user: What is the c source code of the assembly code below?

```asm
<memcpy>:
  endbr64
  mov    %rdi,%rax
  mov    %rdi,%r8
  mov    %rsi,%rcx
  or     %rsi,%rax
  and    $0x3,%eax
  je     L98
L227:
  lea    -0x1(%rdx),%r9d
  test   %edx,%edx
  je     L210
  lea    0x1(%rcx),%rsi
  mov    %rdi,%rax
  sub    %rsi,%rax
  cmp    $0xe,%rax
  jbe    L180
  cmp    $0x6,%r9d
  jbe    L180
  cmp    $0xe,%r9d
  jbe    L191
  mov    %edx,%esi
  xor    %eax,%eax
  shr    $0x4,%esi
  shl    $0x4,%rsi
  nopl   0x0(%rax,%rax,1)
L38:
  movdqu (%rcx,%rax,1),%xmm0
  movups %xmm0,(%rdi,%rax,1)
  add    $0x10,%rax
  cmp    %rax,%rsi
  jne    L38
  mov    %edx,%esi
  and    $0xfffffff0,%esi
  mov    %esi,%eax
  sub    %esi,%r9d
  lea    (%rdi,%rax,1),%r10
  lea    (%rcx,%rax,1),%r11
  cmp    %esi,%edx
  je     L210
  sub    %esi,%edx
  lea    -0x1(%rdx),%esi
  cmp    $0x6,%esi
  jbe    L55
L203:
  mov    (%rcx,%rax,1),%rcx
  mov    %rcx,(%rdi,%rax,1)
  mov    %edx,%eax
  and    $0xfffffff8,%eax
  mov    %eax,%ecx
  sub    %eax,%r9d
  add    %rcx,%r10
  add    %rcx,%r11
  cmp    %eax,%edx
  je     L210
L55:
  movzbl (%r11),%eax
  mov    %al,(%r10)
  test   %r9d,%r9d
  je     L210
  movzbl 0x1(%r11),%eax
  mov    %al,0x1(%r10)
  cmp    $0x1,%r9d
  je     L210
  movzbl 0x2(%r11),%eax
  mov    %al,0x2(%r10)
  cmp    $0x2,%r9d
  je     L210
  movzbl 0x3(%r11),%eax
  mov    %al,0x3(%r10)
  cmp    $0x3,%r9d
  je     L210
  movzbl 0x4(%r11),%eax
  mov    %al,0x4(%r10)
  cmp    $0x4,%r9d
  je     L210
  movzbl 0x5(%r11),%eax
  mov    %al,0x5(%r10)
  cmp    $0x5,%r9d
  je     L210
  movzbl 0x6(%r11),%eax
  mov    %al,0x6(%r10)
L210:
  mov    %r8,%rax
  ret
  cs nopw 0x0(%rax,%rax,1)
L98:
  cmp    $0x3,%edx
  jbe    L227
  lea    0x4(%rcx),%r9
  lea    -0x4(%rdx),%esi
  sub    %r9,%rdi
  mov    %esi,%r9d
  shr    $0x2,%r9d
  cmp    $0x8,%rdi
  jbe    L218
  cmp    $0xb,%esi
  jbe    L218
  add    $0x1,%r9d
  mov    %r9d,%edi
  shr    $0x2,%edi
  shl    $0x4,%rdi
  nopl   0x0(%rax,%rax,1)
L104:
  movdqu (%rcx,%rax,1),%xmm1
  movups %xmm1,(%r8,%rax,1)
  add    $0x10,%rax
  cmp    %rdi,%rax
  jne    L104
  mov    %r9d,%r10d
  and    $0xfffffffc,%r10d
  mov    %r10d,%eax
  lea    0x0(,%r10,4),%edi
  shl    $0x2,%rax
  neg    %edi
  lea    (%r8,%rax,1),%r11
  add    %rcx,%rax
  cmp    %r10d,%r9d
  je     L30
  mov    (%rax),%r9d
  add    %esi,%edi
  mov    %r9d,(%r11)
  cmp    $0x3,%edi
  jbe    L30
  mov    0x4(%rax),%r9d
  sub    $0x4,%edi
  mov    %r9d,0x4(%r11)
  cmp    $0x3,%edi
  jbe    L30
  mov    0x8(%rax),%eax
  mov    %eax,0x8(%r11)
L30:
  shr    $0x2,%esi
  and    $0x3,%edx
  lea    0x1(%rsi),%eax
  shl    $0x2,%rax
  lea    (%r8,%rax,1),%rdi
  add    %rax,%rcx
  jmp    L227
  nopl   0x0(%rax)
L180:
  mov    %edx,%edx
  xor    %eax,%eax
  nopl   0x0(%rax)
L140:
  movzbl (%rcx,%rax,1),%esi
  mov    %sil,(%rdi,%rax,1)
  add    $0x1,%rax
  cmp    %rdx,%rax
  jne    L140
  mov    %r8,%rax
  ret
L191:
  mov    %rcx,%r11
  mov    %rdi,%r10
  xor    %eax,%eax
  jmp    L203
L218:
  add    $0x1,%r9d
  shl    $0x2,%r9
  nopw   0x0(%rax,%rax,1)
L184:
  mov    (%rcx,%rax,1),%edi
  mov    %edi,(%r8,%rax,1)
  add    $0x4,%rax
  cmp    %rax,%r9
  jne    L184
  jmp    L30
```

assistant: ```c
void *memcpy(void *_dst, const void *_src, unsigned int size) {
  unsigned int *dst = _dst;
  const unsigned int *src = _src;
  if (!((unsigned int)dst & 3) && !((unsigned int)src & 3))
    while (size > 3) {
      *dst++ = *src++;
      size -= 4;
    }
  unsigned char *cdst = (unsigned char *)dst;
  unsigned char *csrc = (unsigned char *)src;
  while (size--) {
    *cdst++ = *csrc++;
  }
  return _dst;
}
```