;
; FILE:    do_hdecode_v03.ips
; PURPOSE: Given the high word of the source and desination pages, figure out which HRDINIT slot to use for the header stuff
;	   The routine also copies the source page info of "n/k, dpc(l,h)" into the destination page slot
; METHOD:
;       Input:  $IPRL_HDECODE_PARAM     - holds the source high word to be decoded 
;		$IPRL_HDECODE_PARAM+1	- holds the destination high word to be decoded
;               $IPRP_HDECODE_PAGE*     - The start of the header table area (10 words per header entry)
;       Output: $IPRP_HDECODE_ADDR      - holds the pointer to the header paramters to use (one set for source, one for dest)
;       Internal: $IPRP_HDECODE_WORK    - temp holding area
; RESTRICTON:
;	After the 3-Nov-95 modification, all of the IPRP_HDECODE_PAGE* lables must be consecutive in register space
; HISTORY: Written 14-Aug-95 by M.Morrison
;          30-Aug-95 (MDM) - Changed the name and allowed either of the
;			   - changed considerably (loop and do source and dest page with a single call)
;			   - also copy the n/k, dpc(l,h) from source to dest slots
;	    5-Sep-95 (MDM) - Added some page entries
;	    6-Sep-95 (MDM) - Fixed typo
;	    3-Nov-95 (MDM) - Modified to work by looking through the contents of the lists
;			     rather than having a ton of "case" statements.
;
QSR_DO_HDECODE::
    SETREG   $IPRL_HDECODE_LOOP 0
    COPYREG  $IPRL_HDECODE_PARAM $IPRL_HDECODE_PWORK		;copy the first address to temp working area

HDECODE_LOOP:
    SETREG   $IPRP_HDECODE_WORK  $IPRP_HDECODE_PAGE0		;currently seeing if that list matches (high word)
    COPYRI2D $IPRP_HDECODE_WORK  $IPRL_HDECODE_WORK3 3		;copy the first 3 words into a working area

    COPYREG  $IPRP_HDECODE_ADDR+1 $IPRP_HDECODE_ADDR       	;cheap way to copy the answer from the first time through
								;the loop into the first address location (source)


NEXT_ITEM:
     REGSUB   $IPRL_HDECODE_WORK3+1 $IPRL_HDECODE_PWORK $IPRL_HDECODE_COMP	;compare input addr with addr in list
     BRANCHEQ $IPRL_HDECODE_COMP 0 &FOUND_ITEM

     ADDREGD  $IPRP_HDECODE_WORK 10				;Move forward to next list of 10
     COPYRI2D $IPRP_HDECODE_WORK $IPRL_HDECODE_WORK3 3		;copy the first 3 words into a working area
     BRANCHNE $IPRL_HDECODE_WORK3+1 0xFFFF &NEXT_ITEM
FOUND_ITEM:

    COPYREG   $IPRP_HDECODE_WORK $IPRP_HDECODE_ADDR+1       	;destination (or source) was decoded - save it
								;if it was the source (first run through the loop) it is 
								;copied to the +0 location up above.
    COPYREG  $IPRL_HDECODE_PARAM+1 $IPRL_HDECODE_PWORK		;copy the second address to temp working area
    ADDREGD  $IPRL_HDECODE_LOOP 1
    BRANCHEQ $IPRL_HDECODE_LOOP 1 &HDECODE_LOOP			;go through the loop twice

HDECODE_STEP3:
    ;----- copy the n/k, dpc(l,h) from the source page to the destination page slots

    COPYRD2D $IPRP_HDECODE_ADDR $IPRP_ADD_ADDR 3		;copy the source/dest pointer values to a fixed place (copies extra word)
    ADDREGD  $IPRP_ADD_ADDR 3					;increment forward to the n/k position of source slot
    ADDREGD  $IPRP_ADD_ADDR+1 3					;increment forward to the n/k position of destination slot
    COPYRI2I $IPRP_ADD_ADDR $IPRP_ADD_ADDR+1 3			;copy the n/k, dpc(l,h) from source to dest slots

    RTNQUE