User's Manual

Vol. 3 9-57
PROCESSOR MANAGEMENT AND INITIALIZATION
9.11.8.6 Function 01H—Write Microcode Update Data
This function integrates a new microcode update into the BIOS storage device. Table
9-14 lists the parameters and return codes for the function.
Table 9-14. 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 9-18 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.
STORAGE_FULL The BIOS non-volatile storage area is unable to
accommodate the update because all available update
blocks are filled with updates that are needed for
processors in the system.