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
");
(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