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PDP-10.its/src/system/ch11.defs1

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;;; Copyright (c) 1999 Massachusetts Institute of Technology
;;; See the COPYING file at the top-level directory of this project.
;; CH11 Unibus Chaosnet Interface definitions
CAICSR=3,,764140 ;COMMAND STATUS REG
CH%CSR==0
%CABSY==1 ;0 XMT BUSY (RO)
%CALUP==2 ;1 LOOP BACK (R/W)
%CASPY==4 ;2 RECIEVE MSGS FOR ANY DESTINATION (R/W)
%CARCL==10 ;3 CLEAR THE RECEIVER, IT CAN NOW GOBBLE ANOTHER MSG (WO)
%CAREN==20 ;4 RCV INT ENB (R/W)
%CATEN==40 ;5 XMT INT ENB (R/W)
%CATAB==100 ;6 TRANSMIT ABORTED BY ETHER CONFLICT (RO)
%CATDN==200 ;7 TRANSMIT DONE. SET WHEN TRANSMITTER IS DONE
%CATCL==400 ;8 CLEAR THE TRANSMITTER, MAKING IT READY (WO)
$CALOS==110400 ;9-12 LOST COUNT (RO) [# MSGS RCVED WITH RCV BFR FULL]
; WHEN MSG IS WAITING IN BUFFER, THIS COUNTS
; THE MESSAGES THAT MATCHED OUR DESTINATION OR
; WERE BROADCAST, BUT COULDN'T BE RECIEVED.
; WHEN RECEIVER IS RE-ENABLED (WRITE 1 INTO %CARDN)
; THE COUNT IS THEN CLEARED.
; WHEN A MESSAGE IS LOST, RECEIVER ZAPS ETHER
; SO TRANSMITTER WILL ABORT (IF MESSAGE WAS DESTINED
; TO US.)
%CARST==20000 ;13 I/O RESET (WO)
%CAERR==40000 ;14 CRC ERROR (RO)
%CARDN==100000 ;15 RCV DONE.
CAIMYN==3,,764142 ;MY # (READ ONLY)
CH%MYN==2 ;RETURNS THE [SOURCE] HOST# OF THIS INTERFACE.
CAIWBF=3,,764142 ;WRITE BUFFER (WRITE ONLY)
CH%WBF==2 ;FIRST WAIT FOR TDONE. (OR SET IT VIA CSR)
;FIRST WORD IN RESETS TRANSMITTER AND CLEARS TDONE.
;STORE INTO THIS REGISTER TO WRITE WORDS OF MESSAGE,
;LAST WORD IN IS DESTINATION ADDRESS, THEN READ CAIXMT.
;SOURCE ADDRESS AND CHECK WORD PUT IN BY HARDWARE.
CAIRBF=3,,764144 ;READ BUFFER (READ ONLY)
CH%RBF==4 ;THE FIRST WORD READ WILL BE FILLED TO THE LEFT
;TO MAKE THE MESSAGE RECIEVED A MULTIPLE OF 16 BITS.
;IF THE NUMBER OF DATA BITS IN THE MESSAGE WAS A
;MULTIPLE OF 16, THIS WORD WILL BE THE FIRST WORD PUT
;INTO THE BUFFER BY THE TRANSMITTING HOST.
;THE LAST 3 WORDS READ ARE DESTINATION, SOURCE, CHECK.
CAIRBC=3,,764146 ;RECEIVE BIT COUNTER (READ ONLY)
CH%RBC==6 ;WHEN A MESSAGE HAS BEEN RECEIVED THIS IS ONE LESS THAN
;THE NUMBER OF BITS IN THE MESSAGE (16 X THE
;NUMBER OF WORDS INCLUDING THE THREE OVERHEAD WORDS.)
;AFTER THE LAST WORD (THE CRC WORD) HAS BEEN READ, IT IS 7777
;BITS 10 AND 11 ARE THE HIGH ORDER BITS, AND IF THEY ARE ONE,
;THEN THERE WAS A BUFFER OVERFLOW
CAIXMT=3,,764152 ;READING THIS INITIATES TRANSMISSION (!!)
CH%XMT==12 ;THE VALUE READ IS ONE'S OWN HOST#.
;REFERENCING ADDRESSES IN THE GROUP OF 8 WORDS NOT LISTED HERE, OR
;USING COMBINATIONS OF READ/WRITE NOT LISTED HERE, WILL TYPICALLY CAUSE
;STRANGE AND BIZARRE EFFECTS.