Bug 354 - idea/optimisation: make FP CMP also do INT CMP
Summary: idea/optimisation: make FP CMP also do INT CMP
Status: CONFIRMED
Alias: None
Product: Libre-SOC's first SoC
Classification: Unclassified
Component: ALU (including IEEE754 16/32/64-bit FPU) (show other bugs)
Version: unspecified
Hardware: PC Linux
: --- enhancement
Assignee: Luke Kenneth Casson Leighton
URL:
Depends on:
Blocks:
 
Reported: 2020-05-27 01:46 BST by Luke Kenneth Casson Leighton
Modified: 2020-05-27 01:46 BST (History)
1 user (show)

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Description Luke Kenneth Casson Leighton 2020-05-27 01:46:22 BST 
from mitch alsup on comp.arch:

This all falls out for FREE if you start with FP compare to ZERO and
then figure out how the same logic can be used for integer instead of
the other way around.

I have the logic schematic (3 pages) is you desire to peruse. The overhead
of adding FP to INT compare is around 10% in gate count.