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Power-Programmierung
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1992
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l7.asm
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Assembly Source File
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1992-01-24
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3KB
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63 lines
; C near-callable assembly function for inserting a new node in a
; linked list sorted by ascending order of the Value field. The list
; is circular; that is, it has a dummy node as both the head and the
; tail of the list. The dummy node is a sentinel, containing the
; largest possible Value field setting. Tested with TASM 3.0.
MAX_TEXT_LENGTH equ 100 ;longest allowed Text field
SENTINEL equ 32767 ;largest possible Value field
LinkNode struc
NextNode dw ?
Value dw ?
Text db MAX_TEXT_LENGTH+1 dup(?)
;*** Any number of additional data fields may by present ***
LinkNode ends
.model small
.code
; Inserts the specified node into a ascending-value-sorted linked
; list, such that value-sorting is maintained. Returns a pointer to
; the node after which the new node is inserted.
; C near-callable as:
; struct LinkNode *InsertNodeSorted(struct LinkNode *HeadOfListNode,
; struct LinkNode *NodeToInsert)
parms struc
dw 2 dup (?) ;pushed return address & BP
HeadOfListNode dw ? ;pointer to head node of list
NodeToInsert dw ? ;pointer to node to insert
parms ends
public _InsertNodeSorted
_InsertNodeSorted proc near
push bp
mov bp,sp ;point to stack frame
push si ;preserve register vars
push di
mov si,[bp].NodeToInsert ;point to node to insert
mov ax,[si].Value ;search value
mov di,[bp].HeadOfListNode ;point to linked list in
; which to insert
SearchLoop:
mov bx,di ;advance to the next node
mov di,[bx].NextNode ;point to following node
cmp [di].Value,ax ;is the following node's
; value less than the value
; from the node to insert?
jl SearchLoop ;yes, so continue searching
;no, so we have found our
; insert point
mov ax,[bx].NextNode ;link the new node between
mov [si].NextNode,ax ; the current node and the
mov [bx].NextNode,si ; following node
mov ax,bx ;return pointer to node
; after which we inserted
pop di ;restore register vars
pop si
pop bp
ret
_InsertNodeSorted endp
end