buildLst.pep2

;-------------------------
;BuildLst()
;------------------------
;---Local Variables----
size:      .BLOCK    2         ; size
head:      .BLOCK    2
stringrf:  .BLOCK    2         ;the addr of the str from readSo
next:      .BLOCK    2         ;the addr where we can start putting stuff in the heap
node:      .BLOCK    2
;----------------------


buildLst:  NOP0
           SAVEA
           SAVEX
           CLRA
           CLRX
           STA       size,d
loop:      NOP0
           CLRA
           CALL      readSO    ; calling readSO to read the string
           STA       stringrf,d  ;storing the reference to the String into temp
;------------------------------
           CPA       0,i        ; if readSo returns 0 we are done
           BREQ      done
;-------------------------------
           LDA       4,i    ;length of 4 bytes
           STA       -2,s
           SUBSP     2,i
           CALL      new
           ADDSP     2,i
           STA       node,d  ; storing the ref from new into node
;-----------------------------; this is the place in the stack we will be using
           LDA       size,d    ;Loading size into A
           TSTA                ;testing against 0
           BREQ      first     ;if it's the first element, branch to first
           LDA       node,d
;           STA       next,n    ;store the ref to current node in next for the prev node
           MOVE      node,d,next,d
           ADD       next,d,2,i
           LDA       0,i
           STA       next,n
           BR        insert
;-----------------------------
back:      LDA       stringrf,d  ;store string in first node cell
           STA       node,n
;-----------------------------          ;make ref cell just 0
           MOVE      node,d,next,d      ;LDA    node,d  STA next,d
           ADD       next,d,2,i
           LDA       0,i
           STA       next,n
           INC       size,d
;-----------------------------
           BR        loop

first:     MOVE     node,d,head,d
           BR        back


;--------------------------------------------------------
;-------Insertion Sort-----------------------------------
;--------------------------------------------------------
;Local Vars
;-----------------------------
htemp:      .BLOCK   2  ;current element starting at head
htnext:     .BLOCK   2  ;next ele in linked list.....cell:[htemp][htnext]
htSr:       .BLOCK   2  ; this is the curr string we are on whilst going through the linkedlist
prev:       .BLOCK   2  ; used for if the ele being inserted is greater than current
;-----------------------------
insert:    NOP0
           MOVE   head,d,htemp,d    ;the first run through will be a bit different than what "iloop" is
;------------------------------ getting the addresses       ;mainly, if the element being inserted
           MOVE   htemp,d,htnext,d    ;>     ;              ;is greater than 'head', we use a different
           ADD    htnext,d,2,i        ;>                    ;subprogram (actually that's the only diff)
;--------------------------------
           MOVE   htemp,n,htSr,d  ;must do first element first
           CLRA
;--------------------------------  ;call ScompTo
           PUSH   stringrf,d
           PUSH   htSr,d
           CALL   ScompTo
           ADDSP  4,i
;---------------------------------
           CPA    0,i
           BREQ   link
           BRLT   less
           BRGT   greatr2   ; 'greatr2' because if it's greater here, we have a different method
                            ;to take care of that
;-------------------------------
iloop:     NOP0
;------------------------------------checks if next addr is null
           MOVE   htemp,n,htSr,d    ;r
           PUSH   stringrf,d
           PUSH   htSr,d
           CALL   ScompTo
           ADDSP  4,i
           CPA    0,i
           BRLT   less
           BRGT   greatr


temp:      .BLOCK   2

less:      NOP0
;--------------------------------
           MOVE   htnext,n,temp,d  ; check if the 'next' is null
           LDA    temp,d
           CPA    0,i
           BREQ   link              ; if it is, we just tack it onto the end of the list
;---------------------------------      ; now we need to iterate thorugh the LinkedList
           MOVE   htemp,d,prev,d     ; move current into previous
           MOVE   htnext,n,htemp,d   ;  move the next into curr
           MOVE   htemp,d,htnext,d   ;  get the nextnode for htnext
           ADD    htnext,d,2,i       ;
           BR     iloop             ;keep looping until we get to greater


greatr:  NOP0     ;general case for if string we are inserting is greater
           MOVE     stringrf,d,node,n       ;than an inserted string
           MOVE     htemp,d,next,n
           LDA      prev,d
           ADD      prev,d,2,i
           MOVE     node,d,prev,n
           INC      size,d
           BR       loop

greatr2:   NOP0         ;this one is for if the current element is greater
           MOVE     stringrf,d,node,n       ;than the 'head' element
           MOVE     htemp,d,next,n  ;move the head into next
           MOVE     node,d,head,d
           INC      size,d
           BR       loop

link:      NOP0
;--------------------------------------;this just tacks an element onto the end
           MOVE     stringrf,d,node,n  ;load string into currNode
           MOVE     0,i,next,n          ;make it's reference null
           MOVE     node,d,htnext,n     ;connect the prev ele
           INC      size,d              ;inc size
           BR       loop

done:      LDA       head,d
           RET0