65 lines
2.2 KiB
Plaintext
65 lines
2.2 KiB
Plaintext
/* ARM assembly Raspberry PI */
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/* program areaString.s */
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/* Constantes */
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@ The are no TRUE or FALSE constants in ARM Assembly
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.equ FALSE, 0 @ or other value
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.equ TRUE, 1 @ or other value
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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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szMessTrue: .asciz "The value is true.\n"
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szMessFalse: .asciz "The value is false.\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 r0,#0
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//mov r0,#1 @uncomment pour other test
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cmp r0,#TRUE
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bne 1f
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@ value true
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ldr r0,iAdrszMessTrue
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bl affichageMess
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b 100f
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1: @ value False
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ldr r0,iAdrszMessFalse
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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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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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iAdrszMessTrue: .int szMessTrue
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iAdrszMessFalse: .int szMessFalse
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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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