Vol. 3A 9-43
PROCESSOR MANAGEMENT AND INITIALIZATION
In order to assure that the BIOS function is present, the caller must verify the carry flag, the return code, and the
64-bit signature. The update count reflects the number of 2048-byte blocks available for storage within one non-
volatile RAM.
The loader version number refers to the revision of the update loader program that is included in the system BIOS
image.
9.11.8.6 Function 01H—Write Microcode Update Data
This function integrates a new microcode update into the BIOS storage device. Table 9-15 lists the parameters and
return codes for the function.
SI
Update Count
Number of 2048 update blocks in NVRAM the BIOS allocated to storing
microcode updates
Return Codes (see Table 9-19 for code definitions
SUCCESS
The function completed successfully.
NOT_IMPLEMENTED
The function is not implemented.
Table 9-15. Parameters for the Write Update Data Function
Input
AX
Function Code
0D042H
BL
Sub-function
01H - Write update
ES:DI
Update Address
Real Mode pointer to the Intel Update structure. This buffer is 2048 bytes in
length if the processor supports only fixed-size microcode update or...
Real Mode pointer to the Intel Update structure. This buffer is 64 KBytes in
length if the processor supports a variable-size microcode update.
CX
Scratch Pad1
Real mode segment address of 64 KBytes of RAM block
DX
Scratch Pad2
Real mode segment address of 64 KBytes of RAM block
SI
Scratch Pad3
Real mode segment address of 64 KBytes of RAM block
SS:SP
Stack pointer
32 KBytes of stack minimum
Output
CF
Carry Flag
Carry Set - Failure - AH Contains status
Carry Clear - All return values valid
AH
Return Code
Status of the call
AL
OEM Error
Additional OEM information
Return Codes (see Table 9-19 for code definitions
SUCCESS
The function completed successfully.
NOT_IMPLEMENTED
The function is not implemented.
WRITE_FAILURE
A failure occurred because of the inability to write the storage device.
ERASE_FAILURE
A failure occurred because of the inability to erase the storage device.
READ_FAILURE
A failure occurred because of the inability to read the storage device.
Table 9-14. Parameters for the Presence Test (Contd.)
Input