user: 请将这段汇编代码片段转换成等效的C代码：

```asm
<tm_diffmonths>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  mov    %rdi,%r12
  push   %rbp
  mov    %rsi,%rbp
  push   %rbx
  sub    $0x28,%rsp
  movdqu 0x80(%rsp),%xmm2
  movdqu 0x90(%rsp),%xmm3
  movaps %xmm2,(%rsp)
  movaps %xmm3,0x10(%rsp)
  push   0x78(%rsp)
  push   0x78(%rsp)
  push   0x78(%rsp)
  push   0x78(%rsp)
  call   <tm_getrepresentation@plt>
  add    $0x20,%rsp
  push   0x98(%rsp)
  mov    %rax,%rbx
  push   0x98(%rsp)
  push   0x98(%rsp)
  push   0x98(%rsp)
  call   <tm_getrepresentation@plt>
  add    $0x20,%rsp
  cmp    %rax,%rbx
  je     L79
  mov    D18(%rip),%rax
  mov    (%rax),%edx
  mov    D3(%rip),%rax
  mov    %edx,(%rax)
  add    $0x28,%rsp
  xor    %eax,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax)
L79:
  push   0x98(%rsp)
  mov    $0x1,%ebx
  push   0x98(%rsp)
  push   0x98(%rsp)
  push   0x98(%rsp)
  push   0x98(%rsp)
  push   0x98(%rsp)
  push   0x98(%rsp)
  push   0x98(%rsp)
  call   <tm_diffseconds@plt>
  add    $0x40,%rsp
  test   %rax,%rax
  js     L103
L67:
  movdqa 0x10(%rsp),%xmm4
  movdqa (%rsp),%xmm5
  sub    $0x20,%rsp
  movhps %xmm4,0x30(%rsp)
  movq   %xmm4,%r14
  movq   %xmm5,%r13
  movhps %xmm5,0x20(%rsp)
  movups %xmm5,0xa0(%rsp)
  movups %xmm4,0xb0(%rsp)
  movups %xmm4,0x10(%rsp)
  movups %xmm5,(%rsp)
  push   0x98(%rsp)
  push   0x98(%rsp)
  push   0x98(%rsp)
  push   0x98(%rsp)
  call   <tm_diffcalendarmonths@plt>
  add    $0x40,%rsp
  mov    %eax,%r15d
  cmp    %r13,0x60(%rsp)
  jle    L101
L70:
  xor    %eax,%eax
  test   %r15d,%r15d
  setg   %al
  sub    %eax,%r15d
L1:
  test   %r12,%r12
  je     L58
  lea    0x60(%rsp),%rdi
  mov    %r15d,%esi
  call   <tm_addmonths@plt>
  push   0x98(%rsp)
  mov    %rbp,%rdi
  push   0x98(%rsp)
  push   0x98(%rsp)
  push   0x98(%rsp)
  push   0x98(%rsp)
  push   0x98(%rsp)
  push   0x98(%rsp)
  push   0x98(%rsp)
  call   <tm_diffdays@plt>
  add    $0x40,%rsp
  imul   %ebx,%eax
  mov    %eax,(%r12)
  test   %rbp,%rbp
  je     L58
  mov    0x0(%rbp),%eax
  imul   %ebx,%eax
  mov    %eax,0x0(%rbp)
L58:
  add    $0x28,%rsp
  mov    %ebx,%eax
  imul   %r15d,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax)
L101:
  jne    L1
  mov    (%rsp),%rax
  cmp    %rax,0x68(%rsp)
  jg     L70
  jne    L1
  cmp    %r14,0x70(%rsp)
  jg     L70
  jne    L1
  mov    0x10(%rsp),%rax
  cmp    %rax,0x78(%rsp)
  jle    L1
  jmp    L70
  nopl   0x0(%rax)
L103:
  movdqu 0x60(%rsp),%xmm0
  movdqa (%rsp),%xmm6
  mov    $0xffffffff,%ebx
  movdqu 0x70(%rsp),%xmm1
  movdqa 0x10(%rsp),%xmm7
  movups %xmm6,0x60(%rsp)
  movups %xmm7,0x70(%rsp)
  movaps %xmm1,0x10(%rsp)
  movaps %xmm0,(%rsp)
  jmp    L67
```

assistant: ```c
int tm_diffmonths(struct tm debut, struct tm fin, int *days, int *seconds) {
  if (tm_getrepresentation(debut) != tm_getrepresentation(fin)) {
    errno = EINVAL;
    return 0;
  }
  int coeff = 1;
  if (tm_diffseconds(debut, fin) < 0) {
    struct tm tmp = debut;
    debut = fin;
    fin = tmp;
    coeff = -1;
  }
  int ret = tm_diffcalendarmonths(debut, fin);
  if (fin.tm_mday < debut.tm_mday || (fin.tm_mday == debut.tm_mday && fin.tm_hour < debut.tm_hour) || (fin.tm_mday == debut.tm_mday && fin.tm_hour == debut.tm_hour && fin.tm_min < debut.tm_min) || (fin.tm_mday == debut.tm_mday && fin.tm_hour == debut.tm_hour && fin.tm_min == debut.tm_min && fin.tm_sec < debut.tm_sec))
    if (ret > 0)
      ret--;
  if (days) {
    tm_addmonths(&debut, ret);
    *days = coeff * tm_diffdays(debut, fin, seconds);
    if (seconds)
      *seconds *= coeff;
  }
  return coeff * ret;
}
```