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Starts attempting to kill the need to prepare all bus step sequences in advance.

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Thomas Harte 2019-03-16 21:47:46 -04:00
parent 4cbf2bef82
commit d0c5cf0d2d
3 changed files with 56 additions and 51 deletions
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9
Processors/68000/68000.hpp
View File

@ -12,6 +12,7 @@
#include <cstdint>
#include <iomanip>
#include <iostream>
#include <tuple>
#include <vector>
#include "../../ClockReceiver/ClockReceiver.hpp"
@ -80,7 +81,7 @@ struct Microcycle {
static const int IsProgram = 1 << 6;
int operation = 0;
HalfCycles length = HalfCycles(2);
HalfCycles length = HalfCycles(4);
/*!
For expediency, this provides a full 32-bit byte-resolution address — e.g.
@ -92,6 +93,12 @@ struct Microcycle {
const uint32_t *address = nullptr;
RegisterPair16 *value = nullptr;
bool operator ==(const Microcycle &rhs) const {
return
std::make_tuple(value, address, length, operation, value) ==
std::make_tuple(rhs.value, rhs.address, rhs.length, rhs.operation, rhs.value);
}
// Various inspectors.
/*! @returns true if any data select line is active; @c false otherwise. */

89
Processors/68000/Implementation/68000Storage.cpp
View File

@ -8,7 +8,7 @@
#include "../68000.hpp"
#include <array>
#include <algorithm>
namespace CPU {
namespace MC68000 {
@ -61,12 +61,13 @@ struct ProcessorStorageConstructor {
data from those.
*/
size_t assemble_program(const char *access_pattern, const std::vector<uint32_t *> &addresses = {}, bool read_full_words = true) {
const size_t start = storage_.all_bus_steps_.size();
auto address_iterator = addresses.begin();
RegisterPair32 *scratch_data_read = storage_.bus_data_;
RegisterPair32 *scratch_data_write = storage_.bus_data_;
using Action = BusStep::Action;
std::vector<BusStep> steps;
// Parse the access pattern to build microcycles.
while(*access_pattern) {
ProcessorBase::BusStep step;
@ -81,13 +82,13 @@ struct ProcessorStorageConstructor {
switch(access_pattern[1]) {
default: // This is probably a pure NOP; if what comes after this 'n' isn't actually
// valid, it should be caught in the outer switch the next time around the loop.
storage_.all_bus_steps_.push_back(step);
steps.push_back(step);
++access_pattern;
break;
case '-': // This is two NOPs in a row.
storage_.all_bus_steps_.push_back(step);
storage_.all_bus_steps_.push_back(step);
steps.push_back(step);
steps.push_back(step);
access_pattern += 2;
break;
@ -97,12 +98,12 @@ struct ProcessorStorageConstructor {
step.microcycle.operation = Microcycle::NewAddress | Microcycle::Read | Microcycle::IsProgram; // IsProgram is a guess.
step.microcycle.address = &storage_.effective_address_;
step.microcycle.value = isupper(access_pattern[1]) ? &storage_.stack_pointers_[1].halves.high : &storage_.stack_pointers_[1].halves.low;
storage_.all_bus_steps_.push_back(step);
steps.push_back(step);
step.microcycle.length = HalfCycles(3);
step.microcycle.operation = Microcycle::SelectWord | Microcycle::Read | Microcycle::IsProgram;
step.action = Action::IncrementEffectiveAddress;
storage_.all_bus_steps_.push_back(step);
steps.push_back(step);
access_pattern += 2;
break;
@ -113,12 +114,12 @@ struct ProcessorStorageConstructor {
step.microcycle.operation = Microcycle::NewAddress | Microcycle::Read | Microcycle::IsProgram; // IsProgram is a guess.
step.microcycle.address = &storage_.effective_address_;
step.microcycle.value = isupper(access_pattern[1]) ? &storage_.program_counter_.halves.high : &storage_.program_counter_.halves.low;
storage_.all_bus_steps_.push_back(step);
steps.push_back(step);
step.microcycle.length = HalfCycles(3);
step.microcycle.operation |= Microcycle::SelectWord | Microcycle::Read | Microcycle::IsProgram;
step.action = Action::IncrementEffectiveAddress;
storage_.all_bus_steps_.push_back(step);
steps.push_back(step);
access_pattern += 2;
break;
@ -129,12 +130,12 @@ struct ProcessorStorageConstructor {
step.microcycle.address = &storage_.program_counter_.full;
step.microcycle.value = &storage_.prefetch_queue_[1];
step.action = Action::AdvancePrefetch;
storage_.all_bus_steps_.push_back(step);
steps.push_back(step);
step.microcycle.length = HalfCycles(3);
step.microcycle.operation |= Microcycle::SelectWord | Microcycle::Read | Microcycle::IsProgram;
step.action = Action::IncrementProgramCounter;
storage_.all_bus_steps_.push_back(step);
steps.push_back(step);
access_pattern += 2;
break;
@ -150,11 +151,11 @@ struct ProcessorStorageConstructor {
step.microcycle.operation = Microcycle::NewAddress | (is_read ? Microcycle::Read : 0);
step.microcycle.address = *address_iterator;
step.microcycle.value = isupper(access_pattern[1]) ? &(*scratch_data)->halves.high : &(*scratch_data)->halves.low;
storage_.all_bus_steps_.push_back(step);
steps.push_back(step);
step.microcycle.length = HalfCycles(3);
step.microcycle.operation |= (read_full_words ? Microcycle::SelectWord : Microcycle::SelectByte) | (is_read ? Microcycle::Read : 0);
storage_.all_bus_steps_.push_back(step);
steps.push_back(step);
++address_iterator;
if(!isupper(access_pattern[1])) ++(*scratch_data);
@ -172,36 +173,18 @@ struct ProcessorStorageConstructor {
// Add a final 'ScheduleNextProgram' sentinel.
BusStep end_program;
end_program.action = Action::ScheduleNextProgram;
storage_.all_bus_steps_.push_back(end_program);
steps.push_back(end_program);
return start;
}
struct BusStepCollection {
size_t six_step_Dn;
size_t four_step_Dn;
// The next two are indexed as [source][destination].
size_t double_predec_byte[8][8];
size_t double_predec_word[8][8];
size_t double_predec_long[8][8];
};
BusStepCollection assemble_standard_bus_steps() {
BusStepCollection collection;
collection.four_step_Dn = assemble_program("np");
collection.six_step_Dn = assemble_program("np n");
for(int s = 0; s < 8; ++s) {
for(int d = 0; d < 8; ++d) {
collection.double_predec_byte[s][d] = assemble_program("n nr nr np nw", { &storage_.address_[s].full, &storage_.address_[d].full, &storage_.address_[d].full }, false);
collection.double_predec_word[s][d] = assemble_program("n nr nr np nw", { &storage_.address_[s].full, &storage_.address_[d].full, &storage_.address_[d].full });
// collection.double_predec_long[s][d] = assemble_program("n nr nR nr nR nw np nW", { &address_[s].full, &address_[d].full, &address_[d].full });
}
// If the new steps already exist, just return the existing index to them;
// otherwise insert them.
const auto position = std::search(storage_.all_bus_steps_.begin(), storage_.all_bus_steps_.end(), steps.begin(), steps.end());
if(position != storage_.all_bus_steps_.end()) {
return size_t(position - storage_.all_bus_steps_.begin());
}
return collection;
const auto start = storage_.all_bus_steps_.size();
std::copy(steps.begin(), steps.end(), std::back_inserter(storage_.all_bus_steps_));
return start;
}
/*!
@ -219,7 +202,7 @@ struct ProcessorStorageConstructor {
from known instructions to their disassembly rather than vice versa; especially
(iii) given that there are plentiful disassemblers against which to test work in progress.
*/
void install_instructions(const BusStepCollection &bus_step_collection) {
void install_instructions() {
enum class Decoder {
Decimal,
RegOpModeReg,
@ -268,6 +251,11 @@ struct ProcessorStorageConstructor {
std::vector<size_t> micro_op_pointers(65536, std::numeric_limits<size_t>::max());
// The arbitrary_base is used so that the offsets returned by assemble_program into
// storage_.all_bus_steps_ can be retained and mapped into the final version of
// storage_.all_bus_steps_ at the end.
BusStep arbitrary_base;
// Perform a linear search of the mappings above for this instruction.
for(size_t instruction = 0; instruction < 65536; ++instruction) {
for(const auto &mapping: mappings) {
@ -287,16 +275,15 @@ struct ProcessorStorageConstructor {
storage_.all_micro_ops_.emplace_back(
Action::PredecrementSourceAndDestination1,
&storage_.all_bus_steps_[bus_step_collection.double_predec_byte[source][destination]]);
&arbitrary_base + assemble_program("n nr nr np nw", { &storage_.address_[source].full, &storage_.address_[destination].full, &storage_.address_[destination].full }, false));
storage_.all_micro_ops_.emplace_back(Action::PerformOperation);
storage_.all_micro_ops_.emplace_back();
} else {
storage_.instructions[instruction].source = &storage_.data_[source];
storage_.instructions[instruction].destination = &storage_.data_[destination];
storage_.all_micro_ops_.emplace_back(
Action::PerformOperation,
&storage_.all_bus_steps_[bus_step_collection.six_step_Dn]);
&arbitrary_base + assemble_program("np n"));
storage_.all_micro_ops_.emplace_back();
}
} break;
@ -315,13 +302,18 @@ struct ProcessorStorageConstructor {
}
}
// Finalise micro-op pointers.
// Finalise micro-op and program pointers.
for(size_t instruction = 0; instruction < 65536; ++instruction) {
if(micro_op_pointers[instruction] != std::numeric_limits<size_t>::max()) {
storage_.instructions[instruction].micro_operations = &storage_.all_micro_ops_[micro_op_pointers[instruction]];
auto operation = storage_.instructions[instruction].micro_operations;
while(!operation->is_terminal()) {
operation->bus_program = storage_.all_bus_steps_.data() + (operation->bus_program - &arbitrary_base);
++operation;
}
}
}
}
private:
@ -337,11 +329,8 @@ CPU::MC68000::ProcessorStorage::ProcessorStorage() {
// Create the exception programs.
const size_t reset_offset = constructor.assemble_program("n- n- n- n- n- nn nF nf nV nv np np");
// Install all necessary access patterns.
const auto bus_steps = constructor.assemble_standard_bus_steps();
// Install operations.
constructor.install_instructions(bus_steps);
constructor.install_instructions();
// Realise the exception programs as direct pointers.
reset_program_ = &all_bus_steps_[reset_offset];

9
Processors/68000/Implementation/68000Storage.hpp
View File

@ -68,6 +68,11 @@ class ProcessorStorage {
ScheduleNextProgram
} action = Action::None;
bool operator ==(const BusStep &rhs) const {
if(action != rhs.action) return false;
return microcycle == rhs.microcycle;
}
};
/*!
@ -90,6 +95,10 @@ class ProcessorStorage {
MicroOp() {}
MicroOp(Action action) : action(action) {}
MicroOp(Action action, BusStep *bus_program) : action(action), bus_program(bus_program) {}
inline bool is_terminal() const {
return bus_program == nullptr;
}
};
/*!