[Libre-soc-dev] svp64

Luke Kenneth Casson Leighton lkcl at lkcl.net
Tue Dec 15 04:11:01 GMT 2020

On 12/15/20, Luke Kenneth Casson Leighton <lkcl at lkcl.net> wrote:

> starting from just above the callee saved (CR5) would, using vertical
> increments, mean that scalar CR0 and CR1 were not overwritten for at
> least VL=25.

sorry, didn't complete this.

numbering goes:

    for i in range(VL)
         y = i % 8
         x = i // 8
         CRINDEX = BA + y*8 + i

then, when performing crand etc these operations may be interpreted as
referring to those same vertical stratifications.

think of it this way jacob: if the SV element index refers to CRs in.a
straight linear numbering, starting from CR6, how is crand and cror
and mfcr etc going to work?

starting vectorised cr ops only from CR0.thru 7 and continuing from 0
to VL-1 ain't gonna be very useful, is it?

yes crand cror crnor etc will equally be vectorised.

also, i did say already: the CR numbering needs to start from an
8-aligned point, otherwise it plays hell with the DMs and the routing.


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