user: 请从给定的汇编指令推导出C源代码：

```asm
<fftkey>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x78,%rsp
  mov    %rdi,0x8(%rsp)
  mov    %fs:0x28,%rax
  mov    %rax,0x68(%rsp)
  xor    %eax,%eax
  mov    (%rsi),%eax
  test   %eax,%eax
  jg     L200
  mov    %rdi,%rbx
  mov    %rsi,%r12
  call   <strlen@plt>
  mov    $0x8,%r13d
  cmp    %r13,%rax
  cmovbe %rax,%r13
  test   %rax,%rax
  je     L139
  mov    $0x0,%r14d
  mov    $0x0,%ebp
  movabs $0x43ffffff01ff9,%r15
  jmp    L199
L148:
  movsbl (%rbx),%edi
  call   <toupper@plt>
  jmp    L77
L57:
  test   %r14d,%r14d
  jne    L125
L74:
  add    $0x1,%rbp
  add    $0x1,%rbx
  cmp    %rbp,%r13
  jbe    L139
L199:
  cmpl   $0x0,(%r12)
  jne    L148
  movzbl (%rbx),%eax
L77:
  sub    $0x2d,%eax
  cmp    $0x32,%al
  ja     L196
  bt     %rax,%r15
  jb     L57
L196:
  mov    %rbx,%r14
  cmpb   $0x20,(%rbx)
  jne    L173
  mov    $0x1,%r14d
  jmp    L74
L125:
  cmpl   $0x0,(%r12)
  je     L118
L23:
  movl   $0xcf,(%r12)
  mov    $0xcf,%eax
  jmp    L200
L118:
  lea    0x10(%rsp),%rbx
  mov    0x8(%rsp),%rcx
  lea    D27(%rip),%rdx
  mov    $0x51,%esi
  mov    %rbx,%rdi
  mov    $0x0,%eax
  call   <snprintf@plt>
  mov    %rbx,%rdi
  call   <ffpmsg@plt>
  jmp    L23
L173:
  cmpl   $0x0,(%r12)
  je     L167
L147:
  movl   $0xcf,(%r12)
  mov    $0xcf,%eax
  jmp    L200
L167:
  lea    0x1(%rbp),%ecx
  lea    0x10(%rsp),%rbx
  mov    0x8(%rsp),%r8
  lea    D12(%rip),%rdx
  mov    $0x51,%esi
  mov    %rbx,%rdi
  mov    $0x0,%eax
  call   <snprintf@plt>
  mov    %rbx,%rdi
  call   <ffpmsg@plt>
  movzbl (%r14),%eax
  test   %al,%al
  je     L135
  cmp    $0x9,%al
  jne    L147
  lea    D30(%rip),%rdi
  call   <ffpmsg@plt>
  jmp    L147
L135:
  lea    D31(%rip),%rdi
  call   <ffpmsg@plt>
  jmp    L147
L139:
  mov    (%r12),%eax
L200:
  mov    0x68(%rsp),%rdx
  sub    %fs:0x28,%rdx
  jne    L205
  add    $0x78,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L205:
  call   <__stack_chk_fail@plt>
```

tool_calls: name: read_data
arguments: label: D27
type_infered: string
name: read_data
arguments: label: D12
type_infered: string
name: read_data
arguments: label: D30
type_infered: string
name: read_data
arguments: label: D31
type_infered: string

tool: D27: Keyword name contains embedded space(s): %.8s

tool: D12: Character %d in this keyword is illegal: %.8s

tool: D30:  (This an ASCII TAB (9) character).

tool: D31:  (This a NULL (0) character).

assistant: ```c
int fftkey(const char *keyword, int *status) {
  size_t maxchr, ii;
  int spaces = 0;
  char msg[81], testchar;
  if (*status > 0)
    return (*status);
  maxchr = strlen(keyword);
  if (maxchr > 8)
    maxchr = 8;
  for (ii = 0; ii < maxchr; ii++) {
    if (*status == 0)
      testchar = keyword[ii];
    else
      testchar = toupper(keyword[ii]);
    if ((testchar >= 'A' && testchar <= 'Z') || (testchar >= '0' && testchar <= '9') || testchar == '-' || testchar == '_') {
      if (spaces) {
        if (*status == 0) {
          snprintf(msg, 81, "Keyword name contains embedded space(s): %.8s", keyword);
          ffpmsg(msg);
        }
        return (*status = 207);
      }
    } else if (keyword[ii] == ' ')
      spaces = 1;
    else {
      if (*status == 0) {
        snprintf(msg, 81, "Character %d in this keyword is illegal: %.8s", (int)(ii + 1), keyword);
        ffpmsg(msg);
        if (keyword[ii] == 0)
          ffpmsg(" (This a NULL (0) character).");
        else if (keyword[ii] == 9)
          ffpmsg(" (This an ASCII TAB (9) character).");
      }
      return (*status = 207);
    }
  }
  return (*status);
}
```