Computer Architecture Simulation & Visualisation

Predication

Predication is a technique which aims to reduce pipeline stalls due to control hazards. It allows branches to be removed from the code by executing both the if and else parts of a branch in parallel, removing the problem of mispredicted branches. In the Intel IA-64 for example, an instruction can have a predicate tag appended to it by the compiler and the instruction is only allowed to write its result if the corresponding predicate is true.

A HASE simulation model of the DLX architecture, modified to include predication, has been built and made accessible via the WWW using JavaHASE.

The HASE Predication website explains how predication works in the IA64 and how the HASE DLX Predication model works.

The JavaHASE simulation applet for the DLX can be accessed from the HASE Predication Website or can be downloaded directly:

• Download JavaHASE DLX with Predication applet