z80

What are your favourite ZX Spectrum development tools?

What are your favourite assemblers, compilers, environments, interpreters for the good old ZX Spectrum? ...

What are the best tools for reverse engineering z80 machine code?

A particular assembler/disassembler or something else entirely? ...

Why is there no Z80 like LDIR functionality in C/C++/rtl?

In Z80 machine code, a cheap technique to initialize a buffer to a fixed value, say all blanks. So a chunk of code might look something like this. LD HL, DESTINATION ; point to the source LD DE, DESTINATION + 1 ; point to the destination LD BC, DESTINATION_SIZE - 1 ; copying this many bytes LD (HL), 0X20 ...

Is there a free/demo version of COBOL with multi-user support?

I have been using COBOL 85 for a long time, including work with merging COBOL and Z80 assembly. However traditional COBOL doesn't support multi-user/shareable (ie can run concurrently from various terminals) concepts. Can anyone recommend a newer version of COBOL that will let me rewrite my existing code with minimal effort? Is there ...

Quick divisibility check in ZX81 BASIC

Since many of the Project Euler problems require you to do a divisibility check for quite a number of times, I've been trying to figure out the fastest way to perform this task in ZX81 BASIC. So far I've compared (N/D) to INT(N/D) to check, whether N is dividable by D or not. I have been thinking about doing the test in Z80 machine code...

I need some help to start writing a graphical z80 emulator in c or c++.

Hello, I want to take an interest in writing my own simple emulator for the z80 processor. I have no experience with this type of programming. I am mostly fine with using c-based languages as they are the ones I know best. If anyone could please tell me what I need to accomplish this and give me some good tutorials/references that could ...

Writing an z80 assembler - Lexing ASM and building a parse tree using composition?

Hi guys, I'm very new to the concept of writing an assembler and even after reading a great deal of material, I'm still having difficulties wrapping my head around a couple of concepts. 1) What is the process to actually break up a source file into tokens? I believe this process is called lexing and I've searched high and low for a real...

Z80 ASM BNF structure... I'm am on the right track?

I'm currently trying to get to grips with BNF and attempting to assemble some Z80 ASM code. Since I'm new to both fields So my question is, Am I even on the right track? I am currently trying to write the format of Z80 ASM as EBNF so that I can then figure out where to go from there to create machine code from the source. At the moment I...

Z80 (TI-83+) stops working on CALL

Every time I assemble an application for the TI-83+ calculator (Z80 processor), it stops running at CALL. Here is an example ("Hello") — it starts running just fine, but the calculator freezes at the CALL instruction. Anything I put before CALL works just fine, and anything I put after doesn't run. This is a disassembly of the code, to s...

Z80: How to add 16 and 8 bit registers?

How do you add a 16 and a 8 bit register with carry (for example, HL, and A)? ...

Looking for programs on audio tape/cassette containing programs for Sinclair ZX80 PC?

OK, so back before ice age, I recall having a Sinclair ZX80 PC (with TV as a display, and a cassette tape player as storage device). Obviously, the programs on cassette tapes made a very distinct sound (er... noise) when playing the tape... I was wondering if someone still had those tapes? The reason (and the reason this Q is programmi...

Are bytes/words/addresses signed or unsigned in Z80 assembler/machine code?

I am making an emulator for Z80 binaries but I cannot find out whether all the integer data types are signed or unsigned from the manual or from google. So are the numbers from registers A,B...HL,BC etc signed or not? Also, in machine code are the bytes/words/addresses which come after the instructions as arguments signed or unsigned? ...