Specifications

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The Z80 has a great many (so called) undocumented instructions that (sometimes)
perform useful functions.
DASMx
does not currently support these additional
instructions.
Like the 6502, the Z80 has spawned many variants with opcode compatible
instruction supersets.
DASMx
can be used on code for these devices with the
standard caveat that any of the new instructions will not be disassembled as valid
code (and therefore code threading is not advised.)
Sharp LR35902 (GameBoy processor)
The Sharp LR35902 is the processor used in the hugely popular Nintendo
GameBoy. This processor is a single chip variant of the Zilog Z80. The instruction
set is based on a subset of that of the Z80 but with some additional instructions. Of
those instructions that are shared with the Z80, most are opcode compatible but
there are a few differences.
As a single chip microcontroller, the LR35902 contains various on-chip I/O and
timer functions. These are accessed through a 256 byte memory page starting at
address 0xFF00. The supplied file,
gameboy.sym
, contains a set of known symbol
definitions for these memory mapped registers. This generic GameBoy processor
symbol file may be included in the main symbol file for the disassembly of a
specific binary image. The supplied
tetris.sym
file shows an example of this.
WARNING
: unlike all the other processors supported by
DASMx
, it
has not been possible to obtain official manufacturer's data on the
Sharp LR35902. The information used is derived from a number of
different public domain documents – some of which conflict over
certain details. Consequently, the LR35902 disassembly should be
considered provisional and potentially subject to error.
If anyone has access to genuine Sharp (or other official) data on this
device please contact the author: [e-mail].
Intel MCS-80/85™ (8080 and 8085)
The Intel 8080 and 8085 share an almost identical instruction set. The Intel 8085 is
an enhanced version of the 8080, with two additional instructions (rim and sim)
used to control new serial in and out pins and interrupt inputs.
When disassembling 8080 (and, with provisos, 8085) code the user has the option
of generating either Intel or Zilog mnemonics. To generate Intel mnemonics,
simply specify the CPU type to be 8080 or 8085 as required.