From b7c978e078f499f5b90c19344696e5860e559ccb Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Thu, 22 Jun 2017 20:11:19 -0400
Subject: [PATCH] Added getters for most of the input lines, and attempted to
 round out the ZX81's wait logic.

---
 Machines/ZX8081/ZX8081.cpp |  7 ++++---
 Processors/Z80/Z80.hpp     | 20 +++++++++++++++++++-
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/Machines/ZX8081/ZX8081.cpp b/Machines/ZX8081/ZX8081.cpp
index 4af76c948..184434791 100644
--- a/Machines/ZX8081/ZX8081.cpp
+++ b/Machines/ZX8081/ZX8081.cpp
@@ -36,9 +36,6 @@ int Machine::perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
 		set_hsync(true);
 		if(nmi_is_enabled_) {
 			set_non_maskable_interrupt_line(true);
-			if(!get_halt_line()) {
-				set_wait_line(true);
-			}
 		}
 		video_->run_for_cycles(horizontal_counter_ - vsync_start_cycle_);
 	} else if(previous_counter < vsync_end_cycle_ && horizontal_counter_ >= vsync_end_cycle_) {
@@ -56,6 +53,10 @@ int Machine::perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
 	if(is_zx81_) horizontal_counter_ %= 207;
 	tape_player_.run_for_cycles(cycle.length);
 
+	if(nmi_is_enabled_ && !get_halt_line() && get_non_maskable_interrupt_line()) {
+		set_wait_line(true);
+	}
+
 	if(!cycle.is_terminal()) {
 		return 0;
 	}
diff --git a/Processors/Z80/Z80.hpp b/Processors/Z80/Z80.hpp
index 44579d94c..ce9c9bb46 100644
--- a/Processors/Z80/Z80.hpp
+++ b/Processors/Z80/Z80.hpp
@@ -192,7 +192,7 @@ template <class T> class Processor {
 		};
 		uint8_t request_status_;
 		uint8_t last_request_status_;
-		bool irq_line_;
+		bool irq_line_, nmi_line_;
 		bool bus_request_line_;
 		bool wait_line_;
 
@@ -771,6 +771,7 @@ template <class T> class Processor {
 			request_status_(Interrupt::PowerOn),
 			last_request_status_(Interrupt::PowerOn),
 			irq_line_(false),
+			nmi_line_(false),
 			bus_request_line_(false),
 			pc_increment_(1),
 			scheduled_program_counter_(nullptr) {
@@ -1888,6 +1889,10 @@ template <class T> class Processor {
 			}
 		}
 
+		bool get_interrupt_line() {
+			return irq_line_;
+		}
+
 		/*!
 			Sets the logical value of the non-maskable interrupt line.
 			
@@ -1895,6 +1900,7 @@ template <class T> class Processor {
 		*/
 		void set_non_maskable_interrupt_line(bool value, int offset = 0) {
 			// NMIs are edge triggered and cannot be masked.
+			nmi_line_ = value;
 			if(value) {
 				request_status_ |= Interrupt::NMI;
 				if(offset < 0) {
@@ -1903,6 +1909,10 @@ template <class T> class Processor {
 			}
 		}
 
+		bool get_non_maskable_interrupt_line() {
+			return nmi_line_;
+		}
+
 		/*!
 			Sets the logical value of the bus request line.
 		*/
@@ -1910,6 +1920,10 @@ template <class T> class Processor {
 			bus_request_line_ = value;
 		}
 
+		bool get_bus_request_line() {
+			return bus_request_line_;
+		}
+
 		/*!
 			Sets the logical value of the reset line.
 		*/
@@ -1935,6 +1949,10 @@ template <class T> class Processor {
 			wait_line_ = value;
 		}
 
+		bool get_wait_line() {
+			return wait_line_;
+		}
+
 		/*!
 			For receivers of perform_machine_cycle only. Temporarily rejects the current machine
 			cycle, causing time to be rewinded to its beginning.