View Single Post
  #5  
Old 10-09-2007, 02:57 PM
Geoff Harrison Geoff Harrison is offline
Senior Member
 
Join Date: Feb 2007
Posts: 104
Default

Quote:
Originally Posted by Grant Stockly View Post
Didn't some cylons have two dots that meet each other in the middle. Will that be version 2?
OK, here's another version using indexed mode. It's easier to change the pattern in this one by just changing the table

Code:
Addr    Value
----    ---------
                        ; Display Cylon lights on the Kenbak-1 front panel
                        ; Version 2
003     004                                             ; initialize PC
004     223 000         START   LOAD X, #0              ; X = 0
006     026 033         LOOP    LOAD INDEX A, TABLE     ; set A = next byte from table
010     044 004                 JPD A=0, START          ; restart if at end of tale
012     034 200                 STORE A, 0200           ; display A on LEDs
014     367 022                 JMD WAIT                ; pause
016     203 001                 ADD X, #1               ; decrement X
020     347 006                 JPD LOOP                ; loop to get next pattern
;
022     000             WAIT    .equ 0                  ; return address will be stored here
023     123 020                 LOAD B, #020            ; delay for a count of 020
025     113 001         WAIT1   SUB B, #1               ; decrement B
027     143 025                 JPD B!=0, WAIT1         ; if B != 0 jump to label WAIT1
031     357 022                 JPI WAIT                ; return
;
033     201             TABLE   .equ 10000001
034     102                     .equ 01000010
035     044                     .equ 00100100
036     030                     .equ 00011000
037     044                     .equ 00100100
040     102                     .equ 01000010
041     201                     .equ 10000001
042     000                     .equ 00000000
Quote:
Isn't it amazing, that a pile of TTL chips is 'thinking'?
Yes. I'm almost glad I missed that solder joint, the time I spent looking over the circuit diagrams and state diagrams gave me a good appreciation for John's interesting design. I find some of the Kenbak's quirks quite interesting: the serial architecture of course, the lack of a stack, the variable execution time of the instructions, the accessibility of the registers as memory locations (though some other CPUs do that too).

Does anyone know of other machines that use a serial design like this one?

Geoff.
Reply With Quote