425 lines
18 KiB
Plaintext
425 lines
18 KiB
Plaintext
/* ARM assembly Raspberry PI */
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/* program priorqueue.s */
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/* Constantes */
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.equ STDOUT, 1 @ Linux output console
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.equ EXIT, 1 @ Linux syscall
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.equ WRITE, 4 @ Linux syscall
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.equ NBMAXIELEMENTS, 100
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/*******************************************/
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/* Structures */
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/********************************************/
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/* example structure item */
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.struct 0
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item_priority: @ priority
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.struct item_priority + 4
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item_address: @ string address
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.struct item_address + 4
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item_fin:
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/* example structure heap */
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.struct 0
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heap_size: @ heap size
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.struct heap_size + 4
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heap_items: @ structure of items
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.struct heap_items + (item_fin * NBMAXIELEMENTS)
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heap_fin:
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/*********************************/
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/* Initialized data */
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/*********************************/
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.data
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szMessEmpty: .asciz "Empty queue. \n"
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szMessNotEmpty: .asciz "Not empty queue. \n"
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szMessError: .asciz "Error detected !!!!. \n"
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szMessResult: .ascii "Priority : " @ message result
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sMessPriority: .fill 11, 1, ' '
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.asciz " : "
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szString1: .asciz "Clear drains"
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szString2: .asciz "Feed cat"
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szString3: .asciz "Make tea"
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szString4: .asciz "Solve RC tasks"
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szString5: .asciz "Tax return"
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szCarriageReturn: .asciz "\n"
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/*********************************/
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/* UnInitialized data */
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/*********************************/
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.bss
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.align 4
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Queue1: .skip heap_fin @ queue memory place
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/*********************************/
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/* code section */
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/*********************************/
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.text
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.global main
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main: @ entry of program
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ldr r0,iAdrQueue1 @ queue structure address
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bl isEmpty
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cmp r0,#0
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beq 1f
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ldr r0,iAdrszMessEmpty
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bl affichageMess @ display message empty
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b 2f
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1:
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ldr r0,iAdrszMessNotEmpty
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bl affichageMess @ display message not empty
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2:
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@ init item 1
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ldr r0,iAdrQueue1 @ queue structure address
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mov r1,#3 @ priority
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ldr r2,iAdrszString1
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bl pushQueue @ add item in queue
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cmp r0,#-1 @ error ?
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beq 99f
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ldr r0,iAdrQueue1 @ queue structure address
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bl isEmpty
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cmp r0,#0 @ not empty
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beq 3f
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ldr r0,iAdrszMessEmpty
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bl affichageMess @ display message empty
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b 4f
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3:
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ldr r0,iAdrszMessNotEmpty
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bl affichageMess @ display message not empty
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4:
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@ init item 2
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ldr r0,iAdrQueue1 @ queue structure address
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mov r1,#4 @ priority
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ldr r2,iAdrszString2
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bl pushQueue @ add item in queue
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cmp r0,#-1 @ error ?
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beq 99f
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@ init item 3
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ldr r0,iAdrQueue1 @ queue structure address
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mov r1,#5 @ priority
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ldr r2,iAdrszString3
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bl pushQueue @ add item in queue
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cmp r0,#-1 @ error ?
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beq 99f
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@ init item 4
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ldr r0,iAdrQueue1 @ queue structure address
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mov r1,#1 @ priority
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ldr r2,iAdrszString4
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bl pushQueue @ add item in queue
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cmp r0,#-1 @ error ?
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beq 99f
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@ init item 5
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ldr r0,iAdrQueue1 @ queue structure address
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mov r1,#2 @ priority
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ldr r2,iAdrszString5
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bl pushQueue @ add item in queue
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cmp r0,#-1 @ error ?
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beq 99f
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5:
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ldr r0,iAdrQueue1 @ queue structure address
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bl popQueue @ return item
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cmp r0,#-1 @ end ?
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beq 100f
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mov r2,r1 @ save string address
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ldr r1,iAdrsMessPriority @ conversion priority
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bl conversion10 @ decimal conversion
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ldr r0,iAdrszMessResult
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bl affichageMess @ display message
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mov r0,r2 @ string address
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bl affichageMess @ display message
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ldr r0,iAdrszCarriageReturn
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bl affichageMess
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b 5b @ loop
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99:
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@ error
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ldr r0,iAdrszMessError
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bl affichageMess
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100: @ standard end of the program
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mov r0, #0 @ return code
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mov r7, #EXIT @ request to exit program
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svc #0 @ perform the system call
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iAdrQueue1: .int Queue1
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iAdrszString1: .int szString1
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iAdrszString2: .int szString2
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iAdrszString3: .int szString3
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iAdrszString4: .int szString4
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iAdrszString5: .int szString5
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iAdrszMessError: .int szMessError
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iAdrszMessEmpty: .int szMessEmpty
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iAdrszMessNotEmpty: .int szMessNotEmpty
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iAdrszMessResult: .int szMessResult
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iAdrszCarriageReturn: .int szCarriageReturn
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iAdrsMessPriority: .int sMessPriority
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/******************************************************************/
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/* test if queue empty */
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/******************************************************************/
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/* r0 contains the address of queue structure */
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isEmpty:
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push {r1,lr} @ save registres
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ldr r1,[r0,#heap_size] @ heap size
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cmp r1,#0
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moveq r0,#1 @ empty queue
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movne r0,#0 @ not empty
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pop {r1,lr} @ restaur registers
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bx lr @ return
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/******************************************************************/
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/* add item in queue */
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/******************************************************************/
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/* r0 contains the address of queue structure */
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/* r1 contains the priority of item */
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/* r2 contains the string address */
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pushQueue:
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push {r1-r9,lr} @ save registres
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ldr r3,[r0,#heap_size] @ heap size
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cmp r3,#0 @ heap empty ?
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bne 1f
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add r4,r0,#heap_items @ address of item structure
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str r1,[r4,#item_priority] @ store in first item
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str r2,[r4,#item_address]
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mov r3,#1 @ heap size
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str r3,[r0,#heap_size] @ new heap size
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b 100f
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1:
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mov r4,r3 @ maxi index
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lsr r5,r4,#1 @ current index = maxi / 2
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mov r8,r1 @ save priority
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mov r9,r2 @ save string address
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2: @ insertion loop
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cmp r4,#0 @ end loop ?
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ble 3f
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mov r6,#item_fin @ item size
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mul r6,r5,r6 @ item shift
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add r6,r0
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add r6,#heap_items @ compute address item
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ldr r7,[r6,#item_priority] @ load priority
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cmp r7,r8 @ compare priority
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ble 3f @ <= end loop
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mov r1,r4 @ last index
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mov r2,r5 @ current index
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bl exchange
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mov r4,r5 @ last index = current index
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lsr r5,#1 @ current index / 2
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b 2b
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3: @ store item at last index find
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mov r6,#item_fin @ item size
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mul r6,r4,r6 @ item shift
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add r6,r0
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add r6,#heap_items @ item address
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str r8,[r6,#item_priority]
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str r9,[r6,#item_address]
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add r3,#1 @ increment heap size
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cmp r3,#NBMAXIELEMENTS @ maxi ?
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movge r0,#-1 @ yes -> error
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bge 100f
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str r3,[r0,#heap_size] @ store new size
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100:
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pop {r1-r9,lr} @ restaur registers
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bx lr @ return
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/******************************************************************/
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/* swap two elements of table */
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/******************************************************************/
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/* r0 contains the address of table */
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/* r1 contains the first index */
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/* r2 contains the second index */
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exchange:
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push {r3-r6,lr} @ save registers
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add r5,r0,#heap_items @ address items begin
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mov r3,#item_fin @ item size
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mul r4,r1,r3 @ compute item 1 shift
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add r4,r5 @ compute item 1 address
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mul r6,r2,r3 @ compute item 2 shift
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add r6,r5 @ compute item 2 address
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ldr r5,[r4,#item_priority] @ exchange
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ldr r3,[r6,#item_priority]
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str r3,[r4,#item_priority]
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str r5,[r6,#item_priority]
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ldr r5,[r4,#item_address]
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ldr r3,[r6,#item_address]
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str r5,[r6,#item_address]
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str r3,[r4,#item_address]
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100:
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pop {r3-r6,lr}
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bx lr @ return
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/******************************************************************/
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/* move one element of table */
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/******************************************************************/
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/* r0 contains the address of table */
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/* r1 contains the origin index */
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/* r2 contains the destination index */
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moveItem:
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push {r3-r6,lr} @ save registers
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add r5,r0,#heap_items @ address items begin
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mov r3,#item_fin @ item size
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mul r4,r1,r3 @ compute item 1 shift
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add r4,r5 @ compute item 1 address
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mul r6,r2,r3 @ compute item 2 shift
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add r6,r5 @ compute item 2 address
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ldr r5,[r4,#item_priority] @ exchange
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str r5,[r6,#item_priority]
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ldr r5,[r4,#item_address]
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str r5,[r6,#item_address]
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100:
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pop {r3-r6,lr}
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bx lr @ return
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/******************************************************************/
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/* pop queue */
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/******************************************************************/
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/* r0 contains the address of queue structure */
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/* r0 return priority */
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/* r1 return string address */
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popQueue:
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push {r2-r10,lr} @ save registres
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mov r1,r0 @ save address queue
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bl isEmpty @ control if empty queue
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cmp r0,#1 @ yes -> error
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moveq r0,#-1
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beq 100f
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@ save données à retourner
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mov r0,r1 @ restaur address queue
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add r4,r0,#heap_items @ address of item structure
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ldr r8,[r4,#item_priority] @ save priority first item
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ldr r9,[r4,#item_address] @ save address string first item
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ldr r3,[r0,#heap_size] @ heap size
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sub r7,r3,#1 @ last item
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mov r1,r7
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mov r2,#0 @ first item
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bl moveItem @ move last item in first item
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cmp r7,#1 @ one only item ?
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beq 10f @ yes -> end
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mov r4,#0 @ first index
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1:
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cmp r4,r7 @ = last index
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bge 10f @ yes -> end
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mov r5,r7 @ last index
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cmp r4,#0 @ init current index
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moveq r6,#1 @ = 1
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lslne r6,r4,#1 @ else = first index * 2
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cmp r6,r7 @ current index > last index
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bgt 2f @ yes
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@ no compar priority current item last item
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mov r1,#item_fin
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mul r1,r6,r1
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add r1,r0
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add r1,#heap_items @ address of current item structure
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ldr r1,[r1,#item_priority]
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mov r10,#item_fin
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mul r10,r5,r10
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add r10,r0
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add r10,#heap_items @ address of last item structure
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ldr r10,[r10,#item_priority]
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cmp r1,r10
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movlt r5,r6
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2:
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add r10,r6,#1 @ increment current index
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cmp r10,r7 @ end ?
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bgt 3f @ yes
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mov r1,#item_fin @ no compare priority
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mul r1,r10,r1
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add r1,r0
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add r1,#heap_items @ address of item structure
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ldr r1,[r1,#item_priority]
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mov r2,#item_fin
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mul r2,r5,r2
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add r2,r0
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add r2,#heap_items @ address of item structure
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ldr r2,[r2,#item_priority]
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cmp r1,r2
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movlt r5,r10
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3:
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mov r1,r5 @ move item
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mov r2,r4
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bl moveItem
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mov r4,r5
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b 1b @ and loop
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10:
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sub r3,#1
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str r3,[r0,#heap_size] @ new heap size
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mov r0,r8 @ return priority
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mov r1,r9 @ return string address
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100:
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pop {r2-r10,lr} @ restaur registers
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bx lr @ return
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/******************************************************************/
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/* display text with size calculation */
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/******************************************************************/
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/* r0 contains the address of the message */
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affichageMess:
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push {r0,r1,r2,r7,lr} @ save registres
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mov r2,#0 @ counter length
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1: @ loop length calculation
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ldrb r1,[r0,r2] @ read octet start position + index
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cmp r1,#0 @ if 0 its over
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addne r2,r2,#1 @ else add 1 in the length
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bne 1b @ and loop
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@ so here r2 contains the length of the message
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mov r1,r0 @ address message in r1
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mov r0,#STDOUT @ code to write to the standard output Linux
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mov r7, #WRITE @ code call system "write"
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svc #0 @ call systeme
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pop {r0,r1,r2,r7,lr} @ restaur registers */
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bx lr @ return
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/******************************************************************/
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/* Converting a register to a decimal */
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/******************************************************************/
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/* r0 contains value and r1 address area */
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.equ LGZONECAL, 10
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conversion10:
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push {r1-r4,lr} @ save registers
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mov r3,r1
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mov r2,#LGZONECAL
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1: @ start loop
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bl divisionpar10 @ r0 <- dividende. quotient ->r0 reste -> r1
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add r1,#48 @ digit
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strb r1,[r3,r2] @ store digit on area
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cmp r0,#0 @ stop if quotient = 0
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subne r2,#1 @ previous position
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bne 1b @ else loop
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@ end replaces digit in front of area
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mov r4,#0
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2:
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ldrb r1,[r3,r2]
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strb r1,[r3,r4] @ store in area begin
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add r4,#1
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add r2,#1 @ previous position
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cmp r2,#LGZONECAL @ end
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ble 2b @ loop
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mov r1,#' '
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3:
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strb r1,[r3,r4]
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add r4,#1
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cmp r4,#LGZONECAL @ end
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ble 3b
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100:
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pop {r1-r4,lr} @ restaur registres
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bx lr @return
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/***************************************************/
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/* division par 10 signé */
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/* Thanks to http://thinkingeek.com/arm-assembler-raspberry-pi/*
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/* and http://www.hackersdelight.org/ */
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/***************************************************/
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/* r0 dividende */
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/* r0 quotient */
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/* r1 remainder */
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divisionpar10:
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/* r0 contains the argument to be divided by 10 */
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push {r2-r4} @ save registers */
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mov r4,r0
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mov r3,#0x6667 @ r3 <- magic_number lower
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movt r3,#0x6666 @ r3 <- magic_number upper
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smull r1, r2, r3, r0 @ r1 <- Lower32Bits(r1*r0). r2 <- Upper32Bits(r1*r0)
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mov r2, r2, ASR #2 @ r2 <- r2 >> 2
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mov r1, r0, LSR #31 @ r1 <- r0 >> 31
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add r0, r2, r1 @ r0 <- r2 + r1
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add r2,r0,r0, lsl #2 @ r2 <- r0 * 5
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sub r1,r4,r2, lsl #1 @ r1 <- r4 - (r2 * 2) = r4 - (r0 * 10)
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pop {r2-r4}
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bx lr @ return
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