Intel 253668-032US Benutzerhandbuch

Vol. 3   9-63

PROCESSOR MANAGEMENT AND INITIALIZATION

The READ_FAILURE error code returned by this function has meaning only if the 
control function is implemented in the BIOS NVRAM. The state of this feature 
(enabled/disabled) can also be implemented using CMOS RAM bits where READ 
failure errors cannot occur. 

9.11.8.8   Function 03H—Read Microcode Update Data

This function reads a currently installed microcode update from the BIOS storage into 
a caller-provided RAM buffer. Table 9-17 lists the parameters and return codes. 

Table 9-16.  Mnemonic Values

Mnemonic

Value

Meaning

Enable

1

Enable the Update loading at initialization time.

Query

2

Determine the current state of the update control without 

changing its status.

Table 9-17.  Parameters for the Read Microcode Update Data Function 

Input
AX

Function Code

0D042H

BL

Sub-function

03H - Read Update

ES:DI

Buffer Address

Real Mode pointer to the Intel Update 

structure that will be written with the 

binary data

ECX

Scratch Pad1

Real Mode Segment address of 64 

KBytes of RAM Block (lower 16 bits)

ECX

Scratch Pad2

Real Mode Segment address of 64 

KBytes of RAM Block (upper 16 bits)

DX

Scratch Pad3

Real Mode Segment address of 64 

KBytes of RAM Block

SS:SP

Stack pointer

32 KBytes of Stack Minimum

SI

Update Number

This is the index number of the update 

block to be read. This value is zero based 

and must be less than the update count 

returned from the presence test 

function.

Output
CF

Carry Flag

Carry Set     - Failure - AH contains Status

Carry Clear - All return 

values are valid.
AH

Return Code

Status of the Call