user: 请从给定的汇编指令推导出C源代码：

```asm
<entab>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  mov    %rdi,%r13
  lea    0x1(%rsi),%edi
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x18,%rsp
  call   <malloc@plt>
  mov    %r13,%rsi
  mov    %rax,%r14
  mov    %rax,%rdi
  call   <strcpy@plt>
  movzbl (%r14),%eax
  test   %al,%al
  je     L49
  xor    %r12d,%r12d
  xor    %esi,%esi
  xor    %ecx,%ecx
  jmp    L101
L103:
  mov    %al,(%r15)
  add    $0x1,%r12d
  movslq %edx,%rbx
  mov    %edx,%esi
  add    %r14,%rbx
  movslq %r12d,%rcx
L66:
  movzbl (%rbx),%eax
  test   %al,%al
  je     L63
L101:
  lea    0x0(%r13,%rcx,1),%r15
  lea    0x1(%rsi),%edx
  cmp    $0x20,%al
  jne    L103
  movslq %esi,%rax
  mov    %esi,%ebp
  add    %r14,%rax
  nopl   0x0(%rax)
L65:
  mov    %rax,%rbx
  mov    %ebp,%r8d
  lea    0x1(%rax),%rax
  add    $0x1,%ebp
  cmpb   $0x20,(%rbx)
  je     L65
  mov    %esi,%edi
  mov    %r8d,(%rsp)
  mov    %rcx,0x8(%rsp)
  mov    %esi,0x4(%rsp)
  call   <getStop@plt>
  mov    (%rsp),%r8d
  cmp    %eax,%ebp
  jge    L32
  mov    0x4(%rsp),%esi
  mov    0x8(%rsp),%rcx
  sub    %esi,%ebp
  mov    %ebp,%eax
  sar    $0x1f,%eax
  shr    $0x1d,%eax
  add    %eax,%ebp
  and    $0x7,%ebp
  sub    %eax,%ebp
  cmp    $0x1,%ebp
  jle    L48
  lea    -0x2(%rbp),%edx
  mov    $0x20,%esi
  lea    -0x1(%r12,%rbp,1),%r12d
  mov    %r15,%rdi
  add    $0x1,%rdx
  call   <memset@plt>
  movzbl (%rbx),%eax
  mov    (%rsp),%esi
  movslq %r12d,%rcx
  test   %al,%al
  jne    L101
  nopl   0x0(%rax,%rax,1)
L63:
  add    %rcx,%r13
L49:
  movb   $0x0,0x0(%r13)
  add    $0x18,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nop
L32:
  mov    %ebp,%ecx
  lea    0x8(%rax),%r9d
  mov    $0x9,%esi
  mov    %r15,%rdi
  sub    %eax,%ecx
  mov    %r8d,0x8(%rsp)
  shr    $0x3,%ecx
  mov    %r9d,0x4(%rsp)
  lea    0x1(%rcx),%edx
  mov    %ecx,(%rsp)
  movslq %edx,%rdx
  call   <memset@plt>
  mov    (%rsp),%ecx
  mov    0x4(%rsp),%r9d
  mov    0x8(%rsp),%r8d
  lea    (%r9,%rcx,8),%eax
  lea    0x1(%rcx,%r12,1),%r12d
  sub    %eax,%ebp
  cmp    $0xfffffff9,%ebp
  jl     L79
  movslq %r12d,%rdi
  lea    0x7(%rbp),%edx
  mov    $0x20,%esi
  mov    %r8d,(%rsp)
  add    $0x1,%rdx
  add    %r13,%rdi
  lea    0x8(%r12,%rbp,1),%r12d
  call   <memset@plt>
  mov    (%rsp),%esi
  movslq %r12d,%rcx
  jmp    L66
L48:
  mov    %r8d,%esi
  jmp    L66
L79:
  mov    %r8d,%esi
  movslq %r12d,%rcx
  jmp    L66
```

assistant: ```c
void entab(char *line, int len) {
  int i, m = 0, j, k, stop, nt = 0, nb = 0;
  i = 0;
  j = 0;
  char *copy = (char *)malloc(len + 1);
  strcpy(copy, line);
  while (copy[i] != '\0') {
    if (copy[i] == ' ') {
      k = i;
      while (copy[k++] == ' ')
        ;
      nt = 0;
      nb = 0;
      stop = getStop(i);
      if (k < stop) {
        nb = (k - i) % 8;
        for (m = 0; m < nb - 1; m++) {
          line[j++] = ' ';
        }
      } else {
        while (stop <= k) {
          nt++;
          stop += 8;
        }
        for (m = 0; m < nt; m++) {
          line[j++] = '\t';
        }
        for (m = 0; m < k - stop + 8; m++) {
          line[j++] = ' ';
        }
      }
      i = --k;
    } else {
      line[j++] = copy[i++];
    }
  }
  line[j] = '\0';
}
```