67 lines
2.3 KiB
Plaintext
67 lines
2.3 KiB
Plaintext
/* ARM assembly Raspberry PI */
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/* program loop1.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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/* Initialized data */
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.data
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szMessX: .asciz "X"
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szCarriageReturn: .asciz "\n"
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/* UnInitialized data */
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.bss
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/* code section */
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.text
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.global main
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main: /* entry of program */
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push {fp,lr} /* saves 2 registers */
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mov r2,#0 @ counter loop 1
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1: @ loop start 1
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mov r1,#0 @ counter loop 2
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2: @ loop start 2
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ldr r0,iAdrszMessX
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bl affichageMess
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add r1,#1 @ r1 + 1
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cmp r1,r2 @ compare r1 r2
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ble 2b @ loop label 2 before
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ldr r0,iAdrszCarriageReturn
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bl affichageMess
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add r2,#1 @ r2 + 1
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cmp r2,#5 @ for five loop
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blt 1b @ loop label 1 before
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100: /* standard end of the program */
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mov r0, #0 @ return code
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pop {fp,lr} @restaur 2 registers
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mov r7, #EXIT @ request to exit program
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swi 0 @ perform the system call
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iAdrszMessX: .int szMessX
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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 {fp,lr} /* save registres */
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push {r0,r1,r2,r7} /* save others 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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swi #0 /* call systeme */
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pop {r0,r1,r2,r7} /* restaur others registers */
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pop {fp,lr} /* restaur des 2 registres */
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bx lr /* return */
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