ATARI EMULATOR AND 65 MAC SO I

Atari Emulator And 65 Mac So I

It is assumed that the reader is already familiar with the Atari computer platform and assembly language. The game is to be used at trade shows.All examples will be written for ATasm, a MAC/65 compatible assembler, and will assemble on real hardware using MAC/65 unless specifically stated. BBC Micro Atari 2600 Game Gear Amstrad CPC ZX Spectrum.Produce a high-quality game simulating the behavior of a new aircraft from major aerospace manufacturer. Since our objective is to have the experience of an actual Atari ST, I prefer to use the Atari TOS version 2.06, which can be easily find on websites like EmuParadise.I dont use a Mac so I cant really recommend any emulators, but here are what are generally. Hatari distribution provides the EmuTOS image which is a open source replacement for the Atari TOS. As usual on most of the emulators, you need a ROM image in order to make it boot.

And did I mention that we had to put it all into a cartridge for the end-user!However, other considerations made us tackle this assignment. This is just not enough time to develop all the terrain and bitmaps, type in all the code, and get the whole works debugged. Enjoy your favorite PlayStation VITA games on any device: Windows, Mac.Unlike the usual three to six months allowed for game development, we had four weeks.Four weeks! To develop over 250 pages of assembly code (some 25K of object)? Yes, four weeks.Most sane programmers would have declined the task.

To be sure, we cut things a little close - we delivered the game the day the trade show opened - but we made it.How did we do it? That's the subject of this and several upcoming columns. Third, and most important, were our upcoming bills a second baby was due to arrive any day.So, we accepted the challenge, and delivered the game on schedule. Second was our belief in our equipment.

Software developers take note! The techniques used here can save you weeks of development time and large amounts of money.The first topic we'll cover is assemblers. Anyone who has paid for programming services knows how expensive a programmer's time is herein are some valuable tips to cut down the amount of time required to develop products for the ATARI. Rather, we are speaking of getting a large programming task done very quickly. The individual methods will be covered in these columns, for your use.The emphasis here is not just on getting the job done.

The amount of time that would be wasted by a slow assembler was unacceptable for a project that had to be done in four weeks.We have used a variety of assemblers for the ATARI. In order to write an assembly language program, we need an assembler - and in this case, the best one available, for there would be many assemblies and thousands of lines of code. To be sure, a variety of other languages can possibly be put on cartridge, but we didn't have time to experiment with unknowns.

How fast would you believe 320K of source code assembled in under three minutes? That's about 4000 lines of code per minute, including disk-access time.Why did we decide to go with MAC/65, a relative unknown? Let's look briefly at the other assemblers we have used:Assembler/Editor Cartridge (from Atari). Fortunately, it did, and the MAC/65 turned out to be a key factor in our making this tight deadline it is a fast, debugged assembler and editor rolled into one. We had not used MAC/65 before embarking on this project, so if it had not lived up to its advertising, we would have been in trouble. MAC/65 is from Optimized Systems Software in Sunnyvale, California.I must admit that this was a difficult choice.

(Keep in mind that hand assembling code is very nearly an improvement over the ASM/ED cartridge. We used AMAC for our last large project, and while it was an improvement over the ASM/ED cartridge, it wasn't enough. Naturally, this is a rather slow process, because much analysis must be performed on the source code to make sure the syntax is valid. It takes input from a text editor (usually MEDIT is used) and assembles from the raw source code.

However, there are two problems with RAMDISKs: 1) they are expensive and 2) if the system crashes, the contents of RAMDISK are lost.Atari's Macro Assembler has some other really strange things about it. Thus, going from DOS to AMAC, for instance, is very fast. It is a real shame there is no 'direct' way to go from MEDIT to AMAC, and have both in memory at the same time.At Atari, this problem has been partially solved by using RAMDISK - a product which emulates an Atari disk drive with RAM. Anything having to do with disk drives on the ATARI is very slow.

If the disk to which AMAC is writing the print or object file fills up, the system crashes - just dies. AMAC is resident in fairly low memory, so too many double-density file buffers will overwrite it.Remember, Atari doesn't support double density. In addition, double density is not supported and only works sometimes.

I used Synassembler to develop the software for a memory board disk emulator. This assembler is used in-house at Synpase, with great success. Sure enough, AMAC will create an opcode for it, because it gets past the syntax checker.Supposedly there is a new version of AMAC that fixes these and other bugs, but in the meantime, the slow editing/assembly development process and other problems disqualified AMAC for us.Synassembler (from Synapse Software). Try a STA #$04, for instance (an immediate STA is an impossible concept). Furthermore, your disk's directory will be messed up following such a crash.AMAC will assemble illegal opcodes.

The speed is comparable to MAC/65.The Synassembler also includes a monitor, which I found powerful, but difficult to remember how to use. Hence, even long programs (a few thousand lines) assemble in a few seconds. Synassembler does not have to scan for them, as does AMAC. Assembling this crunched code is a fast process, because the code already has the opcodes and operands labelled. MAC/65 also uses this process. It achieves this speed by 'tokenizing'' or crunching down, source code as it is entered.

First, it has a different syntax for 6502 opcodes. When I could figure out how to do what I wanted to do, the monitor worked well.However, I shied away from the Synassembler for this project for a number of reasons. I wish that there could be a standard for monitors and monitor commands so that I would not have to constantly learn new 'improved' commands I'm happy with the usual old ones.

It gives incorrect errors on:10 TXA This comment is laso flagged as bad.10 LDA #10 whups! two spaces between A and #.10 LDA #1+1 no space between parts of expression.And so on and so on. In a big project, you are practically forced to use segmented files, as charsets, P/M bitmaps, and such must start on page boundaries.The syntax checker has problems. If you use multiple segmented files, as I do, you are out of luck. The BLOAD feature for loading binary files loads only the first segment of the file. How frustrating!Some other things about Synassembler bother me. Example: 'ROL A' in Synassembler is 'ROL' 'ROL A' makes for an assembly error.

On the other hand, a 'leading programmer' tells me that MAE is not bad at all, but that his version is extensively modified from the original MAE. However, I have never used MAE, and did not have time to learn a new syntax and new debugger. If you are just starting out in assembly, the Synassembler might be much easier to use.Another assembler we could have used is MAE. I am starting from behind using the Synassembler because I am used to other syntaxes. The manual is wrong.)When the author gets time to go clean up these trivialities, which should be any time now, the Synassembler will be a nice tool in the meantime, I just don't have the mentality to remember all of its idiosyncracies.

MAC/65 consists of two parts, the editor, and the assembler. It is extremely fast, powerful and thoroughly debugged. Which brings us to MAC/65.MAC/65 was written by Steven Lawrow, from New Jersey, and marketed through OSS.

MAC/ 65 can be invoked in the assembler mode from OS/A + , if you use OS/A +.The editor is line-number oriented, so those of you who have used the Synassembler or ASM/ED will be in familiar territory.

Atari Emulator And Mac 65