Checkpoint | Description |
38 | Initializes different devices through DIM. See DIM Code Checkpoints |
| section of document for more information. |
39 | Initializes |
3A | Initialize RTC date/time. |
3B | Test for total memory installed in the system. Also, Check for DEL or |
| ESC keys to limit memory test. Display total memory in the system. |
3C | Mid POST initialization of chipset registers. |
40 | Detect different devices (Parallel ports, serial ports, and coprocessor |
| in CPU, … etc.) successfully installed in the system and update the |
| BDA, EBDA…etc. |
|
|
50 | Programming the memory hole or any kind of implementation that |
| needs an adjustment in system RAM size if needed. |
52 | Updates CMOS memory size from memory found in memory test. |
| Allocates memory for Extended BIOS Data Area from base memory. |
60 | Initializes |
75 | Initialize |
78 | Initializes IPL devices controlled by BIOS and option ROMs. |
7A | Initializes remaining option ROMs. |
7C | Generate and write contents of ESCD in NVRam. |
84 | Log errors encountered during POST. |
85 | Display errors to the user and gets the user response for error. |
87 | Execute BIOS setup if needed / requested. |
8C | Late POST initialization of chipset registers. |
8E | Program the peripheral parameters. Enable/Disable NMI as selected |
90 | Late POST initialization of system management interrupt. |
A0 | Check boot password if installed. |
A1 | |
A2 | Takes care of runtime image preparation for different BIOS modules. |
| Fill the free area in F000h segment with 0FFh. Initializes the |
| Microsoft IRQ Routing Table. Prepares the runtime language module. |
| Disables the system configuration display if needed. |
A4 | Initialize runtime language module. |
A7 | Displays the system configuration screen if enabled. Initialize the |
| CPU’s before boot, which includes the programming of the MTRR’s. |
A8 | Prepare CPU for OS boot including final MTRR values. |
A9 | Wait for user input at config display if needed. |
AA | Uninstall POST INT1Ch vector and INT09h vector. Deinitializes the |
| ADM module. |
AB | Prepare BBS for Int 19 boot. |
AC | End of POST initialization of chipset registers. |
B1 | Save system context for ACPI. |
00 | Passes control to OS Loader (typically INT19h). |
69