mirror of
https://git.FreeBSD.org/ports.git
synced 2024-10-31 21:57:12 +00:00
106 lines
3.2 KiB
Plaintext
106 lines
3.2 KiB
Plaintext
%
|
|
% Time-stamp: <06/06/94 23:08:26 Michael Bischoff moulder>
|
|
%
|
|
% CP/M emulator README
|
|
%
|
|
|
|
Introduction:
|
|
=============
|
|
|
|
Type 'UNIX' at the CCP prompt to leave the emulator.
|
|
(Or ctrl-@, followed by 'q' any time the keyboard is polled)
|
|
|
|
|
|
WARNING! This software runs only on 386 compatible processors
|
|
and systems which allow nonaligned word/dword memory access.
|
|
|
|
WARNING! This software has no documentation. If you want to use it, you're
|
|
probably a Real Programmer; and Real Programmers don't read documentation.
|
|
|
|
WARNING! This software is supplied AS IS. There is No Warranty!
|
|
|
|
The software emulates an Intel 8080 CPU (quite accurate,
|
|
except for the halfcarry flag for a couple of instructions)
|
|
and a lot of Zilog Z80 instructions (not the complete set).
|
|
Unimplemented instructions are input/output commands (IN A,(nn); OUT (nn),A;
|
|
INI, OUTI, INIR, OTIR, IND, OUTD, INDR, OTDR, IN C,(r), OUT r,(C)), and
|
|
interrupt mode commands (IM 0, IM 1, IM 2, RETN, RETI), and the refresh
|
|
register doesn't count at all.
|
|
|
|
A 486DX2-66 emulates a Z80 clocked at 22 MHz, a 386DX-33 simulates a 6MHz
|
|
Z80. (approximately)
|
|
|
|
|
|
The BDOS emulator does only provide
|
|
- user 0
|
|
- a single drive (A:)
|
|
- access to lowercase-files.
|
|
|
|
A CCP-lookalike command interpreter is provided and the BDOS
|
|
is emulated. The CCP is stored in the file /usr/local/lib/cpm/cpm.sys.
|
|
Any CP/M .COM-files may also go in the directory /usr/local/lib/cpm.
|
|
|
|
If you have an original CP/M, with CCP-address e800, BDOS-address f006,
|
|
and put it in the file /usr/local/lib/cpm/cpm.sys, you can have an
|
|
emulator quite near to the original thing, using the -e option.
|
|
The -e option tells the emulator to use the BDOS from cpm.sys,
|
|
instead of catching the BDOS-calls.
|
|
Pros:
|
|
- a real CP/M running
|
|
- access to CP/M-formatted floppies (you have to set the DPB correctly)
|
|
Try "cpm -e -i /dev/fd1" with a 800 KB CP/M floppy in B:
|
|
(bls = 2K, drm = 255)
|
|
after setting setfdprm -p /dev/fd1 800/1200 or the like.
|
|
|
|
Cons:
|
|
- no access to the Linux filesystem
|
|
|
|
|
|
About the emulator:
|
|
===================
|
|
|
|
Type "cpm -h" for a short usage message.
|
|
You can interrupt the emulator by typing ctrl-@. This will enter
|
|
the debug mode, where you can disassemble z80 memory, dump memory,
|
|
edit data, set listpoints, breakpoints, set counts for breakpoints
|
|
and the like. Type '?' for a short summary.
|
|
|
|
|
|
extensions:
|
|
BDOS:
|
|
there is a new BDOS function (41), "change directory"
|
|
and a CP/M program CD.COM which calls this function.
|
|
|
|
CCP:
|
|
ERA understands the /Q option (question!)
|
|
Example: ERA *.*/Q
|
|
TYPE understands the /W option (wait!)
|
|
Example: TYPE TEST.TXT/W
|
|
You can access files from other user numbers (image mode only)
|
|
Example: ERA *.BAS/2
|
|
|
|
Again: Type UNIX to leave the Emulator.
|
|
|
|
|
|
|
|
TODO:
|
|
=====
|
|
- Improve the emulation of BDOS
|
|
- Allow multiple drives (some as CP/M filesystem images?)
|
|
- implement interrupt modes / signal catching to simulate NMI, INT
|
|
- improve the accuracy of the emulator (but; after all, a Z80 isn't
|
|
8080-compatible as well; the sequence
|
|
XOR A
|
|
DEC A
|
|
JP PO,Z80_installed
|
|
/* an 8080, if we are here */
|
|
will find out...
|
|
- merge the code with xtrs-80, to play GALAXY again!
|
|
|
|
|
|
BUGS:
|
|
=====
|
|
|
|
Surely there are LOTS of bugs. Please send fixes to mbi@mo.math.nat.tu-bs.de
|
|
Bug reports (without fixes) are also accepted, but it would be nice if you
|
|
could track down the bad opcode. |