user: 请从给定的汇编指令推导出C源代码：

```asm
<demux_real_sipro_swap>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  mov    %rdi,-0x28(%rbp)
  mov    %esi,-0x2c(%rbp)
  movl   $0x0,-0x18(%rbp)
  jmp    L34
L73:
  mov    -0x18(%rbp),%eax
  cltq
  lea    (%rax,%rax,1),%rdx
  lea    D4(%rip),%rax
  movzbl (%rdx,%rax,1),%eax
  movzbl %al,%eax
  mov    -0x2c(%rbp),%edx
  imul   %edx,%eax
  mov    %eax,-0x10(%rbp)
  mov    -0x18(%rbp),%eax
  cltq
  lea    (%rax,%rax,1),%rdx
  lea    D18(%rip),%rax
  movzbl (%rdx,%rax,1),%eax
  movzbl %al,%eax
  mov    -0x2c(%rbp),%edx
  imul   %edx,%eax
  mov    %eax,-0xc(%rbp)
  movl   $0x0,-0x14(%rbp)
  jmp    L69
L104:
  mov    -0x10(%rbp),%eax
  and    $0x1,%eax
  test   %eax,%eax
  je     L2
  mov    -0x10(%rbp),%eax
  sar    %eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  sar    $0x4,%al
  movsbl %al,%eax
  jmp    L111
L2:
  mov    -0x10(%rbp),%eax
  sar    %eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  and    $0xf,%eax
L111:
  mov    %eax,-0x8(%rbp)
  mov    -0xc(%rbp),%eax
  and    $0x1,%eax
  test   %eax,%eax
  je     L56
  mov    -0xc(%rbp),%eax
  sar    %eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  sar    $0x4,%al
  movsbl %al,%eax
  jmp    L100
L56:
  mov    -0xc(%rbp),%eax
  sar    %eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  and    $0xf,%eax
L100:
  mov    %eax,-0x4(%rbp)
  mov    -0xc(%rbp),%eax
  and    $0x1,%eax
  test   %eax,%eax
  je     L12
  mov    -0xc(%rbp),%eax
  sar    %eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  and    $0xf,%eax
  mov    %eax,%ecx
  mov    -0x8(%rbp),%eax
  shl    $0x4,%eax
  mov    %eax,%esi
  mov    -0xc(%rbp),%eax
  sar    %eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  or     %esi,%ecx
  mov    %ecx,%edx
  mov    %dl,(%rax)
  jmp    L72
L12:
  mov    -0xc(%rbp),%eax
  sar    %eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  and    $0xfffffff0,%eax
  mov    %eax,%ecx
  mov    -0x8(%rbp),%eax
  mov    %eax,%esi
  mov    -0xc(%rbp),%eax
  sar    %eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  or     %esi,%ecx
  mov    %ecx,%edx
  mov    %dl,(%rax)
L72:
  mov    -0x10(%rbp),%eax
  and    $0x1,%eax
  test   %eax,%eax
  je     L96
  mov    -0x10(%rbp),%eax
  sar    %eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  and    $0xf,%eax
  mov    %eax,%ecx
  mov    -0x4(%rbp),%eax
  shl    $0x4,%eax
  mov    %eax,%esi
  mov    -0x10(%rbp),%eax
  sar    %eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  or     %esi,%ecx
  mov    %ecx,%edx
  mov    %dl,(%rax)
  jmp    L115
L96:
  mov    -0x10(%rbp),%eax
  sar    %eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  and    $0xfffffff0,%eax
  mov    %eax,%ecx
  mov    -0x4(%rbp),%eax
  mov    %eax,%esi
  mov    -0x10(%rbp),%eax
  sar    %eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  or     %esi,%ecx
  mov    %ecx,%edx
  mov    %dl,(%rax)
L115:
  addl   $0x1,-0x10(%rbp)
  addl   $0x1,-0xc(%rbp)
  addl   $0x1,-0x14(%rbp)
L69:
  mov    -0x14(%rbp),%eax
  cmp    -0x2c(%rbp),%eax
  jl     L104
  addl   $0x1,-0x18(%rbp)
L34:
  cmpl   $0x25,-0x18(%rbp)
  jle    L73
  nop
  nop
  pop    %rbp
  ret
```

tool_calls: name: parse_data
arguments: tag: D4
type_guessed: string

tool: 

assistant: ```c
void demux_real_sipro_swap(char buffer[], int bs) {
  static const unsigned char sipr_swaps[38][2] = {{0, 63}, {1, 22}, {2, 44}, {3, 90}, {5, 81}, {7, 31}, {8, 86}, {9, 58}, {10, 36}, {12, 68}, {13, 39}, {14, 73}, {15, 53}, {16, 69}, {17, 57}, {19, 88}, {20, 34}, {21, 71}, {24, 46}, {25, 94}, {26, 54}, {28, 75}, {29, 50}, {32, 70}, {33, 92}, {35, 74}, {38, 85}, {40, 56}, {42, 87}, {43, 65}, {45, 59}, {48, 79}, {49, 93}, {51, 89}, {55, 95}, {61, 76}, {67, 83}, {77, 80}};
  int n;
  for (n = 0; n < 38; ++n) {
    int j;
    int i = bs * sipr_swaps[n][0];
    int o = bs * sipr_swaps[n][1];
    for (j = 0; j < bs; ++j) {
      int x = (i & 1) ? (buffer[i >> 1] >> 4) : (buffer[i >> 1] & 0x0F);
      int y = (o & 1) ? (buffer[o >> 1] >> 4) : (buffer[o >> 1] & 0x0F);
      if (o & 1)
        buffer[o >> 1] = (buffer[o >> 1] & 0x0F) | (x << 4);
      else
        buffer[o >> 1] = (buffer[o >> 1] & 0xF0) | x;
      if (i & 1)
        buffer[i >> 1] = (buffer[i >> 1] & 0x0F) | (y << 4);
      else
        buffer[i >> 1] = (buffer[i >> 1] & 0xF0) | y;
      ++i;
      ++o;
    }
  }
}
```