2. VLIW execution principles

2.1 Some VLIW execution rules

The principles of VLIW execution are as follows:

• several different operations are performed by one instruction ;

• each operation slot is reserved for a defined class of operations;

• fixed latencies are defined for the various operations;

• the hardware requires the operations of a VLIW instruction to be independent;

• the hardware does not control data dependencies between long instructions: this is the case for pure VLIWs. Variants can perform dependency checking, as we shall see in the processors presented in paragraphs