user: Demonstrate the C code that generates the assembly output below:

```asm
<parse_line>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x8,%rsp
  mov    %rdi,%r12
  mov    %rsi,%r14
  mov    %rdx,%r15
  movzbl (%rdi),%eax
  cmp    $0x20,%al
  je     L33
  cmp    $0x9,%al
  jne    L293
L33:
  add    $0x1,%r12
  movzbl (%r12),%eax
  cmp    $0x20,%al
  je     L33
  cmp    $0x9,%al
  je     L33
L293:
  cmp    $0x23,%al
  ja     L276
  movabs $0x800000401,%rdx
  bt     %rax,%rdx
  jb     L32
  mov    %r12,%rbx
  jmp    L131
L297:
  add    $0x1,%rbx
L131:
  movzbl (%rbx),%ebp
  movzbl %bpl,%r13d
  mov    %r13d,%edi
  call   <isalpha@plt>
  cmp    $0x5f,%bpl
  sete   %dl
  cmp    $0x2d,%bpl
  sete   %cl
  or     %cl,%dl
  jne    L297
  test   %eax,%eax
  jne    L297
  mov    %r13d,%edi
  call   <isspace@plt>
  cmp    $0x3d,%bpl
  je     L174
  test   %eax,%eax
  je     L141
L174:
  mov    %rbx,%rdi
  sub    %r12,%rdi
  add    $0x1,%rdi
  mov    $0x0,%eax
  call   <xmalloc@plt>
  cltq
  mov    %rax,(%r14)
  cmp    %r12,%rbx
  ja     L267
L192:
  movb   $0x0,(%rax)
  mov    (%r14),%rdi
  mov    $0x0,%eax
  call   <comind@plt>
  cmp    $0xffffffff,%eax
  jne    L269
  mov    (%r14),%rdi
  call   <free@plt>
  mov    $0x0,%ebp
  jmp    L165
L276:
  mov    %r12,%rbx
  jmp    L131
L141:
  mov    (%r14),%rdi
  call   <free@plt>
  mov    $0x0,%ebp
  jmp    L165
L53:
  add    $0x1,%r12
  cmp    %r12,%rbx
  je     L192
L267:
  movzbl (%r12),%edx
  cmp    $0x5f,%dl
  je     L53
  cmp    $0x2d,%dl
  je     L53
  mov    %dl,(%rax)
  lea    0x1(%rax),%rax
  jmp    L53
L9:
  add    $0x1,%rbx
L269:
  movzbl (%rbx),%r12d
  movzbl %r12b,%edi
  call   <isspace@plt>
  mov    %eax,%ebp
  test   %eax,%eax
  jne    L9
  add    $0x1,%rbx
  cmp    $0x3d,%r12b
  je     L263
  mov    %r14,%rdi
  call   <free@plt>
  jmp    L165
L123:
  add    $0x1,%rbx
L263:
  movzbl (%rbx),%ebp
  movzbl %bpl,%edi
  call   <isspace@plt>
  test   %eax,%eax
  jne    L123
  test   %bpl,%bpl
  je     L113
  cmp    $0xa,%bpl
  je     L113
  mov    %rbx,%rsi
L72:
  add    $0x1,%rsi
  movzbl (%rsi),%eax
  test   %al,%al
  je     L116
  cmp    $0xa,%al
  jne    L72
L116:
  mov    %rbx,%rdi
  mov    $0x0,%eax
  call   <strdupdelim@plt>
  cltq
  mov    %rax,(%r15)
  mov    $0x1,%ebp
L165:
  mov    %ebp,%eax
  add    $0x8,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L113:
  mov    %rbx,%rsi
  jmp    L116
L32:
  mov    $0xffffffff,%ebp
  jmp    L165
```

assistant: ```c
int parse_line(const char *line, char **com, char **val) {
  const char *p = line;
  const char *orig_comptr, *end;
  char *new_comptr;
  while (*p == ' ' || *p == '\t')
    ++p;
  if (!*p || *p == '\n' || *p == '#')
    return -1;
  for (orig_comptr = p; isalpha((unsigned char)(*p)) || *p == '_' || *p == '-'; p++)
    ;
  if (!isspace((unsigned char)(*p)) && (*p != '=')) {
    free(*com);
    return 0;
  }
  *com = (char *)xmalloc(p - orig_comptr + 1);
  for (new_comptr = *com; orig_comptr < p; orig_comptr++) {
    if (*orig_comptr == '_' || *orig_comptr == '-')
      continue;
    *new_comptr++ = *orig_comptr;
  }
  *new_comptr = '\0';
  if (comind(*com) == -1) {
    free(*com);
    return 0;
  }
  for (; isspace((unsigned char)(*p)); p++)
    ;
  if (*p != '=') {
    free(com);
    return 0;
  }
  for (++p; isspace((unsigned char)(*p)); p++)
    ;
  for (end = p; *end && *end != '\n'; end++)
    ;
  *val = strdupdelim(p, end);
  return 1;
}
```