Regarding redundancy of BLTU/BLT or BGT/BGTU instructions

[Tanuj Sharma]

Hello all,

I am working on the implementation of RISC-V architecture to build a processor. While working I came to notice that if we have provided BEQ,BLT and BLTU instructions then the use of BGT,BGTU and even BNE is not required. I think this instructions may be redundant. Please, clarify this to me or guide me where I am wrong.

Tanuj Sharma

IIT PATNA

[Samuel Falvo II]

There is no BGT instruction family. It's BGE, (Branch if Greater than
OR EQUAL). In this sense, you're right: BGT is just BLT with its
operands reversed; however, BGE cannot be synthesized from BLT alone
(you'll need two consecutive branches: BLT and BEQ).

Hope that helps.

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Samuel A. Falvo II