user: Please show me the C implementation that matches the assembly code listed below:

```asm
<njColIDCT>:
  endbr64
  push   %r15
  mov    %rsi,%r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  movslq %edx,%rbp
  push   %rbx
  sub    $0x28,%rsp
  mov    0xc0(%rdi),%r10d
  mov    0x40(%rdi),%esi
  mov    0x20(%rdi),%ebx
  mov    0xe0(%rdi),%ecx
  mov    %r10d,%eax
  mov    0xa0(%rdi),%r13d
  mov    0x80(%rdi),%r11d
  or     %esi,%eax
  mov    0x60(%rdi),%r12d
  mov    (%rdi),%r9d
  or     %ebx,%eax
  shl    $0x8,%r11d
  or     %ecx,%eax
  or     %r13d,%eax
  or     %r12d,%eax
  or     %r11d,%eax
  je     L1
  lea    (%rbx,%rcx,1),%edi
  shl    $0x8,%r9d
  lea    (%r15,%rbp,1),%rdx
  imul   $0x235,%edi,%edi
  add    $0x2000,%r9d
  mov    %rdx,0x10(%rsp)
  imul   $0xfffff2b2,%ecx,%eax
  imul   $0x8e4,%ebx,%ebx
  add    $0x4,%edi
  imul   $0xfffff04f,%r12d,%ecx
  add    %edi,%eax
  add    %edi,%ebx
  lea    0x0(%r13,%r12,1),%edi
  lea    (%r11,%r9,1),%r12d
  sub    %r11d,%r9d
  imul   $0x968,%edi,%edi
  sar    $0x3,%ebx
  sar    $0x3,%eax
  imul   $0xfffffce1,%r13d,%r13d
  imul   $0x620,%esi,%r11d
  add    $0x4,%edi
  add    %edi,%r13d
  add    %edi,%ecx
  lea    (%r10,%rsi,1),%edi
  imul   $0x454,%edi,%edi
  sar    $0x3,%r13d
  sar    $0x3,%ecx
  lea    (%rbx,%r13,1),%esi
  lea    (%rax,%rcx,1),%edx
  sub    %r13d,%ebx
  sub    %ecx,%eax
  imul   $0xfffff138,%r10d,%r10d
  lea    (%rbx,%rax,1),%r14d
  mov    %esi,0x18(%rsp)
  add    $0x4,%edi
  imul   $0xb5,%r14d,%r14d
  mov    %edx,0x4(%rsp)
  add    %edi,%r11d
  sar    $0x3,%r11d
  add    %edi,%r10d
  lea    (%r12,%r11,1),%ecx
  sar    $0x3,%r10d
  sub    %r11d,%r12d
  lea    (%rsi,%rcx,1),%edi
  lea    (%r9,%r10,1),%r13d
  sub    %r10d,%r9d
  sub    $0xffffff80,%r14d
  sar    $0xe,%edi
  mov    %r9d,0x8(%rsp)
  sar    $0x8,%r14d
  sub    %eax,%ebx
  sub    $0xffffff80,%edi
  mov    %ecx,0x1c(%rsp)
  imul   $0xb5,%ebx,%ebx
  call   <njClip@plt>
  lea    0x0(%r13,%r14,1),%edi
  sub    %r14d,%r13d
  mov    %al,(%r15)
  sar    $0xe,%edi
  sar    $0xe,%r13d
  sub    $0xffffff80,%edi
  sub    $0xffffff80,%ebx
  sar    $0x8,%ebx
  call   <njClip@plt>
  mov    0x10(%rsp),%rdx
  mov    0x8(%rsp),%r15d
  mov    %al,(%rdx)
  lea    (%r15,%rbx,1),%edi
  add    %rbp,%rdx
  sar    $0xe,%edi
  mov    %rdx,0x10(%rsp)
  sub    $0xffffff80,%edi
  call   <njClip@plt>
  mov    0x10(%rsp),%rdx
  mov    %al,(%rdx)
  add    %rbp,%rdx
  mov    %rdx,0x8(%rsp)
  mov    0x4(%rsp),%edx
  lea    (%rdx,%r12,1),%edi
  sar    $0xe,%edi
  sub    $0xffffff80,%edi
  call   <njClip@plt>
  mov    0x8(%rsp),%rdx
  sub    0x4(%rsp),%r12d
  sar    $0xe,%r12d
  mov    %al,(%rdx)
  lea    0x80(%r12),%edi
  add    %rbp,%rdx
  mov    %rdx,0x8(%rsp)
  call   <njClip@plt>
  mov    0x8(%rsp),%rdx
  mov    %r15d,%edi
  sub    %ebx,%edi
  mov    %al,(%rdx)
  sar    $0xe,%edi
  lea    (%rdx,%rbp,1),%r12
  sub    $0xffffff80,%edi
  lea    (%r12,%rbp,1),%rbx
  call   <njClip@plt>
  lea    0x80(%r13),%edi
  mov    %al,(%r12)
  call   <njClip@plt>
  mov    0x18(%rsp),%esi
  mov    0x1c(%rsp),%ecx
  mov    %al,(%rbx)
  add    %rbp,%rbx
  sub    %esi,%ecx
  sar    $0xe,%ecx
  lea    0x80(%rcx),%edi
  call   <njClip@plt>
  mov    %al,(%rbx)
  add    $0x28,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   (%rax)
L1:
  lea    0x20(%r9),%edi
  sar    $0x6,%edi
  lea    0x80(%rdi),%edi
  call   <njClip@plt>
  mov    $0x8,%edx
  nop
L4:
  mov    %al,(%r15)
  add    %rbp,%r15
  sub    $0x1,%edx
  jne    L4
  add    $0x28,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
```

assistant: ```c
void njColIDCT(const int *blk, unsigned char *out, int stride) {
  int x0, x1, x2, x3, x4, x5, x6, x7, x8;
  if (!((x1 = blk[8 * 4] << 8) | (x2 = blk[8 * 6]) | (x3 = blk[8 * 2]) | (x4 = blk[8 * 1]) | (x5 = blk[8 * 7]) | (x6 = blk[8 * 5]) | (x7 = blk[8 * 3]))) {
    x1 = njClip(((blk[0] + 32) >> 6) + 128);
    for (x0 = 8; x0; --x0) {
      *out = (unsigned char)x1;
      out += stride;
    }
    return;
  }
  x0 = (blk[0] << 8) + 8192;
  x8 = 565 * (x4 + x5) + 4;
  x4 = (x8 + (2841 - 565) * x4) >> 3;
  x5 = (x8 - (2841 + 565) * x5) >> 3;
  x8 = 2408 * (x6 + x7) + 4;
  x6 = (x8 - (2408 - 1609) * x6) >> 3;
  x7 = (x8 - (2408 + 1609) * x7) >> 3;
  x8 = x0 + x1;
  x0 -= x1;
  x1 = 1108 * (x3 + x2) + 4;
  x2 = (x1 - (2676 + 1108) * x2) >> 3;
  x3 = (x1 + (2676 - 1108) * x3) >> 3;
  x1 = x4 + x6;
  x4 -= x6;
  x6 = x5 + x7;
  x5 -= x7;
  x7 = x8 + x3;
  x8 -= x3;
  x3 = x0 + x2;
  x0 -= x2;
  x2 = (181 * (x4 + x5) + 128) >> 8;
  x4 = (181 * (x4 - x5) + 128) >> 8;
  *out = njClip(((x7 + x1) >> 14) + 128);
  out += stride;
  *out = njClip(((x3 + x2) >> 14) + 128);
  out += stride;
  *out = njClip(((x0 + x4) >> 14) + 128);
  out += stride;
  *out = njClip(((x8 + x6) >> 14) + 128);
  out += stride;
  *out = njClip(((x8 - x6) >> 14) + 128);
  out += stride;
  *out = njClip(((x0 - x4) >> 14) + 128);
  out += stride;
  *out = njClip(((x3 - x2) >> 14) + 128);
  out += stride;
  *out = njClip(((x7 - x1) >> 14) + 128);
}
```