WP2-07.THD (c)1989 Golden Triangle, Inc. (c)1989 Wilson Van Alst =+=+=+=+=+= Fm: Carmen Paone To: Paul Globman Did you catch the note at the end of Nuge's comments on the WP-2 on the first page of this month's P100? =+=+=+=+=+= Fm: Paul Globman To: Carmen Paone Yes ... I just got the mag today and am quite surprised to see Tandy _encouraging_ 3rd party development. In the past they seemed to keep the inner workings of their product a secret and 3rd party developers had to struggle to get whatever info they have. I'd really have to see what they offer in the way of ROM, i/o port, and hardware info before I stand up and cheer. I think the CPU is a Z-80 and I still have the Zilog Z-80 manual and reference cards (the Z-80 reference card is almost a book!). This is a VERY powerful 8-bit processor and it can run circles around the 8085! It has two sets of registers, index registers, relative jumps and calls, 4 byte opcodes, extensive bit manipulation, and more. Most programmers don't use the Z-80 to its full potential. It will be interesting to see what gets developed for this and how the programming is approached. =+=+=+=+=+= Fm: Carmen Paone To: Paul Globman You're right, kiddo, the WP-2 CPU is a Z-80 type CPU with a 5.5296 MHz clock speed. If Tandy parts with their secrets on how to program the WP-2, I wonder what ways they will use to get that info out to the public? The Z-80 CPU sounds like a winner, and I could see - after reading your description - how it would run circles around the 8085. Hey, could we have a new generation of Tandy portables on our hands? =+=+=+=+=+= Fm: Paul Globman To: Carmen Paone Carmen - I used to write Z-80 code many years ago, but with CP/M yeilding to MS -DOS, the Z-80 is relatively unknown today (the Z-88 uses it). Program development is costly and marketing even moreso. Third party vendors would be unlikely to get started with the WP-2 until sales demonstrate a vast potential market. Furthermore, people who spend $250-$300 for a system expect decent software at about 10% to 15% of the cost of the hardware. Selling $100 programs will not make users rally around the flagpole. Tandy will have to sell far more WP-2's than T600's before developers consider the market worth approaching. You will probably see some enthusiasts like yourself trying to put out something useful, but hobbiests don't always have the resources or the time that third party software vendors have. In the beginning there will be a lot of misc. notes about discovered secrets surfacing, and expectations will be high. But in the long run, I think it would be much more worthwhile (read cheaper) for the user to buy the WP-2 for word processing, and the M102 for other tasks, than to try to build the WP-2 into a fully programmable computer. I kinda hope I'm mistaken, but I just don't see the WP-2 becomming much more than what it was intended to be. =+=+=+=+=+= Fm: Carmen Paone To: Paul Globman Your wisdom on the marketing potential for third-party support of the WP-2 has been noted and filed away. Chances are that you are correct in your assessments since you have been down the marketing road a great deal longer than I have. Thanks for taking this kid by the hand and leading him through Z-80 land. I'll do some research on the Z-80 myself as far as programming is concerned, and I hope I can throw some questions down South when I get stuck. =+=+=+=+=+= Fm: Stan Wong To: Carmen Paone As you know the WP-2 is the Z80. The Z80 is essentially a superset of the 8085 used in the M100 series. Any code written for an 8085 will run on the Z80 (machine differences aside -- like I/O port locations, etc.). That means an m/l program written for the M100 could be easily ported to the WP-2 if: o it doesn't make any rom calls o I/O calls (like LCD) are localized ROM calls will either need equivalents in the WP-2 are the equivalent code written. The Z80 CPU provides some powerful indexing and string operations that make some tasks trivial. Smaller programs are the result but again the 8085 can do anything the Z80 can it might take more instructions. Basic programs would not be able to be transferred (actually they could but it would be a big task). =+=+=+=+=+= Fm: Paul Globman To: Stan Wong Stan - I must disagree with your comment about the Z-80 being a superset of the 8085. And for this reason I offer caution about "any code" written for an 8085 running on the Z-80. Both the 8085 and the Z-80 are supersets of the 8080. The 8085 runs the complete 8080 instruction set plus the RIM and SIM instruction (20h and 30h). In the Z-80, 20H and 30H are the first byte of conditional relative jumps, which is a 2-byte instruction. Trying to run 8085 code that contains the RIM or SIM instruction will fail to yield the same result, and could possibly be disasterous. In addition to RIM and SIM, all the other "undocumented" opcodes of the 8085 do not exist in the Z-80. It's a minor point but one worth noting. There's another reason why M100 programs may not easily be ported over to the Z-80 besides the reasons you cited. Remember that absolute addressing is a major factor and RAM in the M100 is from 8000H to 0FFFFH. If a program made no ROM calls, no I/O operations, etc., the program would _still_ have to run in the exact same address locations. =+=+=+=+=+= Fm: Stan Wong To: Paul Globman I don't think that porting most 8085 programs would be too hard (other than the machine specific differences such as ROM calls). I am assuming that source code is available. If the program is well structured then the "core" processing portion would transport easily leaving the machine specific parts to be recoded or translated. I've ported a number of programs from different microprocessors and this is the general approach that seems to work. Of course I've run into many programs that are so badly coded (relative to portablility) that I didn't even start. In the case of the 8085/Z80 (in the CP/M world) I haven't found an 8085 program that wouldn't run on the Z80. Of course most CP/M assembler/compilers seem to generate code, as you say, for the 8080 regardless of the target micrprocessor. Anyway, I didn't say that a conversion would necessarily be easy but since the instruction sets are relatively compatible (at least going from the 8085 to the Z80) then there's hope. Trying to convert an m/l program from a, say MC68000 to the Z80, now that would be hopeless! Starting message #: 189144 Starting date: 27-Oct-89 15:48:53 Participants: Carmen Paone 72677,42 Paul Globman 72227,1661 Stan Wong 70346,1267