/ Spacewar! 4.0TS - normalised source transcription
/ ----------------------------------------------------------------------
/ Transcribed from the scanned listing "spacewar 4.0ts  5/4/63  ddp"
/ (spacewar-4.0ts-4may1963.pdf, 33 pp.), Monty Preonas's ("ddp") "Twin
/ Star" variant of Spacewar! 4.0. Extracted by David M. Berry.
/
/ Per the masswerk genealogy, 4.0TS is version 4.0 with a simplified
/ starfield (4th-magnitude stars removed) and minor hyperspace
/ modifications. The two divergences from 4.0 are confirmed by the scan:
/   (1) the background routine (pt.1, "background" define) makes only
/       THREE dislis calls -- dislis 1j,1q,3 / 2j,2q,2 / 3j,3q,1 -- the
/       "dislis 4j,4q,0" call present in 4.0 is removed; and
/   (2) the starfield data table appended here ("stars by prs for s/w 2b",
/       pp.31-33) likewise omits the 4th-magnitude star group: it carries
/       only 1j/1q, 2j/2q and 3j/3q, not a 4j/4q block.
/   The "minor hyperspace modifications" are visible in the hp1 routine
/   (pt.2, "this routine handles a non-colliding ship invisibly in
/   hyperspace"): after setting the new angle (lac ran / dac i mth),
/   4.0TS does "random / sar 6s / dac i mom", giving the ship a random
/   angular velocity on hyperspace re-entry. The 4.0 listing instead has
/   "setup ~hpt,3" before "lac ran / dac i mth" and closes the hp4 loop
/   with "count ~hpt,hp4" (a fixed spin of the angle), with no random
/   "dac i mom". 4.0TS thus drops the hpt spin loop and randomises mom
/   instead. Otherwise hp1/hp3 are structurally as in 4.0.
/
/ Method: read page by page against the scan images; OCR was used only as
/ a first pass and every numeral and mnemonic was checked by eye. The 4.0
/ listing (spacewar-4.0-2feb1963-(Morris).txt) was used to resolve
/ ambiguous readings of the shared routines, but this is a different
/ version and what the 4.0TS scan actually shows is transcribed.
/ Conventions follow the bitsavers Samson files: "~" marks a variable
/ shown overlined in the original; tabs separate the label, instruction
/ and "/" comment columns.
/
/ Confidence notes:
/   - pt.1 header reads "spacewar 4.0ts  5/4/63  ddp · pt 1".
/   - p.1 carries a definition line, "ioh=xct (nop", that is not present
/     in the 4.0 listing (in 4.0 "ioh" is defined elsewhere); transcribed
/     as it appears, with its "/delay for dpy's" comment.
/   - p.16: "lio ddd / spi i" -- the skip is read as "spi i" (matching the
/     valid PDP-1 form and the 4.0 listing); the scan glyph is ambiguous
/     between "i" and "1".
/   - p.27: 4.0TS prints both labels "st3," and "srt," explicitly, with
/     "srt,  jmp .". This resolves the spot that was illegible at the
/     analogous "st3," label in the 4.0 scan: here st3 is simply a label
/     point that falls through to "srt, jmp .". No content is illegible.
/   - No assembler symbol table or pass-log appears in this scan. Unlike
/     4.0, this listing does NOT carry the game-saver / paper-tape loader
/     patch; instead pp.31-33 hold the separate starfield source ("stars
/     by prs for s/w 2b"), assembled at 6077/ with its own "start 4".
/ ----------------------------------------------------------------------

	spacewar 4.0ts  5/4/63  ddp · pt 1

3/	jmp sbf		/ ignore seq. break
	jmp a40
	jmp a1		/ use test word for control, not iot 11 co
/ interesting and often changed constants
/symb loc   usual value (all instructions are executed,
	/ and may be replaced by jda or jsp)
tno,  6,	law i 41	/ number of torps + 1
tvl,  7,	sar 4s		/ torpedo velocity
rlt, 10,	law i 20	/ torpedo reload time
tlf, 11,	law i 140	/ torpedo life
foo, 12,	-20000		/ fuel supply
maa, 13,	10		/ spaceship angular acceleration
sac, 14,	sar 4s		/ spaceship acceleration
str, 15,	100		/ star capture radius
me1, 16,	6000		/ collision "radius"
me2, 17,	3000		/ above/2
ddd, 20,	-0		/ 0 to save space for ddt
the, 21,	sar 9s		/ amount of torpedo space warpage
mhs, 22,	law i 10	/ number of hyperspace shots
hd1, 23,	law i 40	/ time in hyperspace before breakout
hd2, 24,	law i 100	/ time in hyperspace breakout
hd3, 25,	law i 200	/ time to recharge hyperfield generators
hr1, 26,	scl 9s		/ scale on hyperspatial displacement
hr2, 27,	scl 4s		/ scale on hyperspatially induced velocity
hur, 30,	40000		/ hyperspatial uncertancy
ran, 31,	0		/ random number
grv, 32,	sar 6s		/ gravitational constant
/ place to build a private control word routine.
/ it should leave the control word in the io as follows.
/ high order 4 bits, rotate ccw, rotate cw, (both mean hyperspace)
/	fire rocket, and fire torpedo. Low order 4 bits, same for
/	other ship.  Routine is entered by jsp cwg.
40/
cwr,	jmp mg1		/ normally iot 11 control
. 20/	/ space
ioh=xct (nop		/delay for dpy's
/ routine to flush sequence breakes, if they occur.
sbf,	tyi
	lio 2
	lac 0
	lsm
	jmp i 1
	define
xincr X,Y,INS
	lac Y
	INS ~ssn
	dac Y
	lac X
	INS ~scn
	dac X
	term
	define
yincr X,Y,INS
	lac Y
	INS ~scn
	dac Y
	lac X
	-INS+add+sub ~ssn
	dac X
	terminate
	define
dispatch
	add (. 3
	dap . 1
	jmp .
	term
	define
dispt A,Y,B
	repeat 6, B=B+B
	lio Y
	dpy-A+B
	term
	define
scale A,B,C
	lac A
	sar B
	dac C
	term
	define
diff V,S,SF
	add i V
	dac i V
	xct SF
	add i S
	dac i S
	term
	define
random
	lac ran
	rar 1s
	xor (355670
	add (355670
	dac ran
	term
	define
ranct S,SS,C
	random
	S
	SS
	sma
	cma
	dac C
	terminate
	define
varsft
	dzm ~xys
	dac ~t1
	idx ~xys
v2,	idx ~xys
	lac ~t1
	scr 2s
	dac ~t1
	sza
	jmp v2+R
	scr 2s
	swap
	terminate
	define
undosft
	dac t1
	dio ~t2
	lac ~xys
	add sft
	dap .+1
	lac .
	dac .+6
	dac .+6
	xor (10000	/ change scr to scl or scl to scr.
	dac ~xyt
	lac ~t1
	dio ~t2
	scr .
	scr .
	terminate
	define
integrate A,B
	cli
	lac i A
	scr 9s
	scr 1s
	div ~t1
	hlt
	cma+cli-opr
	xct ~xyt
	xct grv
	dac B
	terminate
sft,	lac .-1
	scr 7s
	scr 6s
	scr 5s
	scr 4s
	scr 3s
	scr 2s
	scr 1s
	scr
	scl 1s
/sine-cosine subroutine · Adams associates
/calling sequence= number in AC, jda sin or jdacos.
/argument is between +2 pi, with binary point to right of bit 3.
/answer has binary point to right of bit 0.  Time = 2.35-? ms.
/changed for auto-multiply , ddp 1/19/63
cos,	0
	dap csx
	lac (62210
	add cos
	dac sin
	jmp .+4
sin,	0
	dap csx
	lac sin
	spa
si1,	add (311040
	sub (62210
	sma
	jmp si2
	add (62210
si3,	ral 2s
	mul (242763
	dac sin
	mul sin
	dac cos
	mul (756103
	add (121312
	mul cos
	add (532511
	mul cos
	add (144417
	mul sin
	scl 3s
	dac cos
	xor sin
	sma
	jmp csx-1
	lac (377777
	lio sin
	spi
	cma
	jmp csx
	lac cos
csx,	jmp .
si2,	cma
	add (62210
	sma
	jmp si3
	add (62210
	spa
	jmp .+3
	sub (62210
	jmp si3
	sub (62210
	jmp si1
/integer square root
/input in ac, binary point to right of bit 17, jda sqt
/answer in ac with binary point between bits 8 and 9
/largest input number = 177777
sqt,	0
	dap sqx
	law i 23
	dac sq1
	dzm sq2
	lio sqt
	dzm sqt
sq3,	isp sq1
	jmp .+3
	lac sq2
sqx,	jmp .
	lac sq2
	sal 1s
	dac sq2
	lac sqt
	rcl 2s
	sza i
	jmp sq3
	dac sqt
	lac sq2
	sal 1s
	add (1
	sub sqt
	sma+sza-skp
	jmp sq3
	spa
	cma
	dac sqt
	idx sq2
	jmp sq3
sq1,	0
sq2,	0
/outline compiler
/ac=where to compile to, call   jda oc
/ot=address of outline table
	define
plinst A
	lac A
	dac i oc
	idx oc
	terminate
	define
comtab A, B
	plinst A
	jsp ocs
	lac B
	jmp oce
	terminate
ocs,	dap ocz		/puts in swap
	dio i oc
	idx oc
	dio i oc
	idx oc
ocz,	jmp .
oc,	0		/outline compiler proper
	dap ocx
	lac i ocx
	dap ocg
	plinst (stf 5
	dap ocm
	idx ocx
ock,	plinst (lac ~sx1
	plinst (lio ~sy1
	clf 6
ocj,	setup ~occ,6
ocg,	lio .		/outline table
och,	cla
	rcl 3s
	dio ~oci
	lio (rcl 9s
	dispatch
	opr
	jmp oc1
oco,	jmp oc2
ocq,	jmp oc3
ocp,	jmp oc4
ocr,	jmp oc5
	jmp oc6
	plinst (szf 5	/7 code
	add (4
	dap ocn
	plinst ocn
	plinst (dac ~sx1
	plinst (dio ~sy1
	plinst (jmp sq6
	plinst (clf 5
	plinst (lac ~scm
	plinst (cma
	plinst (dac ~scm
	plinst (lac ~ssm
	plinst (cma
	plinst (dac ~ssm
	plinst (lac ~csm
	plinst (lio ~ssd
	plinst (dac ~ssd
	plinst (dio ~csm
	plinst (lac ~ssc
	plinst (lio ~csn
	plinst (dac ~csn
	plinst (dio ~ssc
	plinst ocm
ocx,	jmp .
ocm,	jmp .
ocn,	jmp .
oc1,	plinst (add ~ssn
	jsp ocs
	lac (sub ~scn
oce,	dac i oc
	idx oc
	jsp ocs
	plinst (ioh
	lac (dpy-4000
ocd,	dac i oc
	idx oc
	lio ~oci
	count ~occ, och
	idx ocg
	jmp ocj
oc2,	comtab (add ~scm, (add ~ssm
oc3,	comtab (add ~ssc, (sub ~csm
oc4,	comtab (sub ~scm, (sub ~ssm
oc5,	comtab (add ~csn, (sub ~ssd
oc6,	szf 6
	jmp oc9
	stf 6
	plinst (dac ~ssa
	lac (dio ~ssi
	jmp ocd
oc9,	clf 6
	plinst (lac ~ssa
	lac (lio ~ssi
	jmp ocd
/display a star
	define
starp
	add ~bx
	swap
	add ~by
	swap
	ioh
	dpy-4000
	terminate
blp,	dap blx		/star
	szs 60
	jmp blx
	random
	rar 9s
	and (add 340
	spa
	xor (377777
	dac ~bx
	lac ran
	ral 4s
	and (add 340
	spa
	xor (377777
	dac ~by
	jsp bpt
	ioh
blx,	jmp .
bpt,	dap bpx
	random
	sar 9s
	sar 5s
	spa
	cma
	sal 3s
	add (bds
	dap bjm
	cla cli clf 6-opr-opr
	dpy-4000
bjm,	jmp .
bds,	repeat 20, starp
	szf 6
bpx,	jmp .
	stf 6
	cma
	swap
	cma
	swap
	jmp bjm
/background display · 3/13/62, prs.
	define
dislis J, Q, B
	repeat 6, B=B+B
	clf 5
	lac flo+R
	dap fpo+R
fs,	dap fin+R
	dap fyn+R
	idx fyn+R
fin,	lac		/lac X
	sub fpr		/right margin
	sma
	jmp fgr+R
	add (2000
frr,	spq
fou,	jmp fuu+R
fie,	sub (1000
	sal 8s
fyn,	lio		/lio Y
	dpy-i+B
	stf 5
fid,	idx fyn+R
	sad (lio Q+2
	jmp flp+R
	sad fpo+R
	jmp fx+R
	dap fin+R
	idx fyn+R
	jmp fin+R
fgr,	add (-20000+2000
	jmp frr+R
fuu,	szf 5
fx,	jmp flo+R+1	/return
	idx flo+R
	idx flo+R
	sas (Q+2
	jmp fid+R
	law J
	dac flo+R
	jmp fid+R
flp,	lac (lio J
	sad fpo+R
	jmp fx+R
	dap fin+R
	law J+1
	dap fyn+R
	jmp fin+R
fpo,	lio
flo,	J
	terminate
	define
background
	jsp bck
	termin
bck,	dap bcx
	szs 40
	jmp bcx
	isp bcc
bcx,	jmp .
	law i 2
	dac bcc
	dislis 1j,1q,3
	dislis 2j,2q,2
	dislis 3j,3q,1
	isp bkc
	jmp bcx
	law i 20
	dac bkc
	law i 1
	add fpr
	spa
	add (20000
	dac fpr
	jmp bcx
bcc,	0
bkc,	0
fpr,	10000
mul=mus
div=dis
	start

	spacewar 4.0ts  5/4/63  ddp · pt 2
/main control routine for spaceships
nob=30				/total number of colliding objects
ml0,	load ~mtc, -4000	/delay for loop
	init ml1, mtb		/loc of calc routines
	add (nob
	dap mx1		/ x
nx1=mtb nob
	add (nob
	dap my1		/ y
ny1=nx1 nob
	add (nob
	dap ma1		/ count for length of explosion or torp
na1=ny1 nob
	add (nob
	dap mb1		/ count of instructions taken by calc routine
nb1=na1 nob
	add (nob
	dac ~mdx	/ dx
ndx=nb1 nob
	add (nob
	dac ~mdy	/ dy
ndy=ndx nob
	add (nob
	dap mom		/angular velocity
nom=ndy nob
	add (2
	dap mth		/ angle
nth=nom 2
	add (2
	dac ~mfu	/fuel
nfu=nth 2
	add (2
	dac ~mtr	/ no torps remaining
ntr=nfu 2
	add (2
	dap mot		/ outline of spaceship
not=ntr 2
	add (2
	dap mco		/ old control word
nco=not 2
	add (2
	dac ~mh1
nh1=nco 2
	add (2
	dac ~mh2
nh2=nh1 2
	add (2
	dac ~mh3
nh3=nh2 2
	add (2
	dac ~mh4
nh4=nh3 2
nnn=nh4 2
	law ss1
	xor mtb
	sza
	jmp mdn
	law ss2
	xor mtb 1
	sza
	jmp mdn
	law 1		/ test if both ships out of torps
	add ntr
	spa
	jmp md1
	law 1
	add ntr 1
	spa i
	jmp mdn
md1,	xct tlf		/ restart delay is 2X torpedo life
	sal 1s
	dac ~ntd
	jmp ml1
mdn,	count ~ntd,ml1
	stf 1
	stf 2
	law ss1
	xor mtb
	sza
	clf 1
	sza i
	idx ~1sc
	law ss2
	xor mtb 1
	sza
	clf 2
	sza i
	idx ~2sc
	clf 2
	jmp a
a1,	law mg2		/ test word control
	dac ~cwg
	jmp a
a40,	law cwr		/ here from start at 4
	dac ~cwg
	jmp a6
a,	lac ~gct
	sma
	jmp a5
	count ~gct, a5
	lac ~1sc
	sas ~2sc
	jmp a4
	law i 1
	dac ~gct
a5,	lat
	and (40
	sza i
	jmp a2
a4,	lac ~1sc
	lio ~2sc
	hlt
	lat
	and (40
	sza
	jmp a2
	dzm ~1sc
	dzm ~2sc
a6,	lat
	rar 6s
	and (37
	sza
	cma
	dac ~gct
a2,	clear mtb, nnn-1	/ clear out all tables
	law ss1
	dac mtb
	law ss2
	dac mtb 1
	lac (200000
	dac nx1
	dac ny1
	cma
	dac nx1 1
	dac ny1 1
	lac (144420
	dac nth
	law nnn		/ start of outline program
	dac not
	lio ddd
	spi i
	jmp a3
	jda oc		/ compile outline
	ot1
a3,	dac not 1
	jda oc
	ot2
	xct tno
	dac ntr
	dac ntr 1
	lac foo
	dac nfu
	dac nfu+1
	law 2000
	dac nb1
	dac nb1 1
	xct mhs
	dac nh2
	dac nh2 1
	jmp ml0
/ control word get routines
mg1,	dap mg3
	cli
	iot 11
mg3,	jmp .
mg2,	dap mg4
	lat
	swap
mg4,	jmp .
ml1,	lac .		/ 1st control word
	sza i		/ zero if not active
	jmp mq1		/ not active
	swap
	idx ~moc
	spi
	jmp mq4
	law 1
	add ml1
	dap ml2
	law 1
	add mx1
	dap mx2
	law 1
	add my1
	dap my2
	law 1
	add ma1
	dap ma2
	law 1
	add mb1
	dap mb2
mot,	lac .
	dap sp5
ml2,	lac .		/ 2nd control word
	spq		/ can it collide?
	jmp mq2		/ no
mx1,	lac .		/ calc if collision
mx2,	sub .		/ delta x
	spa		/ take abs val
	cma
	dac ~mt1
	sub me1		/ < EPSILON ?
	sma
	jmp mq2		/ no
my1,	lac .
my2,	sub .
	spa
	cma
	sub me1		/ < epsilon ?
	sma
	jmp mq2		/ no
	add ~mt1
	sub me2
	sma
	jmp mq2
	lac (mex 400000	/ yes, EXPLODE
	dac i ml1	/ replace calc routine with explosion
	dac i ml2
	lac i mb1	/ duration of explosion
mb2,	add .
	cma
	sar 8s
	add (1
ma1,	dac .
ma2,	dac .
mq2,	idx mx2		/ end of comparison loop
	idx my2
	idx ma2
	idx mb2
	index ml2, (lac mtb nob, ml2
mq4,	lac i ml1	/ routine for calculating spaceship
	dap . 1		/ or other object and displaying it
	jsp .
mb1,	lac .		/ alter count of number of instructions
	add ~mtc
	dac ~mtc
mq1,	idx mx1		/ end of comparison and display loop
	idx my1
	idx ma1
	idx mb1
	idx ~mdx
	idx ~mdy
	idx mom
	idx mth
	idx ~mfu
	idx ~mtr
	idx mot
	idx mco
	idx ~mh1
	idx ~mh2
	idx ~mh3
	idx ~mh4
	index ml1, (lac mtb nob-1, ml1
	lac i ml1	/ display and compute last point
	sza i		/ if active
	jmp mq3
	dap . 1
	jsp .
	lac i mb1
	add ~mtc
	dac ~mtc
mq3,	background	/ display stars of the heavens
	jsp blp		/ display massive star
	count ~mtc, .	/ use up rest of time of main loop
	jmp ml0		/ repeat whole works
/ misc calculation routines
/ explosion
mex,	dap mxr
	lac i ~mdx
	sar 3s
	add i mx1
	dac i mx1
	lac i ~mdy
	sar 3s
	add i my1
	dac i my1
	law mst
	dap msh
	lac i mb1	/ time involved
	cma cli-opr
	sar 3s
	dac ~mxc
ms1,	sub (140
	sma
	idx msh
mz1,	random
	and (777
	ior (scl
	dac mi1
	random
	scr 9s
	sir 9s
msh,	xct .
mi1,	hlt
	add i my1
	swap
	add i mx1
	dpy-i 300
	count ~mxc, mz1
	count i ma1, mxr
	dzm i ml1
mxr,	jmp .
mst,	scr 1s
	scr 3s
/ torpedo calc routine
tcr,	dap trc
	count i ma1, tc1
	lac (mex 400000
	dac i ml1
	law i 2
	dac i ma1
	jmp trc
tc1,	lac i mx1
	sar 9s
	xct the
	add i ~mdy
	dac i ~mdy
	sar 3s
	add i my1
	dac i my1
	sar 9s
	xct the
	add i ~mdx
	dac i ~mdx
	sar 3s
	add i mx1
	dac i mx1
	dispt 1, i my1, 1
trc,	jmp .
/ hyperspace routines
/ this routine handles a non-colliding ship invisibly
/ in hyperspace
hp1,	dap hp2
	count i ma1, hp2
	law hp3		/ next step
	dac i ml1
	law 7
	dac i mb1
	random
	scr 9s
	sir 9s
	xct hr1
	add i mx1
	dac i mx1
	swap
	add i my1
	dac i my1
	random
	scr 9s
	sir 9s
	xct hr2
	dac i mdy
	dio i mdx
	lac ran
	dac i mth
	random
	sar 6s
	dac i mom
hp4,	lac i mth
	sma
	sub (311040
	spa
	add (311040
	dac i mth
	xct hd2
	dac i ma1
hp2,	jmp .
/ this routine handles a ship breaking out of
/ hyperspace.
hp3,	dap hp5
	count i ma1,hp6
	lac i ~mh1
	dac i ml1
	law 2000
	dac i mb1
	count i ~mh2,hp7
	dzm i ~mh2
hp7,	xct hd3
	dac i ~mh3
	lac i ~mh4
	add hur
	dac i ~mh4
	random
	ior (400000
	add i ~mh4
	spa
	jmp hp5
	lac (mex 400000
	dac i ml1
	law i 10
	dac i ma1
	law 2000
	dac i mb1
hp6,	lac i mx1
	dispt i, i my1, 2
hp5,	jmp .
/ spaceship calc
ss1,	dap srt		/ first spaceship
	jsp i ~cwg
	dio ~scw
	jmp sr0
ss2,	dap srt		/ second spaceship
	jsp i ~cwg
	rir 4s
	dio ~scw
sr0,
sc1,	lio ~scw	/control word
	clf 6 cla-opr	/update angle
	spi
	add maa
	ril 1s
	spi
	sub maa
mom,	add .
	dac i mom
	szs 10
	jmp sr8
	dzm i mom
	ral 7s
sr8,	ril 1s
	spi
	stf 6
	lio i ~mfu
	spi i
	clf 6
mth,	add .
	sma
	sub (311040
	spa
	add (311040
	dac i mth
	jda sin
	dac ~sn
	dzm ~bx
	dzm ~by
	szs 60
	jmp bsg
	lac i mx1
	dac ~t1
	mul ~t1
	scr 1s
	dac ~acx
	cla
	scr 2s
	dio ~iox
	lac i my1
	dac ~t1
	mul ~t1
	scr 1s
	dac ~acy
	cla
	scr 2s
	swap
	add ~iox
	swap
	scl 2s
	add ~acx
	add ~acy
	sub str
	sma i sza-skp
	jmp pof
	add str
	varsft
	dac ~t1
	jda sqt
	mul ~t1
	undosft
	scr 9s
	scr 6s
	szs i 20		/ switch 2 for light star
	scr 2s
	sza
	jmp bsg
	scr 1s
	dio ~t1
	integrate mx1, ~bx
	integrate my1, ~by
bsg,	cla
	sad i ~mfu
	clf 6
	lac i mth
	jda cos
	dac ~cs
	sar 9s
	xct sac
	szf i 6
	cla
	add ~by
	diff ~mdy, my1, (sar 3s
	lac ~sn
	sar 9s
	xct sac
	cma
	szf i 6
	cla
	add ~bx
	diff ~mdx, mx1, (sar 3s
sp1,	scale ~sn, 5s, ~ssn
sp2,	scale ~cs, 5s, ~scn
	lac i mx1
	sub ~ssn
	dac ~sx1
	sub ~ssn
	dac ~stx
	lac i my1
	add ~scn
	dac ~sy1
	add ~scn
	dac ~sty
	scale ~sn, 9s, ssn
	scale ~cs, 9s, scn
	lac ssn
	dac ssm
	add scn
	dac ssc
	dac ssd
	lac ssn
	sub scn
	dac csn
	cma
	dac csm
	lac scn
	dac scm
	cla cli-opr
	dpy-4000
sp5,	jmp .
sq6,	ioh
	ranct sar 9s, sar 4s, ~src
	lio ~scw
	ril 2s
	spi i		/ not blasting
	jmp sq9		/ no tail
sq7,	scale ~sn, 8s, ~ssn
	scale ~cs, 8s, ~scn
	count i ~mfu, st2
	dzm i ~mfu
	jmp sq9
st2,	yincr ~sx1, ~sy1, sub
	dispt i, ~sy1
	count ~src,sq7
sq9,	count i ma1, sr5	/ check if torp tube reloaded
	dzm i ma1	/ prevent count around
mco,	lac .		/ previous control word
	cma
	szs i 30
	clc
	and ~scw	/ present control word
	ral 3s		/ torpedo bit to bit 0
	sma
	jmp sr5		/ no launch
	count i ~mtr, st1	/ check if torpedos exhausted
	dzm i ~mtr	/ prevent count around
	jmp sr5
st1,	init sr1, mtb	/ search for unused object
sr1,	lac .
	sza i		/ 0 if unused
	jmp sr2
	index sr1, (lac mtb nob, sr1
	hlt		/ no space for new objects
	jmp .-1
sr2,	lac (tcr		/ set up torpedo calc
	dac i sr1
	law nob
	add sr1
	dap ss3
	lio ~stx
ss3,	dio .
	add (nob
	dap ss4
	lio ~sty
ss4,	dio .
	add (nob
	dap sr6
	add (nob
	dap sr7
	add (nob
	dap sr3
	add (nob
	dap sr4
	lac ~sn
	xct tvl
	cma
	add i ~mdx
sr3,	dac .
	lac ~cs
	xct tvl
	add i ~mdy
sr4,	dac .
	xct rlt
	dac i ma1	/ permit torp tubes to cool
trf,	xct tlf		/ life of torpedo
sr6,	dac .
	law 20
sr7,	dap .		/ length of torp calc.
sr5,	count i ~mh3, st3	/ hyperbutton active?
	dzm i ~mh3
	lac i ~mh2
	sza i
	jmp st3
	lac ~scw
	cma
	ior i mco
	and (600000
	sza
	jmp st3
	lac i ml1
	dac i ~mh1
	lac (hp1 400000
	dac i ml1
	xct hd1
	dac i ma1
	law 3
	dac i mb1
st3,
srt,	jmp .
/ here to handle spaceships dragged into star
/ spaceship in star
pof,	dzm i ~mdx
	dzm i ~mdy
	szs 50
	jmp po1
	lac (377777
	dac i mx1
	dac i my1
	lac i mb1
	dac ~ssn
	count ~ssn, .
	jmp srt
po1,	lac (mex 400000	/ now go bang
	dac i ml1
	law i 10
	dac i ma1
	jmp srt
/ outlines of spaceships
ot1,	111131
	111111
	111111
	111163
	311111
	146111
	111114
	700000
. 5/
ot2,	013113
	113111
	116313
	131111
	161151
	111633
	365114
	700000
. 5/
	constants
	variables
p,	. 200/		/ space for patches
mtb,			/ table of objects and their properties
	start 4

/ ----------------------------------------------------------------------
/ Starfield source, appended in this scan (pp.31-33). Assembled
/ separately at 6077/ with its own "start 4". This is the SIMPLIFIED
/ starfield of the Twin Star variant: only three magnitude groups
/ (1j/1q, 2j/2q, 3j/3q); the 4th-magnitude group present in the full 4.0
/ starfield is removed. Loaded by the three "dislis" calls in the
/ background routine above.
/ ----------------------------------------------------------------------

stars by prs  for s/w 2b
6077/

/stars 1 · 3/13/62, prs.
	decimal
	define
mark X, Y
	repeat 8, Y=Y+Y
	8192-X	Y
	terminate
1j,	mark 1537, 371		/87 Taur, Aldebaran
	mark 1762, -189		/19 Orio, Rigel
	mark 1990, 168		/58 Orio, Betelgeuze
	mark 2280, -377		/ 9 CMaj, Sirius
	mark 2583, 125		/10 CMin, Procyon
	mark 3431, 283		/32 Leon, Regulus
	mark 4551, -242		/67 Virg, Spica
	mark 4842, 448		/16 Boot, Arcturus
1q,	mark 6747, 196		/53 Aqil, Altair
2j,	mark 1819, 143		/24 Orio, Bellatrix
	mark 1884, -29		/46 Orio
	mark 1910, -46		/50 Orio
	mark 1951, -221		/53 Orio
	mark 2152, -407		/ 2 CMaj
	mark 2230, 375		/24 Gemi
	mark 3201, -187		/30 Hyda, Alphard
	mark 4005, 344		/94 Leon, Denebola
2q,	mark 5975, 288		/55 Ophi
3j,	mark   46, 333		/88 Pegs, Algenib
	mark  362, -244		/31 Ceti
	mark  490, 338		/99 Pisc
	mark  566, -375		/52 Ceti
	mark  621, 462		/ 6 Arie
	mark  764, -78		/68 Ceti, Mira
	mark  900, 64		/86 Ceti
	mark 1007, 84		/92 Ceti
	mark 1243, -230		/23 Erid
	mark 1328, -314		/34 Erid
	mark 1495, 432		/74 Taur
	mark 1496, 356		/78 Taur
	mark 1618, 154		/ 1 Orio
	mark 1644, 52		/ 8 Orio
	mark 1723, -119		/67 Erid
	mark 1755, -371		/ 5 Leps
	mark 1779, -158		/20 Orio
	mark 1817, -57		/28 Orio
	mark 1843, -474		/ 9 Leps
	mark 1860, -8		/34 Orio
	mark 1868, -407		/11 Leps
	mark 1875, 225		/39 Orio
	mark 1880, -136		/44 Orio
	mark 1887, 480		/123 Taur
	mark 1948, -338		/14 Leps
	mark 2274, 296		/31 Gemi
	mark 2460, 380		/54 Gemi
	mark 2470, 504		/55 Gemi
	mark 2513, 193		/ 3 CMin
	mark 2967, 154		/11 Hyda
	mark 3016, 144		/16 Hyda
	mark 3424, 393		/30 Leon
	mark 3496, 463		/41 Leon, Algieba
	mark 3668, -357		/nu Hyda
	mark 3805, 479		/68 Leon
	mark 3806, 364		/10 Leon
	mark 4124, -502		/ 2 Corv
	mark 4157, -387		/ 4 Corv
	mark 4236, -363		/ 7 Corv
	mark 4304, -21		/29 Virg
	mark 4384, 90		/43 Virg
	mark 4421, 262		/47 Virg
	mark 4606, -2		/79 Virg
	mark 4721, 430		/ 8 Boot
	mark 5037, -356		/ 9 Libr
	mark 5186, -205		/27 Libr
	mark 5344, 153		/24 Serp
	mark 5357, 358		/28 Serp
	mark 5373, -71		/32 Serp
	mark 5430, -508		/ 7 Scor
	mark 5459, -445		/ 8 Scor
	mark 5513, -78		/ 1 Ophi
	mark 5536, -101		/ 2 Ophi
	mark 5609, 494		/27 Herc
	mark 5641, -236		/13 Ophi
	mark 5828, -355		/35 Ophi
	mark 5860, 330		/64 Herc
	mark 5984, -349		/55 Serp
	mark 6047, 63		/62 Ophi
	mark 6107, -222		/64 Ophi
	mark 6159, 217		/72 Ophi
	mark 6236, -66		/58 Serp
	mark 6439, -483		/37 Sgtr
	mark 6490, 312		/17 Aqil
	mark 6491, -115		/16 Aqil
	mark 6507, -482		/41 Sgtr
	mark 6602, 66		/30 Aqil
	mark 6721, 236		/50 Aqil
	mark 6794, 437		/12 Sgte
	mark 6862, -25		/65 Aqil
	mark 6914, -344		/ 9 Capr
	mark 7014, 324		/ 6 Dlph
	mark 7318, -137		/22 Aqar
	mark 7391, 214		/ 8 Pegs
	mark 7404, -377		/49 Capr
	mark 7513, -18		/34 Aqar
	mark 7539, 130		/26 Pegs
	mark 7644, -12		/55 Aqar
	mark 7717, 235		/42 Pegs
	mark 7790, -372		/76 Aqar
3q,	mark 7849, 334		/54 Pegs, Markab
	start 4

/ ----------------------------------------------------------------------
/ End of listing. The scan contains no assembler-generated symbol table
/ and no pass-log. Page-break header glyphs read "spw - 1" ... "spw - 33"
/ (handwritten). pt.1 ends with "start" (p.12); the main pt.2 program
/ ends with "start 4" (p.30); the appended starfield ends with its own
/ "start 4" (p.33).
/ ----------------------------------------------------------------------