Intel 253668-032US ユーザーズマニュアル

9-62 Vol. 3

PROCESSOR MANAGEMENT AND INITIALIZATION

9.11.8.7 Function 02H—Microcode Update Control

This function enables loading of binary updates into the processor. Table 9-15 lists
the parameters and return codes for the function.

This control is provided on a global basis for all updates and processors. The caller
can determine the current status of update loading (enabled or disabled) without
changing the state. The function does not allow the caller to disable loading of binary
updates, as this poses a security risk.
The caller specifies the requested operation by placing one of the values from Table
9-16 in the BH register. After successfully completing this function, the BL register
contains either the enable or the disable designator. Note that if the function fails, the
update status return value is undefined.

Table 9-15. Parameters for the Control Update Sub-function

Input
AX

Function Code

0D042H

Sub-function

02H - Control update

Task

See the description below.

Scratch Pad1

Real mode segment of 64 KBytes of RAM block

Scratch Pad2

Real mode segment of 64 KBytes of RAM block

Scratch Pad3

Real mode segment of 64 KBytes of RAM block

SS:SP

Stack pointer

32 kilobytes of stack minimum

Output
CF

Carry Flag

Carry Set - Failure - AH contains status
Carry Clear - All return values valid.

Return Code

Status of the call

OEM Error

Additional OEM Information.

Update Status

Either enable or disable indicator

Return Codes (see Table 9-18 for code definitions)
SUCCESS

Function completed successfully.

READ_FAILURE

A failure occurred because of the inability to read the

storage device.