File content as of revision 0:13e4e935bed6:

 AREA    |.text|, CODE, READONLY
 EXPORT  binasm

binasm PROC
    PUSH {R4, LR}
    
    MOV R1, #0
    MOV R2, #0
    MOV R3, #0

    ; Load GPIO Port 1 base address in register R1 
    LDR     R1, =0x2009C020 ; 0x2009C020 = GPIO port 1 base address
    LDR     R4, =leds

    ;CLEAR LEDS
    MOV.W   R2, #0xB40000
    STR   R2, [R1,#0x1C]
    
    ADD R3, R3, #12 ; COUNTER FOR LOOP
    ADD R0, R0, #1  ; INCREMENT PARAMETER BY 1
    
loop
    ; CLEAR THE CARRY FLAG
    ADC R0, R0, #0

    LDR.W   R2, [R4, R3]
    LSRS R0, R0, #1  

    STRCC   R2, [R1,#0x1C]  ; if==0, clear LED bit
    STRCS   R2, [R1,#0x18]  ; if==1, set LED bit    

    CMP R3, #0
    SUB R3, R3, #4
    BNE loop
    
    POP {R4, PC}
    ENDP

 AREA |.data|, DATA, READWRITE
 EXPORT leds
         
;BIT MASK FOR LED1...LED4

leds DCD 0x040000 
     DCD 0x100000
     DCD 0x200000
     DCD 0x800000
    
    ALIGN
    END