user: 请将这段汇编代码片段转换成等效的C代码:

```asm
<long_add>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %rbx
  sub    $0x1000,%rsp
  orq    $0x0,(%rsp)
  sub    $0xf98,%rsp
  mov    %rdi,-0x1f98(%rbp)
  mov    %rsi,-0x1fa0(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x18(%rbp)
  xor    %eax,%eax
  lea    -0x1f70(%rbp),%rdx
  mov    $0x0,%eax
  mov    $0x1f4,%ecx
  mov    %rdx,%rdi
  rep stos %rax,%es:(%rdi)
  mov    %rdi,%rdx
  mov    %eax,(%rdx)
  add    $0x4,%rdx
  lea    -0xfc0(%rbp),%rdx
  mov    $0x0,%eax
  mov    $0x1f4,%ecx
  mov    %rdx,%rdi
  rep stos %rax,%es:(%rdi)
  mov    %rdi,%rdx
  mov    %eax,(%rdx)
  add    $0x4,%rdx
  movl   $0x0,-0x1f90(%rbp)
  mov    -0x1f98(%rbp),%rax
  mov    %rax,%rdi
  call   <strlen@plt>
  mov    %eax,-0x1f88(%rbp)
  mov    -0x1fa0(%rbp),%rax
  mov    %rax,%rdi
  call   <strlen@plt>
  mov    %eax,-0x1f84(%rbp)
  mov    $0x1,%esi
  mov    $0x3e9,%edi
  call   <calloc@plt>
  mov    %rax,-0x1f78(%rbp)
  cmpl   $0x9,-0x1f88(%rbp)
  jg     L52
  cmpl   $0x9,-0x1f84(%rbp)
  jg     L52
  mov    -0x1f98(%rbp),%rax
  mov    %rax,%rdi
  call   <atol@plt>
  mov    %rax,%rbx
  mov    -0x1fa0(%rbp),%rax
  mov    %rax,%rdi
  call   <atol@plt>
  lea    (%rbx,%rax,1),%rcx
  mov    -0x1f78(%rbp),%rax
  mov    $0xa,%edx
  mov    %rax,%rsi
  mov    %rcx,%rdi
  call   <itoa@plt>
  mov    -0x1f78(%rbp),%rax
  jmp    L8
L52:
  mov    -0x1f84(%rbp),%edx
  mov    -0x1f88(%rbp),%eax
  cmp    %eax,%edx
  cmovge %edx,%eax
  mov    %eax,-0x1f80(%rbp)
  lea    -0x1f70(%rbp),%rcx
  mov    -0x1f98(%rbp),%rax
  mov    $0x3e9,%edx
  mov    %rcx,%rsi
  mov    %rax,%rdi
  call   <str_to_revi@plt>
  lea    -0xfc0(%rbp),%rcx
  mov    -0x1fa0(%rbp),%rax
  mov    $0x3e9,%edx
  mov    %rcx,%rsi
  mov    %rax,%rdi
  call   <str_to_revi@plt>
  movl   $0x0,-0x1f8c(%rbp)
  jmp    L0
L46:
  mov    -0x1f8c(%rbp),%eax
  cltq
  mov    -0x1f70(%rbp,%rax,4),%edx
  mov    -0x1f8c(%rbp),%eax
  cltq
  mov    -0xfc0(%rbp,%rax,4),%eax
  add    %eax,%edx
  mov    -0x1f90(%rbp),%eax
  add    %edx,%eax
  mov    %eax,-0x1f7c(%rbp)
  cmpl   $0x9,-0x1f7c(%rbp)
  setg   %al
  movzbl %al,%eax
  mov    %eax,-0x1f90(%rbp)
  mov    -0x1f7c(%rbp),%edx
  movslq %edx,%rax
  imul   $0x66666667,%rax,%rax
  shr    $0x20,%rax
  sar    $0x2,%eax
  mov    %edx,%esi
  sar    $0x1f,%esi
  sub    %esi,%eax
  mov    %eax,%ecx
  mov    %ecx,%eax
  shl    $0x2,%eax
  add    %ecx,%eax
  add    %eax,%eax
  mov    %edx,%ecx
  sub    %eax,%ecx
  mov    %ecx,%eax
  lea    0x30(%rax),%ecx
  mov    -0x1f8c(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x1f78(%rbp),%rax
  add    %rdx,%rax
  mov    %ecx,%edx
  mov    %dl,(%rax)
  addl   $0x1,-0x1f8c(%rbp)
L0:
  mov    -0x1f8c(%rbp),%eax
  cmp    -0x1f80(%rbp),%eax
  jl     L46
  cmpl   $0x0,-0x1f90(%rbp)
  je     L1
  mov    -0x1f8c(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x1f78(%rbp),%rax
  add    %rdx,%rax
  movb   $0x31,(%rax)
L1:
  mov    -0x1f78(%rbp),%rax
  mov    %rax,%rdi
  call   <strrev@plt>
L8:
  mov    -0x18(%rbp),%rdx
  sub    %fs:0x28,%rdx
  je     L30
  call   <__stack_chk_fail@plt>
L30:
  mov    -0x8(%rbp),%rbx
  leave
  ret
```

assistant: ```c
char *long_add(char *op1, char *op2) {
  char *buf;
  int rev_op1[1001] = {0}, rev_op2[1001] = {0};
  int len1, len2;
  int state = 0;
  int i;
  len1 = strlen(op1);
  len2 = strlen(op2);
  buf = (char *)calloc(1001, sizeof(char));
  if (len1 < 10 && len2 < 10) {
    itoa(atol(op1) + atol(op2), buf, 10);
  } else {
    int max_len = (len1 > len2 ? len1 : len2);
    str_to_revi(op1, rev_op1, 1001);
    str_to_revi(op2, rev_op2, 1001);
    for (i = 0; i < max_len; i++) {
      int sum = rev_op1[i] + rev_op2[i] + state;
      state = (sum >= 10 ? 1 : 0);
      buf[i] = sum % 10 + '0';
    }
    if (state)
      buf[i] = '1';
    return strrev(buf);
  }
  return buf;
}
```