mirror of
https://github.com/MoleskiCoder/EightBit.git
synced 2024-06-12 01:29:27 +00:00
73 lines
1.5 KiB
C++
73 lines
1.5 KiB
C++
#include "stdafx.h"
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#include "Processor.h"
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EightBit::Processor::Processor(Bus& bus)
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: m_bus(bus) {
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}
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DEFINE_PIN_LEVEL_CHANGERS(RESET, Processor);
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DEFINE_PIN_LEVEL_CHANGERS(INT, Processor);
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void EightBit::Processor::handleRESET() {
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raiseRESET();
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}
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void EightBit::Processor::handleINT() {
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raiseINT();
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}
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void EightBit::Processor::memoryWrite(const register16_t address, const uint8_t data) {
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BUS().ADDRESS() = address;
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memoryWrite(data);
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}
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void EightBit::Processor::memoryWrite(const uint8_t data) {
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BUS().DATA() = data;
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memoryWrite();
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}
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void EightBit::Processor::memoryWrite() {
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busWrite();
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}
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void EightBit::Processor::busWrite() {
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BUS().write();
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}
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uint8_t EightBit::Processor::memoryRead(const register16_t address) {
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BUS().ADDRESS() = address;
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return memoryRead();
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}
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uint8_t EightBit::Processor::memoryRead() {
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return busRead();
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}
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uint8_t EightBit::Processor::busRead() {
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return BUS().read();
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}
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int EightBit::Processor::run(const int limit) {
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int current = 0;
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while (LIKELY(powered() && (current < limit)))
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current += step();
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return current;
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}
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int EightBit::Processor::execute(const uint8_t value) {
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opcode() = value;
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return execute();
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}
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// http://graphics.stanford.edu/~seander/bithacks.html#FixedSignExtend
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int8_t EightBit::Processor::signExtend(const int b, uint8_t x) {
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const uint8_t m = bit(b - 1); // mask can be pre-computed if b is fixed
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x = x & (bit(b) - 1); // (Skip this if bits in x above position b are already zero.)
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const auto result = (x ^ m) - m;
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return result;
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}
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void EightBit::Processor::ret() {
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jump(popWord());
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}
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