Hi all,
I have recently become very interested in TASM (Telemark Assembler) after playing with the firmware source for the test harness from B4 Me100. He pointed me to the 8085 table Steve Adolph modified to include the undocumented opcodes and I even found an RCA 1802 table. This led down the rabbit hole of creating a VS Code extension to support TASM and trying to create a table for the Sharp lh5801 processor used in the PC-1500 (TRS-80 PC-2). I did a video about the extension which I will link at the bottom. In creating the lh5801 table I ran into a hitch because it uses an odd type of branch where you have a backward branch opcode and separate forward branch opcode. The single byte argument means you can branch 255 either direction. TASM is not set up to deal with this directly, there is no assembler rule that handles it. The rules 'R1' and 'R2' will give you a one byte or two byte offset relative to the current location but these are in two's compliment. The only logical operations supported are << and AND so there is no way to convert to an absolute value. I can overcome this limitation with the use of macros but wonder if there is another way. I have noticed that one or two tables use rules which are not mentioned in the manual. This makes me wonder what the various rules all do, how many are not mentioned, etc. The problem is the source code seems to not exist on the web and by all accounts everyone who has attempted to contact the author in recent years to register and get the source code have not been able to. So, if you happen to have the source, would you mind sharing? I'm hoping it will shed enough light on what rules are available that are not mentioned. I mentioned the TASM + VS Code video above. I have done several M100 related videos in recent weeks that I failed to mention on the list so rather than make umpteen posts I'll list them all below for anyone who is interested. TASM + VS Code: <https://youtu.be/kamDP5FA6Bg> https://youtu.be/kamDP5FA6Bg NEC PC-8300: <https://youtu.be/rKsD9wdB9K0> https://youtu.be/rKsD9wdB9K0 Olivetti M10: <https://youtu.be/tq8DnnvOAy8> https://youtu.be/tq8DnnvOAy8 Epson HX-20 #1: <https://youtu.be/86zDTuor2NQ> https://youtu.be/86zDTuor2NQ Epson HX-20 #2: <https://youtu.be/g3Ri7zjneHE> https://youtu.be/g3Ri7zjneHE M100 SRAM Tester: <https://youtu.be/5fFRrfUjogs> https://youtu.be/5fFRrfUjogs Jeff Birt
