[Libre-soc-bugs] [Bug 1044] SVP64 implementation of pow(x,y,z)

[bugzilla-daemon at libre-soc.org]

https://bugs.libre-soc.org/show_bug.cgi?id=1044

--- Comment #13 from Jacob Lifshay <programmerjake at gmail.com> ---
I started changing the register assignments to conform to the ABI regarding
volatile/nonvolatile registers, since I want the modular exponentiation
algorithm to be able to store temporaries in registers while calling the
multiply algorithm, however, I discovered a scalar EXTRA2 encoding bug:
https://bugs.libre-soc.org/show_bug.cgi?id=1161

I spent the rest of the day trying to figure that bug out.

(In reply to Luke Kenneth Casson Leighton from comment #11)
> all of these can go in a vertical-first loop, using
> predication 0b1000100010001000 and sv.addi/pm=nn a,b,c
> to "pretend" there is a pair of nested loops.

I'll work on figuring that out and implementing it when I start working on the
REMAP bug, other than changing the registers used, the current multiply
algorithm is imho good enough for the purposes of this bug.

> 
> also same as Andrey, all files require a copyright notice, you
> know this https://bugs.libre-soc.org/show_bug.cgi?id=1126#c13

added.

https://git.libre-soc.org/?p=openpower-isa.git;a=shortlog;h=ca22d9687c91e764bb463ee776fb2f6efbf6eae9

commit ca22d9687c91e764bb463ee776fb2f6efbf6eae9
Author: Jacob Lifshay <programmerjake at gmail.com>
Date:   Thu Sep 14 20:07:18 2023 -0700

    change registers used to avoid r13-31 which are reserved/nonvolatile

    broken -- blocked on https://bugs.libre-soc.org/show_bug.cgi?id=1161

commit 2bfd298a3844af197d265b74c38094a5edc397b1
Author: Jacob Lifshay <programmerjake at gmail.com>
Date:   Thu Sep 14 20:06:59 2023 -0700

    pass in stack pointer

commit e329df6cbcda7752ab68db8c2713bbc795aa03ef
Author: Jacob Lifshay <programmerjake at gmail.com>
Date:   Thu Sep 14 20:04:55 2023 -0700

    log more register read/writes to LogKind.InstrInOuts

commit 4996bc893db92aa80cefb8cb603739b8c5b9b859
Author: Jacob Lifshay <programmerjake at gmail.com>
Date:   Thu Sep 14 17:28:42 2023 -0700

    add copyright stuff

    [skip ci]

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