International Business Machines Corporation
Extended prefix including routing bit for extended instruction format

Abstract:

Techniques for an extended prefix including a routing bit for an extended instruction format are described herein. An aspect includes generating, by an instruction preprocessing module, a first extended instruction corresponding to an internal operation including a first routing bit. Another aspect includes generating, by the instruction preprocessing module, a second extended instruction corresponding to a prefixed instruction set architecture (ISA) instruction including a second routing bit, wherein a value of the second routing bit is opposite a value of the first routing bit. Another aspect includes providing the first extended instruction and the second extended instruction to a central processing unit (CPU). Another aspect includes, based on the value of the first routing bit, routing the internal operation directly to an execution unit of the CPU, and based on the value of the second routing bit, routing the prefixed ISA instruction to a decode/execute path of the CPU.