user: 提供的汇编代码用C语言表示会是什么样子:

```asm
<convolution2d>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x70,%rsp
  mov    %rdi,-0x58(%rbp)
  mov    %rsi,-0x60(%rbp)
  mov    %edx,-0x64(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x8(%rbp)
  xor    %eax,%eax
  movl   $0x1,-0x30(%rbp)
  movl   $0x1,-0x2c(%rbp)
  movl   $0xffffffff,-0x28(%rbp)
  movl   $0xffffffff,-0x24(%rbp)
  movl   $0x1,-0x20(%rbp)
  movl   $0xffffffff,-0x1c(%rbp)
  movl   $0x1,-0x18(%rbp)
  movl   $0x1,-0x14(%rbp)
  movl   $0x1,-0x10(%rbp)
  movl   $0x0,-0x50(%rbp)
  jmp    L51
L114:
  movl   $0x0,-0x4c(%rbp)
  jmp    L46
L64:
  mov    -0x50(%rbp),%eax
  movslq %eax,%rdx
  mov    %rdx,%rax
  shl    $0x2,%rax
  add    %rdx,%rax
  shl    $0x5,%rax
  mov    %rax,%rdx
  mov    -0x60(%rbp),%rax
  add    %rax,%rdx
  mov    -0x4c(%rbp),%eax
  cltq
  pxor   %xmm0,%xmm0
  movsd  %xmm0,(%rdx,%rax,8)
  movl   $0x0,-0x48(%rbp)
  jmp    L60
L80:
  mov    $0x2,%eax
  sub    -0x48(%rbp),%eax
  mov    %eax,-0x40(%rbp)
  movl   $0x0,-0x44(%rbp)
  jmp    L22
L124:
  mov    $0x2,%eax
  sub    -0x44(%rbp),%eax
  mov    %eax,-0x3c(%rbp)
  mov    -0x48(%rbp),%eax
  lea    -0x1(%rax),%edx
  mov    -0x50(%rbp),%eax
  add    %edx,%eax
  mov    %eax,-0x38(%rbp)
  mov    -0x44(%rbp),%eax
  lea    -0x1(%rax),%edx
  mov    -0x4c(%rbp),%eax
  add    %edx,%eax
  mov    %eax,-0x34(%rbp)
  cmpl   $0x0,-0x38(%rbp)
  js     L87
  mov    -0x38(%rbp),%eax
  cmp    -0x64(%rbp),%eax
  jge    L87
  cmpl   $0x0,-0x34(%rbp)
  js     L87
  mov    -0x34(%rbp),%eax
  cmp    -0x64(%rbp),%eax
  jge    L87
  mov    -0x50(%rbp),%eax
  movslq %eax,%rdx
  mov    %rdx,%rax
  shl    $0x2,%rax
  add    %rdx,%rax
  shl    $0x5,%rax
  mov    %rax,%rdx
  mov    -0x60(%rbp),%rax
  add    %rax,%rdx
  mov    -0x4c(%rbp),%eax
  cltq
  movsd  (%rdx,%rax,8),%xmm1
  mov    -0x38(%rbp),%eax
  movslq %eax,%rdx
  mov    %rdx,%rax
  shl    $0x2,%rax
  add    %rdx,%rax
  shl    $0x5,%rax
  mov    %rax,%rdx
  mov    -0x58(%rbp),%rax
  add    %rax,%rdx
  mov    -0x34(%rbp),%eax
  cltq
  movsd  (%rdx,%rax,8),%xmm2
  mov    -0x3c(%rbp),%eax
  movslq %eax,%rcx
  mov    -0x40(%rbp),%eax
  movslq %eax,%rdx
  mov    %rdx,%rax
  add    %rax,%rax
  add    %rdx,%rax
  add    %rcx,%rax
  mov    -0x30(%rbp,%rax,4),%eax
  pxor   %xmm0,%xmm0
  cvtsi2sd %eax,%xmm0
  mulsd  %xmm2,%xmm0
  mov    -0x50(%rbp),%eax
  movslq %eax,%rdx
  mov    %rdx,%rax
  shl    $0x2,%rax
  add    %rdx,%rax
  shl    $0x5,%rax
  mov    %rax,%rdx
  mov    -0x60(%rbp),%rax
  add    %rax,%rdx
  addsd  %xmm1,%xmm0
  mov    -0x4c(%rbp),%eax
  cltq
  movsd  %xmm0,(%rdx,%rax,8)
L87:
  addl   $0x1,-0x44(%rbp)
L22:
  cmpl   $0x2,-0x44(%rbp)
  jle    L124
  addl   $0x1,-0x48(%rbp)
L60:
  cmpl   $0x2,-0x48(%rbp)
  jle    L80
  addl   $0x1,-0x4c(%rbp)
L46:
  mov    -0x4c(%rbp),%eax
  cmp    -0x64(%rbp),%eax
  jl     L64
  addl   $0x1,-0x50(%rbp)
L51:
  mov    -0x50(%rbp),%eax
  cmp    -0x64(%rbp),%eax
  jl     L114
  nop
  mov    -0x8(%rbp),%rax
  sub    %fs:0x28,%rax
  je     L65
  call   <__stack_chk_fail@plt>
L65:
  leave
  ret
```

assistant: ```c
void convolution2d(double arr[][20], double conv[][20], int size) {
  int kernel[3][3] = {{1, 1, -1}, {-1, 1, -1}, {1, 1, 1}};
  int i, j, m, n, mm, nn, ii, jj;
  for (i = 0; i < size; ++i) {
    for (j = 0; j < size; ++j) {
      conv[i][j] = 0;
      for (m = 0; m < 3; ++m) {
        mm = 2 - m;
        for (n = 0; n < 3; ++n) {
          nn = 2 - n;
          ii = i + (m - 1);
          jj = j + (n - 1);
          if (ii >= 0 && ii < size && jj >= 0 && jj < size)
            conv[i][j] += arr[ii][jj] * kernel[mm][nn];
        }
      }
    }
  }
}
```