user: 请从给定的汇编指令推导出C源代码:

```asm
<next_arg>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x40,%rsp
  mov    %rdi,-0x28(%rbp)
  mov    %rsi,-0x30(%rbp)
  mov    %rdx,-0x38(%rbp)
  movl   $0x0,-0x14(%rbp)
  movl   $0x0,-0x10(%rbp)
  movl   $0x0,-0xc(%rbp)
  mov    -0x28(%rbp),%rax
  movzbl (%rax),%eax
  cmp    $0x22,%al
  jne    L139
  addq   $0x1,-0x28(%rbp)
  movl   $0x1,-0x10(%rbp)
  movl   $0x1,-0xc(%rbp)
L139:
  movl   $0x0,-0x18(%rbp)
  jmp    L123
L72:
  mov    -0x18(%rbp),%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  mov    %eax,%edi
  call   <isspace@plt>
  test   %rax,%rax
  je     L90
  cmpl   $0x0,-0x10(%rbp)
  je     L16
L90:
  cmpl   $0x0,-0x14(%rbp)
  jne    L77
  mov    -0x18(%rbp),%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x3d,%al
  jne    L77
  mov    -0x18(%rbp),%eax
  mov    %eax,-0x14(%rbp)
L77:
  mov    -0x18(%rbp),%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x22,%al
  jne    L3
  cmpl   $0x0,-0x10(%rbp)
  sete   %al
  movzbl %al,%eax
  mov    %eax,-0x10(%rbp)
L3:
  addl   $0x1,-0x18(%rbp)
L123:
  mov    -0x18(%rbp),%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  test   %al,%al
  jne    L72
  jmp    L60
L16:
  nop
L60:
  mov    -0x30(%rbp),%rax
  mov    -0x28(%rbp),%rdx
  mov    %rdx,(%rax)
  cmpl   $0x0,-0x14(%rbp)
  jne    L111
  mov    -0x38(%rbp),%rax
  movq   $0x0,(%rax)
  jmp    L37
L111:
  mov    -0x14(%rbp),%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movb   $0x0,(%rax)
  mov    -0x14(%rbp),%eax
  lea    0x1(%rax),%rdx
  mov    -0x28(%rbp),%rax
  add    %rax,%rdx
  mov    -0x38(%rbp),%rax
  mov    %rdx,(%rax)
  mov    -0x38(%rbp),%rax
  mov    (%rax),%rax
  movzbl (%rax),%eax
  cmp    $0x22,%al
  jne    L169
  mov    -0x38(%rbp),%rax
  mov    (%rax),%rax
  lea    0x1(%rax),%rdx
  mov    -0x38(%rbp),%rax
  mov    %rdx,(%rax)
  mov    -0x18(%rbp),%eax
  sub    $0x1,%eax
  mov    %eax,%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x22,%al
  jne    L169
  mov    -0x18(%rbp),%eax
  sub    $0x1,%eax
  mov    %eax,%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movb   $0x0,(%rax)
L169:
  cmpl   $0x0,-0xc(%rbp)
  je     L37
  mov    -0x18(%rbp),%eax
  sub    $0x1,%eax
  mov    %eax,%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x22,%al
  jne    L37
  mov    -0x18(%rbp),%eax
  sub    $0x1,%eax
  mov    %eax,%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movb   $0x0,(%rax)
L37:
  mov    -0x18(%rbp),%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  test   %al,%al
  je     L27
  mov    -0x18(%rbp),%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movb   $0x0,(%rax)
  mov    -0x18(%rbp),%eax
  lea    0x1(%rax),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x8(%rbp)
  jmp    L138
L27:
  mov    -0x18(%rbp),%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x8(%rbp)
L138:
  mov    -0x8(%rbp),%rax
  mov    %rax,%rdi
  call   <skip_spaces@plt>
  leave
  ret
```

assistant: ```c
char *next_arg(char *args, char **param, char **val) {
  unsigned int i, equals = 0;
  int in_quote = 0, quoted = 0;
  char *next;
  if (*args == '"') {
    args++;
    in_quote = 1;
    quoted = 1;
  }
  for (i = 0; args[i]; i++) {
    if (isspace(args[i]) && !in_quote)
      break;
    if (equals == 0) {
      if (args[i] == '=')
        equals = i;
    }
    if (args[i] == '"')
      in_quote = !in_quote;
  }
  *param = args;
  if (!equals)
    *val = NULL;
  else {
    args[equals] = '\0';
    *val = args + equals + 1;
    if (**val == '"') {
      (*val)++;
      if (args[i - 1] == '"')
        args[i - 1] = '\0';
    }
    if (quoted && args[i - 1] == '"')
      args[i - 1] = '\0';
  }
  if (args[i]) {
    args[i] = '\0';
    next = args + i + 1;
  } else
    next = args + i;
  return skip_spaces(next);
}
```