From b7a1363add980c93f08c6f230eba6166a035d8b9 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Mon, 4 Mar 2024 21:09:24 -0500
Subject: [PATCH] Add an incorrect execution loop.

---
 Machines/Acorn/Archimedes/Archimedes.cpp | 57 ++++++++++++++++++++----
 1 file changed, 49 insertions(+), 8 deletions(-)

diff --git a/Machines/Acorn/Archimedes/Archimedes.cpp b/Machines/Acorn/Archimedes/Archimedes.cpp
index f75ff0e50..a4c8fd0e8 100644
--- a/Machines/Acorn/Archimedes/Archimedes.cpp
+++ b/Machines/Acorn/Archimedes/Archimedes.cpp
@@ -16,10 +16,19 @@
 
 #include "../../../InstructionSets/ARM/Executor.hpp"
 
+#include <algorithm>
+#include <array>
+#include <vector>
+
 namespace Archimedes {
 
 struct Memory {
-	std::vector<uint8_t> rom;
+	void set_rom(const std::vector<uint8_t> &rom) {
+		std::copy(
+			rom.begin(),
+			rom.begin() + static_cast<ptrdiff_t>(std::min(rom.size(), rom_.size())),
+			rom_.begin());
+	}
 
 	template <typename IntT>
 	bool write(uint32_t address, IntT source, InstructionSet::ARM::Mode mode, bool trans) {
@@ -42,15 +51,14 @@ struct Memory {
 
 		if(address >= 0x3800000) {
 			has_moved_rom_ = true;
-			source = *reinterpret_cast<const IntT *>(&rom[address - 0x3800000]);
+			source = *reinterpret_cast<const IntT *>(&rom_[address - 0x3800000]);
 		} else if(!has_moved_rom_) {
 			// TODO: this is true only very transiently.
-			source = *reinterpret_cast<const IntT *>(&rom[address]);
+			source = *reinterpret_cast<const IntT *>(&rom_[address]);
 		} else if(address < ram_.size()) {
 			source = *reinterpret_cast<const IntT *>(&ram_[address]);
 		} else {
 			source = 0;
-			printf("Unknown read from %08x [%lu]\n", address, sizeof(IntT));
 		}
 
 		return true;
@@ -59,10 +67,12 @@ struct Memory {
 	private:
 		bool has_moved_rom_ = false;
 		std::array<uint8_t, 4*1024*1024> ram_{};
+		std::array<uint8_t, 2*1024*1024> rom_;
 };
 
 class ConcreteMachine:
 	public Machine,
+	public MachineTypes::MediaTarget,
 	public MachineTypes::TimedMachine,
 	public MachineTypes::ScanProducer
 {
@@ -71,8 +81,19 @@ class ConcreteMachine:
 			const Analyser::Static::Target &target,
 			const ROMMachine::ROMFetcher &rom_fetcher
 		) {
-			(void)target;
-			(void)rom_fetcher;
+			constexpr ROM::Name risc_os = ROM::Name::AcornRISCOS319;
+			ROM::Request request(risc_os);
+			auto roms = rom_fetcher(request);
+			if(!request.validate(roms)) {
+				throw ROMMachine::Error::MissingROMs;
+			}
+
+			executor_.bus.set_rom(roms.find(risc_os)->second);
+
+			// TODO: pick a sensible clock rate; this is just code for '20 MIPS, please'.
+			set_clock_rate(20'000'000);
+
+			insert_media(target.media);
 		}
 
 	private:
@@ -87,11 +108,31 @@ class ConcreteMachine:
 
 		// MARK: - TimedMachine.
 		void run_for(Cycles cycles) override {
-			(void)cycles;
+			auto instructions = cycles.as<int>();
+			while(instructions--) {
+				uint32_t instruction;
+				executor_.bus.read(executor_.pc(), instruction, executor_.registers().mode(), false);
+				// TODO: what if abort? How about pipeline prefetch?
+
+				InstructionSet::ARM::execute<arm_model>(instruction, executor_);
+			}
+		}
+
+		// MARK: - MediaTarget
+		bool insert_media(const Analyser::Static::Media &) override {
+//			int c = 0;
+//			for(auto &disk : media.disks) {
+//				fdc_.set_disk(disk, c);
+//				c++;
+//				if(c == 4) break;
+//			}
+//			return true;
+			return false;
 		}
 
 		// MARK: - ARM execution
-		InstructionSet::ARM::Executor<InstructionSet::ARM::Model::ARMv2, Memory> executor_;
+		static constexpr auto arm_model = InstructionSet::ARM::Model::ARMv2;
+		InstructionSet::ARM::Executor<arm_model, Memory> executor_;
 };
 
 }