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https://github.com/DerekK19/PDP-8-E-Simulator.git
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416 lines
10 KiB
Mathematica
416 lines
10 KiB
Mathematica
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/*
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* PDP-8/E Simulator
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*
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* Copyright © 1994-2015 Bernhard Baehr
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*
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* StateMachine.c - State Machine for the KC8-EA Programmer’s Console
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*
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* This file is part of PDP-8/E Simulator.
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*
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* PDP-8/E Simulator is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#import <Cocoa/Cocoa.h>
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#import "PluginFramework/PDP8.h"
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#import "PluginFramework/Utilities.h"
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#import "StateMachine.h"
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// these bits are in the positions of the "state" display
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#define FETCH 04000
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#define DEFER 02000
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#define EXECUTE 01000
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#define NO_CYCLE 00000
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// opcodes in the instruction register
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#define IR_AND 00000
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#define IR_TAD 00100
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#define IR_ISZ 00200
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#define IR_DCA 00300
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#define IR_JMS 00400
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#define IR_JMP 00500
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#define IR_IOT 00600
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#define IR_OPR 00700
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// values for mdDir: to or from memory
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#define MB_TO_MEM 00000
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#define MB_FROM_MEM 00040
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// coder keys
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#define CODER_KEY_CYCLE @"cycle"
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#define CODER_KEY_MD @"md"
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#define CODER_KEY_MDDIR @"mdDir"
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#define CODER_KEY_IR @"ir"
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#define CODER_KEY_CPMA @"cpma"
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#define CODER_KEY_BUS @"bus"
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#define CODER_KEY_PAUSE @"pause"
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#define CODER_KEY_AUTOINDEX @"autoindex"
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#define CODER_KEY_INTERRUPT_IN_PROGRESS @"interruptInProgress"
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#define CODER_KEY_OLDPC @"oldpc"
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#define CODER_KEY_OLDINST @"oldinst"
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@implementation StateMachine
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- (StateMachine *) initWithPDP8:(PDP8 *)p8
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{
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self = [super init];
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pdp8 = p8;
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[self updateState:NO];
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return self;
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}
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- (StateMachine *) initWithCoder:(NSCoder *)coder pdp8:(PDP8 *)p8
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{
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self = [self initWithCoder:coder];
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pdp8 = p8;
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[self updateState:NO];
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return self;
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}
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- (id) initWithCoder:(NSCoder *)coder
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{
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self = [super init];
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cycle = [coder decodeIntForKey:CODER_KEY_CYCLE];
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md = [coder decodeIntForKey:CODER_KEY_MD];
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mdDir = [coder decodeIntForKey:CODER_KEY_MDDIR];
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ir = [coder decodeIntForKey:CODER_KEY_IR];
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cpma = [coder decodeIntForKey:CODER_KEY_CPMA];
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bus = [coder decodeIntForKey:CODER_KEY_BUS];
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pause = [coder decodeBoolForKey:CODER_KEY_PAUSE];
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autoindex = [coder decodeIntForKey:CODER_KEY_AUTOINDEX];
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interruptInProgress = [coder decodeBoolForKey:CODER_KEY_INTERRUPT_IN_PROGRESS];
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oldpc = [coder decodeIntForKey:CODER_KEY_OLDPC];
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oldinst = [coder decodeIntForKey:CODER_KEY_OLDINST];
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return self;
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}
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- (void) encodeWithCoder:(NSCoder *)coder
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{
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[coder encodeInt:cycle forKey:CODER_KEY_CYCLE];
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[coder encodeInt:md forKey:CODER_KEY_MD];
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[coder encodeInt:mdDir forKey:CODER_KEY_MDDIR];
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[coder encodeInt:ir forKey:CODER_KEY_IR];
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[coder encodeInt:cpma forKey:CODER_KEY_CPMA];
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[coder encodeInt:bus forKey:CODER_KEY_BUS];
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[coder encodeBool:pause forKey:CODER_KEY_PAUSE];
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[coder encodeInt:autoindex forKey:CODER_KEY_AUTOINDEX];
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[coder encodeBool:interruptInProgress forKey:CODER_KEY_INTERRUPT_IN_PROGRESS];
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[coder encodeInt:oldpc forKey:CODER_KEY_OLDPC];
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[coder encodeInt:oldinst forKey:CODER_KEY_OLDINST];
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}
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- (unsigned short) state:(BOOL)sw
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{
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return cycle | ir | mdDir | (sw ? 00010 : 0) | (pause ? 00004 : 0);
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}
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- (unsigned short) status
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{
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return ([pdp8 getL] ? 04000 : 0) // Link
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| ([pdp8 getGTF] ? 02000 : 0) // Greater Than Flag
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| ([pdp8 interruptRequest] ? 01000 : 0) // Interrupt Request
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| ([pdp8 getInhibit] || [pdp8 getDelay] ? 00400 : 0) // NO INT
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| ([pdp8 getEnable] ? 00200 : 0) // Interrupt On
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| (interruptInProgress ? 0 : [pdp8 getUF] ? 00100 : 0) // User Flag
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| ([pdp8 getIF] << 3) // Instruction Field
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| [pdp8 getDF]; // Data Field
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}
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- (unsigned short) md
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{
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return md;
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}
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- (unsigned short) bus
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{
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return bus;
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}
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- (unsigned short) cpma
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{
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return cpma;
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}
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- (BOOL) isInFetchCycle
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{
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return cycle == FETCH;
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}
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- (void) loadAddress
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{
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if ([pdp8 isStopped]) {
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cpma = ([pdp8 getIF] << 12) | [pdp8 getSR];
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bus = [pdp8 getSR];
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[pdp8 setPC:bus];
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cycle = FETCH;
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}
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}
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- (void) loadExtendedAddress
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{
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if ([pdp8 isStopped]) {
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bus = [pdp8 getSR];
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[pdp8 loadExtendedAddress];
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}
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}
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- (void) setDatabus
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{
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bus = [pdp8 getAC];
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if ((md & 07200) == 07200) // 7200 == CLA at seq. 1
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bus = 0;
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if ((md & 07501) == 07501) // 7501 == MQA at seq. 2
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bus |= [pdp8 getMQ];
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if ((md & 07404) == 07404) // 7404 == OSR at seq. 3
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bus |= [pdp8 getSR];
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/* the bus setting may be wrong for group 3 OPRs implemented by the EAE */
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}
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- (void) updateState:(BOOL)exitFromGo
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{
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autoindex = -1;
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if ([pdp8 isStopped]) {
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if ([pdp8 getProgramCounter] != oldpc || [pdp8 memoryAt:oldpc] != oldinst) {
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oldpc = cpma = [pdp8 getProgramCounter];
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oldinst = [pdp8 memoryAt:oldpc];
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cycle = FETCH;
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if (exitFromGo) {
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ir = ([pdp8 getCurrentOpcode] & 07000) >> 3;
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mdDir = MB_FROM_MEM;
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md = [pdp8 getCurrentOpcode];
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[self setDatabus];
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}
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}
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} else {
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/* set state at the end of the next instructions fetch cycle,
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before the instruction is executed */
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bus = [pdp8 getAC];
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if ([pdp8 getEnable] && [pdp8 interruptRequest] &&
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! ([pdp8 getDelay] || [pdp8 getInhibit])) { /* interrupt */
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cpma = 0;
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ir = IR_JMS;
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cycle = EXECUTE;
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} else { /* normal instruction fetch */
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md = [pdp8 memoryAt:[pdp8 getProgramCounter]];
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mdDir = MB_FROM_MEM;
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ir = (md & 07000) >> 3;
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cpma = ([pdp8 getIF] << 12) |
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((md & 00200) ? (cpma & 07600) : 0) | (md & 0177);
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if (ir <= IR_JMP && (md & 00400)) /* indirect MRI */
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cycle = DEFER;
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else if (ir < IR_JMP) /* direct MRI != JMP */
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cycle = EXECUTE;
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else { /* OPR, IOT or direct JMP */
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cycle = FETCH;
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if (ir == IR_JMP)
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cpma = ([pdp8 getIB] << 12) | (cpma & 07777);
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else {
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cpma = ([pdp8 getIF] << 12) | (([pdp8 getPC] + 1) & 07777);
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[self setDatabus];
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if (ir == IR_IOT)
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pause = YES;
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}
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}
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}
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}
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}
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- (void) eaeExecute
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/* check for memory cycles of EAE operate instructions */
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{
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switch (md) {
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case 07403 : /* SCL */
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if ([pdp8 getEAEmode] == EAE_MODE_A) {
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cpma = ([pdp8 getIF] << 12) | (([pdp8 getPC] + 1) & 07777);
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md = [pdp8 memoryAt:cpma];
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mdDir = MB_FROM_MEM;
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}
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break;
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case 07405 : /* MUY */
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case 07407 : /* DVI */
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cpma = ([pdp8 getIF] << 12) | (([pdp8 getPC] + 1) & 07777);
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md = [pdp8 memoryAt:cpma];
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mdDir = MB_FROM_MEM;
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if ([pdp8 getEAEmode] == EAE_MODE_B) {
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if ((cpma & 07770) == 010) {
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autoindex = cpma;
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md = (md + 1) & 07777;
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mdDir = MB_TO_MEM;
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}
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cpma = ([pdp8 getDF] << 12) | md;
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md = (cpma == autoindex) ? ([pdp8 memoryAt:cpma] + 1) & 07777 : [pdp8 memoryAt:cpma];
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mdDir = MB_FROM_MEM;
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}
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break;
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case 07413 : /* SHL */
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case 07415 : /* ASR */
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case 07417 : /* LSR */
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cpma = ([pdp8 getIF] << 12) | (([pdp8 getPC] + 1) & 07777);
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md = [pdp8 memoryAt:cpma];
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mdDir = MB_FROM_MEM;
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break;
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case 07443 : /* DAD */
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if ([pdp8 getEAEmode] == EAE_MODE_B) {
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cpma = ([pdp8 getIF] << 12) | (([pdp8 getPC] + 1) & 07777);
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md = [pdp8 memoryAt:cpma];
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mdDir = MB_FROM_MEM;
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if ((cpma & 07770) == 010) {
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autoindex = cpma;
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md = (md + 1) & 07777;
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mdDir = MB_TO_MEM;
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}
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cpma = ([pdp8 getDF] << 12) | ((md + 1) & 07777);
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md = (cpma == autoindex) ? ([pdp8 memoryAt:cpma] + 1) & 07777 : [pdp8 memoryAt:cpma];
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mdDir = MB_FROM_MEM;
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}
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break;
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case 07445 : /* DST */
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if ([pdp8 getEAEmode] == EAE_MODE_B) {
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cpma = ([pdp8 getIF] << 12) | (([pdp8 getPC] + 1) & 07777);
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md = [pdp8 memoryAt:cpma];
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mdDir = MB_FROM_MEM;
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if ((cpma & 07770) == 010) {
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autoindex = cpma;
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md = (md + 1) & 07777;
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mdDir = MB_TO_MEM;
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}
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cpma = ([pdp8 getDF] << 12) | ((md + 1) & 07777);
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md = [pdp8 getAC];
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mdDir = MB_TO_MEM;
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}
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break;
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}
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}
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- (void) executeSingleCycle
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{
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switch (cycle) {
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case FETCH :
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autoindex = -1;
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bus = [pdp8 getAC];
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if ([pdp8 getEnable] && ! ([pdp8 getDelay] || [pdp8 getInhibit]) && [pdp8 interruptRequest]) {
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interruptInProgress = YES; /* interrupt */
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cpma = 0;
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ir = IR_JMS;
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cycle = EXECUTE;
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} else { /* normal instruction fetch */
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cpma = [pdp8 getProgramCounter];
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md = [pdp8 memoryAt:cpma];
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mdDir = MB_FROM_MEM;
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ir = (md & 07000) >> 3;
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cpma = ([pdp8 getIF] << 12) |
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((md & 0200) ? (cpma & 07600) : 0) | (md & 0177);
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if (ir <= IR_JMP && (md & 0400))
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cycle = DEFER;
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else if (ir < IR_JMP)
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cycle = EXECUTE;
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else {
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[self setDatabus];
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[self eaeExecute];
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if (ir == IR_IOT) {
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bus = [pdp8 getAC];
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|
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pause = YES;
|
|||
|
|
}
|
|||
|
|
[pdp8 step];
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
break;
|
|||
|
|
case DEFER :
|
|||
|
|
if ((cpma & 07770) == 00010) { /* autoindex */
|
|||
|
|
autoindex = cpma;
|
|||
|
|
md = ([pdp8 memoryAt:cpma] + 1) & 07777;
|
|||
|
|
mdDir = MB_TO_MEM; /* incremented value is written back */
|
|||
|
|
} else {
|
|||
|
|
md = [pdp8 memoryAt:cpma];
|
|||
|
|
mdDir = MB_FROM_MEM;
|
|||
|
|
}
|
|||
|
|
cpma = ([pdp8 getDF] << 12) | md;
|
|||
|
|
cycle = EXECUTE;
|
|||
|
|
break;
|
|||
|
|
case EXECUTE :
|
|||
|
|
switch (ir) {
|
|||
|
|
case IR_AND :
|
|||
|
|
md = (cpma == autoindex) ? ([pdp8 memoryAt:cpma] + 1) & 07777 : [pdp8 memoryAt:cpma];
|
|||
|
|
mdDir = MB_FROM_MEM;
|
|||
|
|
break;
|
|||
|
|
case IR_TAD :
|
|||
|
|
md = (cpma == autoindex) ? ([pdp8 memoryAt:cpma] + 1) & 07777 : [pdp8 memoryAt:cpma];
|
|||
|
|
mdDir = MB_FROM_MEM;
|
|||
|
|
break;
|
|||
|
|
case IR_ISZ :
|
|||
|
|
md = (cpma == autoindex) ? ([pdp8 memoryAt:cpma] + 1) & 07777 : [pdp8 memoryAt:cpma];
|
|||
|
|
md = (md + 1) & 07777;
|
|||
|
|
mdDir = MB_TO_MEM;
|
|||
|
|
break;
|
|||
|
|
case IR_DCA :
|
|||
|
|
bus = md = [pdp8 getAC];
|
|||
|
|
mdDir = MB_TO_MEM;
|
|||
|
|
break;
|
|||
|
|
case IR_JMS :
|
|||
|
|
md = ([pdp8 getPC] + (interruptInProgress ? 0 : 1)) & 07777;
|
|||
|
|
mdDir = MB_TO_MEM;
|
|||
|
|
break;
|
|||
|
|
case IR_JMP :
|
|||
|
|
break;
|
|||
|
|
}
|
|||
|
|
interruptInProgress = NO;
|
|||
|
|
cycle = FETCH;
|
|||
|
|
[pdp8 step];
|
|||
|
|
break;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
|
|||
|
|
- (void) examine
|
|||
|
|
{
|
|||
|
|
md = [pdp8 memoryAt:cpma];
|
|||
|
|
[pdp8 setPC:([pdp8 getPC] + 1) & 07777];
|
|||
|
|
cpma = [pdp8 getProgramCounter];
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
|
|||
|
|
- (void) deposit
|
|||
|
|
{
|
|||
|
|
cpma = [pdp8 getProgramCounter];
|
|||
|
|
md = bus = [pdp8 getSR];
|
|||
|
|
if ([pdp8 memorySize] > cpma)
|
|||
|
|
[pdp8 setMemoryAtAddress:cpma toValue:md];
|
|||
|
|
mdDir = MB_TO_MEM;
|
|||
|
|
[pdp8 setPC:([pdp8 getPC] + 1) & 07777];
|
|||
|
|
cpma = [pdp8 getProgramCounter];
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
|
|||
|
|
@end
|