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Re-animation of computer programs

Meijer, F.J.

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Citation for published version (APA):Meijer, F. J. (2001). Re-animation of computer programs.

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Download date: 01 Apr 2020

APPENDIX

A.l COMPUTER DEVELOPMENT

1 HERE ARE major differences between today's computers and its prede­cessors. This is true, not only in their technical aspects, but also regarding software. Computer advancements were characterised by their hardware development. Initially, relays and or vacuum tubes were used. Later, tran­sistors replaced them. Integrated circuits then made it possible to reduce their physical size. The use of highly integrated circuits, such as: the processor on a chip further reduced their size and cost of manufacture to a level affordable by individuals.

Changes to computer hardware were paralleled by rapid advancements in software development. Software progressed from machine code assem­bler language. Higher-level languages rapidly became the chief method for programming and are still used today although more highly refined.

The first computers used designs based on the machine architecture of Babbage and Zuse1. They have become museum pieces. Their programs are not considered for code reconstruction in this study. The first opera­tional computers were developed in an environment where large numbers of operations had to be performed. For example, numerical solutions to differential equations that describe heat transfer in bombs. Their relevant activity language was specialized. This implies that translation to machine code was relatively simple. The main reason for using computers was to speed up calculations that otherwise would have taken years of human effort.

The development of these machines resembles the developments found in nature. They arc charac­terised by successions that are not identical. Each succession was better adapted to its environment. Because of this, they were able to survive. In nature changes take place over millions of years. Man-made systems follow a similar pattern of adaptation. Weaving looms became mechanized by Jaquard's punched tape in 1728. Somewhere around 1830 the shuttle was invented. This significantly mecha­nized the functions of the loom.

[91]

92 RE-ANIMATION OF COMPUTER PROGRAMS

During this period their use was restricted to specific groups of users. They had to provide well-formed statements in their activity language. It was necessary for the programmers to code the appropriate statements into computer language. This was the responsibility of the first group of users. Statements in the human activity language had to be translated into machine code by programmers. This was a highly specialized and com­plex task. Programming was recognized by society as an elite profession and compensated accordingly.

A.2 THE INFLUENCE OF EXPANDING COMPUTER TECHNOLOGY

Over time the number and variety of users increased, with a decreasing emphasis on mathematical functions. The application of computer tech­nology expanded to other fields such as administration, medicine, law enforcement and recreation. In the beginning of the computer era human operators played an important role. Their main task was to initialize the computer and keep it running. Furthermore, their skills were needed to access files that were usually stored on magnetic tape.

Technological developments gave more possibilities and variation. Each technical advancement was accompanied by a wave of new software. Differences in personal computer software are even more noticeable. Formerly, the user was dependent on software written by a programmer. The data, along with the program, was input into the computer via key­punched cards or tape. No interaction was possible between the user and the computer. Higher level programming languages had not yet been developed. Programmers were not supported by an operating system that alleviates many tasks. Today's programs depend on this support. Programs make use of the operating system. The next major advancement was accompanied by the development of the first operating system software. Operating systems will be the subject of the next section.

A.3 THE OPERATING SYSTEM: A SUPPORT SYSTEM

Today's computers differ markedly from their predecessors. This is true

APPENDIX 93

not only in the technical aspects, but also regarding the complexities of the software. In the early days programmers were not supported by an operating system that simplifies many tasks. Now, programmers depend on this type of support.

A.3.1 The need for an operating system

Computers contain a software package stored in an integrated circuit called R O M (Read Only Memory). This software forms part of a still larger package called the operating system. Why it has been incorporated will be further explained.

To solve a particular problem with a computer, a set of bit strings, mainly containing instructions, must be read into memory. Next the external data to be operated upon are brought into memory. In the early days of computing, the programmer was responsible for bringing the set of instructions and the data to be manipulated into main memory. Now­adays these tasks are performed by the operating system. Programmers can concentrate on the solution of problems without having to solve technical problems associated with computer operations.

A.3.2 Some personal computers and their operating system

Personal computers are equipped with an operating system. Different per­sonal computers appeared on the market. The most widely accepted are the IBM - PC and its clones, and Apple's MACINTOSH and its succes­sors. The AMIGA and the ATARI personal computers have not enjoyed the same success. The AMIGA is no longer produced. The Atari Corpora­tion has licensed different manufacturers to produce its computer of which the MILAN seems the most successful2. The PC operating systems that will be discussed are that of the IBM, its clones and the ATARI. The operating system of the IBM called DOS - Disk Operating System - is similar to that of the ATARI called TOS - The Operating System. The same software house has written both. TOS uses the graphic capabilities of the ATARI.

The development of these operating systems for personal computers was gradual. The forerunner of TOS and DOS was CP/M, an operating

2 In what follows ATARI stands for ATARI and its clones.

9 4 RE-ANIMATION OF COMPUTER PROGRAMS

system used in various PCs based on the Z80 processor. The same pro­

ducer developed CP/M, TOS and DOS. Therefore, there is strong

resemblance in function calls. This becomes clear from the following

table.

CP/M ATARI

func# hex function differ­ name function

ent*

0 00 system reset ends current program

1 0 1 console input Cconin read a character typed in

2 02 console output Cconout display a character

3 03 reader input Cauxin read RS232 port

4 04 punch output Cauxout write RS232 port

5 05 list output Cprnout write line printer

6 06 direct console I/O Crawio read and write console

7 07 get I/O byte Crawcin read character

(without echo)

8 08 set I/O byte Cnecin idem + control sign

9 09 print string Cconws write until 0 detected

10 0A read console buffer Cconrs read buffer

11 0B get console status Cconis character in buffer?

12 oc get version number 48 Sversion gives version

number of O.S.

14 0E select disk Dsetdrv set actual drive

15 OF open file 6 1 Fopen open file

16 10 close file 62 Fclose close file

17 11 search for first

occurrence of filename

58 Fsfirst search first occurrence

of filename 18 12 search for next

occurrence

59 Fsnext search filename

19 13 delete file 65 Fdelete delete file 20 14 read sequential 63 Fread read number of bytes 21 15 write sequential 64 Fwrite write number of bytes 22 16 create new file 60 Fcreate open new file 23 17 rename file 86 Frename rename file 25 19 return current disk Dgetdrv determine actual drive 26 1A set DMA address Fsetdta set DTA address 30 I E set file attributes 65 Fattrib read or set file attributes 32 20 set or get user code Super flips modus

function table

APPENDIX 9 5

A3.2.1 Differences in operating systems for personal computers

Differences in the operating systems of the ATARI and CP/M computers apply to the opening, closing, reading and writing of files. For example, the CP /M operating system splits filename and extension. If the name consists of less than six characters the file name is automatically filled up with spaces. This is not the case with the ATARI. In addition, there is a difference in the handling of files. To be sure that data files are written or read at the correct memory address the DMA (Direct Memory Address) must be made known to the computer.3 An example of a difference is the interface between the user and the computer4. Computers using the 68000 processor provide for a graphical interface. This is possible because their operating systems include functions that make it possible to use these capabilities. However, the CP/M machines used a textual interface between user and support system. It requires the user to type in textual commands5. This is not necessary with the ATARI. For example, to de­lete a file only requires moving the cursor to the icon representing the file, pressing the mouse and moving the file icon to the trash/dustbin

A.3.3 'Working method o f the operating system

An operating system can be conceptualised as a kernel surrounded by dif­ferent layers. The kernel of the operating system contains very elementary functions, such as: deciding how much working storage is required for an application. Around the kernel each layer increases its function complexi­ty. The next layer contains functions that were added as computers be­came more complex. It contains, for example, functions to define the number of colors for a color monitor. Moving outward system indepen­dence grows. The availability of these layers enables the user to be more creative. For example, graphic representations, that were formerly diffi-

3 This address, under C P / M , is the hard hexadecimal address 80. Under TOS it is BASEPAGE+80. But, under TOS this DMA address only applies to information about the files. The address has to be given separately when calling the read- or write functions. Under C P / M the same DMA address is used by all file functions. Under T O S it is called DTA (Dish Transfer Address). 4 The MACINTOSH, AMIGA, ATARI and the N E X T computer use the 68000 family processors 5 "delete filename.ext" is an example of such a command. (Ext stands for extension (of the file­name)). 6 The MACINTOSH has the capability to retain the data as long as certain conditions are fulfilled. Furthermore, if the user attempts to delete an application the Macintosh asks for confirmation.

9 6 RE-ANIMATION OF COMPUTER PROGRAMS

cult to program and belonged to the domain of highly skilled program­

mers, can now be easily implemented by the user.

A.3.3.1 Different levels of operating systems software

The first layer is called BIOS (Basic Input Output System. The term basic has nothing to do with the programming language BASIC). BIOS can perform elementary functions. It can read a character from the console or display it on the screen.

The following layer is called XBIOS (eXtended BIOS). As the num­ber of input/output devices grew their routines had to be incorporated in the operating system. XBIOS contains routines to enable these devices to be used without the need of replacing the entire operating system.

The next layers are included in the operating system of the ATARI.7

They are discussed in the following two sections.

A.3.3.2 The Graphics Environment Manager The next layer after XBIOS is called GEM (Graphics Environment Manager). This layer has been added to take advantage of the possibilities offered by modern graphical terminals. It was only possible for earlier computers to output to a TELETYPE. Later a monitor performed the same functions as the TELETYPE. Both output devices could produce only characters. The next developmental stage was a monitor with an addressable screen. This meant that separate points of the screen could be made visible by displaying a dot, not only sequential as with the older apparatuses, but also randomly.8 Such a point is called a pixel, a contrac­tion of'picture element'.

GEM is made of two parts. There was a need for graphical functions at an elementary level. These functions are incorporated in the first part called GEMDOS (GEM Disk Operating System). A number of these functions are contained in BIOS and GEM. The second part handles the mouse and manipulation of the screen. It is called line-A-emulator. This is misleading because nothing is emulated. If the processor detects the hexadecimal number 'A' as first element of an instruction it jumps automatically to a

7 Now that windows has been made possible on the IBM - FC and its clones this is only applicable

to older versions of the operating system for these computers. 8 Randomly here means at any point of the screen.

APPENDIX 97

certain address. To recapitulate, the 'mouse' and graphical functions are to

be found in GEMDOS. The next layer is called VDI (Virtual Device Interface). It makes pro­

grams independent of the display apparatuses. VDI has two parts: a 'low' and 'high' level. The software of the low level is called GDOS (Graphics Device Operating System) the high part makes up the rest of VDI.

A3.33 The Applications Environment Manager.

The outermost layer of the operating system is called AES (Applications

Environment Manager). AES calls complex functions such as menu han­

dling and multitasking.

A3 3.4 Direct and indirect function calls

PC operating systems can be instructed in two ways: direct from the ter­minal, and indirectly by applications. 'Start a program' or 'Print a file' instructions, for example, can be given to the operating system directly via the keyboard or mouse. The application program can also contain the same instruction. These instructions are called functions of the operating system. Performing them is known as system calls.

A.3.4 The working environment

The working environment of a computer is determined by its operating

system functions. Now they offer the user similar working environments.

In essence, the operating systems are basically the same. The Graphic

Environment Manager (GEM) and the Application Environment System

(AES), for example, have made windowing possible on a multitude of dif­

ferent platforms.

A.4 THE COMPUTER, A SPECIAL TECHNICAL SUPPORT

SYSTEM

The computer takes a special place between other technical support sys­tems. Most technical appliances do not communicate linguistically. The first computers communicated in a very restricted way. The only comput­er language available at that time was machine language: bit rows, combi­nations of one's and zero's. The series of events was well defined.

98 RE-ANIMATION OF COMPUTER PROGRAMS

Communication was done by switches: for every bit, one switch. This communication was restricted to experts. Only they were able to express what they wanted the machine to do. Every type had its own language.

When computers were made more accessible the possibility to express what the user wanted the computer to do in a different language, other than machine language, emerged. Higher-level languages for different purposes were developed. As a result of this development constraints emerged. Programmers had to learn numerous higher-level languages. Different types of problems required the development of still other lan­guages. Higher-level languages made it possible to write and run pro­grams on any machine. But, this advantage paid the price of Babylonian speech entanglement. Attempts to develop a computer-Esperanto failed, mainly due to parochial interests.

Users could make use of the higher level languages developed but direct communication with the new support system was not yet possible. Only the operator could input the programs and data that were punched on paper tape or cards. After processing the user could collect the results. The user had to ensure that there were no incorrect punches that could halt the program.

In the best of cases, an expert giving advice in case of unexpected results performed the help function. Often this person was able to find an error by inspecting the holes in the tape or cards. This ability proved of value for only a short time in the history of computing. After keypunch­ing, communication with the computer was made possible through direct input/output via terminals. They were connected to a central computer, called mainframe. These mainframes were expensive and only large insti­tutions could afford them. Therefore, computer time was shared. Each user was allotted a portion of available processing time, called time slice.

Technology progressed and made the development of the personal com­puter (PC) possible. With a PC users decided how and when to use the computer. No longer were they dependent on an operator who decided how long and when their program could run. Nor were they dependent upon a time-sharing system. They took a more central role as computer power became decentralised.

The next major development in computer technology was the mouse.

APPENDIX 99

It made it possible to give commands by simply moving a cursor over the monitor's screen and depressing its button. This eliminated the need to type commands. The next development was the track ball. It performs the same mouse functions without having to move the device.

Interactive programming became possible, albeit, by using a program­ming language, BASIC, that was detested by the computer establishment. It was rejected because it allowed the development of unstructured soft­ware. Other languages, such as ALGOL and PASCAL, became accepted. However, these did not permit interactivity. Users had to acquire special skills. They had to learn how to decompose and design a solution for the problem in terms of a computer language.

A. 5 THE INTERFACE

The events produced by a computer only partially replace the events expressed in the HAL (Human Activity Language) statements. The activi­ty language has to state which events are required by the user. The events generated by the computer must stimulate the user to provide correct commands to achieve the desired result. The piano keyboard provides an example of stimuli that evokes events by the striking of its keys. The activity language of a musician indicates how the notes are to be played. The interface between musician and his instrument provides for the pro­duction of the event called music.

The interface to a support system dictates the way it constrains its users. In the case of piano playing the keyboard has evolved into a form that defines expertise quite precisely. This precise expertise in using computers is not needed and should be avoided by software developers. The role of the computer is to extend interfaces.

Initially, the notion 'interface' referred to hardware needed for machine-to-machine communication. Later, it was used to designate other forms of communication. The user is now able to choose, in a coordinated man­ner, from a number of functions, which control flows of data. Every sup­port system has an interface. Only the ways it manifests itself differ.

100 HE-ANIMATION OF COMPUTER PROGRAMS

A.5.1 The importance o f interfaces

As computer systems have become more complex, the importance of interfaces has grown. They make it possible to gain access to functions to perform tasks, previously done manually, faster, more accurately and cheaper. But, to gain access users have to become more competent: a cer­tain degree of dexterity on the part of the users is necessary such as, the ability to use a mouse, trackball or keyboard9. The interface should be designed to maximise the user's previous experiences.

As a general rule the more sophisticated the interface, the more effec­tive. This means that computer hardware becomes relatively less impor­tant than its software. Interfaces can be linked to many different types of hardware and also link the user to the computer. This linking required the development of a user language to control the functions of the com­puter. It consists of terms such as: problem definition, selection of func­tions, end condition, and solution.

A.6 THE TECHNICAL ASPECTS OF THE PROCESS OF

TRANSFORMATION

Transformation of a machine code program by MALIN is accomplished in a series of steps. For each step a separate program had to be written. The first program is written in assembler code for the 68000 processor. (Cathey, 1986) This assembler emulates the program to be reconstructed and states, which bit strings10 are instructions and which are data. This information is further analysed by other programs of MALIN. It is unlike­ly that all instructions of the machine code program (P) are executed. Another emulator, written in higher-level language, offers a number of options. It can analyse registers" of the source computer (M), state break­points in P and single step through it. There is a difference between a plain emulator and the emulators of MALIN. The plain emulator simu­lates the source computer on the object computer and generated code is not retained and stored The MALIN emulator executes the source com­puter code and stores its information. The package gathers information

9 Competent: the ability of a human agent to judge an act in a specific environment. 10 A bit string consists of a series of zeros and ones to denote the binary representation of instructions

and data. 11 A register is a memory location in the central processor used to store data or adresses.

APPENDIX 101

from P, uses it to generate code, and executes it on the object computer. First some preliminary remarks will be made regarding the structure of

programs.

A. 6.1 Modules

As has been discussed in chapter two a computer program invokes series of events that have to take place so that the stated goal will be reached12. To achieve this instructions are arranged in such a way that the events are invoked in the correct order.

Different architectures are possible regarding computer programs. A pro­gram can be decomposed into modules." There are two types of modules: instruction and data. An instruction module is defined as a number of instructions forming a structure14. Within this module there are only instructions'5. A data module is defined as a number of consecutive loca­tions containing only data.16 A module has only one entry point ended by only one exit point. And can contain instruction and data. Some compil­ers allow for a hierarchical structure in that a module may consist of a number of modules. These distinctions are of importance as MALIN tries to discern these modules. In the listings produced by MALIN a blank line separates them. On machine code level instruction modules are seldom found. This is true especially for programs written in the first era of pro­gramming.

12 Such a goal usually is formulated by a software company at the beginning of a programming cyle, or by a customer who has to solve a special problem. 13 The term module indicates a part of program code contained in a structure. Here it is applied to programs written in assembler. Source code should clearly indicate, by visual aids, these structures. (see also Opler, 1962) 14 Examples of structures are: the for-next , do-while and repeat-until loop. 15 A low level instruction can contain data. These are called immediate data. Low level programming often uses immediate data. The definition of 'block' is only applicable when computer programs are written in higher level languages. 16 After the 8080 had been developed it became clear that the processor contained an error, handling of the carry status is done faulty, in a way which is considered incorrect by literature. To circumvent this error programming on a low level had to be adapted. The Japanese firm N E C developed a pro­cessor - the N E C 8080A that did not contain above mentioned error, the same was done by the American firm AMD which developed the 9080A. Now the problem was that software written for the Intel processor delivered wrong results if run on these processors. So N E C had to produce a 8080 version with the error. The difference between the processors regarding this difficulty is that bit 5 of the status register is used to store the result of a subtraction.

102 RE-ANIMATION OF COMPUTER PROGRAMS

Grouping instructions according to their function is another method of

decomposing a program. Arithmetical, input- and output, parsing mod­

ules are examples of such grouping.

A.6.2 Computers involved in this study

The package has been written for a combination of two computers using respectively an 8-bit processor, the INTEL 8080 or Z80 as the source and a 16-bits, the 68000 MOTOROLA as the target computer. The 68000 has been chosen because it is widely used in personal systems such as Apple's MACINTOSH and Atari's ST-computers17.

A.7 THE PROCESS OF TRANSFORMATION

Step one Transfer the machine code program from the CP /M machine to the object computer, use a modem or a disk. If there are data-files available to be used by the program these have to be transferred also to the object computer.

Step two Start the program called NAME. Input the name of the program (P) to be reconstructed. After entering the name of the program it is stored on the disk. All programs working on the transformation use it.

Step three MALIN's first emulator can now be started. This emulator has been writ­ten in assembler. It contains routines that put information in a file called TRACE. After the program (P) has been emulated, the program TRACE manipulates the TRACE file into a fde with the extension ANP. Then the program SPLITP splits the ANP file into different files. These contain information about the program to be transformed. These files have been discussed in the main text.

Normally all branches of the program (P) are not executed. A separate

5 ST is an acronym for sixteen-thirty two.

APPENDIX IO3

utility program will determine which branches are not being executed and where they can be found. These branches must be executed. The program (P) can be reconstructed only if all instructions and data have been examined.

A.7.1 Emulation o f branches

Step four To execute the branches a separate software emulator has been written. This emulator does not emulate the environment of the source computer. Its only task is to examine the program during execution of certain branches.

A.7.2 A software monitor

Step five After all the above steps are completed, the software emulator Z80EXE can be started. The executor starts by asking for parameters. Next the emulator asks whether the standard extension of the files to be used need to be changed. The emulator activates the monitor program.18 It provides the capability to inspect addresses of the program (P), change their con­tents and modify processor registers. The program (P) can be executed step-by-step, as well automatically until a breakpoint is encountered. If the monitor encounters an error situation, error information is output to the screen and stored in a file called "filename.EPvR".

Initial computers were equipped with a front-panel display. The mon­itor program displays information on the screen of the object computer. A sample of such a display is shown on the next page.

After starting the software monitor the above information is displayed on the screen. Because a CP /M program normally starts at address 100 the program counter points to that address. If this is not the case, manual intervention is required to insure that the program starts at the correct address. By using keys as described below the user can execute, instruc­tion by instruction, inspect register and memory contents, and perform branches to any address in memory.

18 This monitor was originally written for CP/M-systems equipped with the 8080 processor by Lourens Blok at Woerden, Holland. This program has been translated and adapted for use in MALIN.

104 RE-ANIMATION OF COMPUTER PROGRAMS

>PC 0100 CD 62 05 31 94 13 CD 85 05 CD BD 05 CD 11 0118 C3 03 SP F FFF IE D912 D3 09 FF CB 00 00 00 00 00 00 00 00 00 00 00 IY 5FFF 5B E9 84 84 5B 84 5B 00 00 00 00 00 00 00 00 00 00 00 IX F245 00 00 00 00 00 ID 31 00 00 00 00 00 00 00 00 00 00 00 HL 0000 C3 03 E8 95 00 C3 06 00 30 20 34 56 58 05 06 44 00 22 DE EA25 ED 5B 2C EA C9 3B DD 00 DE 36 5A 3B 2C 33 05 30 AC ED BC 0020 84 5B 84 5B 84 5B 84 03 03 04 04 DE E3 4E 3A 2A DE 3E AF 0000

OOEC 00 00F4 00 OOFC 00 0104 94 010C CD 0114 CA OOED 00 00F5 00 OOFD 00 0105 13 010D 11 0115 EB OOEE 00 00F6 00 OOFE 00 0106 CD 010E 01 0116 Ol OOEF 00 00F5 00 OOFF 00 0105 85 010F 18 0115 21 OOFO 00 00F8 00 >0100 CD< 0108 05 0110 F8 0118 Dl 00F1 00 00F9 00 0101 62 0109 CD OUI CD 0119 08 00F2 00 OOFA 00 0102 05 010A BD 0112 OB 011A Ol 00F3 00 >

V

OOFB 00 0103 31 010B 05 0113 02 011B OA

The first two positions of the upper part contain the name of the register followed by its contents. The first seven registers normally function as address pointers. They show the locations of memory followed by con­secutive memory contents. The flag-register designated 'F' has been decoded to show clearly which flags are set. As an example, if the flag-register contains hexadecimal FF it will display: SZ, H, VNC. This means that the Sign, Zero, Half-carry, Parity-Overflow, Add/Subtract and Carry-flags are set.

The cursor '>'in front of a register name denotes which register is open. The contents of that register can be modified by the 'R ' command in combination with the 'dot' (.) command. At any given moment the addressed memory location is also displayed in a vertical row and sur­rounded by '> <'. Giving the dot command moves the register pointer. Typing a hexadecimal number immediately followed by a dot can modify the content of this register. The same applies for memory locations. Typing in a hexadecimal number followed by 'M' can alter them. The memory pointer is moved by typing '+ ' (higher address) or '- ' (lower address).

APPENDIX IO5

Automatic execution takes place after entering the character 'S ' until a

breakpoint is encountered. Sometimes it is necessary to trace a program to

a certain location to make changes. For this reason the breakpoint facility

is incorporated. U p to ten breakpoints can be set after entering ' B ' fol­

lowed by a hexadecimal number. Address 0 always contains a breakpoint.

Using the step-by-step tracing method one and only one instruction is

executed after typing the character '; ' followed by ' return ' . Information is

displayed on the screen. A question mark is printed w h e n input is called

for. The program waits for the user to make an input. After output to the

display the computer waits until any key is pressed before continuing.

After the key pressed, the screen is cleared, and execution of the program

resumes. If a printer is connected to the computer , output can be directed

to that device. If the character 'd' is entered before emulation of the

source program, no information is displayed about the instructions exe­

cuted. This reduces processing time.

As an example a routine that emulates the 8080 stax-instruction follows.

The stax instruction loads the contents of a memory location in the accu­

mulator.

PROCEDURE stax

PRINT A T ( 2 6 , 2 2 ) ; "LD (" ;

c l i s p $ = d i s p $ + " LD ("

IF B T S T ( b y t e | , 4 )

PRINT # 2 ; H E X $ ( d e _ r e g % ) ; " c h a n g e d "

POKE werkgeh%+de_reg%, ac I

PRINT "DE";

disp$=disp$+"DE"

ELSE

PRINT #2;HEX$(bc_reg%);" changed"

POKE werkgeh%+bc reg%,acj

PRINT "BC";

disp$=disp$+"BC"

ENDIF

disp$=disp$+"),A"

PRINT ") , A'S-

PRINT #2;HEX$(pc%);" instruction"

varfile

I 0 6 RE-ANIMATION OF COMPUTER PROGRAMS

INC pc%

PRINT #3;disp$

RETURN

Step six After successful completion of the above the generated files are sorted and possible duplicates are removed. A duplicate exists if part of a program is executed more than once. Next a program is run to determine which instructions and branches were not executed. To do so two files are gen­erated. One file has the extension NOT. It contains instructions or data that have not been executed or used. It also contains a disassembly of this information. The other file uses the extension NOJ. It identifies those branches that have not been executed. This information is used to exe­cute all instructions and branches of the source program.

Step seven When the emulator comes to a breakpoint the generated files must be concatenated and resorted. If all branches have not been executed, step five, six and seven have to be repeated. A separate utility program, contained in MALIN, disassembles instructions not executed. The user should determine whether these instructions are superfluous or not.

Step eight Sometimes programs contain text strings. Those strings applicable to com­ment only should be retained. A special utility program, called BRASC, is included to do this. When all instructions and text strings have been vali­dated the next step can be made: the transformation into executable code. Different programs do this transformation. The first program gives labels to translated instructions of the source program and produces a list of labels used.

After the first program has been completed, the output can be inspect­ed.

The second program does the final work. It transforms the recon­structed code. The following example shows how the 'stax' instruction is transformed.

APPENDIX IO7

PROCEDURE ld_reg_a

ins$="L" + HEX$ (cpm_address%)

IF BTST(byte|,4)

ins$=ins$+" move.1 #lddea,aO"

ELSE

ins$=ins$+" move.1 #ldbca,aO"

ENDIF

PRINT #3; ins$

ins$=" jsr (aO)"

PRINT #3; ins$

RETURN

First a label is generated consisting of the capital L followed by the value of the address of the instruction in the source program (P). Depending on the value of the fourth bit of the operator register DE or register BC should be loaded with the content of the accumulator. The instruction 'jsr (aO) effectuates that the subroutine to effectuate this is called.

If problems are encountered the information is stored. It is located in the file with the extension MSG.

After all instructions of the source program have been transformed, the output generated has to be processed by an assembler.

A.7.3 Possible adaptations o f the transformed program

A transformed program has been designed for the working environment of M. In chapter 5 it was explained that a new support system is never totally new. It always incorporates remnants of older systems, often in novel combinations. The TTP (Tos Takes Parameters) capability of the ATARI computers is an example.

Programmers tool kits can be used to refine the transformed program.

A.8 REQUIREMENTS T O BE POSED T O USERS OF MALIN

The support system in this study is primarily intended for use by those who are competent in developing assembler programs. They have to ful­fill certain conditions. Code reconstruction can be achieved by employing

I 0 8 HE-ANIMATION OF COMPUTER PROGRAMS

their competence. They must possess sufficient knowledge of assembly languages to interpret the code produced. Necessary adjustments to this code cannot be performed without this degree of competence. Similar knowledge is also needed to evaluate old software. Knowledge of other support systems such as a debugger is also necessary. It is an indispensable tool for testing programs written in assembler, or transformed programs19. Finally, users should have a working knowledge of operating systems and comparable support systems. Without this they cannot interpret system calls, let alone adapt them.

A.9 TECHNICAL REQUIREMENTS

The package MALIN requires special hardware. It produces a multitude of information. It is necessary that the object computer has a minimum of 60-megabyte hard disk storage, and one megabyte of RAM. In addition a printer is mandatory. Without hard copies, it is difficult to get an overview or to evaluate the code produced by MALIN.

The hard and software requirements for the ATARI computer (M') are as follows:

Hardware: An ATARI computer type ST or FALCON with at least one megabyte of main memory. A hard disk with a minimum of 60 megabytes and a printer.

Software:

A word processor capable of handling plain ASCII. These are available in

the public domain.

A GFA-BASIC interpreter, preferably version 3.06. A GFA-BASIC pro­gramming development system has been given to subscribers of the English ST-FORMAT magazine.

A 68000 assembler. The Turbo assembler developed by Fritze (Hellwig, 1989) can be used as well as the DEVPAC package of which version two has also been made available to readers of ST-FORMAT

19 debugger: a computer program that supports the user in finding errors in a program.

APPENDIX IOC

CP/M programs. They are available on R O M or floppy disk in the pub-

He domain. They can be obtained from the H C C (Dutch Hobby

Computer Club), Utrecht. A CP/M emulator for the ATARI is also

available in the public domain and can be purchased through the publish­

ers of the ST-news, an ATARI journal.

A. 10 FLOWCHARTS

Main flowchart

Task

make name of CP/M known to MALIN

Description

run the program called NAME

emulate CP/M-program with CP/M-operating system

Z80TRC.T0S generates trace-file

emulate CP/M-program with TOS-operating system

EMU1 emulates CP/M program, determines which bit strings are operators and operands

manipulate code SPLIT1 splits the code generated by EMU1 in the files mentioned above. This information is used to convert the machine code of the source program to plain text. This is used in the second part of the transformation process. Several programs starting with P101 also sort the files.

determine not executed branch instructions

EMU1 stores information about branches executed, instructions not executed and data not used.

NOTUSED collects instructions not executed.

BRANCHBEP collects branch information.

I I O UE-ANIMATION OF COMPUTER PROGRAMS

r—repeat EMU2 emulates the program to be reconstructed. In

addition, it identifies those branches that have not

been executed

SPLITA splits the information generated by EMU2.

This information is sorted by a number of programs

starting with P103

EMU3 executes the branches which were detected by

EMU2. This code is split, sorted and added to the

previously gathered source program information.

-until all branches

have been executed

convert code Instructions not executed and data not used are

redundant information. This information is converted

by DETCODE using static research and is added to

the already generated data. This is accomplished by

the programs CONCAT1, CONCAT2 and CONSORT.

The first addition is done by CONCAT1. Subsequent

ones by CONCAT2.

The CONSORT program then sorts all this information

verify the code The program TSTRS verifies the generated code.

transform in Z80-machine The verified source code is assembled by ASSEM code

compare code with

CP/M-program until no

errors reported.

COMCOM verifies this code with the original program

transform CP/M program TRI generates object code and a label for each

instruction of the source program.

TR2 removes superfluous labels and ensures that

correct ones are generated for each branch.

assemble

-test and debug

transformed program.

This process is repeated

-until all errors removed.

The code generated can be

assembled by any 68000

assembler and debugged by any

68000 debugger.

APPENDIX I I I

Flowchart of GENCOT

init initialise s prog close ;close files

prog open files control code

control code WHILE not all branches have been investigated

REPEAT look in nob file for not fully investigated branches

UNTIL one has been found requiring action look in PTS file whether all instructions of this branch have been processed

IF not transform code

ENDIF WEND

transform code look in not file for instructions not processed IF not

REPEAT store information for instructions not processed in filename.ANA

UNTIL last instruction of the block has been investigated END IF

A. 11 NUMBER OF EXECUTED 68000 INSTRUCTIONS

The following table depicts how many instructions are needed on the object computer (M') for each source computer instruction (M). The first column depicts the number of instructions that are executed for each transformed source computer instruction. The second column contains the instructions that can be executed by the 8080 and Z80 processor. For example the increment BC-reg instruction can be executed by both the 8080 and Z80 processor. The third contains the instructions that can be executed only by the Z80 processor. Its effectuation needs only one instruction executed on the 68000 processor.

112 RE-ANIMATION OF COMPUTER PROGRAMS

number 8080/ of 68000 Z80 instructions instructions

Z80-additional instructions

0 no-operation load reg with reg (8-bit)

increment BC-reg Increment Index-reg load reg immediate (8-bit) Increment DE-reg Increment HL-reg Decrement DE-reg Increment stack-reg Decrement stack-reg Set carry-flag Clear carry-flag Enable interrupt

load refresh reg

load interrupt reg with accu

Load BC-reg immediate Load [BC]-reg from accu Shift left accu through carry Load accu with [BC-reg] Shift right accu through carry Load DE-reg immediate Load [DE]-reg from accu Load accu from [DE-reg] Decrement DE-reg Add HL-reg to HL-reg Load [HL]-reg immediate Load [HL]-regwith reg

Set Bit

Load IX reg immediate Load IY reg immediate Add IX-reg to IX-reg Add IY-reg to IY-reg Reset bit

2/8

3

return depending on parity

Shift left accu Shift right accu Complement accu Pop reg (16 bits) Push reg (16 bits)

Jump to [HL] Load stack-reg from IY

subroutine-call [imm.]

Add IX-reg to BC-reg Add IX-reg to DE-reg Pop IX-reg Push IX-reg Jump to [IX-reg] Load stack-reg from IY

APPENDIX I I 3

3/6

3/8

Jump imm. depending on CC

4/8

4/14/26

4/10 +subroutine

5/6

Return from subroutine depending on CC

Add IX-reg to BC-reg Exchange DE-regwith HL-reg

Rotate through carry

Call subrout. imm dep. on CC Shift Load accu from Interrupt-reg Load immediate[lndex-reg+offset] Add Index-regto stackpointer Load reg with [Index-reg+offset]

Jump immediate depending on CC

Call immediate depending on CC

special input routine

Load stackpointer immediate Load [memory] immediate Load accu [immediate] And accu with reg load accu with [IY-reg+offset] Or accu with reg Compare reg with reg And accu immediate Or accu immediate

Decrement accu and jump immediate if zero

rotate reg

shift reg

5/9 special output routine +subroutine

6 Load HL-reg [immediate] And [HL-reg] Xor reg And [HL-reg] Or [HL-reg] Or reg

special input routine

rotate reg through carry

1 1 4 RE-ANIMATION OF COMPUTER PROGRAMS

Compare reg Jump immediate Return Xor immediate Compare immediate

Subtract reg Subtract reg with carry Xor[HL-reg] Compare [HL-reg] Exchange Stack-reg with HL-reg

Shift left [HL]

Shift right reg

Load DE-reg [immediate] Load BC-reg [immediate] Load IX-reg [immediate] Load [immediate] BC-reg Load [immediate] DE-reg Shift left [IX-reg +offset] Exchange registers Rotate through carry [HL] Rotate reg

Shift through [HL] Subtract HLfrom HL-reg Exchange [stack-reg] with Index­reg Load IY-reg immediate Rotate through carry [IX+offset] Shift [IX+offset]

Increment reg (8 bits) Decrement reg (8 bits)

Load HL-reg immediate Load [immediate] from HL-reg

Restart immediate

Rotate [HL-reg] Load A with refresh-reg Return N Rotate right D-reg Add with carry HL- to h HL-reg Compare [HL], inc. HL, dec BC Compare [HL], dec. HL, inc BC Rotate left D-reg And [index-reg +ofsset] Or [index-reg +ofsset] Rotate [index-reg +ofsset]

Increment [HL-reg] Decrement [HL-reg] Add accu to accu

Load interrupt-reg

negate Load stack-reg immediate Compare [HL], dec. HL, dec. BC

APPENDIX I I 5

9 Halt (see text) +subroutine

special in- output instr. Add with carry Hl-reg to reg-pair Xor [index-reg +offset] Compare [Index-reg +offset]

10 Subtract with carry Hl-reg to reg-pair Load [immediate] from stack-reg Add with carry Hl-reg to stack-reg

10 +subroutine

special input to accu instr.

11 Add with carry accu to accu subtract with carry stack-reg from HL-reg Increment [index-reg +offset] Decrement [index-reg +offset] Decrement index-reg

11 -»-subroutine

special in- output to HL-reg instr.

11 +subroutine +intemal loop

special in- output to HL-reg instr. until condition is satisfied

12 -(-internal loop

13 Load accu with reg Load accu with [HL-reg] Add accu to reg Add accu to [HL-reg] Add accu with carry to reg Add accu with carry to [HL-reg] Add to accu immediate Subtract accu from reg Subtract from accu immediate

special output to HL-reg instr. combined with decrement of regs until condition is satisfied

14 Increment D-reg Subtract [HL-reg] from accu

I l 6 RE-ANIMATION OF COMPUTER PROGRAMS

14 +intemal loop

Load [DE-reg] with [HLreg], combined with increment and decrement registers until condition is satisfied

16 Add to accu [Indexreg+offset] Subtract from accu [Index-reg +offset]

17 Add with carry to reg accu Add with carry to accu immediate Subtract with carry reg from accu Subtract with carry from accu immediate

17 +internal loop

Compare [DE-reg] with [HLreg], combined with increment and decrement registers until condition is satisfied

18 Add with carry [HL-reg] to accu Subtract with carry [HL-reg] from accu

19

20

Pop accu and status-register

Add with carry [Index-reg] to accu Subtract with carry [Index-reg] from accu

21 24

Push accu and status-register Exchange accu and status-register with alternate registers

48 Decimal adjust instruction

APPENDIX I I 7

A. 12 NUMBER OF RUNTIME INSTRUCTIONS FOR TRANSFORMED CODE

number of type instruction instructions

0 no operation load refresh register move registercontents to same register

1 move 8 bit register to register set or complement flag

2 in and decrement 16 bit register move 16 bit register to register move 16 bit immediate data to register move 8 bit register to memory rotate register left add 8 bit register to register

2/8 RPE instruction

3 rotate register right jump to content of register pop and push register load stackpointer

3/6 jump relative

3/8 return conditional from subroutine

4 add 16 bit register to register call if minus

4/8 jump conditional to address

4/14 call conditional subroutine

4/26 Call if not carry

5 logical and operations

5/6 decrement register and jump if not zero

I l 8 RE-ANIMATION OF COMPUTER PROGRAMS

6 logical or operations Jump address return from subroutine compare

7 subtract XTHL instruction

8 in and decrement 8 bit register move 8 bit immediate data to register

9 in and decrement content of memory location add

9+subroutine halt (used for call to function of operating system)

10

11

13

14

16

17

subtract with carry

add with carry subtract with carry register from register pop and push index register

move 8 bit register to register add 8 bit register to register subtract 8 bit register to register

add contents of memory location to register subtract contents of memory location to register

14+internal move contents of memory locations until condition is met loop

add contents of memory location using idex register to register subtract contents of memory location using idex register to register

add with carry 8 bit register to register subtract with carry 8 bit register to register

17+intemal EDB1 loop EDB9

APPENDIX HC

18

19

20

21

24

48

add with carry immediate to register subtract with carry immediate to register

pop status register

add with carry contents of memory location using index register to register subtract with carry contents of memory location using index register to register

push status register

exchange registers with auxiliarry registers

decimal adjust

A.13 Z-80 INSTRUCTION SET AND TRANSFORMATION F O R

THE 68000 PROCESSOR

Hex Mnemonic transforma­tion for the 68000 processor

Hex Mnemonic transforma­tion for the 68000 processor

8E ADC A,(HL) adcahl 83 ADD A,E adae

DD 8E dd ADC A,(IX+ddH) adcaix_d 84 ADD A,H adah

FD 8E dd ADC A,(IY+ddH) adciy_d 85 ADDA.L adal

8F ADC A,A adcaa C6nn ADD A.nnH ada_n

88 ADC A,B adcab 09 ADD HL.BC adhlbc

89 ADC A,C adcac 19 ADD HL.DE adhlde

8A ADC A,D adcad 29 ADD HL.HL adhlhl

8B ADC A,E adcae 39 ADD HL.SP adhlsp

8C ADC A,H adcah DD09 ADD IX.BC adixbc

8D ADC A,L adcal DD19 ADD IX.DE adixde

CE nn ADC A.nnH adc_n DD29 ADD IX.IX adixix

ED4A ADC HL.BC adchlbc DD39 ADD IX.SP adixsp

ED5A ADC HL.DE adchlde FD09 ADD IY.BC addiybc

ED6A ADC HL.HL adchlhl FD19 ADD IY.DE addiyde

ED7A ADC HL.SP adchlsp FD29 ADD IY.IY adiyiy

86 ADD A,(HL) adahl FD39 ADD IY.SP adiysp

DD 86 dd ADD A,(IX+ddH) adaix_d A6 AND (HL) andhl

FD 86 dd ADD A,(IY+ddH) adaiy_d DDA6 dd AND (IX+ddH) andix_d

87 ADD A,A adaa FD A6 dd AND (lY+ddH) andiy_d

80 ADDA.B adab A7 AND A anda

81 ADD A,C adac AO AND B andb

82 ADD A,D adad A l ANDC andc

120 KE-ANIMATION OF COMPUTER PROGRAMS

Hex Mnemonic transforma­tion for the 68000 processor

Hex Mnemonic transforma­tion for the 68000 processor

A2 ANDD andd CB66 BIT 4,(HL) bit4hl

A3 AND E ande DD CB dd 66 BIT 4,(IX+ddH) bit4ix_d

A4 AND H andh FD CB dd 66 BIT 4,(IY+ddH) bit4iy_d

A5 AND L andl CB67 BIT 4,A bit4a

E6nn AND nnH and_n CB60 BIT4.B bit4b

CB46 BITO.(HL) bitOhl CB61 BIT4.C bit4c

DD CB dd 46 BIT 0,(IX+ddFI) bitOix_d CB62 BIT4.D bit4d

FD CB dd 46 BIT 0,(IY+ddH) bitOiy_d CB63 BIT 4,E bit4e

CB47 BIT 0,A bitOa CB64 BIT 4, H bit4h

CB40 BITO.B bitOb CB65 BIT4.L bit4l

CB41 BIT 0,C bitOc CB6E BIT 5,(HL) bit5hl

CB42 BITO.D bitOd DD CB dd 6E BIT 5,(IX+ddH) bit5ix_d

CB43 BIT 0,E bitOe FD CB dd 6E BIT 5,(IY+ddH) bit5iy_d

CB44 BIT 0,H bitOh CB6F BIT 5,A bit5a

CB45 BITO.L bitOl CB68 BIT 5,B bit5b

CB4E BIT 1,(HL) bitlhl CB69 BIT 5,C bit5c

DD CB dd 4E BIT l,(IX+ddH) bitlix_d CB6A BIT 5,D bit5d

FD CB dd 4E BIT l,(IY+ddH) bitliy_d CB6B BIT5.E bit5e

CB4F BIT1.A bitla CB6C BIT 5,H bit5h

CB48 BIT1.B bitlb CB6D BIT5.L bit5l

CB49 BIT 1,C bitlc CB76 BIT6,(HL) bit6hl

CB4A BIT1.D bitld DD CB dd 76 BIT6,(IX+ddH) bit6ix_d

CB4B BIT 1,E bitle FD CB dd 76 BIT6,(IY+ddH) bit6iy_d

CB4C BIT 1,H bitlh CB77 BIT 6,A bit6a

CB 4D BIT 1,L bitl l CB 70 BIT6.B bit6b

CB56 BiT 2,(HL) bit2hl CB71 BIT6.C bit6c

DDCB dd 56 BIT 2,(IX+ddH) bit2ix_d CB 72 BIT6.D bit6d

FD CB dd 56 BIT 2.(IY+ddH) bit2iy_d CB73 BIT6.E bit6e

CB57 BIT 2,A bit2a CB74 BIT 6,H bit6h

CB50 BIT2.B bit2b CB75 BIT6.L bit6l

CB51 BIT2.C bit2c CB 7E BIT 7,(HL) bit7hl

CB52 BIT 2,D bit2d DD CB dd 7E BIT 7,(IX+ddH) bit7ix_d

CB53 BIT 2,E bit2e FD CB dd 7E BIT 7,(IY+ddH) b i t7 iy j

CB54 BIT 2,H bit2h CB 7F BIT7.A bit7a

CB55 BIT2.L bit2l CB78 BIT7.B bit7b

CB5E BIT 3,(HL) bit3hl CB 79 BIT7.C bit7c

DD CB dd 5E BIT 3,(IX+ddH) bit3ix_d CB7A BIT7.D bit7d

FD CB dd 5E BIT 3,(IY+ddH) bit3iy_d CB 7B BIT 7,E bit7e

CB5F BIT 3,A bit3a CB7C BIT 7,H bit7h

CB58 BIT3.B bit3b CB7D BIT7.L bit7l

CB59 BIT3.C bit3c DCnnnnH CALL C,nnnnH callca

CB5A BIT3.D bit3d FC nnnnH CALL M,nnnnH callm

CB5B BIT 3,E bit3e D4 nnnnH CALL NC,nnnnH callnc

CB5C BIT 3,H bit3h CD nnnnH CALL nnnnH call

CB5D BIT 3,L bit3l C4 nnnnH CALL NZ.nnnnH callnz

APPENDIX 121

Hex Mnemonic transforma­tion for the 6 8 0 0 0 processor

Hex Mnemonic transforma­tion for the 6 8 0 0 0 processor

F4 nnnnH CALL P,nnnnH callp EB EXDE.HL exdehl

EC nnnnH CALL PE.nnnnH callpe D9 EXX exx

E4 nnnnH CALL PO,nnnnH callpo 76 HALT

CC nnnnH CALL Z,nnnnH callz

3F CCF ccf 34 INC (HL) inchl

BE CP (HL) cphl DD34 dd INC (IX+ddH) incix_d

DDBE dd CP (IX+ddH) cpix_d FD 34 dd INC (lY+ddH) inciy_d

FDBEdd CP (lY+ddH) cpiy_d 3C INC A inca

BF CPA cpa 0 4 INCB incb

B8 CPB cpb 0 3 INC BC inebe

B9 CPC cpc OC INCC incc

BA CPD cpd 14 INC D incd

BB CPE cpe 13 INC DE incde

BC CPH cph 1C INC E ince

BD CPL cpl 24 INCH inch

FEnn CPnnH cp_n 23 INC HL inchl

EDA9 CPD c p d j n s DD23 INC IX incix

EDB9 CPDR cpdr F D 2 3 INC IY inciy

EDA1 CPI cpi 2C INC L incl

EDB1 CPIR cpir 33 INC SP incsp

2F CPL cpLac

27 DAA daa E9 JP(HL) jphl

35 DEC (HL) dechl DDE9 JP (IX) jpix

DD35 dd DEC (IX+ddH) decix_d FDE9 JP (IY) jpiy

F D 3 5 d d DEC (lY+ddH) deciy_d DA nnn JPC,nnnnH jpc

3D DEÇA deca FA nnnn JP M,nnnnH jpm

05 DEC B decb D2 nnnn JP NC,nnnnH jpnc

OB DEC BC decbc C3 nnnn JP nnnnH jpnnnn

OD DECC decc C2 nnnn JP NZ,nnnnH jpnz

15 DECD deed F2 nnnn JP P.nnnnH jpp

I B DEC DE decde EA nnnn JP PE.nnnnH jppe

I D DEC E dece E2 nnnn JP PO,nnnnH jppo

25 DEC H dech CA nnnn JPZ.nnnnH jpz

2B DEC HL dechl 38 dd JR C.ddH jrc

DD2B DEC IX decix 18 dd JRddH jrn

FD2B DEC IY deciy 30 dd JR NC.ddH jrnc

2D DECL deel 20 dd JR NZ.ddH jrnz

3B DEC SP decsp 28 dd JR Z.ddH jrze

F3 DI di 02 LD (BC),A Idbca

10 dd DJNZ ddH djnz 12 LD (DE),A Innnnea

FB El ei 77 LD (HL),A Idhla

E3 EX (SP),HL exsphl 70 LD (HL),B Idhlb

DDE3 EX (SP),IX exspix 7 1 LD (HL),C Idhlc

FDE3 EX (SP),IY exspiy 72 LD(HL),D Idhld

08 EX AF.AF exaf 73 LD (HL),E Idhle

122 RE-ANIMATION OF COMPUTER PROGRAMS

Hex Mnemonic transforma­tion for the 68000 processor

Hex Mnemonic transforma­tion for the 6 8 0 0 0 processor

74 LD (HL),H Idhlh 47 LDB.A Idba

75 LD (HL),L Idhll 40 LDB.B Idbb

36 nn LD (HL),nnH ldhli_n 4 1 LDB.C Idbc

DD 77 dd LD (IX+ddH),A ldix_da 42 LDB.D Idbd

DD 70 dd LD (IX+ddH),B ldix_db 43 LDB.E Idbe

DD 7 1 dd LD (IX+ddH),C ldix_dc 44 LDB.H Idbh

D D 7 2 d d LD (IX+ddH),D ldix_dd 45 LDB.L Idb

DD 73 dd LD (IX+ddH),E ldix_de 06 nn LD B.nnH ldb_n

DD 74 dd LD (IX+ddH).H ldix_dh ED 4B nnnn LD BC(nnnnH) ldj>c_n

DD75 dd LD (IX+ddH),L ldix_dl 0 1 nnnn LD BC.nnnnH ldbc_n

DD 36 dd nn LD (IX+ddH),nnH ldix_d_n 4E LD C,(HL) Idchl

FD 77 dd LD (IY+ddH),A ldiy_da DD 4E dd LD C,(IX+ddH) ldcix_d

F D 7 0 d d LD (IY+ddH),B ldiy_db FD 4 E d d LD C,(IY+ddH) ldciy_d

F D 7 1 d d LD (IY+ddH),C ldiy_dc 4F LDC.A Idea

FD 72 dd LD (IY+ddH),D ldiy_dd 48 LDC.B Idcb

F D 7 3 d d LD (IY+ddH),E ldiy_de 49 LDC.C Idee

FD 74 dd LD (IY+ddH),H ldiy_dh 4A LDC.D Idcd

FD 75 dd LD (IY+ddH),L ldiy_dl 4B LDC.E Idee

FD 36 dd nn LD (IY+ddH),nnH ldiy_d_n 4C LDC.H Idch

32 nnnn LD (nnnnH).A ld_n_a 4D LDC.L Idcl

ED 43 nnnn LD (nnnnH).BC ld_n_bc OEnn LD C.nnH Idc

ED 53 nnnn LD(nnnnH),DE ld_n_de 56 LD D,(HL) Iddhl

22 nnnn LD(nnnnH),HL ld_n_hl DD 56 dd LD D,(IX+ddH) lddix_d

DD 22 nnnn LD (nnnnH).IX ld_n_ix FD 56 dd LD D,(IY+ddH) lddiy_d

FD 22 nnnn LD(nnnnH),IY ld_n_iy 57 LDD.A Idda

ED 73 nnnn LD (nnnnH).SP ld_n_sp 50 LDD.B Iddb

OA LD A,(BC) Idabc 5 1 LDD.C Iddc

1A LD A,(DE) Idade 52 LDD.D Iddd

7E LD A,(HL) Idahl 53 LDD.E Idde

DD 7E dd LD A,(IX+ddH) ldaix_d 54 LDD.H Iddh

FD 7Edd LD A,(IY+ddH) ldaiy_d 55 LD D,L Iddl

3A nnnn LD A.(nnnnH) ldai_n 16 nn LD D.nnH Idd

7F LD A,A Idaa ED 5B nnnn LD DE.(nnnnH) ld_de_n

78 LD A,B Idab 1 1 nnnn LD DE.nnnnH ldde_n

79 LD A,C Idac 5E LD E,(HL) Idehl

7A LDA,D Idad DD 5E dd LD E,(IX+ddH) ldeix_d

7B LD A,E Idae FD 5E dd LD E,(IY+ddH) ldeiy_d

7C LD A,H Idah 5F LD E,A Idea

ED 57 LD A,l Idai 58 LDE.B Ideb

7D LD A,L Idal 59 LDE.C Idee

3E nn LD A.nnH lda_n 5A LD E,D Ided

ED5F LDA.R Idar 5B LDE.E Idee

46 LD B,(HL) Idbhl 5C LDE.H Ideh

DD 46 BC LD B,(IX+ddH) ldbix_d 5D LD E,L Idel

FD 46 BC LD B,(IY+ddH) ldbiy_d l E n n LD E.nnH Ide

A P P E N D I X 12

Hex Mnemonic transforma­tion for the 68000 processor

Hex Mnemonic transforma­tion for the 6 8 0 0 0 processor

66 LD H,(HL) Idhhl BO ORB orb

DD 6 6 dd LD H,(IX+ddH) ldhix_d B l ORC ore

FD 66 dd LD H,(IY+ddH) ldhiy_d B2 OR D ord

67 LDH,A Idha B3 OR E ore

60 LDH.B Idhb B4 OR H orh

6 1 LDH.C Idhc B5 OR L orl

62 LDH.D Idhd F6nn ORnnH or_n

63 LDH,E Id he

64 LD H,H Idhh F l POP AF popaf

65 LD H,L Idhl C l POP BC popbc

26 nn LD H.nnH Idh D l POP DE popde

2A nnnn LD HL.(nnnnH) ld_hl_n E l POP HL pophl

2 1 nnnn LD HL.nnnnH ldhl_n DDEl POP IX popix

ED 47 LDI.A Idia FD E l POPIY popiy

DD 2A nnnn LD IX.(nnnnH) ldixi_n F5 PUSH AF pushaf

DD 2 1 nnnn LD IX.nnnnH ldix_n C5 PUSH BC pushbc

FD 2A nnnn LD IY,(nnnnH) ld iy_n j D5 PUSH DE pushde

FD 2 1 nnnn LD lY.nnnnH ldiy_n E5 PUSH HL pushhl

6E LD L,(HL) Idlhl DDE5 PUSH IX pushix

DD 6E dd LD L,(IX+ddH) ldix_d FDE5 PUSH IY pushiy

F D 6 E d d LD L,(IY+ddH) ldiy_d C B 8 6 RES 0,(HL) resOhl

6F LDL.A Idia DDCB dd 86 RES 0,(IX+ddH) resOix_d

68 LDL.B Idlb FD CB dd 8 6 RES 0,(IY+ddH) resOiy_d

69 LDL,C Idle C B 8 7 RESO.A resOa

6A LDL,D Id Id C B 8 0 RESO.B resOb

6B LDL.E Idle C B 8 1 RES 0,C resOc

6C LDL.H Idlh C B 8 2 RESO.D resOd

6D LDL.L Idll C B 8 3 RESO.E resOe

2E nn LD L.nnH Idl C B 8 4 RESO.H resOh

ED4F LD R,A Idra C B 8 5 RESO.L resOl

ED 7B nnnn LD SP.(nnnnH) ld_sp_n CB8E RES 1,(HL) res lh l

F9 LDSP.HL Idsphl DD CB dd 8E RES 1,(IX+ddH) resl ix_d

DDF9 LD SP.IX Idspix FD CB dd 8E RES l,(IY+ddH) resl iy_d

FDF9 LD SP.IY Idspiy CB8F RES 1,A res la

3 1 nnnn LD SP.nnnnH Idsp C B 8 8 RES 1,B r e s l b

EDA8 LDD I d d j n s C B 8 9 RES1.C res l c

EDB8 LDDR Iddr CB8A RES 1,D r e s l d

EDAO LDI Idi CB8B RES 1,E r e s l e

EDBO LDIR Idir C B 8 C RES 1,H r e s l h

ED 4 4 NEG neg CB8D RES 1,L res l l

00 NOP nop C B 9 6 RES 2,(HL) res2hl

B6 OR(HL) orhl DD CB dd 96 RES 2,(IX+ddH) res2ix_d

DDB6 dd OR (IX+ddH) orix_d FD CB dd 96 RES 2,(IY+ddH) res2iy_d

F D B 6 d d OR (lY+ddH) oriy_d C B 9 7 RES 2,A res2a

B7 OR A ora C B 9 0 RES2.B res2b

1 2 4 RE-ANIMATION OP COMPUTER PROGRAMS

Hex Mnemonic transforma­tion for the 68000 processor

Hex Mnemonic transforma­tion for the 68000 processor

CB91 RES 2,C res 2c DD CB dd BE RES 7,(IX+ddH) res7ix_d

CB92 RES 2,D res2d FD CB dd BE RES 7,(IY+ddH) res7iy_d

CB93 RES 2,E res2e CB BF RES 7,A res7a

CB94 RES 2,H res2h CB B8 RES 7,B res7b

CB95 RES 2,L res2l CBB9 RES 7,C res7c

CB9E RES 3,(HL) res3hl CB BA RES 7,D res7d

DD CB dd 9E RES 3,(IX+ddH) res3ix_d CB BB RES 7,E res7e

FD CB dd 9E RES 3,(IY+ddH) res3iy_d CB BC RES 7,H res 7 h

CB9F RES 3,A res2a CBBD RES 7,L res7l

CB98 RES3.B res2b C9 RET ret

CB99 RES 3,C res2c D8 RETC retc

CB9A RES 3,D res 2d F8 RET M retm

CB9B RES 3,E res2e DO RET NC retnc

CB9C RES 3,H res2h CO RETNZ retnz

CB9D RES 3,L res2l FO RETP retp

CB A6 RES 4,(HL) res4hl E8 RETPE retpe

DD CB dd A6 RES 4,(IX+ddH) res4ix_d EO RETPO retpo

FD CB dd A6 RES 4,(IY+ddH) res4iy_d C8 RETZ retz

CB A7 RES 4,A res2a

CB AO RES 4,B res2b CB16 RL(HL) rlhl

CB A l RES 4,C res2c DD CB dd 16 RL (IX+ddH) rlix_d

CBA2 RES 4,D res2d FD CB dd 16 RL (lY+ddH) rliy_d

CBA3 RES 4,E res2e CB17 RLA rla

CB A4 RES 4,L res2l CB10 RLB rib

CB AE RES 5,(HL) res5hl CB11 RLC rlc

DD CB dd AE RES 5,(IX+ddH) res5ix_d CB12 RLD rid

FD CB dd AE RES 5,(IY+ddH) res5iy_d CB13 RLE rle

CB AF RES 5,A res5a CB14 RLH rlh

CB A8 RES 5,B res5b CB15 RLL ril

CB A9 RES 5,C res5c 17 RLA rl_ac

CBAA RES 5.D res5d CB06 RLC (HL) rlchl

CB AB RES 5,E res5e DD CB dd 06 RLC (IX+ddH) rlcix_d

CB AC RES 5,H res5h FD CB dd 06 RLC (lY+ddH) rlcix_d

CB AD RES 5,L res5l CB07 RLC A rlca

CB B6 RES 6,(HL) res6hl CBOO RLCB rcb

DD CB dd B6 RES 6,(IX+ddH) res6ix_d CB01 RLCC rice

FD CB dd B6 RES 6,(IY+ddH) res6iy_d CB02 RLCD rlcd

CBB7 RES 6,A res6a CB03 RLC E rice

CB BO RES 6,B res6b CB04 RLC H rich

CB B l RES 6,C res6c CB05 RLCL rlcl

CB B2 RES 6,D res6d 07 RLCA rlc_ac

CB B3 RES 6,E res6e ED6F RLD rldjns

CB B4 RES 6,H res6h CB1E RR(HL) rrhl

CBB5 RES 6,L res6l DD CB dd IE RR (IX+ddH) rrix_d

CB BE RES 7,(HL) res7hl FD CD dd IE RR (IY+ddH) rriy_d

A P P E N D I X 12

Hex Mnemonic transforma­tion for the 6 8 0 0 0 processor

Hex Mnemonic transforma­tion for the 6 8 0 0 0 processor

CB1F RR A ira CBC4 SET 0,H setOa

C B 1 8 RR B rrb CBC5 SET 0,L setOa

C B 1 9 RRC rrc CBCE SET1,(HL) s e t l h l

CB1A RR D rrd DD CB dd CE SET l,(IX+ddH) s e t l i x j

CB1B RR E rre FD CB dd CE SET l,(IY+ddH) set l i y_d

CB1C RR H rrh CBCF SET 1,A s e t l a

CB1D RRL rrl CBC8 SET1.B s e t l b

I F RRA rrr CBC9 SET 1,C s e t l c

CBOE RRC(HL) rrchl CBCA SET 1,D s e t l d

DD CB dd OE RRC (IX+ddH) rrcix_d CBCB S E T I , E s e t l e

FD CB dd OE RRC (lY+ddH) rrciy_d CBCC SET 1,H s e t l h

CBOF RRC A rrca CBCD S E T l . L s e t l l

C B 0 8 RRCB rrcb CBD6 SET 2,(HL) set2hl

C B 0 9 RRCC rrcc DD CB dd D6 SET 2,(IX+ddH) set2ix_d

CBOA RRC D rrcd FD CB dd D6 SET 2,(IY+ddH) set2iy_d

CBOB RRC E rrce CBD7 SET 2,A set2a

CBOC RRC H rrch CBDO SET2.B set2b

CBOD RRC L rrcl C B D 1 SET 2,C set2c

OF RRCA rrc_ac CBD2 SET 2,D set2d

ED 67 RRD rrd_ins CBD3 SET 2,E set2e

C B D 4 SET 2,H set2h

9E SBC A,(HL) sbcahl C B D 5 SET 2,L set2l

DD 9E dd SBC A,(IX+ddH) sbcaix_d CBDE SET 3,(HL) set3hl

F D 9 E d d SBC A,(IY+ddH) sbciy_d DD CB dd DE SET 3,(IX+ddH) set3ix_d

9F SBC A, A sbcaa FD CB dd DE SET 3,(IY+ddH) set3iy_d

98 SBC A,B sbcab CBDF SET 3,A set3a

99 SBC A,C sbcac C B D 8 SET3.B set3b

9A SBC A,D sbcad CBD9 SET 3,C set3c

9B SBC A,E sbcae CBDA SET 3,D set3d

9C SBC A,H sbcah CBDB SET 3,E set3e

9D SBC A,L sbcal CBDC SET 3,H set3h

DEnn SBCA,nnH sbca_n CBDD SET3.L set3l

ED 42 SBC HL.BC sbchlbc CBE6 SET 4,(HL) set4hl

ED 52 SBC HL.DE sbchlde DD CB dd E6 SET 4,(IX+ddH) set4ix_d

ED 62 SBC HL.HL sbchlhl FD CB dd E6 SET 4,(IY+ddH) set4iy_d

ED 72 SBC HL.SP sbchlsp CBE7 SET 4,A set4a

37 SCF scf CBEO SET4.B set 4b

CBC6 SET 0,(HL) setOhl C B E 1 SET 4,C set 4c

DD CB dd C6 SET 0,(IX+ddH) setOix_d CBE2 SET 4,D set4d

FD CB dd C6 SET 0,(IY+ddH) setOiy_d CBE3 SET 4,E set 4e

CBC7 SET 0,A setOa CBE4 SET 4,H set4h

CBCO SETO.B setOa CBE5 SET4.L set4l

C B C 1 SET 0,C setOa CBEE SET 5,(HL) setöhl

CBC2 SETO.D stOa DD CB dd EE SET 5,(IX+ddH) set5ix_d

CBC3 SETO.E setOa FD CB dd EE SET 5,(IY+ddH) set5ix_d

126 RE-ANIMATION OF COMPUTER PROGRAMS

Hex Mnemonic transforma­tion for the 68000 processor

Hex Mnemonic transforma­tion for the 68000 processor

CB EF SET5.A set5a CB29 SRAC rac

CBE8 SET 5,B set5b CB2A SRAD srad

CB E9 SET 5,C set5c CB2B SRA E srae

CB EA SET5.D set5d CB2C SRA H srah

CB EB SET 5,E set5e CB2D SRAL sral

CB EC SET 5,H set5h CB3E SRL(HL) srahl

CBED SET5.L set5l DD CB dd 2E SRL (IX+ddH) srix_d

CB F6 SET 6,(HL) set6hl FD CB dd 2E SRL (lY+ddH) srliy_d

DD CB dd F6 SET 6,(IX+ddH) set6ix_d CB3F SRL A srla

FD CB dd F6 SET 6,(IY+ddH) set6iy_d CB38 SRLB srlb

CB F7 SET 6,A set6a CB39 SRLC srlc

CB FO SET 6.B set6b CB3A SRLD srld

CB Fl SET 6,C set6c CB3B SRL E srle

CB F2 SET 6,D set6d CB3C SRL H srlh

CBF3 SET 6,E set6e CB3D SRLL srll

CB F4 SET 6,H set6h 96 SUB (HL) subhl

CB F5 SET 6,L set6l DD 96 dd SUB (IX+ddH) subix_d

CB FE SET 7,(HL) set7hl FD 96 dd SUB (lY+ddH) subiy_d

DD CB dd FE SET 7,(IX+ddH) set7ix_d 97 SUB A suba

FD CB dd FE SET 7,(IY+ddH) set7iy_d 90 SUBB subb

CB FF SET 7,A set7a 91 SUBC subc

CB F8 SET 7,B set7b 92 SUBD subd

CB F9 SET 7,C set7c 93 SUB E sube

CB FA SET 7,D set7d 94 SUB H subh

CBFB SET 7,E set7e 95 SUBL subi

CBFC SET 7,H set7h D6nn SUB nnH sub_n

CBFD SET 7,L set7l AE XOR (HL) xorhl

CB26 SLA(HL) slahl DD AE dd XOR (IX+ddH) xorix_d

DD CB dd 26 SLA (IX+ddH) slaix_d FD AE dd XOR (lY+ddH) xoriy_d

FD CB dd 26 SLA(IY+ddH) slaiy_d AF XOR A xora

CB 27 SLA A slaa A8 XORB xorb

CB2 0 SLAB slab A9 XORC xorc

CB21 SLAC slac AA XORD xord

CB2 2 SLAD slad AB XOR E xore

CB23 SLA E slae AC XOR H xorh

CB24 SLA H slah AD XORL xorl

CB25 SLAL slal EEnn XOR nnH xor_n

CB2E SRA (HL) srahl

DD CB dd 2E SRA (IX+ddH) sraix_d

FD CB dd 2E SRA(IY+ddH) sraiy_d nn 8-bit argument

CB 2F SRA A sraa nnnn 16-bit argument

CB28 SRAB srab dd 8-bit signed displacement