user: 下面的汇编指令对应的C源代码是什么：

```asm
<string_thirdword>:
  endbr64
  push   %r14
  push   %r13
  push   %r12
  mov    %rdi,%r12
  push   %rbp
  xor    %ebp,%ebp
  push   %rbx
  mov    %r12,%rbx
  call   <strlen@plt>
  jmp    L34
  nopl   0x0(%rax,%rax,1)
L167:
  add    $0x1,%rbx
  cmpb   $0x0,-0x1(%rbx)
  je     L2
  add    $0x1,%ebp
L34:
  movsbl (%rbx),%edi
  call   <isspace@plt>
  test   %rax,%rax
  jne    L167
  movsbl (%rbx),%edi
  test   %dil,%dil
  je     L2
  movslq %ebp,%rax
  lea    0x1(%r12,%rax,1),%rbx
  jmp    L162
  nopl   0x0(%rax)
L198:
  movsbl (%rbx),%edi
  add    $0x1,%rbx
  add    $0x1,%ebp
  test   %dil,%dil
  je     L2
L162:
  call   <isspace@plt>
  test   %rax,%rax
  je     L198
L2:
  movslq %ebp,%rbx
  add    %r12,%rbx
  sub    %ebx,%ebp
  jmp    L121
  nopl   0x0(%rax,%rax,1)
L127:
  add    $0x1,%rbx
  cmpb   $0x0,-0x1(%rbx)
  je     L214
L121:
  movsbl (%rbx),%edi
  lea    0x0(%rbp,%rbx,1),%r13d
  call   <isspace@plt>
  test   %rax,%rax
  jne    L127
  movsbl (%rbx),%edi
  test   %dil,%dil
  je     L214
  movslq %r13d,%rax
  lea    0x1(%r12,%rax,1),%rbx
  jmp    L23
  cs nopw 0x0(%rax,%rax,1)
L223:
  movsbl (%rbx),%edi
  add    $0x1,%rbx
  add    $0x1,%r13d
  test   %dil,%dil
  je     L214
L23:
  call   <isspace@plt>
  test   %rax,%rax
  je     L223
L214:
  movslq %r13d,%rbx
  add    %r12,%rbx
  sub    %ebx,%r13d
  jmp    L271
  nopl   (%rax)
L212:
  add    $0x1,%rbx
  cmpb   $0x0,(%r14)
  je     L230
L271:
  movsbl (%rbx),%edi
  lea    0x0(%r13,%rbx,1),%ebp
  mov    %rbx,%r14
  call   <isspace@plt>
  test   %rax,%rax
  jne    L212
  movsbl (%rbx),%edi
  test   %dil,%dil
  je     L230
  movslq %ebp,%r13
  mov    %ebp,%ebx
  lea    0x1(%r12,%r13,1),%r14
  jmp    L152
  nopl   0x0(%rax,%rax,1)
L59:
  movsbl (%r14),%edi
  add    $0x1,%r14
  add    $0x1,%ebx
  test   %dil,%dil
  je     L186
L152:
  call   <isspace@plt>
  test   %rax,%rax
  je     L59
  sub    $0x1,%ebx
L186:
  cmp    %ebp,%ebx
  jl     L351
L110:
  mov    %ebx,%ecx
  sub    %ebp,%ecx
  cmp    $0x6,%ecx
  jbe    L55
  cmp    %ebp,%ebx
  jl     L55
  lea    0x1(%rcx),%esi
  mov    $0x1,%eax
  cmovge %esi,%eax
  mov    %eax,%edx
  cmp    $0xe,%ecx
  jbe    L190
  mov    %eax,%ecx
  lea    (%r12,%r13,1),%rdi
  xor    %eax,%eax
  shr    $0x4,%ecx
  shl    $0x4,%rcx
  nopw   0x0(%rax,%rax,1)
L203:
  movdqu (%rdi,%rax,1),%xmm0
  movups %xmm0,(%r12,%rax,1)
  add    $0x10,%rax
  cmp    %rcx,%rax
  jne    L203
  mov    %edx,%ecx
  and    $0xfffffff0,%ecx
  mov    %ecx,%r8d
  lea    (%rcx,%rbp,1),%edi
  cmp    %ecx,%edx
  je     L381
L252:
  mov    %edx,%eax
  sub    %ecx,%eax
  lea    -0x1(%rax),%edx
  cmp    $0x6,%edx
  jbe    L338
  add    %r12,%r13
  mov    0x0(%r13,%rcx,1),%rdx
  mov    %rdx,(%r12,%rcx,1)
  mov    %eax,%edx
  and    $0xfffffff8,%edx
  add    %edx,%edi
  add    %edx,%r8d
  cmp    %edx,%eax
  je     L381
L338:
  movslq %edi,%rdx
  lea    0x1(%rdi),%eax
  lea    0x1(%r8),%ecx
  movzbl (%r12,%rdx,1),%r9d
  movslq %r8d,%rdx
  mov    %r9b,(%r12,%rdx,1)
  cmp    %ebx,%eax
  jg     L381
  cltq
  lea    0x2(%rdi),%edx
  lea    0x2(%r8),%r9d
  movslq %ecx,%rcx
  movzbl (%r12,%rax,1),%eax
  mov    %al,(%r12,%rcx,1)
  cmp    %edx,%ebx
  jl     L381
  movslq %edx,%rdx
  lea    0x3(%rdi),%eax
  lea    0x3(%r8),%ecx
  movslq %r9d,%r9
  movzbl (%r12,%rdx,1),%edx
  mov    %dl,(%r12,%r9,1)
  cmp    %eax,%ebx
  jl     L381
  cltq
  lea    0x4(%rdi),%edx
  lea    0x4(%r8),%r9d
  movslq %ecx,%rcx
  movzbl (%r12,%rax,1),%eax
  mov    %al,(%r12,%rcx,1)
  cmp    %edx,%ebx
  jl     L381
  movslq %edx,%rdx
  lea    0x5(%rdi),%eax
  lea    0x5(%r8),%ecx
  movslq %r9d,%r9
  movzbl (%r12,%rdx,1),%edx
  mov    %dl,(%r12,%r9,1)
  cmp    %eax,%ebx
  jl     L381
  cltq
  movslq %ecx,%rcx
  add    $0x6,%edi
  add    $0x6,%r8d
  movzbl (%r12,%rax,1),%eax
  mov    %al,(%r12,%rcx,1)
  cmp    %edi,%ebx
  jl     L381
  movslq %edi,%rdi
  movslq %r8d,%r8
  movzbl (%r12,%rdi,1),%eax
  mov    %al,(%r12,%r8,1)
L381:
  cmp    %ebp,%ebx
  mov    $0x1,%eax
  cmovl  %eax,%esi
  mov    %r12,%rax
  movslq %esi,%rsi
  add    %r12,%rsi
  movb   $0x0,(%rsi)
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  ret
  nopl   0x0(%rax,%rax,1)
L230:
  mov    %ebp,%ebx
  movslq %ebp,%r13
  jmp    L110
  nopw   0x0(%rax,%rax,1)
L55:
  mov    %r12,%rdx
  sub    %r13,%rdx
  cs nopw 0x0(%rax,%rax,1)
L16:
  movzbl (%r12,%r13,1),%eax
  mov    %al,(%rdx,%r13,1)
  add    $0x1,%r13
  cmp    %r13d,%ebx
  jge    L16
  lea    0x1(%rcx),%esi
  jmp    L381
  nopw   0x0(%rax,%rax,1)
L351:
  mov    %r12,%rsi
  mov    %r12,%rax
  movb   $0x0,(%rsi)
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  ret
L190:
  mov    %ebp,%edi
  xor    %ecx,%ecx
  xor    %r8d,%r8d
  jmp    L252
```

assistant: ```c
char *string_thirdword(char *s) {
  int i = 0;
  int j = strlen(s) - 1;
  int k = 0;
  while (isspace(s[i]) && s[i] != '\0')
    i++;
  while (s[i] != '\0') {
    if (isspace(s[i]))
      break;
    i++;
  }
  while (isspace(s[i]) && s[i] != '\0')
    i++;
  while (s[i] != '\0') {
    if (isspace(s[i])) {
      break;
    }
    i++;
  }
  while (isspace(s[i]) && s[i] != '\0')
    i++;
  j = i;
  while (s[j] != '\0') {
    if (isspace(s[j])) {
      j--;
      break;
    }
    j++;
  }
  while (i <= j)
    s[k++] = s[i++];
  s[k] = '\0';
  return s;
}
```