @@ class ConcreteMachine:
}
private:
CPU::Z80::Processor<ConcreteMachine, false, false> z80_;
// MARK: - Memory layout
std::array<uint8_t, 32 * 1024> exos_;
std::array<uint8_t, 256 * 1024> ram_;
std::array<uint8_t, 32 * 1024> exos_;
const uint8_t min_ram_slot_ = 0xff - 3;
const uint8_t *read_pointers_[4] = {nullptr, nullptr, nullptr, nullptr};
@ -209,7 +208,8 @@ class ConcreteMachine:
}
if(offset >= min_ram_slot_) {
const size_t address = (offset - min_ram_slot_) * 0x4000;
const auto ram_floor = 4194304 - ram_.size();
const size_t address = offset * 0x4000 - ram_floor;
page<slot>(&ram_[address], &ram_[address]);
return;
}
@ -236,7 +236,8 @@ class ConcreteMachine:
z80_.run_for(cycles);
}
// MARK: - Video.
// MARK: - Chips.
CPU::Z80::Processor<ConcreteMachine, false, false> z80_;
JustInTimeActor<Nick, HalfCycles, 444923, 125000> nick_;
// Cf. timing guesses above.
};

23
Machines/Enterprise/Nick.cpp
View File

@ -12,17 +12,34 @@
using namespace Enterprise;
Nick::Nick() :
crt_(16 * 57, 16, Outputs::Display::Type::PAL50, Outputs::Display::InputDataType::Red4Green4Blue4) {
Nick::Nick(const uint8_t *ram) :
crt_(16 * 57, 16, Outputs::Display::Type::PAL50, Outputs::Display::InputDataType::Red4Green4Blue4),
ram_(ram) {
// Just use RGB for now.
crt_.set_display_type(Outputs::Display::DisplayType::RGB);
}
void Nick::write(uint16_t address, uint8_t value) {
printf("Nick write: %02x -> %d\n", value, address & 3);
switch(address & 3) {
default:
printf("Unhandled Nick write: %02x -> %d\n", value, address & 3);
printf("Unhandled\n");
break;
case 2:
line_parameter_base_ = uint16_t((line_parameter_base_ & 0xf000) | (value << 4));
break;
case 3:
line_parameter_base_ = uint16_t((line_parameter_base_ & 0x0ff0) | (value << 12));
// Still a mystery to me: the exact meaning of the top two bits here. For now
// just treat a 0 -> 1 transition of the MSB as a forced frame restart.
if((value^line_parameter_control_) & value & 0x80) {
// TODO: restart frame.
printf("Should restart frame from %04x\n", line_parameter_base_);
}
line_parameter_control_ = value & 0xc0;
break;
}
}

7
Machines/Enterprise/Nick.hpp
View File

@ -17,7 +17,7 @@ namespace Enterprise {
class Nick {
public:
Nick();
Nick(const uint8_t *ram);
void write(uint16_t address, uint8_t value);
uint8_t read(uint16_t address);
@ -29,6 +29,11 @@ class Nick {
private:
Outputs::CRT::CRT crt_;
const uint8_t *const ram_;
uint8_t line_parameter_control_ = 0xc0;
uint16_t line_parameter_base_ = 0x0000;
int horizontal_counter_ = 0;
};