ARM asm "hello"

hello.s

// hello world example
// llvm ARM assembly
//
// https://developer.apple.com/library/ios/documentation/Xcode/Conceptual/iPhoneOSABIReference/iPhoneOSABIReference.pdf
// http://www.opensource.apple.com/source/xnu/xnu-2782.1.97//bsd/kern/syscalls.master
//
// void p();

.data
message:
    .ascii  "hello\n"

#ifndef __aarch64__             // assembler-with-cpp

.text
.global _p
.align 4
_p:
    push    {r4-r7, lr}         // save LR, R7, R4-R6
    add     r7, sp, #12         // adjust R7 to point to saved R7
    push    {r8, r10, r11}      // save remaining GPRs (R8, R10, R11)
    sub     sp, sp, #36         // allocate space for local storage
    vpush   {q4-q7}             // save NEON registers

    mov     ip, #4              // syscall for write
    mov     r0, #1              // stdout fd
    ldr     r1, =message
    mov     r2, #6              // length of message
    swi     #0                  // or svc 0x80

    vpop    {q4-q7}             // restore NEON registers
    add     sp, sp, #36         // deallocate space for local storage
    pop     {r8, r10, r11}      // restore R8-R11
    pop     {r4-r7, pc}         // restore R4-R6, saved R7, return to saved LR

#endif