user: 提供的汇编代码用C语言表示会是什么样子:

```asm
<process_plane>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  mov    %rdi,-0x8(%rsp)
  mov    %edx,-0xc(%rsp)
  test   %edx,%edx
  jle    L29
  mov    %edx,%ebx
  lea    0x0(,%rsi,4),%eax
  mov    %rcx,%r15
  mov    %esi,%r13d
  imul   %esi,%ebx
  movslq %eax,%rdx
  movq   $0x0,-0x20(%rsp)
  mov    %rdx,-0x18(%rsp)
  movl   $0x0,-0x10(%rsp)
  mov    %ebx,%eax
  shl    $0x2,%eax
  cltq
  sub    %rdx,%rax
  add    %rax,%r15
  mov    %rdi,%rax
  nopw   0x0(%rax,%rax,1)
L70:
  mov    -0x20(%rsp),%r14
  addl   $0x1,-0x10(%rsp)
  mov    %r15,-0x20(%rsp)
  test   %r14,%r14
  je     L145
  mov    %r15,%rdi
  xor    %edx,%edx
  xor    %ebx,%ebx
  test   %r13d,%r13d
  jle    L27
  nopl   0x0(%rax,%rax,1)
L64:
  movzbl (%rax),%r11d
  lea    0x1(%rax),%r9
  mov    %r11d,%ebp
  sar    $0x4,%r11d
  and    $0xf,%ebp
  mov    %ebp,%r8d
  shl    $0x4,%r8d
  or     %r11d,%r8d
  lea    -0x10(%r8),%ecx
  cmp    $0x1f,%ecx
  jbe    L171
  test   %r11d,%r11d
  je     L17
  movslq %ebx,%rdx
  movslq %r11d,%r8
  xor    %ecx,%ecx
  lea    (%r14,%rdx,4),%r10
  cs nopw 0x0(%rax,%rax,1)
L13:
  movzbl 0x1(%rax,%rcx,1),%edx
  mov    %edx,%esi
  sar    %edx
  mov    %edx,%r12d
  and    $0x1,%esi
  movzbl (%r10,%rcx,4),%esi
  not    %r12d
  cmovne %r12d,%edx
  add    %edx,%esi
  mov    %sil,(%rdi,%rcx,4)
  add    $0x1,%rcx
  cmp    %rcx,%r8
  jne    L13
  add    %r8,%r9
  lea    (%rdi,%r8,4),%rdi
  add    %r11d,%ebx
L17:
  mov    %r9,%rax
  test   %ebp,%ebp
  je     L148
  mov    %ebp,%r8d
L171:
  movslq %ebx,%rax
  movslq %r8d,%rsi
  lea    (%r14,%rax,4),%r10
  xor    %eax,%eax
  nopw   0x0(%rax,%rax,1)
L40:
  movzbl (%r10,%rax,4),%ecx
  add    %edx,%ecx
  mov    %cl,(%rdi,%rax,4)
  add    $0x1,%rax
  cmp    %rax,%rsi
  jne    L40
  lea    (%rdi,%rsi,4),%rdi
  add    %r8d,%ebx
  mov    %r9,%rax
L148:
  cmp    %ebx,%r13d
  jg     L64
L27:
  mov    -0xc(%rsp),%edi
  sub    -0x18(%rsp),%r15
  cmp    %edi,-0x10(%rsp)
  jne    L70
L112:
  sub    -0x8(%rsp),%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L145:
  test   %r13d,%r13d
  jle    L27
  mov    %r15,%rdx
  xor    %esi,%esi
  xor    %r8d,%r8d
  nopl   (%rax)
L119:
  movzbl (%rax),%r9d
  lea    0x1(%rax),%r10
  mov    %r9d,%r11d
  sar    $0x4,%r9d
  and    $0xf,%r11d
  mov    %r11d,%edi
  shl    $0x4,%edi
  or     %r9d,%edi
  lea    -0x10(%rdi),%ecx
  cmp    $0x1f,%ecx
  jbe    L77
  test   %r9d,%r9d
  je     L125
  movslq %r9d,%rdi
  xor    %ecx,%ecx
  cs nopw 0x0(%rax,%rax,1)
L185:
  movzbl 0x1(%rax,%rcx,1),%esi
  mov    %sil,(%rdx,%rcx,4)
  add    $0x1,%rcx
  cmp    %rcx,%rdi
  jne    L185
  add    %rdi,%r10
  lea    (%rdx,%rdi,4),%rdx
  add    %r9d,%r8d
L125:
  mov    %r10,%rax
  test   %r11d,%r11d
  je     L128
  mov    %r11d,%edi
L77:
  movslq %edi,%rax
  mov    %esi,%ecx
  lea    (%rdx,%rax,4),%rax
L33:
  mov    %cl,(%rdx)
  add    $0x4,%rdx
  cmp    %rax,%rdx
  jne    L33
  add    %edi,%r8d
  mov    %r10,%rax
L128:
  cmp    %r8d,%r13d
  jg     L119
  mov    -0xc(%rsp),%edi
  sub    -0x18(%rsp),%r15
  cmp    %edi,-0x10(%rsp)
  jne    L70
  jmp    L112
L29:
  pop    %rbx
  xor    %eax,%eax
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
```

assistant: ```c
int process_plane(unsigned char *in, int width, int height, unsigned char *out, int size) {
  int indexw;
  int indexh;
  int code;
  int collen;
  int replen;
  int color;
  int x;
  int revcode;
  unsigned char *last_line;
  unsigned char *this_line;
  unsigned char *org_in;
  unsigned char *org_out;
  org_in = in;
  org_out = out;
  last_line = 0;
  indexh = 0;
  while (indexh < height) {
    out = (org_out + width * height * 4) - ((indexh + 1) * width * 4);
    color = 0;
    this_line = out;
    indexw = 0;
    if (last_line == 0) {
      while (indexw < width) {
        code = (*(in++));
        replen = code & 0xf;
        collen = (code >> 4) & 0xf;
        revcode = (replen << 4) | collen;
        if ((revcode <= 47) && (revcode >= 16)) {
          replen = revcode;
          collen = 0;
        }
        while (collen > 0) {
          color = (*(in++));
          *out = color;
          out += 4;
          indexw++;
          collen--;
        }
        while (replen > 0) {
          *out = color;
          out += 4;
          indexw++;
          replen--;
        }
      }
    } else {
      while (indexw < width) {
        code = (*(in++));
        replen = code & 0xf;
        collen = (code >> 4) & 0xf;
        revcode = (replen << 4) | collen;
        if ((revcode <= 47) && (revcode >= 16)) {
          replen = revcode;
          collen = 0;
        }
        while (collen > 0) {
          x = (*(in++));
          if (x & 1) {
            x = x >> 1;
            x = x + 1;
            color = -x;
          } else {
            x = x >> 1;
            color = x;
          }
          x = last_line[indexw * 4] + color;
          *out = x;
          out += 4;
          indexw++;
          collen--;
        }
        while (replen > 0) {
          x = last_line[indexw * 4] + color;
          *out = x;
          out += 4;
          indexw++;
          replen--;
        }
      }
    }
    indexh++;
    last_line = this_line;
  }
  return (int)(in - org_in);
}
```