user: Demonstrate the C code that generates the assembly output below:

```asm
<taa_h264_inverse_hadamard_4x4>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  mov    %rdi,-0x28(%rbp)
  mov    %rsi,-0x30(%rbp)
  movl   $0x0,-0x18(%rbp)
  jmp    L28
L27:
  mov    -0x18(%rbp),%eax
  shl    $0x2,%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%edx
  mov    -0x18(%rbp),%eax
  shl    $0x2,%eax
  cltq
  add    $0x2,%rax
  lea    0x0(,%rax,4),%rcx
  mov    -0x28(%rbp),%rax
  add    %rcx,%rax
  mov    (%rax),%eax
  add    %edx,%eax
  mov    %eax,-0x10(%rbp)
  mov    -0x18(%rbp),%eax
  shl    $0x2,%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%eax
  mov    -0x18(%rbp),%edx
  shl    $0x2,%edx
  movslq %edx,%rdx
  add    $0x2,%rdx
  lea    0x0(,%rdx,4),%rcx
  mov    -0x28(%rbp),%rdx
  add    %rcx,%rdx
  mov    (%rdx),%edx
  sub    %edx,%eax
  mov    %eax,-0xc(%rbp)
  mov    -0x18(%rbp),%eax
  shl    $0x2,%eax
  cltq
  add    $0x1,%rax
  lea    0x0(,%rax,4),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%eax
  mov    -0x18(%rbp),%edx
  shl    $0x2,%edx
  movslq %edx,%rdx
  add    $0x3,%rdx
  lea    0x0(,%rdx,4),%rcx
  mov    -0x28(%rbp),%rdx
  add    %rcx,%rdx
  mov    (%rdx),%edx
  sub    %edx,%eax
  mov    %eax,-0x8(%rbp)
  mov    -0x18(%rbp),%eax
  shl    $0x2,%eax
  cltq
  add    $0x1,%rax
  lea    0x0(,%rax,4),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%edx
  mov    -0x18(%rbp),%eax
  shl    $0x2,%eax
  cltq
  add    $0x3,%rax
  lea    0x0(,%rax,4),%rcx
  mov    -0x28(%rbp),%rax
  add    %rcx,%rax
  mov    (%rax),%eax
  add    %edx,%eax
  mov    %eax,-0x4(%rbp)
  mov    -0x18(%rbp),%eax
  shl    $0x2,%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  mov    -0x10(%rbp),%ecx
  mov    -0x4(%rbp),%edx
  add    %ecx,%edx
  mov    %edx,(%rax)
  mov    -0x18(%rbp),%eax
  shl    $0x2,%eax
  cltq
  add    $0x1,%rax
  lea    0x0(,%rax,4),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  mov    -0xc(%rbp),%ecx
  mov    -0x8(%rbp),%edx
  add    %ecx,%edx
  mov    %edx,(%rax)
  mov    -0x18(%rbp),%eax
  shl    $0x2,%eax
  cltq
  add    $0x2,%rax
  lea    0x0(,%rax,4),%rdx
  mov    -0x30(%rbp),%rax
  add    %rax,%rdx
  mov    -0xc(%rbp),%eax
  sub    -0x8(%rbp),%eax
  mov    %eax,(%rdx)
  mov    -0x18(%rbp),%eax
  shl    $0x2,%eax
  cltq
  add    $0x3,%rax
  lea    0x0(,%rax,4),%rdx
  mov    -0x30(%rbp),%rax
  add    %rax,%rdx
  mov    -0x10(%rbp),%eax
  sub    -0x4(%rbp),%eax
  mov    %eax,(%rdx)
  addl   $0x1,-0x18(%rbp)
L28:
  cmpl   $0x3,-0x18(%rbp)
  jle    L27
  movl   $0x0,-0x14(%rbp)
  jmp    L17
L15:
  mov    -0x14(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%edx
  mov    -0x14(%rbp),%eax
  add    $0x8,%eax
  cltq
  lea    0x0(,%rax,4),%rcx
  mov    -0x30(%rbp),%rax
  add    %rcx,%rax
  mov    (%rax),%eax
  add    %edx,%eax
  mov    %eax,-0x10(%rbp)
  mov    -0x14(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%eax
  mov    -0x14(%rbp),%edx
  add    $0x8,%edx
  movslq %edx,%rdx
  lea    0x0(,%rdx,4),%rcx
  mov    -0x30(%rbp),%rdx
  add    %rcx,%rdx
  mov    (%rdx),%edx
  sub    %edx,%eax
  mov    %eax,-0xc(%rbp)
  mov    -0x14(%rbp),%eax
  add    $0x4,%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%eax
  mov    -0x14(%rbp),%edx
  add    $0xc,%edx
  movslq %edx,%rdx
  lea    0x0(,%rdx,4),%rcx
  mov    -0x30(%rbp),%rdx
  add    %rcx,%rdx
  mov    (%rdx),%edx
  sub    %edx,%eax
  mov    %eax,-0x8(%rbp)
  mov    -0x14(%rbp),%eax
  add    $0x4,%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%edx
  mov    -0x14(%rbp),%eax
  add    $0xc,%eax
  cltq
  lea    0x0(,%rax,4),%rcx
  mov    -0x30(%rbp),%rax
  add    %rcx,%rax
  mov    (%rax),%eax
  add    %edx,%eax
  mov    %eax,-0x4(%rbp)
  mov    -0x14(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  mov    -0x10(%rbp),%ecx
  mov    -0x4(%rbp),%edx
  add    %ecx,%edx
  mov    %edx,(%rax)
  mov    -0x14(%rbp),%eax
  add    $0x4,%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  mov    -0xc(%rbp),%ecx
  mov    -0x8(%rbp),%edx
  add    %ecx,%edx
  mov    %edx,(%rax)
  mov    -0x14(%rbp),%eax
  add    $0x8,%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x30(%rbp),%rax
  add    %rax,%rdx
  mov    -0xc(%rbp),%eax
  sub    -0x8(%rbp),%eax
  mov    %eax,(%rdx)
  mov    -0x14(%rbp),%eax
  add    $0xc,%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x30(%rbp),%rax
  add    %rax,%rdx
  mov    -0x10(%rbp),%eax
  sub    -0x4(%rbp),%eax
  mov    %eax,(%rdx)
  addl   $0x1,-0x14(%rbp)
L17:
  cmpl   $0x3,-0x14(%rbp)
  jle    L15
  nop
  nop
  pop    %rbp
  ret
```

assistant: ```c
void taa_h264_inverse_hadamard_4x4(int16_t *coeff, int16_t *block) {
  int tmp0, tmp1, tmp2, tmp3;
  for (int i = 0; i < 4; i++) {
    tmp0 = coeff[i * 4 + 0] + coeff[i * 4 + 2];
    tmp1 = coeff[i * 4 + 0] - coeff[i * 4 + 2];
    tmp2 = coeff[i * 4 + 1] - coeff[i * 4 + 3];
    tmp3 = coeff[i * 4 + 1] + coeff[i * 4 + 3];
    block[i * 4 + 0] = (int16_t)(tmp0 + tmp3);
    block[i * 4 + 1] = (int16_t)(tmp1 + tmp2);
    block[i * 4 + 2] = (int16_t)(tmp1 - tmp2);
    block[i * 4 + 3] = (int16_t)(tmp0 - tmp3);
  }
  for (int i = 0; i < 4; i++) {
    tmp0 = block[0 * 4 + i] + block[2 * 4 + i];
    tmp1 = block[0 * 4 + i] - block[2 * 4 + i];
    tmp2 = block[1 * 4 + i] - block[3 * 4 + i];
    tmp3 = block[1 * 4 + i] + block[3 * 4 + i];
    block[0 * 4 + i] = (int16_t)(tmp0 + tmp3);
    block[1 * 4 + i] = (int16_t)(tmp1 + tmp2);
    block[2 * 4 + i] = (int16_t)(tmp1 - tmp2);
    block[3 * 4 + i] = (int16_t)(tmp0 - tmp3);
  }
}
```