Bug 317 - multi-bit dependency tracking of split (ganged) regfile ports
Summary: multi-bit dependency tracking of split (ganged) regfile ports
Alias: None
Product: Libre-SOC's first SoC
Classification: Unclassified
Component: Source Code (show other bugs)
Version: unspecified
Hardware: PC Mac OS
: Lowest enhancement
Assignee: Luke Kenneth Casson Leighton
Depends on:
Reported: 2020-05-16 23:10 BST by Luke Kenneth Casson Leighton
Modified: 2020-06-30 16:48 BST (History)
1 user (show)

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Description Luke Kenneth Casson Leighton 2020-05-16 23:10:52 BST
see https://bugs.libre-soc.org/show_bug.cgi?id=314#c14

this is a general technique which can be implemented on the INT and FP
regfiles as well as the Condition Registers and sub-fields of other SPRs
to provide W & R hazard protection against *portions* of a regfile.

it critically requires as a direct knock-on consequence that the protected
portion have its own read and write enable line.

thus the regfile may instead of being considered e.g. "64-bit wide" may
instead be considered 8x 8-bit wide, where 64-bit operations must request
*eight* simultaneous read/write-enable lines.

it's sufficiently comprehensive that we need to leave this off the TODO list
for now.