我想提出一个键盘驱动程序我的OSDev OS和我在我的kbd.c一个问题:错误:可变大小的对象可能未被初始化?
kbd.c: In function 'scancoderec':
kbd.c:56:2: error: variable-sized object may not be initialized
register int (ScanCode[strlen(ValEAX)-8]) = 0x00; /* Remove last 8 bits from the value we gathered from EAX to get AH and make that the scancode. */
这里是包含的代码失败行的功能:
int scancoderec() {
__asm__ volatile("movl $0, %eax"); /* Moving 00 to EAX. */
__asm__ volatile("int $0x16 "); /*int 0x16 */
register int ValEAX asm("eax"); /* Let's get eax */
register int (ScanCode[strlen(ValEAX)-8]) = 0x00; /* Remove last 8 bits from the value we gathered from EAX to get AH and make that the scancode. */
}
为什么这是否发生?
编辑:我仍然有这个“ax”是未定义的,这次,在另一个函数中。
kbd.c:65:27: error: 'ax' undeclared (first use in this function)
register int Key = kbdus[ax];
扫描码功能和信息getKey功能的代码:
unsigned short scancodeget()
{
unsigned char ax = 0; /* int 0x16, AH=0 is get keystroke */
__asm__ __volatile__ ("int $0x16\n\t"
: "+a"(ax));
ax = ax >> 8; /* Shift top 8 bits of ax to lower 8 bits */
/* ax now is the scancode returned by BIOS */
return (unsigned short)ax; /* Return the lower 8 bits */
}
int getkey() { /*This could be used as a keyboard driver. */
scancoderec(); /*Get our scancode! */
int Key = kbdus[ax]; /*Use our kbdus array which i copied from a website since i seriously don't want to make an gigantic array */
}
编译器认为你正在声明一个名为'ScanCode'的数组。坦率地说,我不知道你要在代码中做什么。 – user3386109
评论说:“从值中删除最后8位...” - >看起来像“删除最后8个字节...” – chux
嗯,如果'strlen(ValEAX)<= 8',代码肯定会有麻烦。 – chux