user: 下面的汇编指令对应的C源代码是什么：

```asm
<valid_email>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x20,%rsp
  mov    %rdi,-0x18(%rbp)
  movl   $0x0,-0x4(%rbp)
  movl   $0x0,-0x8(%rbp)
  jmp    L277
L311:
  cmpl   $0x8,-0x4(%rbp)
  ja     L289
  mov    -0x4(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  lea    D13(%rip),%rax
  mov    (%rdx,%rax,1),%eax
  cltq
  lea    D13(%rip),%rdx
  add    %rdx,%rax
  notrack jmp *%rax
  mov    -0x8(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x60,%al
  jle    L100
  mov    -0x8(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x7a,%al
  jg     L100
  addl   $0x1,-0x4(%rbp)
  jmp    L100
  mov    -0x8(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x20,%al
  jne    L136
  addl   $0x1,-0x4(%rbp)
  jmp    L136
  mov    -0x8(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x3c,%al
  jne    L157
  addl   $0x1,-0x4(%rbp)
  jmp    L157
  mov    -0x8(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x60,%al
  jle    L216
  mov    -0x8(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x7a,%al
  jg     L216
  addl   $0x1,-0x4(%rbp)
  jmp    L216
  mov    -0x8(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x40,%al
  jne    L212
  addl   $0x1,-0x4(%rbp)
  jmp    L212
  mov    -0x8(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x60,%al
  jle    L86
  mov    -0x8(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x7a,%al
  jg     L86
  addl   $0x1,-0x4(%rbp)
  jmp    L86
  mov    -0x8(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x2e,%al
  jne    L315
  addl   $0x1,-0x4(%rbp)
  jmp    L315
  mov    -0x8(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x60,%al
  jle    L220
  mov    -0x8(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x7a,%al
  jg     L220
  addl   $0x1,-0x4(%rbp)
  jmp    L220
  mov    -0x8(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x3e,%al
  jne    L155
  addl   $0x1,-0x4(%rbp)
  jmp    L155
L100:
  nop
  jmp    L289
L136:
  nop
  jmp    L289
L157:
  nop
  jmp    L289
L216:
  nop
  jmp    L289
L212:
  nop
  jmp    L289
L86:
  nop
  jmp    L289
L315:
  nop
  jmp    L289
L220:
  nop
  jmp    L289
L155:
  nop
L289:
  addl   $0x1,-0x8(%rbp)
L277:
  mov    -0x18(%rbp),%rax
  mov    %rax,%rdi
  call   <strlen@plt>
  cmp    %eax,-0x8(%rbp)
  jl     L311
  cmpl   $0x9,-0x4(%rbp)
  jne    L149
  mov    $0x1,%eax
  jmp    L139
L149:
  mov    $0x0,%eax
L139:
  leave
  ret
```

assistant: ```c
int valid_email(char *email_address) {
  int i, state = 0;
  for (i = 0; i < strlen(email_address); i++) {
    switch (state) {
    case 0: {
      if ((email_address[i] >= 'a') && (email_address[i] <= 'z')) {
        state++;
      }
      break;
    }
    case 1: {
      if (email_address[i] == ' ') {
        state++;
      }
      break;
    }
    case 2: {
      if (email_address[i] == '<') {
        state++;
      }
      break;
    }
    case 3: {
      if ((email_address[i] >= 'a') && (email_address[i] <= 'z')) {
        state++;
      }
      break;
    }
    case 4: {
      if (email_address[i] == '@') {
        state++;
      }
      break;
    }
    case 5: {
      if ((email_address[i] >= 'a') && (email_address[i] <= 'z')) {
        state++;
      }
      break;
    }
    case 6: {
      if (email_address[i] == '.') {
        state++;
      }
      break;
    }
    case 7: {
      if ((email_address[i] >= 'a') && (email_address[i] <= 'z')) {
        state++;
      }
      break;
    }
    case 8: {
      if (email_address[i] == '>') {
        state++;
      }
      break;
    }
    }
  }
  if (state == 9)
    return 1;
  return 0;
}
```