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// 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(
#if defined(__APPLE__)
".globl _PushAllRegistersAndIterateStack \n"
".private_extern _PushAllRegistersAndIterateStack \n"
"_PushAllRegistersAndIterateStack: \n"
#else // !defined(__APPLE__)
".globl PushAllRegistersAndIterateStack \n"
#if !defined(_WIN64)
".type PushAllRegistersAndIterateStack, %function \n"
".hidden PushAllRegistersAndIterateStack \n"
#endif // !defined(_WIN64)
"PushAllRegistersAndIterateStack: \n"
#endif // !defined(__APPLE__)
// 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");
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