dZ80

The dZ80 application was designed to be a freeware Zilog Z80 Processor Code Disassembler.

It will take a raw binary file and disassemble it. It correctly disassembles all known undocumented, but often used, instructions, including those using the IXl/IYl and IXh/IYh registers, as well as the strange looking "LD r, RLC (IX+4)" type instructions. It also supports the Z180 instructions which fill up some holes in the EDxx opcode range.

When disassembling a file, dZ80 needs to know four things: i. Whereabouts in the file the data starts. Some files, such as .SNA files (Sinclair ZX Spectrum snapshots) have a 27 byte header before the start of the data. This obviously must be skipped. By default, dZ80 will not skip any bytes, so you must use the -h=[bytes to skip] command line option to instruct dZ80 to skip the correct amount.

ii. Whereabouts in the Z80's memory space the file starts. Referring again to the .SNA format, this starts at address 16384, going up to 65535. By default, dZ80 assumes that the start of the file corresponds to address 0. To change this, use the -m=[memory base] command line option.

iii. Where in the Z80's address space to start the disassembly. By default dZ80 will disassemble from the address specified by -m (or the default of 0). Use the -s=[start disassembly] command line option to change this.

iv. Where in the Z80's address space to end the disassembly. By default, dZ80 will disassemble to the end of the loaded source file. Use the -e=[end disassembly] command line option to change this.

dZ80 will automatically set the above items i. and ii. to 27 and 16384 respectively for source files with an extension of ".SNA". More file extensions may be supported in future versions.