user: 下面的汇编指令对应的C源代码是什么：

```asm
<css_decode>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x40,%rsp
  mov    %rdi,-0x38(%rbp)
  mov    %rsi,-0x40(%rbp)
  mov    -0x38(%rbp),%rax
  mov    %rax,-0x20(%rbp)
  cmpq   $0x0,-0x38(%rbp)
  jne    L1
  mov    $0xffffffff,%eax
  jmp    L106
L1:
  movq   $0x0,-0x8(%rbp)
  mov    -0x8(%rbp),%rax
  mov    %rax,-0x18(%rbp)
  jmp    L189
L229:
  mov    -0x18(%rbp),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x5c,%al
  jne    L289
  mov    -0x18(%rbp),%rax
  add    $0x1,%rax
  cmp    %rax,-0x40(%rbp)
  jle    L0
  addq   $0x1,-0x18(%rbp)
  movq   $0x0,-0x10(%rbp)
  jmp    L83
L197:
  addq   $0x1,-0x10(%rbp)
L83:
  cmpq   $0x5,-0x10(%rbp)
  jg     L188
  mov    -0x18(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  cmp    %rax,-0x40(%rbp)
  jle    L188
  mov    -0x18(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x2f,%al
  jbe    L385
  mov    -0x18(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x39,%al
  jbe    L197
L385:
  mov    -0x18(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x60,%al
  jbe    L371
  mov    -0x18(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x66,%al
  jbe    L197
L371:
  mov    -0x18(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x40,%al
  jbe    L188
  mov    -0x18(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x46,%al
  jbe    L197
L188:
  cmpq   $0x0,-0x10(%rbp)
  jle    L167
  movl   $0x0,-0x24(%rbp)
  cmpq   $0x6,-0x10(%rbp)
  ja     L156
  mov    -0x10(%rbp),%rax
  lea    0x0(,%rax,4),%rdx
  lea    D3(%rip),%rax
  mov    (%rdx,%rax,1),%eax
  cltq
  lea    D3(%rip),%rdx
  add    %rdx,%rax
  notrack jmp *%rax
  mov    -0x18(%rbp),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdi
  call   <xsingle2c@plt>
  mov    %eax,%ecx
  mov    -0x20(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x20(%rbp)
  mov    %ecx,%edx
  mov    %dl,(%rax)
  jmp    L156
  mov    -0x18(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  lea    -0x2(%rax),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdi
  call   <x2c@plt>
  mov    %rax,%rcx
  mov    -0x20(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x20(%rbp)
  mov    %ecx,%edx
  mov    %dl,(%rax)
  jmp    L156
  mov    -0x18(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  lea    -0x2(%rax),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdi
  call   <x2c@plt>
  mov    %eax,%edx
  mov    -0x20(%rbp),%rax
  mov    %dl,(%rax)
  movl   $0x1,-0x24(%rbp)
  jmp    L156
  mov    -0x18(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  lea    -0x2(%rax),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdi
  call   <x2c@plt>
  mov    %eax,%edx
  mov    -0x20(%rbp),%rax
  mov    %dl,(%rax)
  mov    -0x18(%rbp),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x30,%al
  jne    L142
  movl   $0x1,-0x24(%rbp)
  jmp    L156
L142:
  addq   $0x1,-0x20(%rbp)
  jmp    L156
  mov    -0x18(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  lea    -0x2(%rax),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdi
  call   <x2c@plt>
  mov    %eax,%edx
  mov    -0x20(%rbp),%rax
  mov    %dl,(%rax)
  mov    -0x18(%rbp),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x30,%al
  jne    L177
  mov    -0x18(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x30,%al
  jne    L177
  movl   $0x1,-0x24(%rbp)
  jmp    L4
L177:
  addq   $0x1,-0x20(%rbp)
L4:
  nop
L156:
  cmpl   $0x0,-0x24(%rbp)
  je     L221
  mov    -0x20(%rbp),%rax
  movzbl (%rax),%eax
  test   %al,%al
  je     L232
  mov    -0x20(%rbp),%rax
  movzbl (%rax),%eax
  cmp    $0x5e,%al
  ja     L232
  mov    -0x18(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  lea    -0x3(%rax),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x66,%al
  je     L370
  mov    -0x18(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  lea    -0x3(%rax),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x46,%al
  jne    L232
L370:
  mov    -0x18(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  lea    -0x4(%rax),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x66,%al
  je     L373
  mov    -0x18(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  lea    -0x4(%rax),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x46,%al
  jne    L232
L373:
  mov    -0x20(%rbp),%rax
  movzbl (%rax),%eax
  lea    0x20(%rax),%edx
  mov    -0x20(%rbp),%rax
  mov    %dl,(%rax)
L232:
  addq   $0x1,-0x20(%rbp)
L221:
  mov    -0x18(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  cmp    %rax,-0x40(%rbp)
  jle    L329
  mov    -0x18(%rbp),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  mov    %eax,%edi
  call   <isspace@plt>
  test   %rax,%rax
  je     L329
  addq   $0x1,-0x10(%rbp)
L329:
  addq   $0x1,-0x8(%rbp)
  mov    -0x10(%rbp),%rax
  add    %rax,-0x18(%rbp)
  jmp    L189
L167:
  mov    -0x18(%rbp),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0xa,%al
  jne    L212
  addq   $0x1,-0x18(%rbp)
  jmp    L189
L212:
  mov    -0x18(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x18(%rbp)
  mov    %rax,%rdx
  mov    -0x38(%rbp),%rax
  lea    (%rdx,%rax,1),%rcx
  mov    -0x20(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x20(%rbp)
  movzbl (%rcx),%edx
  mov    %dl,(%rax)
  addq   $0x1,-0x8(%rbp)
  jmp    L189
L0:
  addq   $0x1,-0x18(%rbp)
  jmp    L189
L289:
  mov    -0x18(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x18(%rbp)
  mov    %rax,%rdx
  mov    -0x38(%rbp),%rax
  lea    (%rdx,%rax,1),%rcx
  mov    -0x20(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x20(%rbp)
  movzbl (%rcx),%edx
  mov    %dl,(%rax)
  addq   $0x1,-0x8(%rbp)
L189:
  mov    -0x18(%rbp),%rax
  cmp    -0x40(%rbp),%rax
  jl     L229
  mov    -0x20(%rbp),%rax
  movb   $0x0,(%rax)
  mov    -0x20(%rbp),%rax
  sub    -0x38(%rbp),%rax
L106:
  leave
  ret
```

assistant: ```c
int css_decode(unsigned char *input, long int input_len) {
  unsigned char *d = (unsigned char *)input;
  long int i, j, count;
  if (input == NULL)
    return -1;
  i = count = 0;
  while (i < input_len) {
    if (input[i] == '\\') {
      if (i + 1 < input_len) {
        i++;
        j = 0;
        while ((j < 6) && (i + j < input_len) && ((((input[i + j] >= '0') && (input[i + j] <= '9')) || ((input[i + j] >= 'a') && (input[i + j] <= 'f')) || ((input[i + j] >= 'A') && (input[i + j] <= 'F'))))) {
          j++;
        }
        if (j > 0) {
          int fullcheck = 0;
          switch (j) {
          case 1:
            *d++ = xsingle2c(&input[i]);
            break;
          case 2:
          case 3:
            *d++ = x2c(&input[i + j - 2]);
            break;
          case 4:
            *d = x2c(&input[i + j - 2]);
            fullcheck = 1;
            break;
          case 5:
            *d = x2c(&input[i + j - 2]);
            if (input[i] == '0') {
              fullcheck = 1;
            } else {
              d++;
            }
            break;
          case 6:
            *d = x2c(&input[i + j - 2]);
            if ((input[i] == '0') && (input[i + 1] == '0')) {
              fullcheck = 1;
            } else {
              d++;
            }
            break;
          }
          if (fullcheck) {
            if ((*d > 0x00) && (*d < 0x5f) && ((input[i + j - 3] == 'f') || (input[i + j - 3] == 'F')) && ((input[i + j - 4] == 'f') || (input[i + j - 4] == 'F'))) {
              (*d) += 0x20;
            }
            d++;
          }
          if ((i + j < input_len) && isspace(input[i + j])) {
            j++;
          }
          count++;
          i += j;
        } else if (input[i] == '\n') {
          i++;
        } else {
          *d++ = input[i++];
          count++;
        }
      } else {
        i++;
      }
    } else {
      *d++ = input[i++];
      count++;
    }
  }
  *d = '\0';
  return d - input;
}
```