user: 下面的汇编指令对应的C源代码是什么：

```asm
<hotp>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %rbx
  sub    $0x78,%rsp
  mov    %rdi,-0x68(%rbp)
  mov    %rsi,-0x70(%rbp)
  mov    %edx,-0x74(%rbp)
  mov    %ecx,-0x78(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x18(%rbp)
  xor    %eax,%eax
  mov    %rsp,%rax
  mov    %rax,%rbx
  movl   $0x8,-0x60(%rbp)
  jmp    L76
L26:
  mov    -0x60(%rbp),%eax
  cltq
  mov    -0x74(%rbp),%edx
  mov    %edx,-0x40(%rbp,%rax,4)
  sarl   $0x8,-0x74(%rbp)
L76:
  mov    -0x60(%rbp),%eax
  lea    -0x1(%rax),%edx
  mov    %edx,-0x60(%rbp)
  test   %eax,%eax
  jg     L26
  mov    D13(%rip),%rax
  mov    (%rax),%eax
  movslq %eax,%rdx
  sub    $0x1,%rdx
  mov    %rdx,-0x50(%rbp)
  movslq %eax,%rdx
  mov    %rdx,%r10
  mov    $0x0,%r11d
  movslq %eax,%rdx
  mov    %rdx,%r8
  mov    $0x0,%r9d
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    $0x10,%eax
  sub    $0x1,%rax
  add    %rdx,%rax
  mov    $0x10,%esi
  mov    $0x0,%edx
  div    %rsi
  imul   $0x10,%rax,%rax
  mov    %rax,%rcx
  and    $0xfffffffffffff000,%rcx
  mov    %rsp,%rdx
  sub    %rcx,%rdx
L61:
  cmp    %rdx,%rsp
  je     L42
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L61
L42:
  mov    %rax,%rdx
  and    $0xfff,%edx
  sub    %rdx,%rsp
  mov    %rax,%rdx
  and    $0xfff,%edx
  test   %rdx,%rdx
  je     L43
  and    $0xfff,%eax
  sub    $0x8,%rax
  add    %rsp,%rax
  orq    $0x0,(%rax)
L43:
  mov    %rsp,%rax
  add    $0x3,%rax
  shr    $0x2,%rax
  shl    $0x2,%rax
  mov    %rax,-0x48(%rbp)
  mov    $0x0,%eax
  call   <EVP_sha1@plt>
  mov    %eax,%edi
  mov    -0x48(%rbp),%rsi
  lea    -0x40(%rbp),%rcx
  mov    -0x70(%rbp),%rdx
  mov    -0x68(%rbp),%rax
  sub    $0x8,%rsp
  push   $0x0
  mov    %rsi,%r9
  mov    $0x8,%r8d
  mov    %rax,%rsi
  call   <HMAC@plt>
  add    $0x10,%rsp
  mov    D13(%rip),%rax
  mov    (%rax),%eax
  lea    -0x1(%rax),%edx
  mov    -0x48(%rbp),%rax
  movslq %edx,%rdx
  mov    (%rax,%rdx,4),%eax
  and    $0xf,%eax
  mov    %eax,-0x54(%rbp)
  movl   $0x0,-0x5c(%rbp)
  movl   $0x0,-0x58(%rbp)
  jmp    L53
L3:
  shll   $0x8,-0x5c(%rbp)
  mov    -0x54(%rbp),%edx
  mov    -0x58(%rbp),%eax
  add    %eax,%edx
  mov    -0x48(%rbp),%rax
  movslq %edx,%rdx
  mov    (%rax,%rdx,4),%eax
  or     %eax,-0x5c(%rbp)
  addl   $0x1,-0x58(%rbp)
L53:
  cmpl   $0x3,-0x58(%rbp)
  jle    L3
  andl   $0x7fffffff,-0x5c(%rbp)
  mov    -0x78(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  lea    D5(%rip),%rax
  mov    (%rdx,%rax,1),%ecx
  mov    -0x5c(%rbp),%eax
  cltd
  idiv   %ecx
  mov    %edx,%eax
  mov    %rbx,%rsp
  mov    -0x18(%rbp),%rdx
  sub    %fs:0x28,%rdx
  je     L77
  call   <__stack_chk_fail@plt>
L77:
  mov    -0x8(%rbp),%rbx
  leave
  ret
```

assistant: ```c
int32_t hotp(const uint8_t *K, const size_t Klen, uint64_t C, const int digits) {
  uint8_t counter[8];
  for (int i = 8; i-- > 0;) {
    counter[i] = C;
    C >>= 8;
  }
  uint8_t hash[SHA_DIGEST_LENGTH];
  HMAC(EVP_sha1(), K, Klen, counter, 8, hash, NULL);
  int offset = hash[SHA_DIGEST_LENGTH - 1] & 0x0F;
  uint32_t value = 0;
  for (int i = 0; i < 4; ++i) {
    value <<= 8;
    value |= hash[offset + i];
  }
  value &= 0x7FFFFFFF;
  static uint32_t pow10[10] = {1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000};
  return value % pow10[digits];
}
```