# MIT License
#
# Copyright (c) 2023 Neil Webber
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
from itertools import chain
from types import SimpleNamespace
from machine import PDP1170
from pdptraps import PDPTraps
import unittest
import random
class TestMethods(unittest.TestCase):
PDPLOGLEVEL = 'INFO'
# DISCLAIMER ABOUT TEST CODING PHILOSOPHY:
# For the most part, actual PDP-11 machine code is created and
# used to establish the test conditions, as this provides additional
# (albeit haphazard) testing of the functionality. Occasionally it's
# just too much hassle to do that and the pdp object is manipulated
# directly via methods/attributes to establish conditions.
# There's no rhyme or reason in picking the approach for a given test.
# used to create various instances, collects all the options
# detail into this one place...
@classmethod
def make_pdp(cls):
return PDP1170(console=False, loglevel=cls.PDPLOGLEVEL)
@staticmethod
def ioaddr(p, offs):
"""Given a within-IO-page IO offset, return an IO addr."""
return (offs + p.mmu.iopage_base) & 0o177777
# convenience routine to load word values into physical memory
@staticmethod
def loadphysmem(p, words, addr):
for a, w in enumerate(words, start=(addr >> 1)):
p.physmem[a] = w
# some of these can't be computed at class definition time, so...
@classmethod
def usefulconstants(cls):
p = cls.make_pdp() # meh, need this for some constants
ns = SimpleNamespace()
# Kernel instruction space PDR registers
ns.KISD0 = cls.ioaddr(p, p.mmu.APR_KERNEL_OFFS)
# Kernel data space PDR registers
ns.KDSD0 = ns.KISD0 + 0o20
# Kernel instruction space PAR registers
ns.KISA0 = ns.KDSD0 + 0o20
# Kernel data space PAR registers
ns.KDSA0 = ns.KISA0 + 0o20
# User mode similar
ns.UISD0 = cls.ioaddr(p, p.mmu.APR_USER_OFFS)
ns.UDSD0 = ns.UISD0 + 0o20
ns.UISA0 = ns.UDSD0 + 0o20
ns.UDSA0 = ns.UISA0 + 0o20
return ns
#
# Create and return a test machine with a simple memory mapping:
# Kernel Instruction space seg 0 points to physical 0
# Kernel Data space segment 0 also points to physical 0
# User instruction space seg 0 points to physical 0o20000
# User Data space seg 0 points to physical 0o40000
# and turns on the MMU
#
def simplemapped_pdp(self, p=None, addons=[]):
if p is None:
p = self.make_pdp()
cn = self.usefulconstants()
# this is a table of instructions that ...
# Puts the system stack at 0o20000 (8K)
# Puts 0o22222 into physical location 0o20000
# Puts 0o33333 into physical location 0o20002
# Puts 0o44444 into physical location 0o40000
# Sets Kernel Instruction space A0 to point to physical 0
# Sets Kernel Data space A0 to point to the first 8K physical memory
# Sets Kernel Data space A7 to point to the IO page
# Sets User Instruction space A0 to point to physical 0o20000
# sets User Data space D0 to point to physical 0o40000
# and turns on the MMU with I/D sep
#
# These instructions will be placed at 2K in memory
#
setup_instructions = (
0o012706, 0o20000, # put system stack at 8k and works down
0o012737, 0o22222, 0o20000,
0o012737, 0o33333, 0o20002,
0o012737, 0o44444, 0o40000,
# point both kernel seg 0 PARs to physical zero
0o005037, cn.KISA0, # CLR $KISA0
0o005037, cn.KDSA0, # CLR $KDSA0
# kernel seg 7 D space PAR to I/O page (at 22-bit location)
0o012737, 0o017760000 >> 6, cn.KDSA0 + (7 * 2),
# user I seg 0 to 0o20000, user D seg 0 to 0o40000
0o012737, 0o20000 >> 6, cn.UISA0,
0o012737, 0o40000 >> 6, cn.UDSA0,
# set the PDRs for segment zero
0o012703, 0o077406, # MOV #77406,R3
# 77406 = PDR<2:0> = ACF = 0o110 = read/write
# PLF<14:8> =0o0774 = full length (128*64 bytes = 8K)
0o010337, cn.KISD0, # MOV R3,KISD0 ...
0o010337, cn.KDSD0,
0o010337, cn.UISD0,
0o010337, cn.UDSD0,
# PDR for segment 7
0o010337, cn.KDSD0 + (7 * 2),
# set previous mode to USER, keeping current mode KERNEL, pri 7
0o012737, (p.KERNEL << 14) | (p.USER << 12) | (7 << 5),
self.ioaddr(p, p.PS_OFFS),
# turn on 22-bit mode, unibus mapping, and I/D sep for k & u
0o012737, 0o000065, self.ioaddr(p, p.mmu.MMR3_OFFS),
# turn on relocation mode ... yeehah! (MMR0 known zero here)
0o005237, self.ioaddr(p, p.mmu.MMR0_OFFS), # INC MMR0
)
instloc = 0o4000 # 2K
self.loadphysmem(p, chain(setup_instructions, addons, (0o0,)), instloc)
return p, instloc
# these tests end up testing a other stuff too of course, including MMU
def test_mfpi(self):
# ((r0, ..., rN) results, (instructions)), ...
tvecs = (
# r1=2, mfpi (r1) -> r0; expect r0 = 33333
((0o33333,), (0o012701, 0o02, 0o006511, 0o012600)),
# r1=0, mfpi (r1) -> r0; expect r0 = 22222
((0o22222,), (0o012701, 0o00, 0o006511, 0o012600)),
)
for rslts, insts in tvecs:
with self.subTest(rslts=rslts, insts=insts):
p, pc = self.simplemapped_pdp(addons=insts)
p.run(pc=pc)
for rN, v in enumerate(rslts):
self.assertEqual(p.r[rN], v)
def test_mtpi(self):
# need an instance just for the constants, meh
px = self.make_pdp()
tvecs = (
((0o1717,), (0o012746, 0o1717, 0o006637, 0o02,
# turn MMU back off (!)
0o005037, self.ioaddr(px, px.mmu.MMR0_OFFS),
0o013700, 0o20002)),
)
for rslts, insts in tvecs:
with self.subTest(rslts=rslts, insts=insts):
p, pc = self.simplemapped_pdp(addons=insts)
p.run(pc=pc)
for rN, v in enumerate(rslts):
self.assertEqual(p.r[rN], v)
def test_add_sub(self):
p = self.make_pdp()
testvecs = (
# (op0, op1, expected op0 + op1, nzvc, expected op0 - op1, nzvc)
# None for nzvc means dont test that (yet/for-now/need to verify)
(1, 1, 2, 0, 0, 4), # 1 + 1 = 2(_); 1 - 1 = 0(Z)
(1, 32767, 32768, 0o12, 32766, 0),
(0, 0, 0, 0o04, 0, 0o04),
(32768, 1, 32769, 0o10, 32769, 0o13),
(65535, 1, 0, 0o05, 2, 1),
)
testloc = 0o10000
add_loc = testloc
sub_loc = testloc + 4
p.physmem[add_loc >> 1] = 0o060001 # ADD R0,R1
p.physmem[(add_loc >> 1) + 1] = 0
p.physmem[sub_loc >> 1] = 0o160001 # SUB R0,R1
p.physmem[(sub_loc >> 1) + 1] = 0
for r0, r1, added, a_nzvc, subbed, s_nzvc in testvecs:
with self.subTest(r0=r0, r1=r1, op="add"):
p.r[0] = r0
p.r[1] = r1
p.run(pc=add_loc)
self.assertEqual(p.r[1], added)
if a_nzvc is not None:
self.assertEqual(p.psw & 0o17, a_nzvc)
with self.subTest(r0=r0, r1=r1, op="sub"):
p.r[0] = r0
p.r[1] = r1
p.run(pc=sub_loc)
self.assertEqual(p.r[1], subbed)
if s_nzvc is not None:
self.assertEqual(p.psw & 0o17, s_nzvc)
def test_bne(self):
p = self.make_pdp()
loopcount = 0o1000
insts = (
# Program is:
# MOV loopcount,R1
# CLR R0
# LOOP: INC R0
# DEC R1
# BNE LOOP
# HALT
0o012701, loopcount, 0o005000, 0o005200, 0o005301, 0o001375, 0)
instloc = 0o4000
self.loadphysmem(p, insts, instloc)
p.run(pc=instloc)
self.assertEqual(p.r[0], loopcount)
self.assertEqual(p.r[1], 0)
def test_cc(self):
# various condition code tests
p = self.make_pdp()
insts = (
# program is:
# CLR R0
# BEQ 1f
# HALT
# 1: CCC
# BNE 1f
# HALT
# 1: DEC R0
# MOV @#05000,R1 ; see discussion below
# MOV @#05002,R2 ; see discussion below
# CMP R1,R2
# BLE 1f
# HALT
# 1: DEC R0
# CMP R2,R1
# BGT 1f
# HALT
# 1: DEC R0
# HALT
#
# and the program will poke various test cases into locations
# 5000 and 5002, with the proviso that 5000 is always the lesser.
#
# Given that, after running the program R0 should be 65553
0o005000, 0o101401, 0o0, 0o000257, 0o001001, 0, 0o005300,
# MOV @#5000 etc
0o013701, 0o5000, 0o013702, 0o5002,
# CMP R1,R2 BLE
0o020102, 0o003401, 0, 0o005300,
# CMP R2,R1 BGT
0o020201, 0o003001, 0, 0o005300,
0)
instloc = 0o4000
self.loadphysmem(p, insts, instloc)
# just a convenience so the test data can use neg numbers
def s2c(x):
return x & 0o177777
for lower, higher in ((0, 1), (s2c(-1), 0), (s2c(-1), 1),
(s2c(-32768), 32767),
(s2c(-32768), 0), (s2c(-32768), 32767),
(17, 42), (s2c(-42), s2c(-17))):
p.physmem[0o5000 >> 1] = lower
p.physmem[0o5002 >> 1] = higher
with self.subTest(lower=lower, higher=higher):
p.run(pc=instloc)
self.assertEqual(p.r[0], 65533)
# probably never a good idea, but ... do some random values
for randoms in range(1000):
a = random.randint(-32768, 32767)
b = random.randint(-32768, 32767)
while a == b:
b = random.randint(-32768, 32767)
if a > b:
a, b = b, a
p.physmem[0o5000 >> 1] = s2c(a)
p.physmem[0o5002 >> 1] = s2c(b)
with self.subTest(lower=a, higher=b):
p.run(pc=instloc)
self.assertEqual(p.r[0], 65533)
def test_unscc(self):
# more stuff like test_cc but specifically testing unsigned Bxx codes
p = self.make_pdp()
insts = (
# program is:
# CLR R0
# MOV @#05000,R1 ; see discussion below
# MOV @#05002,R2 ; see discussion below
# CMP R1,R2
# BCS 1f ; BCS same as BLO
# HALT
# 1: DEC R0
# CMP R2,R1
# BHI 1f
# HALT
# 1: DEC R0
# HALT
#
# test values in 5000,5002 .. unsigned and 5002 always higher
#
# Given that, after running the program R0 should be 65534
0o005000,
# MOV @#5000 etc
0o013701, 0o5000, 0o013702, 0o5002,
# CMP R1,R2 BCS
0o020102, 0o103401, 0, 0o005300,
# CMP R2,R1 BHI
0o020201, 0o101001, 0, 0o005300,
0)
instloc = 0o4000
self.loadphysmem(p, insts, instloc)
for lower, higher in ((0, 1), (0, 65535), (32768, 65535),
(65534, 65535),
(32767, 32768),
(17, 42)):
p.physmem[0o5000 >> 1] = lower
p.physmem[0o5002 >> 1] = higher
with self.subTest(lower=lower, higher=higher):
p.run(pc=instloc)
self.assertEqual(p.r[0], 65534)
# probably never a good idea, but ... do some random values
for randoms in range(1000):
a = random.randint(0, 65535)
b = random.randint(0, 65535)
while a == b:
b = random.randint(0, 65535)
if a > b:
a, b = b, a
p.physmem[0o5000 >> 1] = a
p.physmem[0o5002 >> 1] = b
with self.subTest(lower=a, higher=b):
p.run(pc=instloc)
self.assertEqual(p.r[0], 65534)
def test_ash1(self):
# this code sequence taken from Unix startup, it's not really
# much of a test.
insts = (0o012702, 0o0122451, # mov #122451,R2
0o072227, 0o0177772, # ash -6,R2
0o042702, 0o0176000, # bic #0176000,R2
0) # R2 should be 1224
p = self.make_pdp()
instloc = 0o4000
self.loadphysmem(p, insts, instloc)
p.run(pc=instloc)
self.assertEqual(p.r[2], 0o1224)
def test_br(self):
# though the bug has been fixed, this is a test of whether
# all branch offset values work correctly. Barn door shut...
p = self.make_pdp()
# the idea is a block of INC R0 instructions
# followed by a halt, then a spot for a branch
# then a block of INC R1 instructions followed by a halt
#
# By tweaking the BR instruction (different forward/back offsets)
# and starting execution at the BR, the result on R0 and R1
# will show if the correct branch offset was effected.
#
# NOTE: 0o477 (branch offset -1) is a tight-loop branch to self
# and that case is tested separately.
#
insts = [0o5200] * 300 # 300 INC R0 instructions
insts += [0] # 1 HALT instruction
insts += [0o477] # BR instruction .. see below
# want to know where in memory this br will is
brspot = len(insts) - 1
insts += [0o5201] * 300 # 300 INC R1 instructions
insts += [0] # 1 HALT instruction
# put that mess into memory at an arbitrary spot
baseloc = 0o10000
for a, w in enumerate(insts, start=(baseloc >> 1)):
p.physmem[a] = w
# test the negative offsets:
# Set R0 to 65535 (-1)
# Set R1 to 17
# -1 is a special case, that's the tight loop and not tested here
# -2 reaches the HALT instruction only, R0 will remain 65535
# -3 reaches back to one INC R0, R0 will be 0
# -4 reaches back two INC R0's, R0 will be 1
# and so on
# 0o400 | offset starting at 0o376 will be the BR -2 case
expected_R0 = 65535
for offset in range(0o376, 0o200, -1):
p.physmem[(baseloc >> 1) + brspot] = (0o400 | offset)
p.r[0] = 65535
p.r[1] = 17
# note the 2* because PC is an addr vs physmem word index
p.run(pc=baseloc + (2*brspot))
with self.subTest(offset=offset):
self.assertEqual(p.r[0], expected_R0)
self.assertEqual(p.r[1], 17)
expected_R0 = (expected_R0 + 1) & 0o177777
# and the same sort of test but with forward branching
expected_R1 = 42 + 300
for offset in range(0, 0o200):
p.physmem[(baseloc >> 1) + brspot] = (0o400 | offset)
p.r[0] = 17
p.r[1] = 42
# note the 2* because PC is an addr vs physmem word index
p.run(pc=baseloc + (2*brspot))
with self.subTest(offset=offset):
self.assertEqual(p.r[0], 17)
self.assertEqual(p.r[1], expected_R1)
expected_R1 = (expected_R1 - 1) & 0o177777
def test_trap(self):
# test some traps
p = self.make_pdp()
# put a handlers for different traps into memory
# starting at location 0o10000 (4K). This just knows
# that each handler is 3 words long, the code being:
# MOV something,R4
# RTT
#
# where the "something" changes with each handler.
handlers_addr = 0o10000
handlers = (
0o012704, 0o4444, 0o000006, # for vector 0o004
0o012704, 0o1010, 0o000006, # for vector 0o010
0o012704, 0o3030, 0o000006, # for vector 0o030
0o012704, 0o3434, 0o000006 # for vector 0o034
)
self.loadphysmem(p, handlers, handlers_addr)
# and just jam the vectors in place
p.physmem[2] = handlers_addr # vector 0o004
p.physmem[3] = 0 # new PSW, stay in kernel mode
p.physmem[4] = handlers_addr + 6 # each handler above was 6 bytes
p.physmem[5] = 0
p.physmem[12] = handlers_addr + 12 # vector 0o30 (EMT)
p.physmem[13] = 0
p.physmem[14] = handlers_addr + 18 # vector 0o34 (TRAP)
p.physmem[15] = 0
# (tnum, insts)
testvectors = (
# this will reference an odd address, trap 4
(0o4444, (
# establish reasonable stack pointer (at 8K)
0o012706, 0o20000,
# CLR R3 and R4 so will know if they get set to something
0o005003, 0o005004,
# put 0o1001 into R0
0o012700, 0o1001,
# and reference it ... boom!
0o011001,
# show that the RTT got to here by putting magic into R3
0o012703, 0o123456)),
# this will execute a reserved instruction trap 10
(0o1010, (
# establish reasonable stack pointer (at 8K)
0o012706, 0o20000,
# CLR R3 and R4 so will know if they get set to something
0o005003, 0o005004,
# 0o007777 is a reserved instruction ... boom!
0o007777,
# show that the RTT got to here by putting magic into R3
0o012703, 0o123456)),
# this will execute an EMT instruction
(0o3030, (
# establish reasonable stack pointer (at 8K)
0o012706, 0o20000,
# CLR R3 and R4 so will know if they get set to something
0o005003, 0o005004,
# EMT #42
0o104042,
# show that the RTT got to here by putting magic into R3
0o012703, 0o123456)),
# this will execute an actual TRAP instruction
(0o3434, (
# establish reasonable stack pointer (at 8K)
0o012706, 0o20000,
# CLR R3 and R4 so will know if they get set to something
0o005003, 0o005004,
# TRAP #17
0o104417,
# show that the RTT got to here by putting magic into R3
0o012703, 0o123456)),
)
for R4, insts in testvectors:
self.loadphysmem(p, insts, 0o3000)
p.run(pc=0o3000)
self.assertEqual(p.r[3], 0o123456)
self.assertEqual(p.r[4], R4)
def test_trapcodes(self):
# a more ambitious testing of TRAP which verifies all
# available TRAP instruction codes work
p = self.make_pdp()
# poke the TRAP vector info directly in
p.physmem[14] = 0o10000 # vector 0o34 (TRAP) --> 0o10000
p.physmem[15] = 0
# this trap handler puts the trap # into R3
handler = (
# the saved PC is at the top of the stack ... get it
0o011600, # MOV (SP),R0
# get the low byte of the instruction which is the trap code
# note that the PC points after the TRAP instruction so
# MOVB -2(R0),R3
0o116003, 0o177776,
# RTT
6)
self.loadphysmem(p, handler, 0o10000)
# just bash a stack pointer directly in
p.r[6] = 0o20000 # 8K and working down
for i in range(256):
insts = (
0o104400 | i, # TRAP #i
0o010301, # MOV R3,R1 just to show RTT worked
0)
self.loadphysmem(p, insts, 0o30000)
p.run(pc=0o30000)
self.assertEqual(p.r[3], p.r[1])
# because the machine code did MOVB, values over 127 get
# sign extended, so take that into consideration
if i > 127:
trapexpected = 0xFF00 | i
else:
trapexpected = i
self.assertEqual(p.r[1], trapexpected)
# test_mmu_1 .. test_mmu_N .. a variety of MMU tests.
#
# Any of the other tests that use simplemapped_pdp() implicitly
# test some aspects of the MMU but these are more targeted tests.
# NOTE: it's a lot easier to test via the methods than via writing
# elaborate PDP-11 machine code so that's what these do.
def test_mmu_1(self):
# test the page length field support
p = self.make_pdp()
# using ED=0 (segments grow upwards), create a (bizarre!)
# user DSPACE mapping where the the first segment has length 0,
# the second has 16, the third has 32 ... etc and then check
# that that valid addresses map correctly and invalid ones fault
# correctly. NOTE that there are subtle semantics to the so-called
# "page length field" ... in a page that grows upwards, a plf of
# zero means that to be INVALID the block number has to be greater
# than zero (therefore "zero" length really means 64 bytes of
# validity) and there is a similar off-by-one semantic to ED=1
# downward pages. The test understands this.
cn = self.usefulconstants()
for segno in range(8):
p.mmu.wordRW(cn.UDSA0 + (segno*2), (8192 * segno) >> 6)
pln = segno * 16
p.mmu.wordRW(cn.UDSD0 + (segno*2), (pln << 8) | 0o06)
# enable user I/D separation
p.mmu.MMR3 |= 0o01
# turn on the MMU!
p.mmu.MMR0 = 1
for segno in range(8):
basea = segno * 8192
maxvalidoffset = 63 + ((segno * 64) * 16)
for o in range(8192):
if o <= maxvalidoffset:
_ = p.mmu.v2p(basea + o, p.USER, p.mmu.DSPACE,
p.mmu.CYCLE.READ)
else:
with self.assertRaises(PDPTraps.MMU):
_ = p.mmu.v2p(basea + o, p.USER, p.mmu.DSPACE,
p.mmu.CYCLE.READ)
def test_mmu_2(self):
# same test as _1 but with ED=1 so segments grow downwards
# test the page length field support
p = self.make_pdp()
cn = self.usefulconstants()
for segno in range(8):
p.mmu.wordRW(cn.UDSA0 + (segno*2), (8192 * segno) >> 6)
pln = 0o177 - (segno * 16)
p.mmu.wordRW(cn.UDSD0 + (segno*2), (pln << 8) | 0o16)
# enable user I/D separation
p.mmu.MMR3 |= 0o01
# turn on the MMU!
p.mmu.MMR0 = 1
for segno in range(8):
basea = segno * 8192
minvalidoffset = 8192 - (64 + ((segno * 64) * 16))
for o in range(8192):
if o >= minvalidoffset:
_ = p.mmu.v2p(basea + o, p.USER, p.mmu.DSPACE,
p.mmu.CYCLE.READ)
else:
with self.assertRaises(PDPTraps.MMU):
_ = p.mmu.v2p(basea + o, p.USER, p.mmu.DSPACE,
p.mmu.CYCLE.READ)
def test_ubmap(self):
p = self.make_pdp()
ubmaps = self.ioaddr(p, p.ub.UBMAP_OFFS)
# code paraphrased from UNIX startup, creates a mapping pattern
# that the rest of the code expects (and fiddles upper bits)
# So ... test that.
for i in range(0, 62, 2):
p.mmu.wordRW(ubmaps + (2 * i), i << 12 & 0o1777777)
p.mmu.wordRW(ubmaps + (2 * (i + 1)), 0)
# XXX there is no real test yet because the UBMAPs
# are all just dummied up right now
# this is not a unit test, invoke it using timeit etc
def speed_test_setup(self, *, loopcount=10000, mmu=True, inst=None):
p, pc = self.simplemapped_pdp()
# the returned pdp is loaded with instructions for setting up
# the mmu; only do them if that's what is wanted
if mmu:
p.run(pc=pc)
# by default the instruction being timed will be MOV R1,R0
# but other instructions could be used. MUST ONLY BE ONE WORD
if inst is None:
inst = 0o010100
# now load the test timing loop... 9 MOV R1,R0 instructions
# and an SOB for looping (so 10 instructions per loop)
insts = (0o012704, loopcount, # loopcount into R4
inst,
inst,
inst,
inst,
inst,
inst,
inst,
inst,
inst,
0o077412, # SOB R4 back to first inst
0) # HALT
instloc = 0o4000
for a2, w in enumerate(insts):
p.mmu.wordRW(instloc + (2 * a2), w)
return p, instloc
def speed_test_run(self, p, instloc):
p.run(pc=instloc)
if __name__ == "__main__":
unittest.main()