1/* Copyright (c) 2013-2016 Jeffrey Pfau
  2 *
  3 * This Source Code Form is subject to the terms of the Mozilla Public
  4 * License, v. 2.0. If a copy of the MPL was not distributed with this
  5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
  6#include "lr35902.h"
  7
  8#include "isa-lr35902.h"
  9
 10void LR35902Init(struct LR35902Core* cpu) {
 11	cpu->master->init(cpu, cpu->master);
 12	size_t i;
 13	for (i = 0; i < cpu->numComponents; ++i) {
 14		if (cpu->components[i] && cpu->components[i]->init) {
 15			cpu->components[i]->init(cpu, cpu->components[i]);
 16		}
 17	}
 18}
 19
 20void LR35902Deinit(struct LR35902Core* cpu) {
 21	if (cpu->master->deinit) {
 22		cpu->master->deinit(cpu->master);
 23	}
 24	size_t i;
 25	for (i = 0; i < cpu->numComponents; ++i) {
 26		if (cpu->components[i] && cpu->components[i]->deinit) {
 27			cpu->components[i]->deinit(cpu->components[i]);
 28		}
 29	}
 30}
 31
 32void LR35902SetComponents(struct LR35902Core* cpu, struct LR35902Component* master, int extra, struct LR35902Component** extras) {
 33	cpu->master = master;
 34	cpu->numComponents = extra;
 35	cpu->components = extras;
 36}
 37
 38
 39void LR35902HotplugAttach(struct LR35902Core* cpu, size_t slot) {
 40	if (slot >= cpu->numComponents) {
 41		return;
 42	}
 43	cpu->components[slot]->init(cpu, cpu->components[slot]);
 44}
 45
 46void LR35902HotplugDetach(struct LR35902Core* cpu, size_t slot) {
 47	if (slot >= cpu->numComponents) {
 48		return;
 49	}
 50	cpu->components[slot]->deinit(cpu->components[slot]);
 51}
 52
 53void LR35902Reset(struct LR35902Core* cpu) {
 54	cpu->af = 0;
 55	cpu->bc = 0;
 56	cpu->de = 0;
 57	cpu->hl = 0;
 58
 59	cpu->sp = 0;
 60	cpu->pc = 0;
 61
 62	cpu->instruction = 0;
 63
 64	cpu->cycles = 0;
 65	cpu->nextEvent = 0;
 66	cpu->executionState = LR35902_CORE_FETCH;
 67	cpu->halted = 0;
 68
 69	cpu->irqPending = false;
 70	cpu->irqh.reset(cpu);
 71}
 72
 73void LR35902RaiseIRQ(struct LR35902Core* cpu, uint8_t vector) {
 74	cpu->irqPending = true;
 75	cpu->irqVector = vector;
 76}
 77
 78static void _LR35902InstructionIRQFinish(struct LR35902Core* cpu) {
 79	cpu->index = cpu->sp + 1;
 80	cpu->bus = cpu->pc >> 8;
 81	cpu->executionState = LR35902_CORE_MEMORY_STORE;
 82	cpu->instruction = _lr35902InstructionTable[0]; // NOP
 83	cpu->pc = cpu->irqVector;
 84	cpu->memory.setActiveRegion(cpu, cpu->pc);
 85}
 86
 87static void _LR35902InstructionIRQ(struct LR35902Core* cpu) {
 88	cpu->sp -= 2; /* TODO: Atomic incrementing? */
 89	cpu->index = cpu->sp;
 90	cpu->bus = cpu->pc;
 91	cpu->executionState = LR35902_CORE_MEMORY_STORE;
 92	cpu->instruction = _LR35902InstructionIRQFinish;
 93	cpu->irqh.setInterrupts(cpu, false);
 94}
 95
 96static void _lr35902Step(struct LR35902Core* cpu) {
 97	++cpu->cycles;
 98	enum LR35902ExecutionState state = cpu->executionState;
 99	++cpu->executionState;
100	cpu->executionState &= 3;
101	switch (state) {
102	case LR35902_CORE_FETCH:
103		if (cpu->irqPending) {
104			cpu->index = cpu->sp;
105			cpu->irqPending = false;
106			cpu->instruction = _LR35902InstructionIRQ;
107			break;
108		}
109		cpu->bus = cpu->memory.cpuLoad8(cpu, cpu->pc);
110		cpu->instruction = _lr35902InstructionTable[cpu->bus];
111		++cpu->pc;
112		break;
113	case LR35902_CORE_EXECUTE:
114		cpu->instruction(cpu);
115		break;
116	case LR35902_CORE_MEMORY_LOAD:
117		cpu->bus = cpu->memory.load8(cpu, cpu->index);
118		break;
119	case LR35902_CORE_MEMORY_STORE:
120		cpu->memory.store8(cpu, cpu->index, cpu->bus);
121		break;
122	case LR35902_CORE_READ_PC:
123		cpu->bus = cpu->memory.load8(cpu, cpu->pc);
124		++cpu->pc;
125		break;
126	case LR35902_CORE_STALL:
127		cpu->instruction = _lr35902InstructionTable[0]; // NOP
128		break;
129	default:
130		break;
131	}
132}
133
134void LR35902Tick(struct LR35902Core* cpu) {
135	_lr35902Step(cpu);
136	if (cpu->cycles >= cpu->nextEvent) {
137		cpu->irqh.processEvents(cpu);
138	}
139}
140
141void LR35902Run(struct LR35902Core* cpu) {
142	while (cpu->cycles < cpu->nextEvent) {
143		_lr35902Step(cpu);
144	}
145	cpu->irqh.processEvents(cpu);
146}