gistfile1.txt

#include <atomic>

class SpinLock {
    std::atomic_flag locked = ATOMIC_FLAG_INIT ;
public:
    void lock() {
        while (locked.test_and_set(std::memory_order_acquire)) { ; }
    }
    void unlock() {
        locked.clear(std::memory_order_release);
    }
};

int main() {
    SpinLock l;
    l.lock();
    l.unlock();
}

gistfile2.txt

std::operator&(std::memory_order, std::__memory_order_modifier):
  sub sp, sp, #16
  str w0, [sp, 12]
  str w1, [sp, 8]
  ldr w1, [sp, 12]
  ldr w0, [sp, 8]
  and w0, w1, w0
  add sp, sp, 16
  ret
SpinLock::lock():
  sub sp, sp, #32
  str x0, [sp, 8]
.L6:
  ldr x0, [sp, 8]
  str x0, [sp, 24]
  mov w0, 2
  str w0, [sp, 20]
  ldr x0, [sp, 24]
  mov w1, 1
.L8:
  ldaxrb w2, [x0]
  stlxrb w3, w1, [x0]
  cbnz w3, .L8
  uxtb w0, w2
  cmp w0, 0
  beq .L7
  b .L6
.L7:
  nop
  add sp, sp, 32
  ret
SpinLock::unlock():
  stp x29, x30, [sp, -48]!
  add x29, sp, 0
  str x0, [x29, 24]
  ldr x0, [x29, 24]
  str x0, [x29, 40]
  mov w0, 3
  str w0, [x29, 36]
  mov w1, 65535
  ldr w0, [x29, 36]
  bl std::operator&(std::memory_order, std::__memory_order_modifier)
  str w0, [x29, 32]
  ldr x0, [x29, 40]
  stlrb wzr, [x0]
  nop
  ldp x29, x30, [sp], 48
  ret
main:
  stp x29, x30, [sp, -32]!
  add x29, sp, 0
  strb wzr, [x29, 24]
  add x0, x29, 24
  bl SpinLock::lock()
  add x0, x29, 24
  bl SpinLock::unlock()
  mov w0, 0
  ldp x29, x30, [sp], 32
  ret