text: // Copyright 2020 the V8 project authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  // Push all callee-saved registers to get them on the stack for conservative
  // stack scanning.
  //
  // See asm/x64/push_registers_clang.cc for why the function is not generated
  // using clang.
  //
  // Do not depend on V8_TARGET_OS_* defines as some embedders may override the
  // GN toolchain (e.g. ChromeOS) and not provide them.
  
  // We maintain 16-byte alignment.
  //
  // Calling convention source:
  // https://en.wikipedia.org/wiki/Calling_convention#ARM_(A64)
  
  asm(".globl PushAllRegistersAndIterateStack             \n"
  #ifndef _WIN64
      ".type PushAllRegistersAndIterateStack, %function   \n"
      ".hidden PushAllRegistersAndIterateStack            \n"
  #endif
      "PushAllRegistersAndIterateStack:                   \n"
      // x19-x29 are callee-saved.
      "  stp x19, x20, [sp, #-16]!                        \n"
      "  stp x21, x22, [sp, #-16]!                        \n"
      "  stp x23, x24, [sp, #-16]!                        \n"
      "  stp x25, x26, [sp, #-16]!                        \n"
      "  stp x27, x28, [sp, #-16]!                        \n"
      "  stp fp, lr,   [sp, #-16]!                        \n"
      // Maintain frame pointer.
      "  mov fp, sp                                       \n"
      // Pass 1st parameter (x0) unchanged (Stack*).
      // Pass 2nd parameter (x1) unchanged (StackVisitor*).
      // Save 3rd parameter (x2; IterateStackCallback)
      "  mov x7, x2                                       \n"
      // Pass 3rd parameter as sp (stack pointer).
      "  mov x2, sp                                       \n"
      "  blr x7                                           \n"
      // Load return address.
      "  ldr lr, [sp, #8]                                 \n"
      // Restore frame pointer and pop all callee-saved registers.
      "  ldr fp, [sp], #96                                \n"
      "  ret                                              \n");
  