ARM7 assembly program Sort integers

integer-sort.s

@@@ OPEN INPUT FILE, READ INTEGER FROM FILE, PRINT IT, CLOSE INPUT FILE
.equ SWI_Open, 0x66      @open a file
.equ SWI_Close,0x68     @close a file
.equ SWI_PrChr,0x00     @ Write an ASCII char to Stdout
.equ SWI_PrStr, 0x69     @ Write a null-ending string
.equ SWI_PrInt,0x6b     @ Write an Integer
.equ SWI_RdInt,0x6c     @ Read an Integer from a file
.equ Stdout, 1           @ Set output target to be Stdout
.equ SWI_Exit, 0x11      @ Stop execution
.global _start
.text

_start:

@ == Open an input file for reading =============================
@ if problems, print message to Stdout and exit
ldr r0,=InFileName  @ set Name for input file
mov r1,#0           @ mode is input
swi SWI_Open        @ open file for input
bcs InFileError     @ Check Carry-Bit (C): if= 1 then ERROR

@ Save the file handle in memory:
ldr r1,=InFileHandle     @ if OK, load input file handle
str r0,[r1]                 @ save the file handle

@ == Read integers until end of file ============================= RLoop:
RLoop:
    ldr r0,=InFileHandle @ load input file handle
    ldr r0,[r0]
    swi SWI_RdInt   @ read the integer into R0
    bcs EofReached  @ Check Carry-Bit (C): if= 1 then EOF reached
    @ print the integer to Stdout
    mov r1,r0       @ R1 = integer to print
    mov R0,#Stdout
    swi SWI_PrInt
    mov R0,#Stdout  @ print new line
    ldr r1, =NL
    swi SWI_PrStr
bal RLoop



@ keep reading till end of file
@ == End of file ===============================================
EofReached:
mov R0, #Stdout @ print last message ldr R1, =EndOfFileMsg
swi SWI_PrStr
@ == Close a file ===============================================
ldr R0, =InFileHandle
ldr R0, [R0]
swi SWI_Close
@================================================================
Exit: 
swi SWI_Exit            @ stop executing 
InFileError: 
mov R0, #Stdout 
ldr R1, =FileOpenInpErrMsg 
swi SWI_PrStr 
bal Exit                @ give up, go to end
@================================================================
.data 
.align
Array: .skip 20 * 4
InFileHandle:       .skip       4 
InFileName:         .asciz      "input.txt"
FileOpenInpErrMsg:  .asciz      "Failed to open input file \n" 
EndOfFileMsg:       .asciz      "End of file reached\n" 
ColonSpace:         .asciz": " 
NL:             .asciz      "\n "   @ new line
.end