user: 下面的汇编指令对应的C源代码是什么:

```asm
<border_extend>:
  endbr64
  push   %r15
  mov    %esi,%eax
  mov    %edx,%r11d
  mov    %ecx,%esi
  push   %r14
  mov    %r8d,%r14d
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  mov    %rdi,%rbx
  test   %edx,%edx
  jle    L133
  cmp    %eax,%ecx
  jle    L133
  movslq %eax,%rdx
  movslq %ecx,%r9
  sub    %eax,%ecx
  xor    %r8d,%r8d
  lea    (%rdi,%rdx,1),%rdi
  lea    -0x1(%rcx),%eax
  lea    0x1(%rbx,%rdx,1),%rdx
  add    %rax,%rdx
  nopl   (%rax)
L198:
  movzbl -0x1(%rdi),%ecx
  mov    %rdi,%rax
  nopw   0x0(%rax,%rax,1)
L57:
  mov    %cl,(%rax)
  add    $0x1,%rax
  cmp    %rdx,%rax
  jne    L57
  add    $0x1,%r8d
  add    %r9,%rdi
  add    %r9,%rdx
  cmp    %r8d,%r11d
  jne    L198
L133:
  cmp    %r14d,%r11d
  jge    L19
  test   %esi,%esi
  jle    L19
  mov    %esi,%eax
  mov    %r11d,%edi
  mov    %esi,%edx
  mov    %esi,%r15d
  neg    %eax
  shr    $0x4,%edx
  imul   %esi,%edi
  lea    -0x1(%rsi),%r13d
  cltq
  lea    -0x1(%rdx),%r10d
  and    $0xf,%r15d
  mov    %esi,%r12d
  lea    (%rbx,%rax,1),%rdx
  add    $0x1,%r10
  movslq %esi,%r8
  and    $0xfffffff0,%r12d
  mov    %rdx,-0x18(%rsp)
  mov    %r13d,%edx
  movslq %edi,%rdi
  shl    $0x4,%r10
  lea    0x1(%rbx,%rdx,1),%rdx
  lea    (%rax,%rdi,1),%r9
  add    %rdx,%rax
  mov    %rax,-0x10(%rsp)
  lea    -0x1(%r15),%eax
  mov    %eax,-0x1c(%rsp)
  nopl   (%rax)
L228:
  lea    -0x1(%rdi),%rdx
  lea    (%rdi,%rbx,1),%rax
  sub    %r9,%rdx
  cmp    $0xe,%rdx
  jbe    L177
  cmp    $0x6,%r13d
  jbe    L177
  cmp    $0xe,%r13d
  jbe    L111
  lea    (%r9,%rbx,1),%rcx
  xor    %edx,%edx
  nopw   0x0(%rax,%rax,1)
L113:
  movdqu (%rcx,%rdx,1),%xmm1
  movups %xmm1,(%rax,%rdx,1)
  add    $0x10,%rdx
  cmp    %r10,%rdx
  jne    L113
  cmp    %r12d,%esi
  je     L81
  cmpl   $0x6,-0x1c(%rsp)
  mov    %r15d,%ebp
  jbe    L17
  mov    %r12d,%ecx
  mov    %r12d,%edx
L237:
  add    %rbx,%rcx
  movq   (%rcx,%r9,1),%xmm0
  movq   %xmm0,(%rcx,%rdi,1)
  mov    %ebp,%ecx
  and    $0xfffffff8,%ecx
  add    %ecx,%edx
  cmp    %ebp,%ecx
  je     L81
L166:
  mov    %edx,%ecx
  sub    %esi,%ecx
  movslq %ecx,%rcx
  movzbl (%rax,%rcx,1),%ebp
  movslq %edx,%rcx
  mov    %bpl,(%rax,%rcx,1)
  lea    0x1(%rdx),%ecx
  cmp    %esi,%ecx
  jge    L81
  mov    %ecx,%ebp
  movslq %ecx,%rcx
  sub    %esi,%ebp
  movslq %ebp,%rbp
  movzbl (%rax,%rbp,1),%ebp
  mov    %bpl,(%rax,%rcx,1)
  lea    0x2(%rdx),%ecx
  cmp    %ecx,%esi
  jle    L81
  mov    %ecx,%ebp
  movslq %ecx,%rcx
  sub    %esi,%ebp
  movslq %ebp,%rbp
  movzbl (%rax,%rbp,1),%ebp
  mov    %bpl,(%rax,%rcx,1)
  lea    0x3(%rdx),%ecx
  cmp    %ecx,%esi
  jle    L81
  mov    %ecx,%ebp
  movslq %ecx,%rcx
  sub    %esi,%ebp
  movslq %ebp,%rbp
  movzbl (%rax,%rbp,1),%ebp
  mov    %bpl,(%rax,%rcx,1)
  lea    0x4(%rdx),%ecx
  cmp    %ecx,%esi
  jle    L81
  mov    %ecx,%ebp
  movslq %ecx,%rcx
  sub    %esi,%ebp
  movslq %ebp,%rbp
  movzbl (%rax,%rbp,1),%ebp
  mov    %bpl,(%rax,%rcx,1)
  lea    0x5(%rdx),%ecx
  cmp    %ecx,%esi
  jle    L81
  mov    %ecx,%ebp
  add    $0x6,%edx
  movslq %ecx,%rcx
  sub    %esi,%ebp
  movslq %ebp,%rbp
  movzbl (%rax,%rbp,1),%ebp
  mov    %bpl,(%rax,%rcx,1)
  cmp    %edx,%esi
  jle    L81
  mov    %edx,%ecx
  movslq %edx,%rdx
  sub    %esi,%ecx
  movslq %ecx,%rcx
  movzbl (%rax,%rcx,1),%ecx
  mov    %cl,(%rax,%rdx,1)
L81:
  add    $0x1,%r11d
  add    %r8,%rdi
  add    %r8,%r9
  cmp    %r11d,%r14d
  jne    L228
L19:
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   (%rax)
L177:
  mov    -0x18(%rsp),%rax
  mov    -0x10(%rsp),%rdx
  add    %rdi,%rax
  lea    (%rdx,%rdi,1),%rcx
  nopl   0x0(%rax)
L181:
  movzbl (%rax),%edx
  add    $0x1,%rax
  mov    %dl,-0x1(%rax,%r8,1)
  cmp    %rcx,%rax
  jne    L181
  jmp    L81
L111:
  mov    %esi,%ebp
  xor    %ecx,%ecx
  xor    %edx,%edx
  jmp    L237
L17:
  mov    %r12d,%edx
  jmp    L166
```

assistant: ```c
void border_extend(unsigned char *frame, int w1, int h1, int w2, int h2) {
  int i;
  int j;
  unsigned char *fp;
  {
    j = 0;
    while (j < h1) {
      fp = frame + j * w2;
      i = w1;
      while (i < w2) {
        *(fp + i) = *(fp + (i - 1));
        i++;
      }
      j++;
    }
    j = h1;
    while (j < h2) {
      fp = frame + j * w2;
      i = 0;
      while (i < w2) {
        *(fp + i) = *(fp + (i - w2));
        i++;
      }
      j++;
    }
    return;
  }
}
```