From 9135396cae31f976284734e45b210eea52140bbf Mon Sep 17 00:00:00 2001 From: Luke Kenneth Casson Leighton Date: Mon, 8 Nov 2021 16:17:26 +0000 Subject: [PATCH] comments --- src/soc/simple/core.py | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/src/soc/simple/core.py b/src/soc/simple/core.py index a37b9ba4..f9dc2dc1 100644 --- a/src/soc/simple/core.py +++ b/src/soc/simple/core.py @@ -270,7 +270,11 @@ class NonProductionCore(ControlBase): # enable the required Function Unit based on the opcode decode # note: this *only* works correctly for simple core when one and - # *only* one FU is allocated per instruction + # *only* one FU is allocated per instruction. what is actually + # required is one PriorityPicker per group of matching fnunits, + # and for only one actual FU to be "picked". this basically means + # when ReservationStations are enabled it will be possible to + # monitor multiple outstanding processing properly. for funame, fu in fus.items(): fnunit = fu.fnunit.value enable = Signal(name="en_%s" % funame, reset_less=True) @@ -323,6 +327,10 @@ class NonProductionCore(ControlBase): comb += fu.rdmaskn.eq(~rdmask) # set ready/valid signalling. if busy, means refuse incoming issue + # XXX note: for an in-order core this is far too simple. busy must + # be gated with the *availability* of the incoming (requested) + # instruction, where Core must be prepared to store-and-hold + # an instruction if no FU is available. comb += self.p.o_ready.eq(~busy_o) return fu_bitdict -- 2.30.2