This is a collection of Intel®’ IA32® Software Developer's Manuals (URL of the day) and AMD' AMD64 Architecture Programmer's Manual together with the related specifications, application notes, white papers, and change logs. The collection aims to keep all available revisions. It was originally created by Michal Necasek, see OS/2 Museum.

If you have a public document, related to the IA32® specifications and missing from the collection, please mail it to me. The content of this URL and all sub-ULRs is available for convenient bulk download by rsync x86docs password "" (empty).

CLRBHB

Clear Branch History clears the branch history for the current context to the extent that branch history information created before the CLRBHB instruction cannot be used by code before the CLRBHB instruction to exploitatively control the execution of any indirect branches in code in the current context that appear in program order after the instruction.

It has encodings from the following instruction sets: A32 ( A1 ) and T32 ( T1 ) .

A1
(FEAT_CLRBHB)

Decode for this encoding

if !IsFeatureImplemented(FEAT_CLRBHB) then ExecuteAsNOP(); end;

T1
(FEAT_CLRBHB)

Decode for this encoding

if !IsFeatureImplemented(FEAT_CLRBHB) then ExecuteAsNOP(); end;