Bug 768 - fast emulation traps with trap address based on PO and XO
Summary: fast emulation traps with trap address based on PO and XO
Status: CONFIRMED
Alias: None
Product: Libre-SOC's first SoC
Classification: Unclassified
Component: Source Code (show other bugs)
Version: unspecified
Hardware: Other Linux
: --- enhancement
Assignee: Luke Kenneth Casson Leighton
URL:
Depends on:
Blocks:
 
Reported: 2022-01-26 22:32 GMT by Jacob Lifshay
Modified: 2022-01-26 22:45 GMT (History)
2 users (show)

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Description Jacob Lifshay 2022-01-26 22:32:34 GMT 
as discussed in meeting -- todo add more details

targeted speed: as fast as a function call
Comment 1 Jacob Lifshay 2022-01-26 22:34:26 GMT 
ideas: hw swap-out caller-saved regs so interrupt handler can just be a c function
Comment 2 Luke Kenneth Casson Leighton 2022-01-26 22:45:15 GMT 
(In reply to Jacob Lifshay from comment #1)
> ideas: hw swap-out caller-saved regs so interrupt handler can just be a c
> function

paul mentioned something about the e300? how it was a software-emulated
MMU and consequently there was a bit in the MSR you could set which
enabled swapping at exception time of the top 4 GPRs into SPRs *in addition*
to SRR0/1