user: 提供的汇编代码用C语言表示会是什么样子:

```asm
<vpx_post_proc_down_and_across_mb_row_c>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x70,%rsp
  mov    %rdi,-0x48(%rbp)
  mov    %rsi,-0x50(%rbp)
  mov    %edx,-0x54(%rbp)
  mov    %ecx,-0x58(%rbp)
  mov    %r8d,-0x5c(%rbp)
  mov    %r9,-0x68(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x8(%rbp)
  xor    %eax,%eax
  movl   $0x0,-0x28(%rbp)
  jmp    L48
L50:
  mov    -0x48(%rbp),%rax
  mov    %rax,-0x20(%rbp)
  mov    -0x50(%rbp),%rax
  mov    %rax,-0x18(%rbp)
  movl   $0x0,-0x24(%rbp)
  jmp    L103
L139:
  mov    -0x54(%rbp),%eax
  lea    (%rax,%rax,1),%edx
  mov    -0x24(%rbp),%eax
  sub    %edx,%eax
  movslq %eax,%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  mov    %al,-0x2f(%rbp)
  mov    -0x24(%rbp),%eax
  sub    -0x54(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  mov    %al,-0x2e(%rbp)
  mov    -0x24(%rbp),%edx
  mov    -0x54(%rbp),%eax
  add    %edx,%eax
  movslq %eax,%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  mov    %al,-0x2d(%rbp)
  mov    -0x54(%rbp),%eax
  lea    (%rax,%rax,1),%edx
  mov    -0x24(%rbp),%eax
  add    %edx,%eax
  movslq %eax,%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  mov    %al,-0x2c(%rbp)
  mov    -0x24(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  mov    %al,-0x33(%rbp)
  movzbl -0x33(%rbp),%eax
  sub    -0x2f(%rbp),%al
  movzbl %al,%eax
  mov    %eax,%edi
  call   <abs@plt>
  mov    -0x24(%rbp),%edx
  movslq %edx,%rcx
  mov    -0x68(%rbp),%rdx
  add    %rcx,%rdx
  movzbl (%rdx),%edx
  cmp    %dl,%al
  jae    L58
  movzbl -0x33(%rbp),%eax
  sub    -0x2e(%rbp),%al
  movzbl %al,%eax
  mov    %eax,%edi
  call   <abs@plt>
  mov    -0x24(%rbp),%edx
  movslq %edx,%rcx
  mov    -0x68(%rbp),%rdx
  add    %rcx,%rdx
  movzbl (%rdx),%edx
  cmp    %dl,%al
  jae    L58
  movzbl -0x33(%rbp),%eax
  sub    -0x2d(%rbp),%al
  movzbl %al,%eax
  mov    %eax,%edi
  call   <abs@plt>
  mov    -0x24(%rbp),%edx
  movslq %edx,%rcx
  mov    -0x68(%rbp),%rdx
  add    %rcx,%rdx
  movzbl (%rdx),%edx
  cmp    %dl,%al
  jae    L58
  movzbl -0x33(%rbp),%eax
  sub    -0x2c(%rbp),%al
  movzbl %al,%eax
  mov    %eax,%edi
  call   <abs@plt>
  mov    -0x24(%rbp),%edx
  movslq %edx,%rcx
  mov    -0x68(%rbp),%rdx
  add    %rcx,%rdx
  movzbl (%rdx),%edx
  cmp    %dl,%al
  jae    L58
  movzbl -0x2f(%rbp),%edx
  movzbl -0x2e(%rbp),%eax
  add    %edx,%eax
  add    $0x1,%eax
  sar    %eax
  mov    %al,-0x2b(%rbp)
  movzbl -0x2c(%rbp),%edx
  movzbl -0x2d(%rbp),%eax
  add    %edx,%eax
  add    $0x1,%eax
  sar    %eax
  mov    %al,-0x2a(%rbp)
  movzbl -0x2b(%rbp),%edx
  movzbl -0x2a(%rbp),%eax
  add    %edx,%eax
  add    $0x1,%eax
  sar    %eax
  mov    %al,-0x29(%rbp)
  movzbl -0x29(%rbp),%edx
  movzbl -0x33(%rbp),%eax
  add    %edx,%eax
  add    $0x1,%eax
  sar    %eax
  mov    %al,-0x33(%rbp)
L58:
  mov    -0x24(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rax,%rdx
  movzbl -0x33(%rbp),%eax
  mov    %al,(%rdx)
  addl   $0x1,-0x24(%rbp)
L103:
  mov    -0x24(%rbp),%eax
  cmp    -0x5c(%rbp),%eax
  jl     L139
  mov    -0x50(%rbp),%rax
  mov    %rax,-0x20(%rbp)
  mov    -0x50(%rbp),%rax
  mov    %rax,-0x18(%rbp)
  mov    -0x20(%rbp),%rax
  sub    $0x1,%rax
  mov    -0x20(%rbp),%rdx
  movzbl (%rdx),%edx
  mov    %dl,(%rax)
  mov    -0x20(%rbp),%rdx
  sub    $0x2,%rdx
  movzbl (%rax),%eax
  mov    %al,(%rdx)
  mov    -0x5c(%rbp),%eax
  cltq
  lea    -0x1(%rax),%rdx
  mov    -0x20(%rbp),%rax
  add    %rax,%rdx
  mov    -0x5c(%rbp),%eax
  cltq
  lea    0x1(%rax),%rcx
  mov    -0x20(%rbp),%rax
  add    %rcx,%rax
  movzbl (%rdx),%edx
  mov    %dl,(%rax)
  mov    -0x5c(%rbp),%edx
  movslq %edx,%rcx
  mov    -0x20(%rbp),%rdx
  add    %rcx,%rdx
  movzbl (%rax),%eax
  mov    %al,(%rdx)
  movl   $0x0,-0x24(%rbp)
  jmp    L64
L135:
  mov    -0x24(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  mov    %al,-0x33(%rbp)
  mov    -0x24(%rbp),%eax
  cltq
  lea    -0x2(%rax),%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%edx
  movzbl -0x33(%rbp),%eax
  sub    %edx,%eax
  movzbl %al,%eax
  mov    %eax,%edi
  call   <abs@plt>
  mov    -0x24(%rbp),%edx
  movslq %edx,%rcx
  mov    -0x68(%rbp),%rdx
  add    %rcx,%rdx
  movzbl (%rdx),%edx
  cmp    %dl,%al
  jae    L117
  mov    -0x24(%rbp),%eax
  cltq
  lea    -0x1(%rax),%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%edx
  movzbl -0x33(%rbp),%eax
  sub    %edx,%eax
  movzbl %al,%eax
  mov    %eax,%edi
  call   <abs@plt>
  mov    -0x24(%rbp),%edx
  movslq %edx,%rcx
  mov    -0x68(%rbp),%rdx
  add    %rcx,%rdx
  movzbl (%rdx),%edx
  cmp    %dl,%al
  jae    L117
  mov    -0x24(%rbp),%eax
  cltq
  lea    0x1(%rax),%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%edx
  movzbl -0x33(%rbp),%eax
  sub    %edx,%eax
  movzbl %al,%eax
  mov    %eax,%edi
  call   <abs@plt>
  mov    -0x24(%rbp),%edx
  movslq %edx,%rcx
  mov    -0x68(%rbp),%rdx
  add    %rcx,%rdx
  movzbl (%rdx),%edx
  cmp    %dl,%al
  jae    L117
  mov    -0x24(%rbp),%eax
  cltq
  lea    0x2(%rax),%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%edx
  movzbl -0x33(%rbp),%eax
  sub    %edx,%eax
  movzbl %al,%eax
  mov    %eax,%edi
  call   <abs@plt>
  mov    -0x24(%rbp),%edx
  movslq %edx,%rcx
  mov    -0x68(%rbp),%rdx
  add    %rcx,%rdx
  movzbl (%rdx),%edx
  cmp    %dl,%al
  jae    L117
  mov    -0x24(%rbp),%eax
  cltq
  lea    -0x2(%rax),%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movzbl %al,%edx
  mov    -0x24(%rbp),%eax
  cltq
  lea    -0x1(%rax),%rcx
  mov    -0x20(%rbp),%rax
  add    %rcx,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  add    %edx,%eax
  add    $0x1,%eax
  sar    %eax
  mov    %al,-0x32(%rbp)
  mov    -0x24(%rbp),%eax
  cltq
  lea    0x2(%rax),%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movzbl %al,%edx
  mov    -0x24(%rbp),%eax
  cltq
  lea    0x1(%rax),%rcx
  mov    -0x20(%rbp),%rax
  add    %rcx,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  add    %edx,%eax
  add    $0x1,%eax
  sar    %eax
  mov    %al,-0x31(%rbp)
  movzbl -0x32(%rbp),%edx
  movzbl -0x31(%rbp),%eax
  add    %edx,%eax
  add    $0x1,%eax
  sar    %eax
  mov    %al,-0x30(%rbp)
  movzbl -0x30(%rbp),%edx
  movzbl -0x33(%rbp),%eax
  add    %edx,%eax
  add    $0x1,%eax
  sar    %eax
  mov    %al,-0x33(%rbp)
L117:
  mov    -0x24(%rbp),%eax
  and    $0x3,%eax
  cltq
  movzbl -0x33(%rbp),%edx
  mov    %dl,-0xc(%rbp,%rax,1)
  cmpl   $0x1,-0x24(%rbp)
  jle    L75
  mov    -0x24(%rbp),%eax
  sub    $0x2,%eax
  and    $0x3,%eax
  mov    %eax,%ecx
  mov    -0x24(%rbp),%eax
  cltq
  lea    -0x2(%rax),%rdx
  mov    -0x18(%rbp),%rax
  add    %rax,%rdx
  movslq %ecx,%rax
  movzbl -0xc(%rbp,%rax,1),%eax
  mov    %al,(%rdx)
L75:
  addl   $0x1,-0x24(%rbp)
L64:
  mov    -0x24(%rbp),%eax
  cmp    -0x5c(%rbp),%eax
  jl     L135
  mov    -0x24(%rbp),%eax
  sub    $0x2,%eax
  and    $0x3,%eax
  mov    %eax,%ecx
  mov    -0x24(%rbp),%eax
  cltq
  lea    -0x2(%rax),%rdx
  mov    -0x18(%rbp),%rax
  add    %rax,%rdx
  movslq %ecx,%rax
  movzbl -0xc(%rbp,%rax,1),%eax
  mov    %al,(%rdx)
  mov    -0x24(%rbp),%eax
  sub    $0x1,%eax
  and    $0x3,%eax
  mov    %eax,%ecx
  mov    -0x24(%rbp),%eax
  cltq
  lea    -0x1(%rax),%rdx
  mov    -0x18(%rbp),%rax
  add    %rax,%rdx
  movslq %ecx,%rax
  movzbl -0xc(%rbp,%rax,1),%eax
  mov    %al,(%rdx)
  mov    -0x54(%rbp),%eax
  cltq
  add    %rax,-0x48(%rbp)
  mov    -0x58(%rbp),%eax
  cltq
  add    %rax,-0x50(%rbp)
  addl   $0x1,-0x28(%rbp)
L48:
  mov    -0x28(%rbp),%eax
  cmp    0x10(%rbp),%eax
  jl     L50
  nop
  mov    -0x8(%rbp),%rax
  sub    %fs:0x28,%rax
  je     L80
  call   <__stack_chk_fail@plt>
L80:
  leave
  ret
```

assistant: ```c
void vpx_post_proc_down_and_across_mb_row_c(unsigned char *src_ptr, unsigned char *dst_ptr, int src_pixels_per_line, int dst_pixels_per_line, int cols, unsigned char *f, int size) {
  unsigned char *p_src, *p_dst;
  int row;
  int col;
  unsigned char v;
  unsigned char d[4];
  for (row = 0; row < size; row++) {
    p_src = src_ptr;
    p_dst = dst_ptr;
    for (col = 0; col < cols; col++) {
      unsigned char p_above2 = p_src[col - 2 * src_pixels_per_line];
      unsigned char p_above1 = p_src[col - src_pixels_per_line];
      unsigned char p_below1 = p_src[col + src_pixels_per_line];
      unsigned char p_below2 = p_src[col + 2 * src_pixels_per_line];
      v = p_src[col];
      if ((abs(v - p_above2) < f[col]) && (abs(v - p_above1) < f[col]) && (abs(v - p_below1) < f[col]) && (abs(v - p_below2) < f[col])) {
        unsigned char k1, k2, k3;
        k1 = (p_above2 + p_above1 + 1) >> 1;
        k2 = (p_below2 + p_below1 + 1) >> 1;
        k3 = (k1 + k2 + 1) >> 1;
        v = (k3 + v + 1) >> 1;
      }
      p_dst[col] = v;
    }
    p_src = dst_ptr;
    p_dst = dst_ptr;
    p_src[-2] = p_src[-1] = p_src[0];
    p_src[cols] = p_src[cols + 1] = p_src[cols - 1];
    for (col = 0; col < cols; col++) {
      v = p_src[col];
      if ((abs(v - p_src[col - 2]) < f[col]) && (abs(v - p_src[col - 1]) < f[col]) && (abs(v - p_src[col + 1]) < f[col]) && (abs(v - p_src[col + 2]) < f[col])) {
        unsigned char k1, k2, k3;
        k1 = (p_src[col - 2] + p_src[col - 1] + 1) >> 1;
        k2 = (p_src[col + 2] + p_src[col + 1] + 1) >> 1;
        k3 = (k1 + k2 + 1) >> 1;
        v = (k3 + v + 1) >> 1;
      }
      d[col & 3] = v;
      if (col >= 2)
        p_dst[col - 2] = d[(col - 2) & 3];
    }
    p_dst[col - 2] = d[(col - 2) & 3];
    p_dst[col - 1] = d[(col - 1) & 3];
    src_ptr += src_pixels_per_line;
    dst_ptr += dst_pixels_per_line;
  }
}
```