Linux Source Learning (3) 2013-2-27

The process of SETUP.S

1. Use ROM BIOS interrupt to read system hardware information and store to 0x90000 location that is the original BOOTSECT.S location

2. Move the system module from the 0x10000 location to the 0x00000

3. Loading IDTR and GDTR

4. Turn on the A20 address line

5. Reset the 8259A interrupt vector to set the 0x00~0x0f to 0x20~0x2f

6. Set CR0 Register to enter protection mode

7. Jump to the front of the system module Head.s start execution

About A20 Address lines

The A0~a19 address line is required in real mode to determine if the high address is turned on by A20 signal.

The A20 signal read was implemented at the time by a free IO port P2 on the 8042 keyboard.

The memory view at this time

Collected in 2013-02-25 from the Baidu space article has a problem? Click here to give us feedback

Linux Source Learning (3) 2013-2-27