|Column Tag:||Programmer's Forum
MacNosy Gets a Facelift
By Steve Jasik, Jasik Designs, Menlo Park, CA
Apple announced the availability of MacworkStation in the January developer newsletter in a small article. I think that this is what Scully has been talking about in some of his recent speeches when he mentions the Mac as a workstation. The only problem with the MacworkStation [a software program] is that instead of making it a public domain standard, Apple is licensing the source code for $1500 to "interested" parties. My present feeling is that it would do more for Mac sales to sell the source code for a nominal fee then to license it.
MacworkStation is a host based applications environment that enables host computer software to control the Macintosh user interface on a Macintosh. The idea behind the MacworkStation is that it's a way of writing applications on a host so it can utilize the graphic interface of the Macintosh. Just think, soon we will be able to log on to MAUG or Delphi and instead of emulating a teletype or a VT 100, we will have menus and windows, etc.
MacworkStation consists of two parts, a protocol definition and a first implementation of that protocol. The protocol defines commands which are sent to the Macintosh, telling it what to do (put up a dialog box, etc). Events are defined to pass back to the host what is happening on the Macintosh. Note that much of what happens on the Mac need not be sent back to the host. The other part is a Macintosh Application that implements the protocol definition on a Macintosh. It is a generalized Macintosh application that is capable of being driven by an external process (the host). Unlike terminal emulation, the MacworkStation allows the host full access to the windows, pull down menus, dialogs, and other features of the Macintosh user interface.
I hope this gives you enough information to whet your appetite. Just think of putting the Mac user interface on your favorite mainframe application. You will have to modifiy the mainframe end of it to send the appropiate commands to the Mac. But it might just make life pleasant for us grunts out there in hackerdom.
For More information contact Apple Software licensing at (408) 973-4667 or write a letter to Scully requesting that MacworkStation be made a public standard.
New MacNosy Version 2
Over the past year MacNosy has helped many programmers learn about the Macintosh OS, and the workings of other Mac programs. Meeting some of my users at trade shows has been fun for me. Many of their suggestions have been incorporated in Version 2 [denoted as V2] of MacNosy.
The reasons for V2 of Nosy are the introduction of the 128K ROM's, and the addition of features such as the context sensative symbol substitution discussed below. This was what I started with. By the time I was finsihed coding, the mini editor has been substantially extended to include displays of procedures by double clicking on a procedure name, and the ability to interactively create seperate, mergable comment files had been added.
Nosy Does Windows!
The introduction of the Mac user interface makes Nosy much easier to use. The illustration in figure 1 shows the procedure "browser" window partially obscured by the display of a procedure. The Display menu allows one to bring up windows containing the listing of a procedure, the references to any symbol, the complete reference list of system symbols referenced, the complete reference list of trapnames referenced, the listing of all the strings in the program, the list of code blocks in the program, etc.
Fig. 1 Windows supported
Note that Nosy now lists the formal parameter list with the listing of a trap call, and for I/O calls, it knows that the register A0 holds the address of the parameter block, so in between the defination of A0 and the trap call it substitutes names of the structure variables. For a procedure that creates a stack frame with a "LINK A6" instruction, references of the form -d(A6) are to local variables, and are named "vxx_n", and those of the form d(A6) are the parameters "param1", "param2",... , and if it is a function, the function result is called "funRslt".
Other additions to the Window mode of Nosy are displays of information in its internal tables. They include a list of the structure names known to Nosy, lists of trapnames and their parameter lists, the names and values of the system global symbols, and a file listing most of constant definations for field values (event mask values and such).
Fig. 2 Symbols Displayed
New ROM Secrets
I have had a set of the new ROM's for a few weeks, and in addition to getting Nosy to disassemble them, I have made a few observations about the code in it. About 30K is devoted to resources, and to find out what they are use the "Rsrc map" list in window mode (Chicago font, WDEF0, etc). Other facts of interest are the methods used to speedup BlockMove and the QuickDraw routines. The code in Blockmove is unrolled, that is the loop body has been replicated a number of times to cut down on the number of increment and test instructions. The reason for this is that the 68000 used in the Mac is "bus limited", and anything one can do to cut down the number of instructions executed in a loop will speed it up.
Consider the loop:
for i := 1 to 20 do a[i] := b[i];
by rewriting it as:
for i := 1 to 20 by 2 do begin
a[i] := b[i]; a[i+1] := b[i+1]
We eliminate the execution time associated with 10 increment and test instructions at the cost of extra space by duplicating the assignment statement.
Another interesting tidbit about the new ROM's are that they contain some 68020 instructions. Yes, Nosy knows about the 68020 instructions, and the FPU (68881) co-processor instructions. The new ROM's have been setup to run on a variety of machines as evidenced by some of the new EQU's.
Last November I made a "ROM comments" version of Nosy available along with a comments file that Nosy read in and merged with the disassembly listings it produces. In V2 I have extended this capability so any file can be commented, and provided a way that one can interactively create the comment files in window mode. Another little goodie that was added in conjunction with the comment mode was to "annotate" MOVEQ xx,D0 instructions with a comment of the form "; err = name" if Nosy's symbol dictionary contained an error number for the value.
Copy De-protection Techniques
Another use of Nosy is the location of copy protection code. To prefix this discussion, note that during manufacture (disk duplication), the duplicator writes the disk in a non-standard way by including non-standard data or address markers, or some other devious device so as to make the disk difficult to copy. During the execution of the program it checks the disk for the existance of this "mark", and if it finds it procedes normally. This checking code is usually refered to as copy protection code.
Fortunately for us the program itself cannot be "marked", for if it were, the segment loader could not read it, so Nosy can read the file in, and if the copy protection code can be found, and eliminated, the program is still usable. A number of the facilities in Nosy are useful in the location of copy protection code. The reference maps, lists of the resources ("please insert master disk"), the "Strings" display, the Search Mark command, and the conVert address command. The Search Mark command searchs for references of the form "$D5 ....." which are used to setup the Sony drivers for non-standard reads. If the procedure that references that data area contains references to any of the disk driver variables, then Nosy displays the message "ahoy matey, x marks the spot (base of the copy protection code)", and lists the chain of procedures that call it. One can then inspect the chain of procedures to find a suitable place to patch the code.
Trying to keep up with the changing copy protection methods is a never ending game, as evidenced by the frequent updates to Copy-To-Mac. I have sharpened some of the checks in Nosy so that it doesn't blow up or follow incorrect paths during the treewalk. This was done after I checked out some games, and found that they were putting garbage in the "CODE 0" segment.
Other additions to V2 are the support of Desk accessories in Window mode, and the support of Switcher in all modes. Nosy is a continually evolving program to which I have been and will be adding bug fixs and new features. The current version of Nosy may be downloaded from my SIG on Delphi by those who have purchased it. At this time I am not sure what future directions Nosy will take, but some of the things under consideration are:
- to add features to the window mode so as to make it easier to use
- to make it into a debugger
- to add a symbolic simulation of the register contents along with some more flow analysis so it handles languages with register based calling sequences better, and produces a more informative reference map (knows the difference between Loads and Stores).
[MacNosy version 2 is available through the MacTutor store for $85. -Ed]
Fig. 3 "TREF Wind"