mirror of
https://github.com/TomHarte/CLK.git
synced 2024-12-29 13:29:46 +00:00
124 lines
4.1 KiB
C++
124 lines
4.1 KiB
C++
//
|
|
// Parser.hpp
|
|
// Clock Signal
|
|
//
|
|
// Created by Thomas Harte on 16/01/21.
|
|
// Copyright © 2021 Thomas Harte. All rights reserved.
|
|
//
|
|
|
|
#ifndef InstructionSets_M50740_Parser_hpp
|
|
#define InstructionSets_M50740_Parser_hpp
|
|
|
|
#include <cstdint>
|
|
#include "Decoder.hpp"
|
|
#include "../AccessType.hpp"
|
|
|
|
namespace InstructionSet::M50740 {
|
|
|
|
template<typename Target, bool include_entries_and_accesses> struct Parser {
|
|
void parse(Target &target, const uint8_t *storage, uint16_t start, uint16_t closing_bound) {
|
|
Decoder decoder;
|
|
|
|
while(start <= closing_bound) {
|
|
const auto next = decoder.decode(&storage[start], 1 + closing_bound - start);
|
|
if(next.first <= 0) {
|
|
// If there weren't enough bytes left before the closing bound to complete
|
|
// an instruction, but implicitly there were some bytes left, announce overflow
|
|
// and terminate.
|
|
target.announce_overflow(start);
|
|
return;
|
|
} else {
|
|
// Pass on the instruction.
|
|
target.announce_instruction(start, next.second);
|
|
|
|
if constexpr(!include_entries_and_accesses) {
|
|
// Do a simplified test: is this a terminating operation?
|
|
switch(next.second.operation) {
|
|
case Operation::RTS: case Operation::RTI: case Operation::BRK:
|
|
case Operation::JMP: case Operation::BRA:
|
|
return;
|
|
|
|
default: break;
|
|
}
|
|
} else {
|
|
// Check for end of stream and potential new entry points.
|
|
switch(next.second.operation) {
|
|
// Terminating instructions.
|
|
case Operation::RTS: case Operation::RTI: case Operation::BRK:
|
|
return;
|
|
|
|
// Terminating operations, possibly with implied additional entry point.
|
|
case Operation::JMP:
|
|
if(next.second.addressing_mode == AddressingMode::Absolute) {
|
|
target.add_entry(uint16_t(storage[start + 1] | (storage[start + 2] << 8)));
|
|
}
|
|
return;
|
|
case Operation::BRA:
|
|
target.add_entry(uint16_t(start + 2 + int8_t(storage[start + 1])));
|
|
return;
|
|
|
|
// Instructions that suggest another entry point but don't terminate parsing.
|
|
case Operation::BCC: case Operation::BCS:
|
|
case Operation::BVC: case Operation::BVS:
|
|
case Operation::BMI: case Operation::BPL:
|
|
case Operation::BNE: case Operation::BEQ:
|
|
target.add_entry(uint16_t(start + 2 + int8_t(storage[start + 1])));
|
|
break;
|
|
case Operation::JSR:
|
|
switch(next.second.addressing_mode) {
|
|
default: break;
|
|
case AddressingMode::Absolute:
|
|
target.add_entry(uint16_t(storage[start + 1] | (storage[start + 2] << 8)));
|
|
break;
|
|
case AddressingMode::SpecialPage:
|
|
target.add_entry(uint16_t(storage[start + 1] | 0x1f00));
|
|
break;
|
|
}
|
|
break;
|
|
|
|
case Operation::BBS0: case Operation::BBS1: case Operation::BBS2: case Operation::BBS3:
|
|
case Operation::BBS4: case Operation::BBS5: case Operation::BBS6: case Operation::BBS7:
|
|
case Operation::BBC0: case Operation::BBC1: case Operation::BBC2: case Operation::BBC3:
|
|
case Operation::BBC4: case Operation::BBC5: case Operation::BBC6: case Operation::BBC7:
|
|
switch(next.second.addressing_mode) {
|
|
default: break;
|
|
case AddressingMode::AccumulatorRelative:
|
|
target.add_entry(uint16_t(start + 2 + int8_t(storage[start + 1])));
|
|
break;
|
|
case AddressingMode::ZeroPageRelative:
|
|
target.add_entry(uint16_t(start + 3 + int8_t(storage[start + 2])));
|
|
break;
|
|
}
|
|
break;
|
|
|
|
|
|
default: break;
|
|
}
|
|
|
|
// Provide any fixed address accesses.
|
|
switch(next.second.addressing_mode) {
|
|
case AddressingMode::Absolute:
|
|
target.add_access(uint16_t(storage[start + 1] | (storage[start + 2] << 8)), access_type(next.second.operation));
|
|
break;
|
|
case AddressingMode::ZeroPage: case AddressingMode::ZeroPageRelative:
|
|
target.add_access(storage[start + 1], access_type(next.second.operation));
|
|
break;
|
|
case AddressingMode::ImmediateZeroPage:
|
|
target.add_access(storage[start + 2], access_type(next.second.operation));
|
|
break;
|
|
|
|
default: break;
|
|
}
|
|
}
|
|
|
|
// Advance.
|
|
start += next.first;
|
|
}
|
|
}
|
|
}
|
|
};
|
|
|
|
}
|
|
|
|
#endif /* InstructionSets_M50740_Parser_hpp */
|