What does this Assembly snippet output?

1.global _main
2.align 2
3_main:
4    stp x29, x30, [sp, #-48]!
5    stp x19, x20, [sp, #16]
6    adrp x19, arr@PAGE
7    add x19, x19, arr@PAGEOFF
8    mov w20, #0
9    mov w9, #4
10loop:
11    cbz w9, done
12    ldrb w8, [x19], #1
13    add w20, w20, w8
14    sub w9, w9, #1
15    b loop
16done:
17    sub sp, sp, #16
18    str x20, [sp]
19    adrp x0, fmt@PAGE
20    add x0, x0, fmt@PAGEOFF
21    bl _printf
22    add sp, sp, #16
23    ldp x19, x20, [sp, #16]
24    ldp x29, x30, [sp], #48
25    mov w0, #0
26    ret
27.section __DATA,__data
28arr: .byte 3, 7, 11, 9
29.section __TEXT,__cstring
30fmt: .asciz "%d\n"