From 9c04d851e4877e72bdb5b0e42f163bb49da0886d Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Mon, 31 Jul 2017 07:29:50 -0400
Subject: [PATCH] Added the basics necessary to get the CPU ticking over, at a
 nominal 4Mhz but with the wait states that I currently believe to be
 accurate.

---
 ClockReceiver/ClockReceiver.hpp    |  8 ++++++++
 Machines/AmstradCPC/AmstradCPC.cpp | 10 ++++++++++
 Machines/AmstradCPC/AmstradCPC.hpp |  3 +++
 3 files changed, 21 insertions(+)

diff --git a/ClockReceiver/ClockReceiver.hpp b/ClockReceiver/ClockReceiver.hpp
index 515d3216b..893ce2875 100644
--- a/ClockReceiver/ClockReceiver.hpp
+++ b/ClockReceiver/ClockReceiver.hpp
@@ -95,9 +95,17 @@ template <class T> class WrappedInt {
 			return *static_cast<T *>(this);
 		}
 
+		inline T &operator &=(const T &rhs) {
+			length_ &= rhs.length_;
+			return *static_cast<T *>(this);
+		}
+
 		inline T operator +(const T &rhs) const			{	return T(length_ + rhs.length_);	}
 		inline T operator -(const T &rhs) const			{	return T(length_ - rhs.length_);	}
 
+		inline T operator %(const T &rhs) const			{	return T(length_ % rhs.length_);	}
+		inline T operator &(const T &rhs) const			{	return T(length_ & rhs.length_);	}
+
 		inline T operator -() const						{	return T(- length_);				}
 
 		inline bool operator <(const T &rhs) const		{	return length_ < rhs.length_;		}
diff --git a/Machines/AmstradCPC/AmstradCPC.cpp b/Machines/AmstradCPC/AmstradCPC.cpp
index 01cf8bec6..424328fef 100644
--- a/Machines/AmstradCPC/AmstradCPC.cpp
+++ b/Machines/AmstradCPC/AmstradCPC.cpp
@@ -10,7 +10,16 @@
 
 using namespace AmstradCPC;
 
+Machine::Machine() {
+	// primary clock is 4Mhz
+	set_clock_rate(4000000);
+}
+
 HalfCycles Machine::perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
+	// Amstrad CPC timing scheme: assert WAIT for three out of four cycles
+	clock_offset_ = (clock_offset_ + cycle.length) & HalfCycles(7);
+	set_wait_line(clock_offset_ >= HalfCycles(2));
+
 	return HalfCycles(0);
 }
 
@@ -38,6 +47,7 @@ std::shared_ptr<Outputs::Speaker> Machine::get_speaker() {
 }
 
 void Machine::run_for(const Cycles cycles) {
+	CPU::Z80::Processor<Machine>::run_for(cycles);
 }
 
 void Machine::configure_as_target(const StaticAnalyser::Target &target) {
diff --git a/Machines/AmstradCPC/AmstradCPC.hpp b/Machines/AmstradCPC/AmstradCPC.hpp
index 905f16cea..293ca06f7 100644
--- a/Machines/AmstradCPC/AmstradCPC.hpp
+++ b/Machines/AmstradCPC/AmstradCPC.hpp
@@ -22,6 +22,8 @@ class Machine:
 	public CRTMachine::Machine,
 	public ConfigurationTarget::Machine {
 	public:
+		Machine();
+
 		HalfCycles perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle);
 		void flush();
 
@@ -37,6 +39,7 @@ class Machine:
 
 	private:
 		std::shared_ptr<Outputs::CRT::CRT> crt_;
+		HalfCycles clock_offset_;
 };
 
 }