164 lines
6.3 KiB
Plaintext
164 lines
6.3 KiB
Plaintext
/* ARM assembly Raspberry PI */
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/* program sleepAsm.s */
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/* Constantes */
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.equ STDIN, 0 @ Linux input console
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.equ STDOUT, 1 @ Linux output console
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.equ EXIT, 1 @ Linux syscall
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.equ READ, 3 @ Linux syscall
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.equ WRITE, 4 @ Linux syscall
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.equ SLEEP, 0xa2 @ Linux syscall
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.equ BUFFERSIZE, 100
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/* Initialized data */
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.data
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szMessQuest: .asciz "Enter the time to sleep in seconds : "
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szMessError: .asciz "Error occured.\n"
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szMessSleep: .asciz "Sleeping Zzzzzzz.\n"
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szMessAwake: .asciz "Awake!!!\n"
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szCarriageReturn: .asciz "\n"
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/* UnInitialized data */
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.bss
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.align 4
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ZonesAttente:
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iSecondes: .skip 4
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iMicroSecondes: .skip 4
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ZonesTemps: .skip 8
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sBuffer: .skip BUFFERSIZE
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/* code section */
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.text
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.global main
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main:
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ldr r0,iAdrszMessQuest @ display invite message
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bl affichageMess
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mov r0,#STDIN @ input standard linux
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ldr r1,iAdrsBuffer
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mov r2,#BUFFERSIZE
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mov r7,#READ @ read input string
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svc 0
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cmp r0,#0 @ read error ?
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ble 99f
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@
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ldr r0,iAdrsBuffer @ buffer address
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bl conversionAtoD @ conversion string in number in r0
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ldr r1,iAdriSecondes
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str r0,[r1] @ store second number in area
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ldr r0,iAdrszMessSleep @ display sleeping message
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bl affichageMess
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ldr r0,iAdrZonesAttente @ delay area
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ldr r1,iAdrZonesTemps @
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mov r7,#SLEEP @ call system SLEEP
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svc 0
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cmp r0,#0 @ error sleep ?
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blt 99f
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ldr r0,iAdrszMessAwake @ display awake message
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bl affichageMess
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mov r0, #0 @ return code
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b 100f
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99: @ display error message
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ldr r0,iAdrszMessError
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bl affichageMess
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mov r0, #1 @ return code
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100: @ standard end of the program
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mov r7, #EXIT @ request to exit program
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svc 0 @ perform system call
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iAdrszMessQuest: .int szMessQuest
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iAdrszMessError: .int szMessError
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iAdrszMessSleep: .int szMessSleep
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iAdrszMessAwake: .int szMessAwake
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iAdriSecondes: .int iSecondes
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iAdrZonesAttente: .int ZonesAttente
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iAdrZonesTemps: .int ZonesTemps
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iAdrsBuffer: .int sBuffer
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iAdrszCarriageReturn: .int szCarriageReturn
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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 registers
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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 system
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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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/* Convert a string to a number stored in a registry */
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/******************************************************************/
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/* r0 contains the address of the area terminated by 0 or 0A */
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/* r0 returns a number */
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conversionAtoD:
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push {fp,lr} @ save 2 registers
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push {r1-r7} @ save others registers
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mov r1,#0
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mov r2,#10 @ factor
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mov r3,#0 @ counter
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mov r4,r0 @ save address string -> r4
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mov r6,#0 @ positive sign by default
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mov r0,#0 @ initialization to 0
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1: /* early space elimination loop */
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ldrb r5,[r4,r3] @ loading in r5 of the byte located at the beginning + the position
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cmp r5,#0 @ end of string -> end routine
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beq 100f
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cmp r5,#0x0A @ end of string -> end routine
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beq 100f
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cmp r5,#' ' @ space ?
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addeq r3,r3,#1 @ yes we loop by moving one byte
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beq 1b
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cmp r5,#'-' @ first character is -
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moveq r6,#1 @ 1 -> r6
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beq 3f @ then move on to the next position
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2: /* beginning of digit processing loop */
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cmp r5,#'0' @ character is not a number
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blt 3f
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cmp r5,#'9' @ character is not a number
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bgt 3f
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/* character is a number */
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sub r5,#48
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ldr r1,iMaxi @ check the overflow of the register
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cmp r0,r1
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bgt 99f @ overflow error
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mul r0,r2,r0 @ multiply par factor 10
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add r0,r5 @ add to r0
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3:
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add r3,r3,#1 @ advance to the next position
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ldrb r5,[r4,r3] @ load byte
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cmp r5,#0 @ end of string -> end routine
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beq 4f
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cmp r5,#0x0A @ end of string -> end routine
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beq 4f
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b 2b @ loop
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4:
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cmp r6,#1 @ test r6 for sign
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moveq r1,#-1
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muleq r0,r1,r0 @ if negatif, multiply par -1
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b 100f
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99: /* overflow error */
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ldr r0,=szMessErrDep
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bl affichageMess
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mov r0,#0 @ return zero if error
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100:
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pop {r1-r7} @ restaur other registers
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pop {fp,lr} @ restaur 2 registers
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bx lr @return procedure
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/* constante program */
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iMaxi: .int 1073741824
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szMessErrDep: .asciz "Too large: overflow 32 bits.\n"
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.align 4
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