161 lines
4.9 KiB
Plaintext
161 lines
4.9 KiB
Plaintext
/* ARM assembly Raspberry PI */
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/* program rot13.s */
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/* for constantes see task include a file in arm assembly */
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/************************************/
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/* Constantes */
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/************************************/
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.include "../constantes.inc"
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.equ STRINGSIZE, 500
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/************************************/
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/* Initialized data */
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/************************************/
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.data
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szMessString: .asciz "String :\n"
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szMessEncrip: .asciz "\nEncrypted :\n"
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szMessDecrip: .asciz "\nDecrypted :\n"
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szString1: .asciz "{NOWHERE! abcd xyz 1234}"
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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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szString2: .skip STRINGSIZE
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szString3: .skip STRINGSIZE
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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:
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ldr r0,iAdrszMessString @ display message
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bl affichageMess
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ldr r0,iAdrszString1 @ display string
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bl affichageMess
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ldr r0,iAdrszString1
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ldr r1,iAdrszString2
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bl encryptRot13
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ldr r0,iAdrszMessEncrip
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bl affichageMess
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ldr r0,iAdrszString2 @ display string
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bl affichageMess
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ldr r0,iAdrszString2
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ldr r1,iAdrszString3
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bl decryptRot13
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ldr r0,iAdrszMessDecrip
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bl affichageMess
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ldr r0,iAdrszString3 @ display string
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bl affichageMess
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ldr r0,iAdrszCarriageReturn
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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 system call
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iAdrszMessString: .int szMessString
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iAdrszMessDecrip: .int szMessDecrip
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iAdrszMessEncrip: .int szMessEncrip
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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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iAdrszCarriageReturn: .int szCarriageReturn
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/******************************************************************/
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/* encrypt strings */
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/******************************************************************/
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/* r0 contains the address of the string1 */
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/* r1 contains the address of the encrypted string */
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encryptRot13:
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push {r3,r4,lr} @ save registers
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mov r3,#0 @ counter byte string 1
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mov r2,#13 @ rot characters number
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1:
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ldrb r4,[r0,r3] @ load byte string 1
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cmp r4,#0 @ zero final ?
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streqb r4,[r1,r3]
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moveq r0,r3
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beq 100f
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cmp r4,#65 @ < A ?
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strltb r4,[r1,r3]
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addlt r3,#1
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blt 1b
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cmp r4,#90 @ > Z
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bgt 2f
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add r4,r2 @ add key
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cmp r4,#90 @ > Z
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subgt r4,#26
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strb r4,[r1,r3]
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add r3,#1
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b 1b
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2:
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cmp r4,#97 @ < a ?
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strltb r4,[r1,r3]
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addlt r3,#1
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blt 1b
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cmp r4,#122 @> z
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strgtb r4,[r1,r3]
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addgt r3,#1
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bgt 1b
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add r4,r2
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cmp r4,#122
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subgt r4,#26
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strb r4,[r1,r3]
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add r3,#1
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b 1b
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100:
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pop {r3,r4,lr} @ restaur registers
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bx lr @ return
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/******************************************************************/
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/* decrypt strings */
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/******************************************************************/
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/* r0 contains the address of the encrypted string1 */
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/* r1 contains the address of the decrypted string */
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decryptRot13:
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push {r3,r4,lr} @ save registers
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mov r3,#0 @ counter byte string 1
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mov r2,#13 @ rot characters number
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1:
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ldrb r4,[r0,r3] @ load byte string 1
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cmp r4,#0 @ zero final ?
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streqb r4,[r1,r3]
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moveq r0,r3
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beq 100f
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cmp r4,#65 @ < A ?
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strltb r4,[r1,r3]
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addlt r3,#1
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blt 1b
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cmp r4,#90 @ > Z
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bgt 2f
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sub r4,r2 @ substract key
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cmp r4,#65 @ < A
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addlt r4,#26
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strb r4,[r1,r3]
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add r3,#1
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b 1b
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2:
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cmp r4,#97 @ < a ?
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strltb r4,[r1,r3]
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addlt r3,#1
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blt 1b
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cmp r4,#122 @ > z
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strgtb r4,[r1,r3]
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addgt r3,#1
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bgt 1b
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sub r4,r2 @ substract key
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cmp r4,#97 @ < a
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addlt r4,#26
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strb r4,[r1,r3]
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add r3,#1
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b 1b
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100:
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pop {r3,r4,lr} @ restaur registers
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bx lr @ return
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/***************************************************/
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/* ROUTINES INCLUDE */
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/***************************************************/
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/* for this file see task include a file in language ARM assembly*/
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.include "../affichage.inc"
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