ReferenceProjects/riscv-bluespec-classic
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now using wire instead of FIFO

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This commit is contained in:
Yehowshua Immanuel 2025-04-02 03:03:39 -04:00
parent e055b1bbdf
commit d1e3358197
1 changed files with 4 additions and 6 deletions
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10
bs/TagEngine.bs
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@ -26,7 +26,7 @@ mkTagEngine =
-- we really only use inUseVec after emptying out our `resetTagCounter` buffer
-- perhaps rename this variable to better communicate that
inUseVec :: Vector numTags (Reg Bool)
inUseVec <- replicateM |> mkReg True
inUseVec <- replicateM |> mkReg False
-- Since Bluespec doesn't allow us to initialize FIFOs with values at
-- reset, we can pretend as if the buffer within our tagFIFO is populated
@ -72,9 +72,11 @@ mkTagEngine =
case resetTagCounter of
Just 0 -> do
resetTagCounter := Nothing
(select inUseVec 0) := True
return 0
Just tag -> do
resetTagCounter := Just |> tag - 1
(select inUseVec tag) := True
return tag
Nothing -> do
let tag = freeQueue.first
@ -85,16 +87,12 @@ mkTagEngine =
-- so it is advisable that the caller of `retireTag` only attempt to retire valid tags.
-- Internally, the tagEngine will keep a correct and consistent state since TagEngine
-- validates tags before attempting to retire them.
-- Also worth noting the TagEngin will ignore attempts to retire a tag you just
-- requested in the same cycle. This is enforce with `tag > tagCounter` below.
retireTag :: UIntLog2N(numTags) -> Action
retireTag tag =
do
let
tagValid = tag < reifiedNumTags
tagInUse = case resetTagCounter of
Just tagCounter -> tag > tagCounter
Nothing -> readReg (select inUseVec tag)
tagInUse = readReg (select inUseVec tag)
if (tagValid && tagInUse)
then do
retireTag := tag