user: 请显示与下面列出的汇编代码相匹配的C语言实现:

```asm
<Tcl_Backslash>:
  endbr64
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x8,%rsp
  mov    %rdi,%r12
  mov    %rsi,%rbp
  movzbl 0x1(%rdi),%ebx
  cmp    $0x4d,%bl
  jle    L12
  lea    -0x5b(%rbx),%eax
  cmp    $0x22,%al
  ja     L32
  lea    -0x5b(%rbx),%eax
  cmp    $0x22,%al
  ja     L23
  movzbl %al,%eax
  lea    D8(%rip),%rdx
  movslq (%rdx,%rax,4),%rax
  add    %rdx,%rax
  notrack jmp *%rax
L12:
  cmp    $0x1f,%bl
  jle    L23
  lea    -0x20(%rbx),%ecx
  mov    $0x1,%eax
  shl    %cl,%rax
  test   $0x8000015,%eax
  jne    L251
  cmp    $0x4d,%bl
  je     L158
  cmp    $0x43,%bl
  je     L181
L23:
  movsbl %bl,%eax
  sub    $0x30,%eax
  cmp    $0x9,%eax
  ja     L165
  sub    $0x30,%ebx
  movzbl 0x2(%r12),%edx
  movsbl %dl,%eax
  sub    $0x30,%eax
  cmp    $0x9,%eax
  jbe    L294
  mov    $0x2,%eax
  jmp    L315
  mov    $0x2,%eax
  mov    $0x1b,%ebx
  jmp    L315
  mov    $0x2,%eax
  mov    $0xa,%ebx
  jmp    L315
  mov    $0x2,%eax
  mov    $0x9,%ebx
  jmp    L315
L181:
  movzbl 0x2(%rdi),%r13d
  movsbl %r13b,%edi
  call   <isspace@plt>
  test   %r13b,%r13b
  je     L250
  test   %eax,%eax
  jne    L250
  mov    %r13d,%ebx
  and    $0x1f,%ebx
  mov    $0x3,%eax
  cmp    $0x4d,%r13b
  jne    L315
  movzbl 0x3(%r12),%ebx
  movsbl %bl,%edi
  call   <isspace@plt>
  test   %bl,%bl
  je     L271
  test   %eax,%eax
  jne    L271
  and    $0x1f,%ebx
  or     $0xffffff80,%ebx
  mov    $0x4,%eax
  jmp    L315
L158:
  movzbl 0x2(%rdi),%r12d
  movsbl %r12b,%edi
  call   <isspace@plt>
  test   %r12b,%r12b
  je     L146
  test   %eax,%eax
  jne    L146
  lea    -0x80(%r12),%ebx
  mov    $0x3,%eax
  jmp    L315
  mov    $0x2,%eax
L315:
  test   %rbp,%rbp
  je     L100
  mov    %eax,0x0(%rbp)
L100:
  mov    %ebx,%eax
  add    $0x8,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  ret
L294:
  lea    -0x30(%rdx,%rbx,8),%ebx
  movzbl 0x3(%r12),%edx
  movsbl %dl,%eax
  sub    $0x30,%eax
  cmp    $0x9,%eax
  jbe    L29
  mov    $0x3,%eax
  jmp    L315
L29:
  lea    -0x30(%rdx,%rbx,8),%ebx
  mov    $0x4,%eax
  jmp    L315
  mov    $0x2,%eax
  mov    $0x8,%ebx
  jmp    L315
L251:
  mov    $0x2,%eax
  jmp    L315
L32:
  mov    $0x1,%eax
  mov    $0x5c,%ebx
  jmp    L315
L250:
  mov    $0x1,%eax
  jmp    L315
L271:
  mov    $0x3,%eax
  mov    $0xd,%ebx
  jmp    L315
L146:
  mov    $0x1,%eax
  jmp    L315
L165:
  mov    $0x1,%eax
  mov    $0x5c,%ebx
  jmp    L315
```

assistant: ```c
char Tcl_Backslash(src, readPtr)
char *src;
int *readPtr;
{
  register char *p = src + 1;
  char result;
  int count;
  count = 2;
  switch (*p) {
  case 'b':
    result = '\b';
    break;
  case 'e':
    result = 033;
    break;
  case 'n':
    result = '\n';
    break;
  case 't':
    result = '\t';
    break;
  case 'C':
    p++;
    if (isspace(*p) || (*p == 0)) {
      result = 'C';
      count = 1;
      break;
    }
    count = 3;
    if (*p == 'M') {
      p++;
      if (isspace(*p) || (*p == 0)) {
        result = 'M' & 037;
        break;
      }
      count = 4;
      result = (*p & 037) | 0200;
      break;
    }
    count = 3;
    result = *p & 037;
    break;
  case 'M':
    p++;
    if (isspace(*p) || (*p == 0)) {
      result = 'M';
      count = 1;
      break;
    }
    count = 3;
    result = *p + 0200;
    break;
  case '}':
  case '{':
  case ']':
  case '[':
  case '$':
  case ' ':
  case ';':
  case '"':
  case '\\':
    result = *p;
    break;
  default:
    if (isdigit(*p)) {
      result = *p - '0';
      p++;
      if (!isdigit(*p)) {
        break;
      }
      count = 3;
      result = (result << 3) + (*p - '0');
      p++;
      if (!isdigit(*p)) {
        break;
      }
      count = 4;
      result = (result << 3) + (*p - '0');
      break;
    }
    result = '\\';
    count = 1;
    break;
  }
  if (readPtr != 0) {
    *readPtr = count;
  }
  return result;
}
```