libnx/crt0/switch_crt0.s

.section ".crt0","ax"
.global _start

_start:
    bl startup
    .ascii "HOMEBREW"

startup:
    // get aslr base
    sub  x28, x30, #4

    // clear .bss
    adrp x0, __bss_start__
    adrp x1, __bss_end__
    add  x0, x0, #:lo12:__bss_start__
    add  x1, x1, #:lo12:__bss_end__
    sub  x1, x1, x0  // calculate size
    add  x1, x1, #7  // round up to 8
    bic  x1, x1, #7

bss_loop: 
    str  xzr, [x0], #8
    subs x1, x1, #8
    bne  bss_loop

    // process .dynamic section
    mov  x0, x28
    adrp x1, _DYNAMIC
    add  x1, x1, #:lo12:_DYNAMIC
    bl   __nx_dynamic

    // initialize system
    mov  x0, x28
    bl   __nx_init

    // call entrypoint
    mov  x0, #0 // argc
    mov  x1, #0 // argv
    adrp x30, __nx_exit
    add  x30, x30, #:lo12:__nx_exit
    b    main