[Libre-soc-isa] [Bug 794] SVP64 REMAP for utf8

[bugzilla-daemon at libre-soc.org]

https://bugs.libre-soc.org/show_bug.cgi?id=794

--- Comment #30 from Luke Kenneth Casson Leighton <lkcl at lkcl.net> ---
ok so whilst svshape2 doesn't yet exist you can use svindex:

    setvl
    svstep
    sv.addi
    svindex
    blah

so you set the length, then get svstep to output the indices
into an array, then add one to them, then use them.

once the array of offsets is set up as long as you don't
overwrite them obviously they are reusable, it only takes
one instruction (svindex) to activate them.

there is a persistent mode for svindex and a nonpersistent.
you almost certainly want the nonpersistent one, for which
the rmm argument is a bitmask which specifies whether,
in lsb to msb order, RA RB RC RT EA/2nd-outputreg is to
be REMAPped.

so if you want only RB of sv.add *RT,*RA,*RB to be REMAPped
set rmm=0b00010.  RT and RA, set rmm=0b01001

this same rmm field will be in the svshape2 instruction as
well.

-- 
You are receiving this mail because:
You are on the CC list for the bug.