.macro EXIT_
        mov    r0, $0          @ Return code
        mov    r7, $1          @ sys_exit
        svc    0x00000000
.endm

.macro GETCHAR
        mov     r0, $0          @ stdin
        ldr     r1, =in_ch      @ Address
        mov     r2, $1          @ length
        mov     r7, $3          @ sys_read
        svc     0x00000000
.endm

.macro PUTCHAR
        mov   r7, $4
        mov   r0, $1
        ldr   r1, =out_ch
        str   r2, [r1]
        mov   r2, $1
        svc   0x00000000
.endm
