libc/src/setjmp/x86_64/longjmp.cpp

//===-- Implementation of longjmp -----------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "src/setjmp/longjmp.h"
#include "include/llvm-libc-macros/offsetof-macro.h"
#include "src/__support/common.h"
#include "src/__support/macros/config.h"

#if !defined(LIBC_TARGET_ARCH_IS_X86)
#error "Invalid file include"
#endif

namespace LIBC_NAMESPACE_DECL {

#ifdef __i386__
[[gnu::naked]]
LLVM_LIBC_FUNCTION(void, longjmp, (jmp_buf, int)) {
  asm(R"(
      mov 0x4(%%esp), %%ecx
      mov 0x8(%%esp), %%eax
      cmpl $0x1, %%eax
      adcl $0x0, %%eax

      mov %c[ebx](%%ecx), %%ebx
      mov %c[esi](%%ecx), %%esi
      mov %c[edi](%%ecx), %%edi
      mov %c[ebp](%%ecx), %%ebp
      mov %c[esp](%%ecx), %%esp

      jmp *%c[eip](%%ecx)
      )" ::[ebx] "i"(offsetof(__jmp_buf, ebx)),
      [esi] "i"(offsetof(__jmp_buf, esi)), [edi] "i"(offsetof(__jmp_buf, edi)),
      [ebp] "i"(offsetof(__jmp_buf, ebp)), [esp] "i"(offsetof(__jmp_buf, esp)),
      [eip] "i"(offsetof(__jmp_buf, eip)));
}
#else
[[gnu::naked]]
LLVM_LIBC_FUNCTION(void, longjmp, (jmp_buf, int)) {
  asm(R"(
      cmpl $0x1, %%esi
      adcl $0x0, %%esi
      movq %%rsi, %%rax

      movq %c[rbx](%%rdi), %%rbx
      movq %c[rbp](%%rdi), %%rbp
      movq %c[r12](%%rdi), %%r12
      movq %c[r13](%%rdi), %%r13
      movq %c[r14](%%rdi), %%r14
      movq %c[r15](%%rdi), %%r15
      movq %c[rsp](%%rdi), %%rsp
      jmpq *%c[rip](%%rdi)
      )" ::[rbx] "i"(offsetof(__jmp_buf, rbx)),
      [rbp] "i"(offsetof(__jmp_buf, rbp)), [r12] "i"(offsetof(__jmp_buf, r12)),
      [r13] "i"(offsetof(__jmp_buf, r13)), [r14] "i"(offsetof(__jmp_buf, r14)),
      [r15] "i"(offsetof(__jmp_buf, r15)), [rsp] "i"(offsetof(__jmp_buf, rsp)),
      [rip] "i"(offsetof(__jmp_buf, rip)));
}
#endif

} // namespace LIBC_NAMESPACE_DECL