PDP7-Unix/sys/s8.s
"** 01-s1.pdf page 48
" s8
" manifests
mnproc = 10 " number of processes
dspbsz = 270 " display buffer size
ndskbs = 4 " number of buffers at dskbs
" flags
.insys: 0 " "in system"
.int1: 0 " inode for user interrupt 1
.int2: 0 " inode for user interrupt 2
.ac: 0 " saved AC from Priotity Interrupt
.savblk: 0 " set by system call, cleared by disk i/o
.dsptm: 0 " display restart countdown (10 ticks)
.dskb: 0 " set on disk interrupt
.dske: 0 " status from disk interrupt
" pointers
tadu: tad ulist
dacu: dac ulist
maxquant: 30
ofilesp: u.ofiles
idskpp: i.dskps
dskbufp: dskbuf
edspbuf: dspbuf+dspbsz
dspbufp3: dspbuf+3
fblksp: s.fblks
dacq1: dac q1
lacq1: lac q1
q2p: q2
" strings
initf:
<in>; <it>; 040040; 040040 " was <i>n;<i>t;< > ;< > but as.s unhappy!
" constants
d0: 0
d1: 1
d2: 2
d3: 3
d4: 4
d5: 5
d6: 6
d7: o7: 07
d8: 8
d9: 9
o12: d10: 10
o14: 014
o15: 015
o17: 017
o20: 020
o33: 033
o40: 040
o55: 055
o77: 077
d65:o101: 0101
d33: 33
o132: 0132
o134: 0134
o137: 0137
o155: 0155
o177: 0177
"** 01-s1.pdf page 49
o212: 0212
o375: 0375
o777: 0777
o2000: 02000
o4000: 04000
d7999: 7999
o10000: 010000
o17762: 017762
o17777: 017777
o20001: 020001
o40000: 040000
o40001: 040001
o70000: 070000
o77777: 077777
o100000: 0100000
o140000: 0140000
o200000: 0200000
o200001: 0200001
o300000: 0300000
o400000: 0400000
o500000: 0500000
o577777: 0577777
o600000: 0600000
o640000: 0640000
o700000: 0700000
o777700: 0777700
o777760: 0777760
dm3: -3
dm1: -1
9: .=.+t " per-routine temp variables
c1: .=.+1 " not used?
q1: q2;q2+98 " ** 90? 96?? " queue element free list?
.=.+14
" queues (two words each, head and tail pointers?)
" 1: tty input
" 2: tty output
" 3: display keyboard
" 4: paper tape reader
" 5: paper tape punch
q2:
.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0
.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0
.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0
.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0
.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;.+2;0;0;0
dsploc: .=.+1
dsplno: .=.+1
dspbuf:
0065057;0147740;0160000 " display commands: see 03-scope.pdf pg 20
" PARAM: clear blink, clear light pen, scale=1, intensity=3
" X-Y: invisible, no delay, Y=01740 (992)
" X-Y: invisible, settling delay, X=0
.=.+30
coldentry:
dzm 0100 " not re-entrant
caf " clear all flags
ion " enable interrupts
clon " clear clock flag
law 3072 " initialize display....
wcga
jms dspinit
law dspbuf " set display buffer to default
jms movdsp
cla " read system block from disk
jms dskio; 06000
jms copy; dskbuf; sysdata; ulist-sysdata " copy to system data
lac d3 " look for "init" in default directory
jms namei; initf
jms halt
"** 01-s1.pdf page 50
jms iget
cla
jms iread; 4096; 4096 " read in "init"
jmp 4096 " start process 1
. = dspbuf+dspbsz+3
dskbuf = 07700
dskbs: .=.+65+65+65+65 " ndskbs buffers (block number + block)
edskbsp: .
uquant: .=.+1 " number of ticks user has been running
dspbufp: .=.+1 " pointer to display buffer
pbsflgs: .=.+2 " buttons on last tick, last button interrupt
mode: .=.+1
nttychar: .=.+1 " CR to send next, or zero
npptchar: .=.+1
ttydelay: .=.+1 " delay count for TTY output
name: .=.+4
lnkaddr: .=.+1
char: .=.+1
dskaddr: .=.+1
uniqpid: 1 " pid generator
lu: .=.+4 " user (process) table entry copy
sfiles: .=.+10 " wait addresses for special files
" (bit vector of waiting processes?)
" offsets: 0: ttyin, 1: ttyout, 2: keyboard,
" 3: ptr, 4: ptp, 6: display
dpdata:
dpstat: .=.+1
dpread: .=.+1
dpwrite: .=.+1
dpchar: .=.+1
dspdata:
.dspb: .=.+1
.lpba: .=.+1 "** 4 written on listing
crdata:
crread: .=.+1
crchar: .=.+1
sysdata: " system data 64 words saved to disk
s.nxfblk: .=.+1 " pointer to next free block??
s.nfblks: .=.+1 " number of free blocks (in fblks?)
s.fblks: .=.+10 " cached free block numbers
s.uniq: .=.+1 " next unique value
s.tim: .=.+2 " (up?)time in 60Hz ticks (low, high)
" process table
" first word
" bits 0:2 -- status
" 0: free slot
" 1: in/ready
" 2: in/notready
" 3: out/ready
" 4: out/notready??
" bits 3:17 -- disk swap address/8
" second word: process pid
" third word: smes/rmes status:
" 0: not waiting
" -1: this process waiting (rmes)
" other: complement of sender pid
" fourth word: smes message
ulist:
0131000;1;0;0
0031040;0;0;0
0031100;0;0;0
0031140;0;0;0
0031200;0;0;0
0031240;0;0;0
0031300;0;0;0
0031340;0;0;0
0031400;0;0;0
0031440;0;0;0
userdata: " "ustruct" (swappable)
u.ac: 0 " user AC
u.mq: 0 " user MQ
u.rq: .=.+9 " user 010-017, user PC
u.uid: -1 " user id
u.pid: 1 " process id
u.cdir: 3 " connected directory (inode number?)
u.ulistp: ulist " pointer to process table entry
u.swapret: 0 " kernel routine to resume at after swap in
u.base: 0 " start of user buffer
u.count: 0 " size of user buffer
"** 01-s1.pdf page 51
u.limit: 0 " end of user buffer
u.ofiles: .=.+30 " open files (10 "fnode" entries)
u.dspbuf: 0
u.intflg: 1
.=userdata+64
ii: .=.+1 " The current i-node number stored in inode
inode: " disk inode in memory:
i.flags: .=.+1 " inode flags
" 400000 in use
" 200000 large file
" 000040 special device (indicated by inum)
" 000020 directory
" 000010 owner read
" 000004 owner write
" 000002 world read
" 000001 world write
i.dskps: .=.+7 " disk block numbers (indirect if "large file")
i.uid: .=.+1 " owner
i.nlks: .=.+1 " link count (negative)
i.size: .=.+1 " size (in words)
i.uniq: .=.+1 " unique number
.= inode+12
di: .=.+1 " directory index
dnode: " directory entry:
d.i: .=.+1 " inode number
d.name: .=.+4 " name (space padded)
d.uniq: .=.+1 " unique number from directory inode
. = dnode+8
fnode: " open file entry
f.flags: .=.+1 " see below
f.badd: .=.+1 " offset
f.i: 0 " file i-number
" f.flags:
" 400000 in use
" 000002 read
" 000001 write