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Command-line arguments: Difference between revisions
Add task to ARM assembly Raspberry pi
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(Add task to ARM assembly Raspberry pi) |
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Line 98:
return (item 1 of argv)
end run
</lang>
=={{header|ARM Assembly}}==
{{works with|as|Raspberry Pi}}
<lang ARM Assembly>
/* ARM assembly Raspberry PI */
/* program commandLine.s */
/* Constantes */
.equ STDOUT, 1 @ Linux output console
.equ EXIT, 1 @ Linux syscall
.equ WRITE, 4 @ Linux syscall
/* Initialized data */
.data
szCarriageReturn: .asciz "\n"
/* UnInitialized data */
.bss
.align 4
/* code section */
.text
.global main
main: @ entry of program
push {fp,lr} @ saves registers
add fp,sp,#8 @ fp <- start address
ldr r4,[fp] @ number of Command line arguments
add r5,fp,#4 @ first parameter address
mov r2,#0 @ init loop counter
loop:
ldr r0,[r5,r2,lsl #2] @ string address parameter
bl affichageMess @ display string
ldr r0,iAdrszCarriageReturn
bl affichageMess @ display carriage return
add r2,#1 @ increment counter
cmp r2,r4 @ number parameters ?
blt loop @ loop
100: @ standard end of the program
mov r0, #0 @ return code
pop {fp,lr} @restaur registers
mov r7, #EXIT @ request to exit program
swi 0 @ perform the system call
iAdrszCarriageReturn: .int szCarriageReturn
/******************************************************************/
/* display text with size calculation */
/******************************************************************/
/* r0 contains the address of the message */
affichageMess:
push {r0,r1,r2,r7,lr} @ save registres
mov r2,#0 @ counter length
1: @ loop length calculation
ldrb r1,[r0,r2] @ read octet start position + index
cmp r1,#0 @ if 0 its over
addne r2,r2,#1 @ else add 1 in the length
bne 1b @ and loop
@ so here r2 contains the length of the message
mov r1,r0 @ address message in r1
mov r0,#STDOUT @ code to write to the standard output Linux
mov r7, #WRITE @ code call system "write"
svc #0 @ call systeme
pop {r0,r1,r2,r7,lr} @ restaur 2 registres
bx lr @ return
</lang>
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