user: 提供的汇编代码用C语言表示会是什么样子：

```asm
<des_encrypt>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x38,%rsp
  mov    %esi,%r13d
  mov    %fs:0x28,%rax
  mov    %rax,0x28(%rsp)
  xor    %eax,%eax
  test   %rdx,%rdx
  je     L1
  mov    %rdi,%r12
  mov    %rdx,%r15
  lea    -0x1(%rsi),%edx
  mov    %edx,%eax
  sar    $0x1f,%eax
  shr    $0x1d,%eax
  add    %eax,%edx
  and    $0x7,%edx
  sub    %edx,%eax
  lea    0x8(%rax),%eax
  cltd
  shr    $0x1d,%edx
  lea    (%rax,%rdx,1),%ebx
  and    $0x7,%ebx
  sub    %edx,%ebx
  lea    (%rbx,%rsi,1),%eax
  cmp    $0x106,%eax
  jg     L9
  lea    0x19(%rsp),%rdi
  mov    %ebx,%esi
  mov    $0x0,%eax
  call   <des_random_get@plt>
  test   %ebx,%ebx
  jle    L38
  lea    0x1(%r13),%esi
  movslq %esi,%rsi
  mov    %rsi,%rdx
  mov    $0x0,%eax
  mov    $0x1,%ecx
  sub    %esi,%ecx
L106:
  mov    %edx,%r13d
  cltq
  movzbl 0x19(%rsp,%rax,1),%eax
  mov    %al,-0x1(%r12,%rdx,1)
  lea    (%rcx,%rdx,1),%eax
  cwtl
  add    $0x1,%rdx
  cmp    %eax,%ebx
  jg     L106
L38:
  cmp    $0x2,%r13d
  jle    L105
  mov    $0x2,%eax
  mov    $0x0,%edx
L108:
  movswq %ax,%rcx
  xor    (%r12,%rcx,1),%dl
  add    $0x1,%eax
  movswl %ax,%ecx
  cmp    %r13d,%ecx
  jl     L108
  lea    0x1(%r13),%ebx
  mov    %ebx,0xc(%rsp)
  movslq %r13d,%rax
  mov    %dl,(%r12,%rax,1)
  lea    0x20(%rsp),%rdi
  mov    $0x8,%esi
  mov    $0x0,%eax
  call   <des_random_get@plt>
  movslq %ebx,%rax
  mov    0x20(%rsp),%rdx
  mov    %rdx,(%r12,%rax,1)
L0:
  mov    $0x2,%r14d
  mov    $0x2,%eax
  lea    0x28(%rsp),%rbx
  jmp    L73
L105:
  lea    0x1(%r13),%edi
  mov    %edi,%ebx
  mov    %edi,0xc(%rsp)
  movslq %r13d,%rax
  movb   $0x0,(%r12,%rax,1)
  lea    0x20(%rsp),%rdi
  mov    $0x8,%esi
  mov    $0x0,%eax
  call   <des_random_get@plt>
  movslq %ebx,%rax
  mov    0x20(%rsp),%rdx
  mov    %rdx,(%r12,%rax,1)
  cmp    $0x2,%ebx
  jg     L0
L101:
  lea    0x9(%r13),%eax
L107:
  mov    0x28(%rsp),%rdx
  sub    %fs:0x28,%rdx
  jne    L123
  add    $0x38,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L27:
  movswq %r14w,%rbp
  add    %r12,%rbp
  lea    0x8(%r15),%rsi
  mov    %rbp,%r8
  mov    $0x1,%ecx
  mov    $0x3,%edx
  mov    %r15,%rdi
  mov    $0x0,%eax
  call   <EuroDes@plt>
  mov    0x0(%rbp),%rax
  mov    %rax,0x20(%rsp)
  add    $0x8,%r14d
  movswl %r14w,%eax
  cmp    0xc(%rsp),%eax
  jge    L101
L73:
  cltq
  add    %r12,%rax
  lea    0x20(%rsp),%rdx
L20:
  movzbl (%rdx),%ecx
  xor    %cl,(%rax)
  add    $0x1,%rax
  add    $0x1,%rdx
  cmp    %rbx,%rdx
  jne    L20
  jmp    L27
L1:
  mov    %esi,%eax
  jmp    L107
L9:
  mov    $0xffffffff,%eax
  jmp    L107
L123:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
int des_encrypt(unsigned char *buffer, int len, unsigned char *deskey) {
  unsigned char checksum = 0;
  unsigned char noPadBytes;
  unsigned char padBytes[7];
  char ivec[8];
  short i;
  if (!deskey)
    return len;
  noPadBytes = (8 - ((len - 1) % 8)) % 8;
  if (len + noPadBytes + 1 >= 272 - 8)
    return -1;
  des_random_get(padBytes, noPadBytes);
  for (i = 0; i < noPadBytes; i++)
    buffer[len++] = padBytes[i];
  for (i = 2; i < len; i++)
    checksum ^= buffer[i];
  buffer[len++] = checksum;
  des_random_get((unsigned char *)ivec, 8);
  memcpy(buffer + len, ivec, 8);
  for (i = 2; i < len; i += 8) {
    unsigned char j;
    const unsigned char flags = (1 << 0) | (1 << 1);
    for (j = 0; j < 8; j++)
      buffer[i + j] ^= ivec[j];
    EuroDes(deskey, deskey + 8, flags, 1, buffer + i);
    memcpy(ivec, buffer + i, 8);
  }
  len += 8;
  return len;
}
```