INTRODUCTION

 The BNL787 defined  locations  (in  787SSP:BNL787_RES_D.MAR)
 are  described below.  Space is reserved for extra locations
 that may be added later.

 All code written for BNL787 experiment must use the  defined
 SSP_independent  locations for the purposes described below.
 Those locations whose use is SSP_dependent may be left empty
 if  not  needed.   However, if they are used, they should be
 used as described below, and not diverted to some other use.




 WRITTEN_EVERY_COMMAND


 The following words are input to the SSP by the master.  Two
 words,  $COMMAND  and  $MASTER_ID  must  be written on every
 command.   The  other  words  may  be  written  less  often.
 $COMMAND and $MASTER_ID, must be written on every command.

Additional Information on:

 WRITTEN_BEFORE_INIT

 The following commands must be written  prior  to  the  INIT
 command  being  given.   They  need not be written again, as
 they must remain unchanged throughout the run.

Additional Information on:

 READ_EVERY_COMMAND


 The following words must be read by the master on completion
 of every command:

Additional Information on:

 BUFFER_LOCATIONS_AND_SIZES


 The first four words (address and length  of  data  buffers)
 would  normally be read by the Master after the end of spill
 (ESPI) command has been given.  The last two words need only


 be read if an error return code is generated.

Additional Information on:

 COUNTERS


 The following counters are incremented throughout  the  run,
 and are only cleared on a START command.

Additional Information on:

 CRATE_AND_CABLE_SEGMENTS

 The following should be filled on receipt of  command  INIT,
 and may be read out by the master and written on tape at the
 beginning of run.

Additional Information on:

 POINTERS


 These are provided so that  the  master  can  read  out  any
 SSP_dependent counters and/or histograms using a block read.
 The starting address and length (in  32-bit  words)  of  the
 data block are all that is required.

Additional Information on: