mirror of
https://github.com/TomHarte/CLK.git
synced 2025-01-22 19:31:27 +00:00
Evict the PIT.
This commit is contained in:
parent
d3e90ce006
commit
ee6012f6e9
@ -8,6 +8,8 @@
|
||||
|
||||
#include "PCCompatible.hpp"
|
||||
|
||||
#include "PIT.hpp"
|
||||
|
||||
#include "../../InstructionSets/x86/Decoder.hpp"
|
||||
#include "../../InstructionSets/x86/Flags.hpp"
|
||||
#include "../../InstructionSets/x86/Instruction.hpp"
|
||||
@ -82,6 +84,10 @@ class PIC {
|
||||
return 0;
|
||||
}
|
||||
|
||||
template <int vector>
|
||||
void raise() {
|
||||
}
|
||||
|
||||
private:
|
||||
bool single_pic_ = false;
|
||||
bool four_byte_vectors_ = false;
|
||||
@ -197,199 +203,6 @@ class DMA {
|
||||
} channels_[4];
|
||||
};
|
||||
|
||||
template <bool is_8254>
|
||||
class PIT {
|
||||
public:
|
||||
template <int channel> uint8_t read() {
|
||||
const auto result = channels_[channel].read();
|
||||
printf("PIT: read from %d; %02x\n", channel, result);
|
||||
return result;
|
||||
}
|
||||
|
||||
template <int channel> void write(uint8_t value) {
|
||||
printf("PIT: write to %d\n", channel);
|
||||
channels_[channel].write(value);
|
||||
}
|
||||
|
||||
void set_mode(uint8_t value) {
|
||||
const int channel_id = (value >> 6) & 3;
|
||||
if(channel_id == 3) {
|
||||
read_back_ = is_8254;
|
||||
|
||||
// TODO: decode rest of read-back command.
|
||||
return;
|
||||
}
|
||||
|
||||
printf("PIT: set mode on %d\n", channel_id);
|
||||
|
||||
Channel &channel = channels_[channel_id];
|
||||
switch((value >> 4) & 3) {
|
||||
default:
|
||||
channel.latch_value();
|
||||
return;
|
||||
|
||||
case 1: channel.latch_mode = LatchMode::LowOnly; break;
|
||||
case 2: channel.latch_mode = LatchMode::HighOnly; break;
|
||||
case 3: channel.latch_mode = LatchMode::LowHigh; break;
|
||||
}
|
||||
channel.is_bcd = value & 1;
|
||||
channel.next_access_high = false;
|
||||
|
||||
const auto operating_mode = (value >> 1) & 7;
|
||||
switch(operating_mode) {
|
||||
default: channel.mode = OperatingMode(operating_mode); break;
|
||||
case 6: channel.mode = OperatingMode::RateGenerator; break;
|
||||
case 7: channel.mode = OperatingMode::SquareWaveGenerator; break;
|
||||
}
|
||||
|
||||
// Set up operating mode.
|
||||
switch(channel.mode) {
|
||||
default:
|
||||
printf("PIT: %d switches to unimplemented mode %d\n", channel_id, int(channel.mode));
|
||||
break;
|
||||
|
||||
case OperatingMode::InterruptOnTerminalCount:
|
||||
channel.output = false;
|
||||
channel.awaiting_reload = true;
|
||||
break;
|
||||
|
||||
case OperatingMode::RateGenerator:
|
||||
channel.output = true;
|
||||
channel.awaiting_reload = true;
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
void run_for(Cycles cycles) {
|
||||
// TODO: be intelligent enough to take ticks outside the loop when appropriate.
|
||||
auto ticks = cycles.as<int>();
|
||||
while(ticks--) {
|
||||
bool output_changed;
|
||||
output_changed = channels_[0].advance(1);
|
||||
output_changed |= channels_[1].advance(1);
|
||||
output_changed |= channels_[2].advance(1);
|
||||
}
|
||||
}
|
||||
|
||||
private:
|
||||
// Supported only on 8254s.
|
||||
bool read_back_ = false;
|
||||
|
||||
enum class LatchMode {
|
||||
LowOnly,
|
||||
HighOnly,
|
||||
LowHigh,
|
||||
};
|
||||
|
||||
enum class OperatingMode {
|
||||
InterruptOnTerminalCount = 0,
|
||||
HardwareRetriggerableOneShot = 1,
|
||||
RateGenerator = 2,
|
||||
SquareWaveGenerator = 3,
|
||||
SoftwareTriggeredStrobe = 4,
|
||||
HardwareTriggeredStrobe = 5,
|
||||
};
|
||||
|
||||
struct Channel {
|
||||
LatchMode latch_mode = LatchMode::LowHigh;
|
||||
OperatingMode mode = OperatingMode::InterruptOnTerminalCount;
|
||||
bool is_bcd = false;
|
||||
|
||||
bool gated = false;
|
||||
bool awaiting_reload = true;
|
||||
|
||||
uint16_t counter = 0;
|
||||
uint16_t reload = 0;
|
||||
uint16_t latch = 0;
|
||||
bool output = false;
|
||||
|
||||
bool next_access_high = false;
|
||||
|
||||
void latch_value() {
|
||||
latch = counter;
|
||||
}
|
||||
|
||||
bool advance(int ticks) {
|
||||
if(gated || awaiting_reload) return false;
|
||||
|
||||
// TODO: BCD mode is completely ignored below. Possibly not too important.
|
||||
const bool initial_output = output;
|
||||
switch(mode) {
|
||||
case OperatingMode::InterruptOnTerminalCount:
|
||||
// Output goes permanently high upon a tick from 1 to 0; reload value is not used on wraparound.
|
||||
output |= counter <= ticks;
|
||||
counter -= ticks;
|
||||
break;
|
||||
|
||||
case OperatingMode::RateGenerator:
|
||||
// Output goes low upon a tick from 2 to 1. It goes high again on 1 to 0, and the reload value is used.
|
||||
if(counter <= ticks) {
|
||||
counter = reload - ticks + counter;
|
||||
} else {
|
||||
counter -= ticks;
|
||||
}
|
||||
output = counter != 1;
|
||||
break;
|
||||
|
||||
default:
|
||||
// TODO.
|
||||
break;
|
||||
}
|
||||
|
||||
return output != initial_output;
|
||||
}
|
||||
|
||||
void write(uint8_t value) {
|
||||
switch(latch_mode) {
|
||||
case LatchMode::LowOnly:
|
||||
reload = (reload & 0xff00) | value;
|
||||
break;
|
||||
case LatchMode::HighOnly:
|
||||
reload = uint16_t((reload & 0x00ff) | (value << 8));
|
||||
break;
|
||||
case LatchMode::LowHigh:
|
||||
next_access_high ^= true;
|
||||
if(next_access_high) {
|
||||
reload = (reload & 0xff00) | value;
|
||||
return;
|
||||
}
|
||||
|
||||
reload = uint16_t((reload & 0x00ff) | (value << 8));
|
||||
break;
|
||||
}
|
||||
|
||||
awaiting_reload = false;
|
||||
|
||||
switch(mode) {
|
||||
case OperatingMode::InterruptOnTerminalCount:
|
||||
case OperatingMode::RateGenerator:
|
||||
counter = reload;
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
uint8_t read() {
|
||||
switch(latch_mode) {
|
||||
case LatchMode::LowOnly: return uint8_t(latch);
|
||||
case LatchMode::HighOnly: return uint8_t(latch >> 8);
|
||||
default:
|
||||
case LatchMode::LowHigh:
|
||||
next_access_high ^= true;
|
||||
return next_access_high ? uint8_t(latch) : uint8_t(latch >> 8);
|
||||
break;
|
||||
}
|
||||
}
|
||||
} channels_[3];
|
||||
|
||||
// TODO:
|
||||
//
|
||||
// channel 0 is connected to IRQ 0;
|
||||
// channel 1 is used for DRAM refresh;
|
||||
// channel 2 is gated by a PPI output and feeds into the speaker.
|
||||
//
|
||||
// RateGenerator: output goes high if gated.
|
||||
};
|
||||
|
||||
struct Registers {
|
||||
public:
|
||||
static constexpr bool is_32bit = false;
|
||||
|
209
Machines/PCCompatible/PIT.hpp
Normal file
209
Machines/PCCompatible/PIT.hpp
Normal file
@ -0,0 +1,209 @@
|
||||
//
|
||||
// PIT.hpp
|
||||
// Clock Signal
|
||||
//
|
||||
// Created by Thomas Harte on 20/11/2023.
|
||||
// Copyright © 2023 Thomas Harte. All rights reserved.
|
||||
//
|
||||
|
||||
#ifndef PIT_hpp
|
||||
#define PIT_hpp
|
||||
|
||||
namespace PCCompatible {
|
||||
|
||||
template <bool is_8254>
|
||||
class PIT {
|
||||
public:
|
||||
template <int channel> uint8_t read() {
|
||||
const auto result = channels_[channel].read();
|
||||
printf("PIT: read from %d; %02x\n", channel, result);
|
||||
return result;
|
||||
}
|
||||
|
||||
template <int channel> void write(uint8_t value) {
|
||||
printf("PIT: write to %d\n", channel);
|
||||
channels_[channel].write(value);
|
||||
}
|
||||
|
||||
void set_mode(uint8_t value) {
|
||||
const int channel_id = (value >> 6) & 3;
|
||||
if(channel_id == 3) {
|
||||
read_back_ = is_8254;
|
||||
|
||||
// TODO: decode rest of read-back command.
|
||||
return;
|
||||
}
|
||||
|
||||
printf("PIT: set mode on %d\n", channel_id);
|
||||
|
||||
Channel &channel = channels_[channel_id];
|
||||
switch((value >> 4) & 3) {
|
||||
default:
|
||||
channel.latch_value();
|
||||
return;
|
||||
|
||||
case 1: channel.latch_mode = LatchMode::LowOnly; break;
|
||||
case 2: channel.latch_mode = LatchMode::HighOnly; break;
|
||||
case 3: channel.latch_mode = LatchMode::LowHigh; break;
|
||||
}
|
||||
channel.is_bcd = value & 1;
|
||||
channel.next_access_high = false;
|
||||
|
||||
const auto operating_mode = (value >> 1) & 7;
|
||||
switch(operating_mode) {
|
||||
default: channel.mode = OperatingMode(operating_mode); break;
|
||||
case 6: channel.mode = OperatingMode::RateGenerator; break;
|
||||
case 7: channel.mode = OperatingMode::SquareWaveGenerator; break;
|
||||
}
|
||||
|
||||
// Set up operating mode.
|
||||
switch(channel.mode) {
|
||||
default:
|
||||
printf("PIT: %d switches to unimplemented mode %d\n", channel_id, int(channel.mode));
|
||||
break;
|
||||
|
||||
case OperatingMode::InterruptOnTerminalCount:
|
||||
channel.output = false;
|
||||
channel.awaiting_reload = true;
|
||||
break;
|
||||
|
||||
case OperatingMode::RateGenerator:
|
||||
channel.output = true;
|
||||
channel.awaiting_reload = true;
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
void run_for(Cycles cycles) {
|
||||
// TODO: be intelligent enough to take ticks outside the loop when appropriate.
|
||||
auto ticks = cycles.as<int>();
|
||||
while(ticks--) {
|
||||
bool output_changed;
|
||||
output_changed = channels_[0].advance(1);
|
||||
output_changed |= channels_[1].advance(1);
|
||||
output_changed |= channels_[2].advance(1);
|
||||
}
|
||||
}
|
||||
|
||||
private:
|
||||
// Supported only on 8254s.
|
||||
bool read_back_ = false;
|
||||
|
||||
enum class LatchMode {
|
||||
LowOnly,
|
||||
HighOnly,
|
||||
LowHigh,
|
||||
};
|
||||
|
||||
enum class OperatingMode {
|
||||
InterruptOnTerminalCount = 0,
|
||||
HardwareRetriggerableOneShot = 1,
|
||||
RateGenerator = 2,
|
||||
SquareWaveGenerator = 3,
|
||||
SoftwareTriggeredStrobe = 4,
|
||||
HardwareTriggeredStrobe = 5,
|
||||
};
|
||||
|
||||
struct Channel {
|
||||
LatchMode latch_mode = LatchMode::LowHigh;
|
||||
OperatingMode mode = OperatingMode::InterruptOnTerminalCount;
|
||||
bool is_bcd = false;
|
||||
|
||||
bool gated = false;
|
||||
bool awaiting_reload = true;
|
||||
|
||||
uint16_t counter = 0;
|
||||
uint16_t reload = 0;
|
||||
uint16_t latch = 0;
|
||||
bool output = false;
|
||||
|
||||
bool next_access_high = false;
|
||||
|
||||
void latch_value() {
|
||||
latch = counter;
|
||||
}
|
||||
|
||||
bool advance(int ticks) {
|
||||
if(gated || awaiting_reload) return false;
|
||||
|
||||
// TODO: BCD mode is completely ignored below. Possibly not too important.
|
||||
const bool initial_output = output;
|
||||
switch(mode) {
|
||||
case OperatingMode::InterruptOnTerminalCount:
|
||||
// Output goes permanently high upon a tick from 1 to 0; reload value is not used on wraparound.
|
||||
output |= counter <= ticks;
|
||||
counter -= ticks;
|
||||
break;
|
||||
|
||||
case OperatingMode::RateGenerator:
|
||||
// Output goes low upon a tick from 2 to 1. It goes high again on 1 to 0, and the reload value is used.
|
||||
if(counter <= ticks) {
|
||||
counter = reload - ticks + counter;
|
||||
} else {
|
||||
counter -= ticks;
|
||||
}
|
||||
output = counter != 1;
|
||||
break;
|
||||
|
||||
default:
|
||||
// TODO.
|
||||
break;
|
||||
}
|
||||
|
||||
return output != initial_output;
|
||||
}
|
||||
|
||||
void write(uint8_t value) {
|
||||
switch(latch_mode) {
|
||||
case LatchMode::LowOnly:
|
||||
reload = (reload & 0xff00) | value;
|
||||
break;
|
||||
case LatchMode::HighOnly:
|
||||
reload = uint16_t((reload & 0x00ff) | (value << 8));
|
||||
break;
|
||||
case LatchMode::LowHigh:
|
||||
next_access_high ^= true;
|
||||
if(next_access_high) {
|
||||
reload = (reload & 0xff00) | value;
|
||||
return;
|
||||
}
|
||||
|
||||
reload = uint16_t((reload & 0x00ff) | (value << 8));
|
||||
break;
|
||||
}
|
||||
|
||||
awaiting_reload = false;
|
||||
|
||||
switch(mode) {
|
||||
case OperatingMode::InterruptOnTerminalCount:
|
||||
case OperatingMode::RateGenerator:
|
||||
counter = reload;
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
uint8_t read() {
|
||||
switch(latch_mode) {
|
||||
case LatchMode::LowOnly: return uint8_t(latch);
|
||||
case LatchMode::HighOnly: return uint8_t(latch >> 8);
|
||||
default:
|
||||
case LatchMode::LowHigh:
|
||||
next_access_high ^= true;
|
||||
return next_access_high ? uint8_t(latch) : uint8_t(latch >> 8);
|
||||
break;
|
||||
}
|
||||
}
|
||||
} channels_[3];
|
||||
|
||||
// TODO:
|
||||
//
|
||||
// channel 0 is connected to IRQ 0;
|
||||
// channel 1 is used for DRAM refresh;
|
||||
// channel 2 is gated by a PPI output and feeds into the speaker.
|
||||
//
|
||||
// RateGenerator: output goes high if gated.
|
||||
};
|
||||
|
||||
}
|
||||
|
||||
#endif /* PIT_hpp */
|
@ -1142,6 +1142,7 @@
|
||||
425739302AFBE47700B7D1E4 /* InOut.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = InOut.hpp; sourceTree = "<group>"; };
|
||||
425739362B051EA800B7D1E4 /* PCCompatible.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = PCCompatible.hpp; sourceTree = "<group>"; };
|
||||
425739372B051EA800B7D1E4 /* PCCompatible.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = PCCompatible.cpp; sourceTree = "<group>"; };
|
||||
4267A9C72B0C26FA008A59BB /* PIT.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = PIT.hpp; sourceTree = "<group>"; };
|
||||
4281572E2AA0334300E16AA1 /* Carry.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Carry.hpp; sourceTree = "<group>"; };
|
||||
428168372A16C25C008ECD27 /* LineLayout.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = LineLayout.hpp; sourceTree = "<group>"; };
|
||||
428168392A37AFB4008ECD27 /* DispatcherTests.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = DispatcherTests.mm; sourceTree = "<group>"; };
|
||||
@ -2360,8 +2361,9 @@
|
||||
425739352B051EA800B7D1E4 /* PCCompatible */ = {
|
||||
isa = PBXGroup;
|
||||
children = (
|
||||
425739362B051EA800B7D1E4 /* PCCompatible.hpp */,
|
||||
425739372B051EA800B7D1E4 /* PCCompatible.cpp */,
|
||||
425739362B051EA800B7D1E4 /* PCCompatible.hpp */,
|
||||
4267A9C72B0C26FA008A59BB /* PIT.hpp */,
|
||||
);
|
||||
path = PCCompatible;
|
||||
sourceTree = "<group>";
|
||||
|
Loading…
x
Reference in New Issue
Block a user