From 35e045d7a72cebf4e97aacd3c7fd0e9167f2bbaf Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Thu, 1 Jun 2017 22:16:22 -0400
Subject: [PATCH] Made a first attempt at the correct segue into the three main
 kinds of interrupt, though the programs aren't written yet. So undefined
 behaviour would abound were an interrupt to occur. But it lets me figure out
 what effect the check has on performance. I hope little.

---
 Processors/Z80/Z80.hpp | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/Processors/Z80/Z80.hpp b/Processors/Z80/Z80.hpp
index 62e22404e..97ef7562b 100644
--- a/Processors/Z80/Z80.hpp
+++ b/Processors/Z80/Z80.hpp
@@ -148,7 +148,9 @@ struct MicroOp {
 		SetInFlags,
 		SetZero,
 
-		IndexedPlaceHolder
+		IndexedPlaceHolder,
+
+		Reset
 	};
 	Type type;
 	void *source;
@@ -206,6 +208,9 @@ template <class T> class Processor: public MicroOpScheduler<MicroOp> {
 
 			InstructionPage() : r_step_(1) {}
 		};
+		std::vector<MicroOp> reset_program_;
+		std::vector<MicroOp> irq_program_[3];
+		std::vector<MicroOp> nmi_program_;
 		InstructionPage *current_instruction_page_;
 
 		InstructionPage base_page_;
@@ -685,8 +690,21 @@ template <class T> class Processor: public MicroOpScheduler<MicroOp> {
 		void run_for_cycles(int number_of_cycles) {
 
 #define advance_operation() \
-	current_instruction_page_ = &base_page_;	\
-	scheduled_program_counter_ = base_page_.fetch_decode_execute_data;
+	if(last_request_status_) {	\
+		halt_mask_ = 0xff;	\
+		if(last_request_status_ & (Interrupt::PowerOn | Interrupt::Reset)) {	\
+			request_status_ &= ~Interrupt::PowerOn;	\
+			scheduled_program_counter_ = reset_program_.data();	\
+		} else if(last_request_status_ & Interrupt::NMI) {	\
+			request_status_ &= ~Interrupt::NMI;	\
+			scheduled_program_counter_ = nmi_program_.data();	\
+		} else if(last_request_status_ & Interrupt::IRQ) {	\
+			scheduled_program_counter_ = irq_program_[interrupt_mode_].data();	\
+		}	\
+	} else {	\
+		current_instruction_page_ = &base_page_;	\
+		scheduled_program_counter_ = base_page_.fetch_decode_execute_data;	\
+	}
 
 			number_of_cycles_ += number_of_cycles;
 			if(!scheduled_program_counter_) {
@@ -1390,6 +1408,7 @@ template <class T> class Processor: public MicroOpScheduler<MicroOp> {
 
 					case MicroOp::RETN:
 						iff1_ = iff2_;
+						if(irq_line_ && iff1_) request_status_ |= Interrupt::IRQ;
 					break;
 
 					case MicroOp::HALT: