user: 下面的汇编指令对应的C源代码是什么：

```asm
<decode_block6>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  mov    %rdi,-0x28(%rbp)
  mov    %esi,-0x2c(%rbp)
  mov    %rdx,-0x38(%rbp)
  movl   $0x0,-0xc(%rbp)
  jmp    L14
L8:
  mov    -0x28(%rbp),%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  shl    $0x8,%eax
  mov    %eax,%edx
  mov    -0x28(%rbp),%rax
  add    $0x1,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  add    %edx,%eax
  mov    %ax,-0x12(%rbp)
  addq   $0x2,-0x28(%rbp)
  movzwl -0x12(%rbp),%eax
  test   %ax,%ax
  js     L19
  movzwl -0x12(%rbp),%eax
  shr    $0x8,%ax
  mov    %ax,-0x14(%rbp)
  movzwl -0x14(%rbp),%eax
  and    $0x38,%eax
  mov    %ax,-0xe(%rbp)
  andw   $0x7,-0x14(%rbp)
  shlw   $0x2,-0xe(%rbp)
  shlw   -0x14(%rbp)
  movzwl -0xe(%rbp),%eax
  or     %ax,-0x14(%rbp)
  movzwl -0x14(%rbp),%eax
  mov    %eax,%edx
  mov    -0x38(%rbp),%rax
  mov    %dl,(%rax)
  movzwl -0x12(%rbp),%eax
  movzbl %al,%eax
  mov    %ax,-0x14(%rbp)
  movzwl -0x14(%rbp),%eax
  and    $0x38,%eax
  mov    %ax,-0xe(%rbp)
  andw   $0x7,-0x14(%rbp)
  shlw   $0x2,-0xe(%rbp)
  shlw   -0x14(%rbp)
  movzwl -0xe(%rbp),%eax
  or     %ax,-0x14(%rbp)
  mov    -0x38(%rbp),%rax
  add    $0x1,%rax
  movzwl -0x14(%rbp),%edx
  mov    %dl,(%rax)
  addq   $0x2,-0x38(%rbp)
  subl   $0x2,-0x2c(%rbp)
  addl   $0x2,-0xc(%rbp)
  jmp    L14
L19:
  movzwl -0x12(%rbp),%eax
  and    $0x1f,%eax
  mov    %ax,-0x14(%rbp)
  andw   $0x7fff,-0x12(%rbp)
  shrw   $0x5,-0x12(%rbp)
  subl   $0x2,-0x2c(%rbp)
  movzwl -0x12(%rbp),%eax
  neg    %rax
  mov    %rax,%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x8(%rbp)
  jmp    L10
L47:
  mov    -0x8(%rbp),%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  shl    $0x8,%eax
  mov    %eax,%edx
  mov    -0x8(%rbp),%rax
  add    $0x1,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  add    %edx,%eax
  mov    %ax,-0x10(%rbp)
  addq   $0x2,-0x8(%rbp)
  subw   $0x1,-0x14(%rbp)
  movzwl -0x10(%rbp),%eax
  shr    $0x8,%ax
  mov    %eax,%edx
  mov    -0x38(%rbp),%rax
  mov    %dl,(%rax)
  mov    -0x38(%rbp),%rax
  add    $0x1,%rax
  movzwl -0x10(%rbp),%edx
  mov    %dl,(%rax)
  addq   $0x2,-0x38(%rbp)
  addl   $0x2,-0xc(%rbp)
L10:
  cmpw   $0x0,-0x14(%rbp)
  jne    L47
L14:
  cmpl   $0x0,-0x2c(%rbp)
  jne    L8
  mov    -0xc(%rbp),%eax
  pop    %rbp
  ret
```

assistant: ```c
int decode_block6(unsigned char *in, int length, unsigned char *out) {
  unsigned short t0, t1, t3;
  int len = 0;
  while (length != 0) {
    t0 = (((in)[0] << 8) + ((in)[1]));
    in += 2;
    if ((0x8000 & t0) == 0) {
      unsigned short t2;
      t1 = t0 >> 8;
      t2 = t1 & 0x38;
      t1 = t1 & 0x07;
      t2 <<= 2;
      t1 <<= 1;
      t1 |= t2;
      *out = t1;
      t1 = t0 & 0xFF;
      t2 = t1 & 0x38;
      t1 = t1 & 0x07;
      t2 <<= 2;
      t1 <<= 1;
      t1 |= t2;
      *(out + 1) = t1;
      out += 2;
      length -= 2;
      len += 2;
    } else {
      unsigned char *t2;
      t1 = t0 & 0x1F;
      t0 = t0 & 0x7FFF;
      t0 >>= 5;
      length -= 2;
      t2 = out - t0;
      while (t1 != 0) {
        t3 = (((t2)[0] << 8) + ((t2)[1]));
        t2 += 2;
        t1 -= 1;
        do {
          (out)[0] = ((t3) >> 8) & 0xFF;
          (out)[1] = ((t3)) & 0xFF;
        } while (0);
        out += 2;
        len += 2;
      }
    }
  }
  return len;
}
```