$Revision: 425 $
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;; ;;
;; QUEUE.INC ;;
;; ;;
;; Buffer queue management for Menuet OS TCP/IP Stack ;;
;; ;;
;; Version 0.3 29 August 2002 ;;
;; ;;
;; Copyright 2002 Mike Hibbett, mikeh@oceanfree.net ;;
;; ;;
;; See file COPYING for details ;;
;; ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;*******************************************************************
; Interface
;
; queueInit Configures the queues to empty
; dequeue Removes a buffer pointer from a queue
; queue Inserts a buffer pointer into a queue
; freeBuff Adds the buffer pointer to the list of free buffers
; queueSize Returns the number of entries in a queue
;
; The various defines for queue names can be found in stack.inc
;
;*******************************************************************
;***************************************************************************
; Function
; freeBuff
;
; Description
; Adds a buffer number to the beginning of the free list.
; buffer number in eax ( ms word zeroed )
; all other registers preserved
; This always works, so no error returned
;***************************************************************************
freeBuff:
push ebx
push ecx
mov ebx, EMPTY_QUEUE
shl ebx, 1
add ebx, queues
cli ; Ensure that another process does not interfer
movzx ecx, word [ebx]
mov [ebx], ax
shl eax, 1
add eax, queueList
mov [eax], cx
sti
pop ecx
pop ebx
ret
;***************************************************************************
; Function
; queueSize
;
; Description
; Counts the number of entries in a queue
; queue number in ebx ( ms word zeroed )
; Queue size returned in eax
; This always works, so no error returned
;***************************************************************************
queueSize:
xor eax, eax
shl ebx, 1
add ebx, queues
movzx ecx, word [ebx]
cmp cx, NO_BUFFER
je qs_exit
qs_001:
inc eax
shl ecx, 1
add ecx, queueList
movzx ecx, word [ecx]
cmp cx, NO_BUFFER
je qs_exit
jmp qs_001
qs_exit:
ret
;***************************************************************************
; Function
; queue
;
; Description
; Adds a buffer number to the *end* of a queue
; This is quite quick because these queues will be short
; queue number in eax ( ms word zeroed )
; buffer number in ebx ( ms word zeroed )
; all other registers preserved
; This always works, so no error returned
;***************************************************************************
queue:
push ebx
shl ebx, 1
add ebx, queueList ; eax now holds address of queue entry
mov [ebx], word NO_BUFFER ; This buffer will be the last
cli
shl eax, 1
add eax, queues ; eax now holds address of queue
movzx ebx, word [eax]
cmp bx, NO_BUFFER
jne qu_001
pop ebx
; The list is empty, so add this to the head
mov [eax], bx
jmp qu_exit
qu_001:
; Find the last entry
shl ebx, 1
add ebx, queueList
mov eax, ebx
movzx ebx, word [ebx]
cmp bx, NO_BUFFER
jne qu_001
mov ebx, eax
pop eax
mov [ebx], ax
qu_exit:
sti
ret
;***************************************************************************
; Function
; dequeue
;
; Description
; removes a buffer number from the head of a queue
; This is fast, as it unlinks the first entry in the list
; queue number in eax ( ms word zeroed )
; buffer number returned in eax ( ms word zeroed )
; all other registers preserved
;
;***************************************************************************
dequeue:
push ebx
shl eax, 1
add eax, queues ; eax now holds address of queue
mov ebx, eax
cli
movzx eax, word [eax]
cmp ax, NO_BUFFER
je dq_exit
push eax
shl eax, 1
add eax, queueList ; eax now holds address of queue entry
mov ax, [eax]
mov [ebx], ax
pop eax
dq_exit:
sti
pop ebx
ret
;***************************************************************************
; Function
; queueInit
;
; Description
; Initialises the queues to empty, and creates the free queue
; list.
;
;***************************************************************************
queueInit:
mov esi, queues
mov ecx, NUMQUEUES
mov ax, NO_BUFFER
qi001:
mov [esi], ax
inc esi
inc esi
loop qi001
mov esi, queues + ( 2 * EMPTY_QUEUE )
; Initialise empty queue list
xor ax, ax
mov [esi], ax
mov ecx, NUMQUEUEENTRIES - 1
mov esi, queueList
qi002:
inc ax
mov [esi], ax
inc esi
inc esi
loop qi002
mov ax, NO_BUFFER
mov [esi], ax
ret