PDP-11 Chess VI (Belle) By Ken Thompson (1973) ported

[cpeters]

Hello Jim;

yes, I did read the doc: When not invoked with the xboard option it speaks its own language (doesn't understand 'usermove' so it replies with 'eh?').

However selfcompiled or your binary (linux this time) it somtetimes follow book-lines up to the first deviation, then it stalls (never in xboard-mode) or ...or.

It is supposed to work like this, right?

Code: Select all

./pdp-11_chess_6_64_ja_linux 
PDP-11 Chess Engine
  Search depth: 8
  Opening book: ON
 
Book file: book.dat (274 bytes)
Opening book loaded successfully
mfmt
Algebraic notation ON
time 10
Time control enabled: 10 seconds per move
e2e4
1. e2e4
Computer plays: g8f6
1. ... g8f6
c2c3
2. c2c3
Computer plays: d7d5
2. ... d7d5
a2a4
3. a2a4
Computer plays: c8f5
3. ... c8f5
a4a5
4. a4a5
Computer plays: e7e6
4. ... e7e6
a5a6
5. a5a6
Computer plays: b8c6
5. ... b8c6

etc...
Often it moves instantly, seldom not (it computes then), or it stalls.

No book:

Code: Select all

./pdp-11_chess_6_64_ja_linux 
PDP-11 Chess Engine
  Search depth: 8
  Opening book: ON
 
Book file: book.dat (274 bytes)
Opening book loaded successfully
mfmt
Algebraic notation ON
time 20
Time control enabled: 20 seconds per move
book
Opening book OFF
e2e4
1. e2e4
Thinking for up to 20 seconds...
 
  Thinking for 20 seconds... d1/+897 d2/+977 d3/+897 d4/+977 d5/+867 d6/+887 d7/+865
  d7 in 18.0s (target: 20s)
Computer plays: e2d1
1. ... e2d1

I think there are bugs (or it's on my side)

Code: Select all

232f06c3627eedd8b1f75db0b8515ec5  chess_6.7z
aa266623a665259e24667683add27d02  pdp-11_chess_6_64_ja.zip

greetings

[Jim Ablett]

Hello Jim;

yes, I did read the doc: When not invoked with the xboard option it speaks its own language (doesn't understand 'usermove' so it replies with 'eh?').

However selfcompiled or your binary (linux this time) it somtetimes follow book-lines up to the first deviation, then it stalls (never in xboard-mode) or ...or.

It is supposed to work like this, right?

Code: Select all

./pdp-11_chess_6_64_ja_linux 
PDP-11 Chess Engine
  Search depth: 8
  Opening book: ON
 
Book file: book.dat (274 bytes)
Opening book loaded successfully
mfmt
Algebraic notation ON
time 10
Time control enabled: 10 seconds per move
e2e4
1. e2e4
Computer plays: g8f6
1. ... g8f6
c2c3
2. c2c3
Computer plays: d7d5
2. ... d7d5
a2a4
3. a2a4
Computer plays: c8f5
3. ... c8f5
a4a5
4. a4a5
Computer plays: e7e6
4. ... e7e6
a5a6
5. a5a6
Computer plays: b8c6
5. ... b8c6

etc...
Often it moves instantly, seldom not (it computes then), or it stalls.

No book:

Code: Select all

./pdp-11_chess_6_64_ja_linux 
PDP-11 Chess Engine
  Search depth: 8
  Opening book: ON
 
Book file: book.dat (274 bytes)
Opening book loaded successfully
mfmt
Algebraic notation ON
time 20
Time control enabled: 20 seconds per move
book
Opening book OFF
e2e4
1. e2e4
Thinking for up to 20 seconds...
 
  Thinking for 20 seconds... d1/+897 d2/+977 d3/+897 d4/+977 d5/+867 d6/+887 d7/+865
  d7 in 18.0s (target: 20s)
Computer plays: e2d1
1. ... e2d1

I think there are bugs (or it's on my side)

Code: Select all

232f06c3627eedd8b1f75db0b8515ec5  chess_6.7z
aa266623a665259e24667683add27d02  pdp-11_chess_6_64_ja.zip

greetings

Yes. there is a bug. I will fix it. Side to move is messed up in console mode.
Must of happened when I was implementing winboard mode.

Jim.

[Jim Ablett]

Update:

Fixed play in console mode.

Proton link: (same link updated)
https://drive.proton.me/urls/SYXDFSN22W#s412WevZRDVY

Smash link:
https://fromsmash.com/PDP11CHESS64JA

Jim.

[cpeters]

Hello Jim!

The 'not working' on newer *BSDs is fixed also.

Thank you!

[Jim Ablett]

Update:

Fixes to winboard time control (time forfeit fixes)

Proton link: (same link updated)
https://drive.proton.me/urls/SYXDFSN22W#s412WevZRDVY

Smash link:
https://fromsmash.com/PDP11CHESSJA

Jim.

[CRoberson]

It's in the download package. Unfortunately I had to patch some missing logic (some of original logic contained in ancient assembler I couldn't decifer) with some modern routines to get it working satisfactorily.
It's about 95% ported code / 5% new code. Playing strength around the original's reported elo rating of 1450.

Jim.

How cool. I know PDP-11 assembler. Learned it back in the early 1980s on a PDP 11-34 running RSTS.

[ehenkes]

PDP-11 Chess Engine
Search depth: 8
Opening book: ON

Book file: book.dat (134 bytes)
Opening book loaded successfully
Thinking time set to 10 secs (default)
alg
e2e4
1. e2e4
Computer plays: g8f6
1. ... g8f6

8 R N B Q K B N R
7 P P P P P P P P
6 - * - * - * - *
5 - * - * - * - *
4 - * - * - * - *
3 - * - * - * - *
2 p p p p p p p p
1 r n b q k b n r

a b c d e f g h [Algebraic format: ON]

It does not carry out the moves. Pls help.

[Jim Ablett]

PDP-11 Chess Engine
Search depth: 8
Opening book: ON

Book file: book.dat (134 bytes)
Opening book loaded successfully
Thinking time set to 10 secs (default)
alg
e2e4
1. e2e4
Computer plays: g8f6
1. ... g8f6

8 R N B Q K B N R
7 P P P P P P P P
6 - * - * - * - *
5 - * - * - * - *
4 - * - * - * - *
3 - * - * - * - *
2 p p p p p p p p
1 r n b q k b n r

a b c d e f g h [Algebraic format: ON]

It does not carry out the moves. Pls help.

Code: Select all

PDP-11 Chess Engine
  Search depth: 8
  Opening book: ON

Book file: book.dat (134 bytes)
Opening book loaded successfully
Thinking time set to 10 secs (default)
mfmt
Algebraic notation ON
book
Opening book OFF
e2e4
1. e2e4
Thinking for up to 10 seconds...

  Thinking for 10 seconds... d1/+0 d2/+80 d3/+0 d4/+0 d5/-20 d6/+0
  d7 in 9.0s (target: 10s)
Computer plays: g8f6
1. ... g8f6

8  R N B Q K B - R
7  P P P P P P P P
6  - * - * - N - *
5  - * - * - * - *
4  - * - * p * - *
3  - * - * - * - *
2  p p p p - p p p
1  r n b q k b n r

   a b c d e f g h   [Algebraic format: ON]

not alg, mfmt

Jim.

[Tibono]

Hi Jim,
according to my tests, the issue is not about mfmt vs alg; the issue is with 'book on' status.
In console mode, only 'book off' option works (Windows version).
Warm regards,
Eric