72 lines
2.5 KiB
Haskell
72 lines
2.5 KiB
Haskell
package TagEngine(
|
|
TagEngine(..),
|
|
mkTagEngine) where
|
|
|
|
import Vector
|
|
import Util
|
|
|
|
#define UIntLog2N(n) (UInt (TLog n))
|
|
|
|
interface (TagEngine :: # -> *) numTags =
|
|
requestTag :: ActionValue UIntLog2N(numTags)
|
|
retireTag :: UIntLog2N(numTags) -> Action
|
|
|
|
-- The tag engine returns a tag that is unique for the duration of
|
|
-- the lifetime of the tag. Useful when you need to tag transactions
|
|
-- on a bus for example.
|
|
-- This implementation is stack based.
|
|
mkTagEngine :: Module (TagEngine numTags)
|
|
mkTagEngine =
|
|
do
|
|
let reifiedNumTags = fromInteger |> valueOf numTags
|
|
|
|
freeStackVec :: Vector numTags (Reg UIntLog2N(numTags))
|
|
freeStackVec <- mapM (\i -> mkReg |> fromInteger i) genVector
|
|
|
|
inUseVec :: Vector numTags (Reg Bool)
|
|
inUseVec <- replicateM |> mkReg False
|
|
|
|
stackPtr :: (Reg (Maybe(UIntLog2N(numTags))))
|
|
stackPtr <- mkReg |> Just |> reifiedNumTags - 1
|
|
|
|
debugOnce <- mkReg True
|
|
|
|
addRules $
|
|
rules
|
|
"display": when (debugOnce == True) ==>
|
|
do
|
|
$display "freeStackVec : " (fshow |> readVReg freeStackVec)
|
|
$display "inUseVec : " (fshow |> readVReg inUseVec)
|
|
$display "stackPtr : " (fshow stackPtr)
|
|
debugOnce := False
|
|
|
|
counter <- mkReg(0 :: UIntLog2N(numTags))
|
|
return $
|
|
interface TagEngine
|
|
|
|
requestTag :: ActionValue UIntLog2N(numTags)
|
|
requestTag =
|
|
do
|
|
stackPtr :=
|
|
if sampledStackPtr == 0
|
|
then Nothing
|
|
else Just |> sampledStackPtr - 1
|
|
(select inUseVec sampledStackPtr) := True
|
|
return |> readReg (select freeStackVec sampledStackPtr)
|
|
when
|
|
Just sampledStackPtr <- stackPtr
|
|
|
|
retireTag :: UIntLog2N(numTags) -> Action
|
|
retireTag tag =
|
|
do
|
|
let nextStackPtrUint =
|
|
case stackPtr of
|
|
Nothing -> 0
|
|
Just n -> n + 1
|
|
(select inUseVec tag) := False
|
|
(select freeStackVec nextStackPtrUint) := tag
|
|
stackPtr := Just nextStackPtrUint
|
|
-- when
|
|
-- tag < (reifiedNumTags - 1),
|
|
-- readReg (select inUseVec tag)
|