user: 请从给定的汇编指令推导出C源代码:

```asm
<entab>:
  endbr64
  push   %r15
  push   %r14
  mov    %edi,%r14d
  push   %r13
  xor    %r13d,%r13d
  push   %r12
  xor    %r12d,%r12d
  push   %rbp
  xor    %ebp,%ebp
  push   %rbx
  sub    $0x18,%rsp
  mov    %esi,0xc(%rsp)
  nopl   0x0(%rax)
L79:
  xor    %eax,%eax
  call   <getchar@plt>
  mov    %eax,%ebx
  mov    D2(%rip),%rax
  cmp    %ebx,(%rax)
  je     L268
  cmp    $0x20,%ebx
  setne  %dl
  cmp    0xc(%rsp),%r13d
  setge  %al
  test   %ebp,%ebp
  jne    L145
  cmp    $0xa,%ebx
  je     L145
  test   %dl,%dl
  je     L269
  test   %al,%al
  je     L269
  movsbl %bl,%edi
  add    $0x1,%r12d
  call   <putchar@plt>
  nopl   0x0(%rax,%rax,1)
L124:
  lea    -0x9(%rbx),%eax
  cmp    $0x1,%eax
  jbe    L231
  cmp    %r12d,%r14d
  jg     L265
L231:
  xor    %eax,%eax
  xor    %r12d,%r12d
  cmp    $0xa,%ebx
  cmove  %eax,%r13d
L265:
  cmp    0xc(%rsp),%r13d
  jge    L79
  movsbl %bl,%edi
  add    $0x1,%r13d
  call   <putchar@plt>
  jmp    L79
  xchg   %ax,%ax
L269:
  cmp    $0x20,%ebx
  jne    L124
  cmp    $0x1,%al
  sbb    $0xffffffff,%ebp
  jmp    L124
  nopl   0x0(%rax)
L145:
  test   %ebp,%ebp
  jle    L269
  test   %dl,%dl
  je     L269
  cmp    %r14d,%ebp
  jl     L5
  test   %al,%al
  jne    L42
  cmp    %r14d,%ebp
  jge    L124
L5:
  test   %al,%al
  je     L124
L181:
  mov    %ebp,%r15d
  nopl   (%rax)
L107:
  mov    $0x20,%edi
  call   <putchar@plt>
  sub    $0x1,%r15d
  jne    L107
  test   %ebp,%ebp
  mov    $0x1,%eax
  movsbl %bl,%edi
  cmovg  %ebp,%eax
  sub    %eax,%ebp
  call   <putchar@plt>
  jmp    L124
  nopl   0x0(%rax)
L42:
  mov    $0x9,%edi
  sub    %r14d,%ebp
  call   <putchar@plt>
  cmp    %ebp,%r14d
  jle    L42
  test   %r12d,%r12d
  jle    L108
  nopw   0x0(%rax,%rax,1)
L242:
  mov    $0x20,%edi
  call   <putchar@plt>
  sub    $0x1,%r12d
  jne    L242
L108:
  test   %ebp,%ebp
  je     L203
  cmp    %ebp,%r14d
  jg     L181
L20:
  lea    -0x9(%rbx),%eax
  cmp    $0x1,%eax
  jbe    L231
  jmp    L79
  nopw   0x0(%rax,%rax,1)
L268:
  mov    $0xa,%edi
  call   <putchar@plt>
  add    $0x18,%rsp
  xor    %eax,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax,%rax,1)
L203:
  movsbl %bl,%edi
  call   <putchar@plt>
  jmp    L20
```

assistant: ```c
int entab(int TABSTOP, int m) {
  int c, spc, column, counter;
  spc = column = counter = 0;
  while ((c = getchar()) != EOF) {
    if (spc == 0 && c != '\n' && c != ' ' && counter >= m) {
      column++;
      putchar(c);
    }
    if (spc > 0 && c != ' ' && spc >= TABSTOP && counter >= m) {
      while (spc >= TABSTOP) {
        putchar('\t');
        spc -= TABSTOP;
      }
      while (column > 0) {
        putchar(' ');
        column--;
      }
      if (spc == 0)
        putchar(c);
    }
    if (spc > 0 && c != ' ' && spc < TABSTOP && counter >= m) {
      while (spc > 0 && spc < TABSTOP) {
        putchar(' ');
        spc--;
      }
      putchar(c);
    }
    if (c == ' ' && counter >= m)
      spc++;
    if (column >= TABSTOP || c == '\n' || c == '\t')
      column = 0;
    if (c == '\n')
      counter = 0;
    if (counter < m) {
      counter++;
      putchar(c);
    }
  }
  putchar('\n');
  return 0;
}
```