user: 下面的汇编指令对应的C源代码是什么：

```asm
<memset_c>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x30,%rsp
  mov    %rdi,-0x28(%rbp)
  mov    %esi,%eax
  mov    %edx,-0x30(%rbp)
  mov    %al,-0x2c(%rbp)
  cmpl   $0x3,-0x30(%rbp)
  ja     L36
  cmpl   $0x0,-0x30(%rbp)
  je     L121
  movzbl -0x2c(%rbp),%edx
  mov    -0x28(%rbp),%rax
  mov    %dl,(%rax)
L121:
  cmpl   $0x1,-0x30(%rbp)
  jbe    L77
  mov    -0x28(%rbp),%rax
  lea    0x1(%rax),%rdx
  movzbl -0x2c(%rbp),%eax
  mov    %al,(%rdx)
L77:
  cmpl   $0x3,-0x30(%rbp)
  jne    L8
  mov    -0x28(%rbp),%rax
  lea    0x2(%rax),%rdx
  movzbl -0x2c(%rbp),%eax
  mov    %al,(%rdx)
L8:
  mov    -0x28(%rbp),%rax
  jmp    L193
L36:
  movzbl -0x2c(%rbp),%eax
  mov    %eax,-0x18(%rbp)
  mov    -0x30(%rbp),%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x8(%rbp)
  mov    -0x18(%rbp),%eax
  shl    $0x18,%eax
  mov    %eax,-0x14(%rbp)
  mov    -0x14(%rbp),%eax
  shr    $0x8,%eax
  or     %eax,-0x14(%rbp)
  mov    -0x14(%rbp),%eax
  shr    $0x10,%eax
  or     -0x14(%rbp),%eax
  mov    %eax,-0x18(%rbp)
  mov    -0x28(%rbp),%rax
  and    $0x1,%eax
  test   %eax,%eax
  je     L45
  mov    -0x28(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x28(%rbp)
  mov    -0x18(%rbp),%edx
  mov    %dl,(%rax)
L45:
  mov    -0x28(%rbp),%rax
  and    $0x2,%eax
  test   %eax,%eax
  je     L65
  mov    -0x18(%rbp),%eax
  mov    %eax,%edx
  mov    -0x28(%rbp),%rax
  mov    %dx,(%rax)
  addq   $0x2,-0x28(%rbp)
L65:
  mov    -0x8(%rbp),%rax
  sub    -0x28(%rbp),%rax
  mov    %eax,-0x1c(%rbp)
  mov    -0x28(%rbp),%rax
  mov    %rax,-0x10(%rbp)
  cmpl   $0x3,-0x1c(%rbp)
  jbe    L160
  mov    -0x10(%rbp),%rax
  and    $0x4,%eax
  test   %eax,%eax
  je     L160
  mov    -0x10(%rbp),%rax
  lea    0x4(%rax),%rdx
  mov    %rdx,-0x10(%rbp)
  mov    -0x18(%rbp),%edx
  mov    %edx,(%rax)
  subl   $0x4,-0x1c(%rbp)
L160:
  cmpl   $0x1f,-0x1c(%rbp)
  jbe    L4
  mov    -0x10(%rbp),%rax
  and    $0x8,%eax
  test   %eax,%eax
  je     L139
  mov    -0x18(%rbp),%edx
  mov    -0x18(%rbp),%ecx
  mov    -0x10(%rbp),%rax
  mov    %ecx,%esi
  mov    %rax,%rdi
  call   <WriteUnsigned2@plt>
  mov    %rax,-0x10(%rbp)
L139:
  mov    -0x10(%rbp),%rax
  and    $0x10,%eax
  test   %eax,%eax
  je     L165
  mov    -0x18(%rbp),%edi
  mov    -0x18(%rbp),%ecx
  mov    -0x18(%rbp),%edx
  mov    -0x18(%rbp),%esi
  mov    -0x10(%rbp),%rax
  mov    %edi,%r8d
  mov    %rax,%rdi
  call   <WriteUnsigned4@plt>
  mov    %rax,-0x10(%rbp)
L165:
  mov    -0x8(%rbp),%rax
  sub    -0x10(%rbp),%rax
  mov    %eax,-0x1c(%rbp)
  subl   $0x20,-0x1c(%rbp)
  jmp    L78
L154:
  mov    -0x18(%rbp),%edi
  mov    -0x18(%rbp),%ecx
  mov    -0x18(%rbp),%edx
  mov    -0x18(%rbp),%esi
  mov    -0x10(%rbp),%rax
  mov    %edi,%r8d
  mov    %rax,%rdi
  call   <WriteUnsigned4@plt>
  mov    %rax,-0x10(%rbp)
  mov    -0x18(%rbp),%edi
  mov    -0x18(%rbp),%ecx
  mov    -0x18(%rbp),%edx
  mov    -0x18(%rbp),%esi
  mov    -0x10(%rbp),%rax
  mov    %edi,%r8d
  mov    %rax,%rdi
  call   <WriteUnsigned4@plt>
  mov    %rax,-0x10(%rbp)
  subl   $0x20,-0x1c(%rbp)
L78:
  mov    -0x1c(%rbp),%eax
  test   %eax,%eax
  jns    L154
  mov    -0x1c(%rbp),%eax
  and    $0x10,%eax
  test   %eax,%eax
  je     L42
  mov    -0x18(%rbp),%edi
  mov    -0x18(%rbp),%ecx
  mov    -0x18(%rbp),%edx
  mov    -0x18(%rbp),%esi
  mov    -0x10(%rbp),%rax
  mov    %edi,%r8d
  mov    %rax,%rdi
  call   <WriteUnsigned4@plt>
  mov    %rax,-0x10(%rbp)
L42:
  andl   $0xf,-0x1c(%rbp)
L4:
  subl   $0x8,-0x1c(%rbp)
  jmp    L163
L191:
  mov    -0x18(%rbp),%edx
  mov    -0x18(%rbp),%ecx
  mov    -0x10(%rbp),%rax
  mov    %ecx,%esi
  mov    %rax,%rdi
  call   <WriteUnsigned2@plt>
  mov    %rax,-0x10(%rbp)
  subl   $0x8,-0x1c(%rbp)
L163:
  mov    -0x1c(%rbp),%eax
  test   %eax,%eax
  jns    L191
  mov    -0x1c(%rbp),%eax
  and    $0x4,%eax
  test   %eax,%eax
  je     L184
  mov    -0x10(%rbp),%rax
  lea    0x4(%rax),%rdx
  mov    %rdx,-0x10(%rbp)
  mov    -0x18(%rbp),%edx
  mov    %edx,(%rax)
L184:
  mov    -0x10(%rbp),%rax
  mov    %rax,-0x28(%rbp)
  mov    -0x1c(%rbp),%eax
  and    $0x2,%eax
  test   %eax,%eax
  je     L134
  mov    -0x18(%rbp),%eax
  mov    %eax,%edx
  mov    -0x28(%rbp),%rax
  mov    %dx,(%rax)
  addq   $0x2,-0x28(%rbp)
L134:
  mov    -0x1c(%rbp),%eax
  and    $0x1,%eax
  test   %eax,%eax
  je     L7
  mov    -0x28(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x28(%rbp)
  mov    -0x18(%rbp),%edx
  mov    %dl,(%rax)
L7:
  mov    $0x0,%eax
L193:
  leave
  ret
```

assistant: ```c
char *memset_c(char *restrict ptr, unsigned char fillC, unsigned len) {
  if (len <= 3) {
    if (len >= 1)
      ptr[0] = fillC;
    if (len > 1)
      ptr[1] = fillC;
    if (len == 3)
      ptr[2] = fillC;
    return ptr;
  }
  unsigned fill = (unsigned)fillC;
  char *end = ptr + len;
  {
    unsigned shift = fill << 24;
    shift = shift | (shift >> 8);
    fill = shift | (shift >> 16);
  }
  if ((unsigned)ptr & 1)
    *ptr++ = fill;
  if ((unsigned)ptr & 2) {
    *(unsigned short *)ptr = fill;
    ptr += 2;
  }
  unsigned remain = end - ptr;
  unsigned *restrict wordptr = (unsigned *restrict)ptr;
  if (remain >= 4 && ((unsigned)wordptr & 4)) {
    *wordptr++ = fill;
    remain -= 4;
  }
  if (remain >= 32) {
    if ((unsigned)wordptr & 8)
      wordptr = WriteUnsigned2(wordptr, fill, fill);
    if ((unsigned)wordptr & 16)
      wordptr = WriteUnsigned4(wordptr, fill, fill, fill, fill);
    remain = end - (char *)wordptr;
    remain -= 32;
    while ((int)remain >= 0) {
      wordptr = WriteUnsigned4(wordptr, fill, fill, fill, fill);
      wordptr = WriteUnsigned4(wordptr, fill, fill, fill, fill);
      remain -= 32;
    }
    if ((unsigned)remain & 16)
      wordptr = WriteUnsigned4(wordptr, fill, fill, fill, fill);
    remain &= 0xFU;
  }
  remain -= 8;
  while ((int)remain >= 0) {
    wordptr = WriteUnsigned2(wordptr, fill, fill);
    remain -= 8;
  }
  if (remain & 4)
    *wordptr++ = fill;
  ptr = (char *restrict)wordptr;
  if (remain & 2) {
    *(unsigned short *)ptr = fill;
    ptr += 2;
  }
  if (remain & 1)
    *ptr++ = fill;
  return 0;
}
```