a gcc 4.2.4 bug(被stos指令累加后%edi作为参数的)

a gcc 4.2.4 bug(被stos指令累加后%edi作为参数的)

*
 * Ok, now we can initialize the rest of the tty devices and can count
 * on memory allocations, interrupts etc..
 */
int tty_init(void)
{
    if (sizeof(struct tty_struct) > PAGE_SIZE)
        panic("size of tty structure > PAGE_SIZE!");

/*
     * dev_tty_driver and dev_console_driver are actually magic
     * devices which get redirected at open time.  Nevertheless,
     * we register them so that register_chrdev is called
     * appropriately.
     */
    memset(&dev_tty_driver, 0, sizeof(struct tty_driver));
    dev_tty_driver.magic = TTY_DRIVER_MAGIC;
    dev_tty_driver.name = "tty";
    dev_tty_driver.name_base = 0;
    dev_tty_driver.major = TTY_MAJOR;
    dev_tty_driver.minor_start = 0;
    dev_tty_driver.num = 1;
    
    if (tty_register_driver(&dev_tty_driver))
        panic("Couldn't register /dev/tty driver\n");
        
        
(gdb) disassemble
Dump of assembler code for function tty_init:
0x0013ff5c <tty_init+0>:    push   %edi
0x0013ff5d <tty_init+1>:    sub    $0x14,%esp
0x0013ff60 <tty_init+4>:    mov    $0x16bb40,%edi
0x0013ff65 <tty_init+9>:    xor    %eax,%eax
0x0013ff67 <tty_init+11>:    mov    $0x27,%ecx
0x0013ff6c <tty_init+16>:    cld    
0x0013ff6d <tty_init+17>:    rep stos %eax,%es:(%edi)
0x0013ff6f <tty_init+19>:    movl   $0x5402,0x16bb40
0x0013ff79 <tty_init+29>:    movl   $0x1567ed,0x16bb44
0x0013ff83 <tty_init+39>:    movl   $0x0,0x16bb48
0x0013ff8d <tty_init+49>:    movw   $0x4,0x16bb4c
0x0013ff96 <tty_init+58>:    movw   $0x0,0x16bb4e
0x0013ff9f <tty_init+67>:    movw   $0x1,0x16bb50
0x0013ffa8 <tty_init+76>:    push   %edi
0x0013ffa9 <tty_init+77>:    call   0x13fec4 <tty_register_driver>

注:%edi被stos又作为tty_register_driver参数，显然不对，这应该是gcc 4.2.4的bug