user: Converte this assembly snippet into its equivalent C code:

```asm
<add>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  lea    -0x7000(%rsp),%r11
L32:
  sub    $0x1000,%rsp
  orq    $0x0,(%rsp)
  cmp    %r11,%rsp
  jne    L32
  sub    $0x548,%rsp
  pxor   %xmm0,%xmm0
  mov    %rdi,%r14
  mov    %rsi,%r13
  lea    0x10(%rsp),%rdi
  xor    %esi,%esi
  mov    %fs:0x28,%rax
  mov    %rax,0x7538(%rsp)
  xor    %eax,%eax
  mov    %rdx,%rbp
  mov    $0x2700,%edx
  movaps %xmm0,(%rsp)
  call   <memset@plt>
  pxor   %xmm0,%xmm0
  mov    $0x2700,%edx
  xor    %esi,%esi
  lea    0x2720(%rsp),%rdi
  movaps %xmm0,0x2710(%rsp)
  mov    %rsp,%r15
  call   <memset@plt>
  mov    %r14,%rdi
  call   <strlen@plt>
  mov    %r13,%rdi
  mov    %eax,%r12d
  call   <strlen@plt>
  mov    %r14,%rdi
  mov    %r15,%rsi
  lea    0x2710(%rsp),%r14
  mov    %eax,%ebx
  call   <rev@plt>
  mov    %r14,%rsi
  mov    %r13,%rdi
  call   <rev@plt>
  cmp    %ebx,%r12d
  cmovge %r12d,%ebx
  test   %ebx,%ebx
  jle    L30
  lea    -0x1(%rbx),%eax
  mov    %ebx,%r9d
  mov    %r15,%rcx
  mov    %r14,%rsi
  lea    0x4e20(%rsp),%r8
  lea    0x1(%rsp,%rax,1),%r10
  xor    %eax,%eax
  mov    %r8,%rdi
  jmp    L93
  nopl   0x0(%rax,%rax,1)
L25:
  movb   $0x30,(%rcx)
  movsbl %r11b,%edx
  sub    $0x30,%edx
L10:
  add    %eax,%edx
  add    $0x1,%rcx
  add    $0x1,%rsi
  add    $0x1,%rdi
  movslq %edx,%rax
  mov    %edx,%r11d
  imul   $0x66666667,%rax,%rax
  sar    $0x1f,%r11d
  sar    $0x22,%rax
  sub    %r11d,%eax
  mov    %edx,%r11d
  lea    (%rax,%rax,4),%ebx
  add    %ebx,%ebx
  sub    %ebx,%r11d
  add    $0x30,%r11d
  mov    %r11b,-0x1(%rdi)
  cmp    %r10,%rcx
  je     L23
L93:
  movsbl (%rcx),%edx
  movsbl (%rsi),%r11d
  test   %dl,%dl
  je     L25
  sub    $0x30,%edx
  test   %r11b,%r11b
  je     L70
  lea    -0x30(%r11,%rdx,1),%edx
  jmp    L10
  nopw   0x0(%rax,%rax,1)
L70:
  movb   $0x30,(%rsi)
  jmp    L10
  nopl   (%rax)
L23:
  cmp    $0x9,%edx
  jle    L19
  movslq %r9d,%rdx
  add    $0x30,%eax
  add    $0x1,%r9d
  mov    %al,0x4e20(%rsp,%rdx,1)
L19:
  movslq %r9d,%r9
  mov    %rbp,%rsi
  mov    %r8,%rdi
  movb   $0x0,0x4e20(%rsp,%r9,1)
  call   <rev@plt>
  mov    0x7538(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L14
  add    $0x7548,%rsp
  xor    %eax,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax)
L30:
  xor    %r9d,%r9d
  lea    0x4e20(%rsp),%r8
  jmp    L19
L14:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
int add(char *a, char *b, char *c) {
  char first[10000] = {}, second[10000] = {};
  char sumation[10000];
  int lens, lenf, tem, sum, carry, i;
  lenf = strlen(a);
  lens = strlen(b);
  rev(a, first);
  rev(b, second);
  if (lens > lenf)
    tem = lens;
  else
    tem = lenf;
  carry = 0;
  for (i = 0; i < tem; i++) {
    if (first[i] == '\0')
      first[i] = '0';
    else if (second[i] == '\0')
      second[i] = '0';
    sum = first[i] - '0' + second[i] - '0' + carry;
    sumation[i] = sum % 10 + '0';
    carry = sum / 10;
  }
  if (carry > 0) {
    sumation[i] = carry + '0';
    i++;
  }
  sumation[i] = '\0';
  rev(sumation, c);
  return 0;
}
```