From bb73eb0db35f9784ba5864386ec079d93f5aca84 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Thu, 28 Apr 2022 15:35:40 -0400
Subject: [PATCH] Start working on an isolation of 68000 instruction execution.
---
InstructionSets/M68k/Perform.hpp | 38 +++++++++
InstructionSets/M68k/Status.hpp | 77 +++++++++++++++++++
.../Clock Signal.xcodeproj/project.pbxproj | 8 +-
3 files changed, 121 insertions(+), 2 deletions(-)
create mode 100644 InstructionSets/M68k/Perform.hpp
create mode 100644 InstructionSets/M68k/Status.hpp
diff --git a/InstructionSets/M68k/Perform.hpp b/InstructionSets/M68k/Perform.hpp
new file mode 100644
index 000000000..142a08dc8
--- /dev/null
+++ b/InstructionSets/M68k/Perform.hpp
@@ -0,0 +1,38 @@
+//
+// Perform.hpp
+// Clock Signal
+//
+// Created by Thomas Harte on 28/04/2022.
+// Copyright © 2022 Thomas Harte. All rights reserved.
+//
+
+#ifndef InstructionSets_M68k_Perform_h
+#define InstructionSets_M68k_Perform_h
+
+#include "Model.hpp"
+#include "Instruction.hpp"
+#include "Status.hpp"
+#include "../../Numeric/RegisterSizes.hpp"
+
+namespace InstructionSet {
+namespace M68k {
+
+struct NullExceptionHandler {
+ void raise_exception(int) {}
+ void consume_cycles(int) {}
+};
+
+/// Performs @c op using @c source and @c dest (which mmay be ignored as per the semantics of the operation).
+/// And change in provcessor status will be applied to @c status. If this operation raises an exception or consumes
+/// additional cycles due to the particular value of the operands (on the 68000, think DIV or MUL), that'll be notified to
+/// @c exception_handler.
+template <
+ Operation op,
+ Model model,
+ typename ExceptionHandler
+> void perform(CPU::RegisterPair32 &source, CPU::RegisterPair32 &dest, Status &status, ExceptionHandler &exception_handler);
+
+}
+}
+
+#endif /* InstructionSets_M68k_Perform_h */
diff --git a/InstructionSets/M68k/Status.hpp b/InstructionSets/M68k/Status.hpp
new file mode 100644
index 000000000..10359239a
--- /dev/null
+++ b/InstructionSets/M68k/Status.hpp
@@ -0,0 +1,77 @@
+//
+// Status.hpp
+// Clock Signal
+//
+// Created by Thomas Harte on 28/04/2022.
+// Copyright © 2022 Thomas Harte. All rights reserved.
+//
+
+#ifndef InstructionSets_M68k_Status_h
+#define InstructionSets_M68k_Status_h
+
+namespace InstructionSet {
+namespace M68k {
+
+struct Status {
+ /* b15 */
+ uint_fast32_t trace_flag_ = 0; // The trace flag is set if this value is non-zero.
+
+ /* b13 */
+ int is_supervisor_ = 0; // 1 => processor is in supervisor mode; 0 => it isn't.
+
+ /* b7–b9 */
+ int interrupt_level_ = 0; // The direct integer value of thee current interrupt level.
+
+ /* b0–b4 */
+ uint_fast32_t zero_result_ = 0; // The zero flag is set if this value is zero.
+ uint_fast32_t carry_flag_ = 0; // The carry flag is set if this value is non-zero.
+ uint_fast32_t extend_flag_ = 0; // The extend flag is set if this value is non-zero.
+ uint_fast32_t overflow_flag_ = 0; // The overflow flag is set if this value is non-zero.
+ uint_fast32_t negative_flag_ = 0; // The negative flag is set if this value is non-zero.
+
+ /// Gets the current condition codes.
+ constexpr uint16_t ccr() const {
+ return
+ (carry_flag_ ? 0x0001 : 0x0000) |
+ (overflow_flag_ ? 0x0002 : 0x0000) |
+ (zero_result_ ? 0x0000 : 0x0004) |
+ (negative_flag_ ? 0x0008 : 0x0000) |
+ (extend_flag_ ? 0x0010 : 0x0000);
+ }
+
+ /// Gets the current value of the status register.
+ constexpr uint16_t status() const {
+ return uint16_t(
+ ccr() |
+ (interrupt_level_ << 8) |
+ (trace_flag_ ? 0x8000 : 0x0000) |
+ (is_supervisor_ << 13)
+ );
+ }
+
+ /// Sets the current condition codes.
+ constexpr void set_ccr(uint16_t ccr) {
+ carry_flag_ = (ccr) & 0x0001;
+ overflow_flag_ = (ccr) & 0x0002;
+ zero_result_ = ((ccr) & 0x0004) ^ 0x0004;
+ negative_flag_ = (ccr) & 0x0008;
+ extend_flag_ = (ccr) & 0x0010;
+ }
+
+ /// Sets the current value of the status register;
+ /// @returns @c true if the processor finishes in supervisor mode; @c false otherwise.
+ constexpr bool set_status(uint16_t status) {
+ set_ccr(status);
+
+ interrupt_level_ = (status >> 8) & 7;
+ trace_flag_ = status & 0x8000;
+ is_supervisor_ = (status >> 13) & 1;
+
+ return is_supervisor_;
+ }
+};
+
+}
+}
+
+#endif /* InstructionSets_M68k_Status_h */
diff --git a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
index b4c22e7ea..6b5d6d875 100644
--- a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
+++ b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
@@ -1932,6 +1932,8 @@
4BB4BFB722A4372E0069048D /* StaticAnalyser.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = StaticAnalyser.hpp; sourceTree = "<group>"; };
4BB4BFB822A4372E0069048D /* StaticAnalyser.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = StaticAnalyser.cpp; sourceTree = "<group>"; };
4BB5B995281B1D3E00522DA9 /* RegisterSizes.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = RegisterSizes.hpp; sourceTree = "<group>"; };
+ 4BB5B996281B1E3F00522DA9 /* Perform.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Perform.hpp; sourceTree = "<group>"; };
+ 4BB5B997281B1F7B00522DA9 /* Status.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Status.hpp; sourceTree = "<group>"; };
4BB697C91D4B6D3E00248BDF /* TimedEventLoop.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = TimedEventLoop.cpp; sourceTree = "<group>"; };
4BB697CA1D4B6D3E00248BDF /* TimedEventLoop.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = TimedEventLoop.hpp; sourceTree = "<group>"; };
4BB697CC1D4BA44400248BDF /* CommodoreGCR.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = CommodoreGCR.cpp; path = Encodings/CommodoreGCR.cpp; sourceTree = "<group>"; };
@@ -3157,10 +3159,12 @@
4B79629B2819681F008130F9 /* M68k */ = {
isa = PBXGroup;
children = (
+ 4B79629F2819681F008130F9 /* Decoder.cpp */,
+ 4B79629E2819681F008130F9 /* Decoder.hpp */,
4B79629C2819681F008130F9 /* Instruction.hpp */,
4B79629D2819681F008130F9 /* Model.hpp */,
- 4B79629E2819681F008130F9 /* Decoder.hpp */,
- 4B79629F2819681F008130F9 /* Decoder.cpp */,
+ 4BB5B996281B1E3F00522DA9 /* Perform.hpp */,
+ 4BB5B997281B1F7B00522DA9 /* Status.hpp */,
);
path = M68k;
sourceTree = "<group>";