user: 提供的汇编代码用C语言表示会是什么样子：

```asm
<vp8_short_fdct4x4_c>:
  endbr64
  mov    %edx,%ecx
  push   %r15
  mov    %rsi,%rax
  mov    %rdi,%r9
  shr    $0x1f,%ecx
  push   %r14
  lea    (%rcx,%rdx,1),%r10d
  push   %r13
  push   %r12
  sar    %r10d
  push   %rbp
  movslq %r10d,%r10
  push   %rbx
  movswl 0x6(%rdi),%r11d
  add    %r10,%r10
  movswl (%rdi),%ecx
  movswl 0x2(%rdi),%edx
  add    %r10,%r9
  movswl 0x4(%rdi),%esi
  mov    %ecx,%r8d
  mov    %edx,%edi
  add    %r11d,%ecx
  shl    $0x3,%ecx
  sub    %esi,%edi
  sub    %r11d,%r8d
  add    %esi,%edx
  shl    $0x3,%edx
  shl    $0x3,%edi
  mov    %ecx,%esi
  shl    $0x3,%r8d
  sub    %edx,%esi
  lea    (%rdx,%rcx,1),%ebp
  imul   $0x8a9,%edi,%ecx
  mov    %si,0x4(%rax)
  imul   $0x14e8,%r8d,%edx
  mov    %si,-0x34(%rsp)
  imul   $0x8a9,%r8d,%r8d
  mov    %bp,(%rax)
  movswl %bp,%ebp
  imul   $0xffffeb18,%edi,%edi
  lea    0x38a4(%rcx,%rdx,1),%esi
  sar    $0xc,%esi
  lea    0x1d4c(%r8,%rdi,1),%edx
  mov    %si,0x2(%rax)
  movswl %si,%esi
  sar    $0xc,%edx
  mov    %dx,0x6(%rax)
  movswl 0x6(%r9),%ebx
  movswl (%r9),%r8d
  movswl 0x4(%r9),%r11d
  mov    %edx,-0x14(%rsp)
  movswl 0x2(%r9),%edx
  mov    %r8d,%edi
  add    %ebx,%r8d
  mov    %edx,%ecx
  shl    $0x3,%r8d
  sub    %ebx,%edi
  add    %r11d,%edx
  shl    $0x3,%edx
  sub    %r11d,%ecx
  shl    $0x3,%edi
  mov    %r8d,%ebx
  shl    $0x3,%ecx
  sub    %edx,%ebx
  lea    (%rdx,%r8,1),%r13d
  imul   $0x14e8,%edi,%edx
  mov    %r13w,0x8(%rax)
  movswl %r13w,%r13d
  imul   $0x8a9,%ecx,%r8d
  mov    %bx,0xc(%rax)
  imul   $0x8a9,%edi,%edi
  mov    %bx,-0x30(%rsp)
  lea    0x38a4(%r8,%rdx,1),%r8d
  sar    $0xc,%r8d
  imul   $0xffffeb18,%ecx,%ecx
  add    %r10,%r9
  mov    %r8w,0xa(%rax)
  movswl %r8w,%r8d
  lea    0x1d4c(%rdi,%rcx,1),%edx
  mov    %edx,%ecx
  sar    $0xc,%ecx
  mov    %cx,0xe(%rax)
  movswl (%r9),%edx
  movswl 0x6(%r9),%r12d
  movswl 0x4(%r9),%edi
  mov    %ecx,-0x10(%rsp)
  movswl 0x2(%r9),%ecx
  mov    %edx,%r15d
  sub    %r12d,%r15d
  add    %r12d,%edx
  mov    %ecx,%r11d
  mov    %r15d,%ebx
  add    %edi,%ecx
  shl    $0x3,%edx
  shl    $0x3,%ecx
  sub    %edi,%r11d
  shl    $0x3,%ebx
  shl    $0x3,%r11d
  lea    (%rcx,%rdx,1),%r12d
  sub    %ecx,%edx
  imul   $0x8a9,%r11d,%edi
  mov    %r12w,0x10(%rax)
  movswl %r12w,%r12d
  imul   $0x14e8,%ebx,%ecx
  mov    %dx,0x14(%rax)
  movswl %dx,%edx
  imul   $0x8a9,%ebx,%ebx
  imul   $0xffffeb18,%r11d,%r11d
  lea    0x38a4(%rdi,%rcx,1),%edi
  sar    $0xc,%edi
  lea    0x1d4c(%rbx,%r11,1),%ecx
  lea    (%r9,%r10,1),%r11
  mov    %di,0x12(%rax)
  movswl %di,%edi
  sar    $0xc,%ecx
  mov    %cx,0x16(%rax)
  movswl 0x6(%r11),%r15d
  movswl %cx,%ecx
  movswl (%r11),%r10d
  movswl 0x2(%r11),%r9d
  movswl 0x4(%r11),%r14d
  mov    %r10d,%ebx
  mov    %r9d,%r11d
  add    %r15d,%r10d
  shl    $0x3,%r10d
  sub    %r14d,%r11d
  sub    %r15d,%ebx
  add    %r14d,%r9d
  shl    $0x3,%r9d
  shl    $0x3,%r11d
  mov    %r10d,%r15d
  shl    $0x3,%ebx
  sub    %r9d,%r15d
  lea    (%r9,%r10,1),%r14d
  imul   $0x8a9,%r11d,%r10d
  movswl %r14w,%r14d
  imul   $0x14e8,%ebx,%r9d
  imul   $0xffffeb18,%r11d,%r11d
  imul   $0x8a9,%ebx,%ebx
  lea    0x38a4(%r10,%r9,1),%r9d
  sar    $0xc,%r9d
  lea    0x1d4c(%rbx,%r11,1),%r10d
  lea    0x0(%rbp,%r14,1),%r11d
  movswl %r9w,%r9d
  sar    $0xc,%r10d
  mov    %r11d,-0x24(%rsp)
  sub    %r14d,%ebp
  lea    0x0(%r13,%r12,1),%r11d
  sub    %r12d,%r13d
  mov    %esi,%r12d
  mov    %r11d,-0x20(%rsp)
  lea    (%rsi,%r9,1),%r14d
  mov    %r13d,-0x1c(%rsp)
  mov    %ebp,%r13d
  lea    (%r8,%rdi,1),%ebp
  sub    %edi,%r8d
  mov    %r8d,-0x18(%rsp)
  sub    %r9d,%r12d
  movswl %r15w,%edi
  movswl %r10w,%r10d
  movswl -0x34(%rsp),%r8d
  mov    %r12d,%r11d
  movswl -0x30(%rsp),%r9d
  mov    %ebp,-0xc(%rsp)
  lea    0x7(%r14,%rbp,1),%ebp
  mov    %r8d,%r12d
  lea    (%rdi,%r8,1),%esi
  lea    (%rdx,%r9,1),%r15d
  sub    %edx,%r9d
  sub    %edi,%r12d
  movswl -0x10(%rsp),%edi
  movswl -0x14(%rsp),%edx
  sar    $0x4,%ebp
  mov    %esi,-0x28(%rsp)
  lea    (%rdi,%rcx,1),%ebx
  sub    %ecx,%edi
  mov    -0x20(%rsp),%ecx
  lea    (%rdx,%r10,1),%r8d
  mov    %ebx,-0x34(%rsp)
  mov    -0x24(%rsp),%ebx
  sub    %r10d,%edx
  mov    %edi,%esi
  mov    -0x28(%rsp),%edi
  mov    -0x34(%rsp),%r10d
  mov    %r15d,-0x2c(%rsp)
  mov    %edx,%r15d
  lea    0x7(%rbx,%rcx,1),%edx
  mov    -0x2c(%rsp),%ebx
  mov    %r9d,-0x30(%rsp)
  imul   $0x14e8,%r13d,%ecx
  sar    $0x4,%edx
  mov    %r14d,-0x10(%rsp)
  lea    0x7(%rbx,%rdi,1),%r9d
  lea    0x7(%r8,%r10,1),%ebx
  mov    %esi,-0x14(%rsp)
  movd   %edx,%xmm0
  sar    $0x4,%r9d
  sar    $0x4,%ebx
  pinsrw $0x1,%ebp,%xmm0
  mov    -0x24(%rsp),%edx
  imul   $0x8a9,-0x1c(%rsp),%edi
  movd   %r9d,%xmm3
  pinsrw $0x1,%ebx,%xmm3
  punpckldq %xmm3,%xmm0
  lea    0x2ee0(%rdi,%rcx,1),%ecx
  sar    $0x10,%ecx
  cmp    $0x1,%r13d
  sbb    $0xffff,%cx
  imul   $0x14e8,%r11d,%edi
  imul   $0x8a9,-0x18(%rsp),%r10d
  movd   %ecx,%xmm1
  mov    -0x10(%rsp),%ecx
  lea    0x2ee0(%r10,%rdi,1),%r10d
  sar    $0x10,%r10d
  cmp    $0x1,%r11d
  sbb    $0xffff,%r10w
  imul   $0x14e8,%r12d,%r14d
  imul   $0x8a9,-0x30(%rsp),%edi
  pinsrw $0x1,%r10d,%xmm1
  lea    0x2ee0(%r14,%rdi,1),%edi
  sar    $0x10,%edi
  cmp    $0x1,%r12d
  sbb    $0xffff,%di
  imul   $0x8a9,%esi,%r14d
  movd   %edi,%xmm2
  mov    %r14d,%esi
  imul   $0x14e8,%r15d,%r14d
  lea    0x2ee0(%rsi,%r14,1),%r14d
  sar    $0x10,%r14d
  cmp    $0x1,%r15d
  sbb    $0xffff,%r14w
  imul   $0x8a9,%r13d,%edi
  sub    -0x20(%rsp),%edx
  pinsrw $0x1,%r14d,%xmm2
  sar    $0x4,%edx
  punpckldq %xmm2,%xmm1
  punpcklqdq %xmm1,%xmm0
  movups %xmm0,(%rax)
  sub    -0xc(%rsp),%ecx
  mov    -0x28(%rsp),%esi
  movd   %edx,%xmm0
  imul   $0xffffeb18,-0x1c(%rsp),%r9d
  sub    -0x2c(%rsp),%esi
  add    $0x7,%ecx
  imul   $0xffffeb18,-0x18(%rsp),%r10d
  sar    $0x4,%esi
  sub    -0x34(%rsp),%r8d
  sar    $0x4,%ecx
  imul   $0xffffeb18,-0x14(%rsp),%ebx
  add    $0x7,%r8d
  movd   %esi,%xmm3
  lea    0xc738(%rdi,%r9,1),%edi
  sar    $0x4,%r8d
  pinsrw $0x1,%ecx,%xmm0
  imul   $0x8a9,%r11d,%r9d
  sar    $0x10,%edi
  pinsrw $0x1,%r8d,%xmm3
  movd   %edi,%xmm1
  punpckldq %xmm3,%xmm0
  lea    0xc738(%r9,%r10,1),%r11d
  imul   $0xffffeb18,-0x30(%rsp),%r10d
  sar    $0x10,%r11d
  imul   $0x8a9,%r12d,%r9d
  pinsrw $0x1,%r11d,%xmm1
  lea    0xc738(%r10,%r9,1),%r9d
  imul   $0x8a9,%r15d,%r10d
  sar    $0x10,%r9d
  movd   %r9d,%xmm2
  lea    0xc738(%r10,%rbx,1),%r10d
  pop    %rbx
  pop    %rbp
  sar    $0x10,%r10d
  pop    %r12
  pop    %r13
  pinsrw $0x1,%r10d,%xmm2
  pop    %r14
  pop    %r15
  punpckldq %xmm2,%xmm1
  punpcklqdq %xmm1,%xmm0
  movups %xmm0,0x10(%rax)
  ret
```

assistant: ```c
void vp8_short_fdct4x4_c(short *input, short *output, int pitch) {
  int i;
  int a1, b1, c1, d1;
  short *ip = input;
  short *op = output;
  for (i = 0; i < 4; i++) {
    a1 = ((ip[0] + ip[3]) << 3);
    b1 = ((ip[1] + ip[2]) << 3);
    c1 = ((ip[1] - ip[2]) << 3);
    d1 = ((ip[0] - ip[3]) << 3);
    op[0] = a1 + b1;
    op[2] = a1 - b1;
    op[1] = (c1 * 2217 + d1 * 5352 + 14500) >> 12;
    op[3] = (d1 * 2217 - c1 * 5352 + 7500) >> 12;
    ip += pitch / 2;
    op += 4;
  }
  ip = output;
  op = output;
  for (i = 0; i < 4; i++) {
    a1 = ip[0] + ip[12];
    b1 = ip[4] + ip[8];
    c1 = ip[4] - ip[8];
    d1 = ip[0] - ip[12];
    op[0] = (a1 + b1 + 7) >> 4;
    op[8] = (a1 - b1 + 7) >> 4;
    op[4] = ((c1 * 2217 + d1 * 5352 + 12000) >> 16) + (d1 != 0);
    op[12] = (d1 * 2217 - c1 * 5352 + 51000) >> 16;
    ip++;
    op++;
  }
}
```