user: 提供的汇编代码用C语言表示会是什么样子：

```asm
<replace>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x50,%rsp
  mov    %rdi,-0x38(%rbp)
  mov    %rsi,-0x40(%rbp)
  mov    %rdx,-0x48(%rbp)
  mov    -0x40(%rbp),%rdx
  mov    -0x38(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <strstr@plt>
  mov    %rax,-0x8(%rbp)
  cmpq   $0x0,-0x8(%rbp)
  jne    L45
  mov    -0x38(%rbp),%rax
  jmp    L56
L45:
  mov    -0x48(%rbp),%rax
  mov    %rax,%rdi
  call   <strlen@plt>
  mov    %eax,-0x18(%rbp)
  mov    -0x40(%rbp),%rax
  mov    %rax,%rdi
  call   <strlen@plt>
  mov    %eax,-0x14(%rbp)
  mov    -0x38(%rbp),%rax
  mov    %rax,%rdi
  call   <strlen@plt>
  sub    -0x14(%rbp),%eax
  mov    %eax,-0x10(%rbp)
  mov    -0x8(%rbp),%rax
  sub    -0x38(%rbp),%rax
  mov    %eax,-0x1c(%rbp)
  movl   $0x0,-0x20(%rbp)
  movl   $0x0,-0x24(%rbp)
  jmp    L36
L54:
  mov    -0x1c(%rbp),%eax
  sub    -0x24(%rbp),%eax
  mov    %eax,-0xc(%rbp)
  mov    -0x24(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x38(%rbp),%rax
  lea    (%rdx,%rax,1),%rsi
  mov    -0x20(%rbp),%eax
  cltq
  lea    D8(%rip),%rdx
  lea    (%rax,%rdx,1),%rcx
  mov    -0xc(%rbp),%eax
  mov    %eax,%edx
  mov    %rcx,%rdi
  call   <strncpy@plt>
  mov    -0xc(%rbp),%eax
  add    %eax,-0x20(%rbp)
  mov    -0xc(%rbp),%eax
  add    %eax,-0x24(%rbp)
  mov    -0x20(%rbp),%eax
  cltq
  lea    D8(%rip),%rdx
  add    %rax,%rdx
  mov    -0x48(%rbp),%rax
  mov    %rax,%rsi
  mov    %rdx,%rdi
  call   <strcpy@plt>
  mov    -0x18(%rbp),%eax
  add    %eax,-0x20(%rbp)
  mov    -0x14(%rbp),%eax
  add    %eax,-0x24(%rbp)
  mov    -0x24(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x38(%rbp),%rax
  add    %rax,%rdx
  mov    -0x40(%rbp),%rax
  mov    %rax,%rsi
  mov    %rdx,%rdi
  call   <strstr@plt>
  mov    %rax,-0x8(%rbp)
  cmpq   $0x0,-0x8(%rbp)
  je     L36
  mov    -0x8(%rbp),%rax
  sub    -0x38(%rbp),%rax
  mov    %eax,-0x1c(%rbp)
L36:
  mov    -0x24(%rbp),%eax
  cmp    -0x10(%rbp),%eax
  jg     L55
  cmpq   $0x0,-0x8(%rbp)
  jne    L54
L55:
  mov    -0x24(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x38(%rbp),%rax
  add    %rax,%rdx
  mov    -0x20(%rbp),%eax
  cltq
  lea    D8(%rip),%rcx
  add    %rcx,%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <strcpy@plt>
  lea    D8(%rip),%rax
L56:
  leave
  ret
```

assistant: ```c
char *replace(char *string, char *oldpiece, char *newpiece) {
  int str_index, newstr_index, oldpiece_index, end, new_len, old_len, cpy_len;
  char *c;
  static char newstring[10000];
  if ((c = (char *)strstr(string, oldpiece)) == NULL)
    return string;
  new_len = strlen(newpiece);
  old_len = strlen(oldpiece);
  end = strlen(string) - old_len;
  oldpiece_index = c - string;
  newstr_index = 0;
  str_index = 0;
  while (str_index <= end && c != NULL) {
    cpy_len = oldpiece_index - str_index;
    strncpy(newstring + newstr_index, string + str_index, cpy_len);
    newstr_index += cpy_len;
    str_index += cpy_len;
    strcpy(newstring + newstr_index, newpiece);
    newstr_index += new_len;
    str_index += old_len;
    if ((c = (char *)strstr(string + str_index, oldpiece)) != NULL)
      oldpiece_index = c - string;
  }
  strcpy(newstring + newstr_index, string + str_index);
  return newstring;
}
```