> On Jan 24, 2020, at 6:26 PM, Kevin Handy <khandy2...@gmail.com> wrote:
>
> I was watching some youtube videos about the PiDP-11, and they all seemed to
> end up typing in a hand-assembled program into the emulator.
>
> It got me to thinking about the macro11 assembler in simtools, however that
> program only appears to output object files, not binary ones. simh appears to
> only accept binary filesm not object files.
>
> Is there some way to bridge the gap? Is there some method to bridge he gap?
> marco11 to output binary files, a linker to convert object files to binary
> ones, or simh to accept object files.
>
> For the PiDP-11 users, they could prooblbly work from a listing where a
> hard-coded base address is given, but others might want to try something that
> is too long to want to key it in.
>
> If this is already possible, some documentation on the process would be
> useful. This would also make simtools more useful.
>
> This applies to all the other emulations that have assemblers available also.
This probably isn't quite what you're looking for, but if not it could be
tweaked.
For running parts of the GCC test suite for the PDP11 target, I wanted to be
able to run its output on SIMH. Here is a simple Python program that turns
Unix style a.out files (the archaic PDP11 flavor rather than the later flavor
used in some other platforms) into DEC standard paper tape binary loader files
that SIMH will accept.
paul
#!/usr/bin/env python
"""Convert a PDP11 a.out file to papertape loader format
(a.k.a. "formatted binary").
"""
DEBUG = 0
import sys
import struct
DEFBASE = 01000 # program first word address
TSTART = 020 # start of text in input file
def csum (data):
cs = 0
for c in data:
cs += ord (c)
return chr ((256 - cs) & 0xff)
inf = open (sys.argv[1], "rb")
data = inf.read ()
inf.close ()
m, tlen, dlen, bsslen, stlen, xfer = struct.unpack ("<HHHHHH", data[:12])
if DEBUG:
print "text length %06o data length %06o bss %06o transfer %0o0" % \
(tlen, dlen, bsslen, xfer)
# See if we can figure out the program base. Assume that if
# the first instuction is "mov #foo, sp" then foo is the
# program base.
op, base, x = struct.unpack ("<HHH", data[TSTART:TSTART + 6])
if op == 012737 and base == 0340 and x == 0177776:
# Start is mov #340, @#ps
op, base = struct.unpack ("<HH", data[TSTART + 6:TSTART + 10])
if not (op == 012706 and (base & 1) == 0):
# No obvious base, assume the default
base = DEFBASE
print "defaulting base to %06o" % base
elif DEBUG:
print "base is %06o" % base
if m != 0407 and m != 0410:
print "Unexpected magic number: %04o" % m
sys.exit (1)
if TSTART + tlen + dlen > len (data):
print "text or data section beyond end of input"
sys.exit (1)
if TSTART + tlen + dlen > 0160000:
print "Program is too large: %o" % (TSTART + tlen + dlen)
sys.exit (1)
if xfer < base or xfer > base + tlen:
print "transfer address %06o is out of range" % xfer
sys.exit (1)
# Data starts on an even address. Note: this is a function of the
# link script used. Without a script, the linker apparently pads to a
# multiple of 0400, but pdp11-simh.ld just does alignment to even.
dbase = base + tlen
dbase = (dbase + 1) & -2
if DEBUG:
print "text base %06o data base %06o" % (base, dbase)
outf = open (sys.argv[2], "wb")
text = data[TSTART:tlen + TSTART]
data = data[TSTART + tlen:TSTART + tlen + dlen]
l = len (text) + 6
text = struct.pack ("<HHH", 1, l, base) + text
text += csum (text)
outf.write (text)
if DEBUG:
print "text: %d bytes" % l
if data:
l = len (data) + 6
data = struct.pack ("<HHH", 1, l, dbase) + data
data += csum (data)
outf.write (data)
if DEBUG:
print "data: %d bytes" % l
hdr = struct.pack ("<HHH", 1, 6, xfer)
hdr += csum (hdr)
outf.write (hdr)
if DEBUG:
print "transfer: 6 bytes"
outf.close ()
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