1 Apout -- Simulate PDP-11 Unix a.out binaries
4 Warren Toomey wkt@tuhs.org
9 This program is a user-level simulator for UNIX a.out binaries. Binaries
10 for V1, V2, V5, V6, V7, 2.9BSD and 2.11BSD can be run with this simulator.
11 The user-mode PDP-11 instructions are simulated, and TRAP instructions
12 are emulated by calling equivalent native-mode system calls.
14 The advantages of an a.out simulator over a full-blown PDP-11 simulator are:
16 + system calls can be done natively, thus speeding up execution
17 + the simulator is less of a CPU-hog than a full-blown PDP-11 simulator
18 + you don't need a simulated operating system or a simulated file system
20 Apout can be obtained via anonymous ftp at minnie.tuhs.org in the
21 directory pub/PDP-11/Sims/Apout. The directory pub/PDP-11/Sims/Apout/UnixBins
22 contains tar archives of a.out binaries from several versions of UNIX.
26 The program is now at release 2.3 Alpha2. Most of the binaries from V5, V6
27 and V7 run fine. All of the V5/V6/V7 system calls are caught, but some are
28 ignored and some generate EPERM errors. The V1, V2, 2.9BSD and 2.11BSD
29 environments are still under construction: see the file LIMITATIONS for
30 details. Finally, the simulator won't run on a big-endian machine.
34 I have only tested this program on FreeBSD 2.x and 3.x, and on RedHat
35 Linux 2.2. It should compile on a 32-bit little-endian machine with
36 some form of Unix; you may need to change some header file includes etc.
37 See `defines.h' for the details. In particular, if your system doesn't have
40 int8_t, int16_t, int32_t, u_int8_t, u_int16_t, u_int32_t
42 or if your compiler doesn't have char=1 byte, short= 2 bytes, int=4 bytes,
43 then alter the relevant typedefs in `defines.h'.
45 The Makefile has two sets of CFLAGS/LDFLAGS: one set is for debugging, and
46 the other set is for speed. If you define the C pre-processor macro `DEBUG',
47 then this includes debugging code into the program. I use it quite heavily
48 when trying to fix niggling problems.
50 If you remove the -DEMU211 macro definition from the Makefile, the emulation
51 of 2.11BSD will not be compiled in to the simulator. Similarly, if you remove
52 the -DEMUV1 macro definition from the Makefile, the emulation of 1st and 2nd
53 Edition UNIX will not be compiled in to the simulator. By default, EMUV1
57 Once you have configured apout, now type `make'. Hopefully, things will
58 compile ok. You will eventually get the `apout' program.
60 Now go find an old PDP-11 UNIX binary, e.g 7th Edition cal, and say:
62 % setenv APOUT_ROOT / # for now
65 If the simulator is working, the calendar for 1970 will be printed out.
66 The V7 shell works, and from there, you can run other programs.
73 Finally, install apout in /usr/local/bin, and the manual page apout.1 in
74 the appropriate place. If you can't use the man page because of incompatible
75 macros, then apout.0 is a text file which has the pre-formatted man page.
79 When debugging is compiled in, the program has several options:
81 -inst turns on instruction tracing, which is _very_ verbose
82 -trap turns on TRAP tracing; not all syscalls have debugging code
83 -jsr prints out the details of each jsr and rts
84 -fp prints out some details of floating-point instructions
86 All debugging output goes out to the file `apout.dbg'. These debugging options
87 are mainly used for testing apout, and so the output in apout.dbg may not be
92 Apout has the concept of a simulated root filesystem for the simulated PDP-11
93 binaries. When working with filenames, if the filenames are relative, they
94 stay relative. If the filenames are absolute (i.e /usr/...), then apout
95 prepends the value of the environment variable APOUT_ROOT to the filename.
96 This allows you to say:
98 # setenv APOUT_ROOT /usr/misc/v7root
100 before running apout to set the `root' of the filesystem wherever you want.
101 You MUST set APOUT_ROOT before running apout.
105 There's lots to do. Here's what I'd like to do, in a somewhat ordered list.
107 + Verify that the instruction simulation and high priority
108 the syscalls all work correctly
109 + Complete some of the syscalls that are med priority
111 + Speed the simulator up med priority
116 main.c parses any arguments, loads the binary and calls run()
117 cpu.c holds the main instruction decode/execute loop
118 itab.c holds function lookup tables for all instructions
119 ea.c holds functions to decode the PDP-11 addressing modes
120 debug.c holds strings for all emulated opcodes
122 single.c single.c, double.c and branch.c hold most of the functions
123 double.c which perform the PDP-11 user-mode instructions. The code
124 branch.c in these files comes from a PDP-11 simulator by Eric Edwards
125 fp.c partially emulates FP instructions
127 aout.c determines what type of a.out the binary is, and what UNIX
128 magic.c environment to set up. If V5/V6/V7, trap instructions fall
129 v7trap.c into v7trap.c which runs them using native system calls
132 v1trap.c if the binary is a 1st or 2nd Edition binary, traps fall
133 v1trap.h into v1trap.c, which likewise does the syscalls natively
134 ke11a.c emulates the KE11A extended arithmetic unit, used by V1/V2
136 bsdtrap.c if the binary is a 2.11BSD binary, trap instructions fall
137 bsdtrap.h into bsdtrap.c, which likewise does the syscalls natively
138 bsd_ioctl.c 2.11BSD ioctl calls are handled with this file
140 defines.h holds function & typedef prototypes and useful cpp macros