From 724dfbe1f7f1019e7cbed65400013a06fe603ba0 Mon Sep 17 00:00:00 2001
From: Gergo ERDI <gergo@erdi.hu>
Date: Mon, 25 Nov 2024 20:41:04 +0800
Subject: [PATCH] Move block RAM reset value into the `ClearOnReset`
 constructor of `ResetStrategy`, to avoid arguments that are only going to be
 ignored on `NoClearOnReset`

---
 .../2024-11-25T20_38_27+08_00_reset_strategy  |  2 +
 clash-prelude/src/Clash/Explicit/BlockRam.hs  | 38 +++++++++----------
 clash-prelude/src/Clash/Prelude/BlockRam.hs   | 10 ++---
 3 files changed, 24 insertions(+), 26 deletions(-)
 create mode 100644 changelog/2024-11-25T20_38_27+08_00_reset_strategy

diff --git a/changelog/2024-11-25T20_38_27+08_00_reset_strategy b/changelog/2024-11-25T20_38_27+08_00_reset_strategy
new file mode 100644
index 0000000000..563801fe99
--- /dev/null
+++ b/changelog/2024-11-25T20_38_27+08_00_reset_strategy
@@ -0,0 +1,2 @@
+CHANGED: `ResetStrategy` now contains the reset function/value, to avoid
+dummy arguments on `NoClearOnReset`
\ No newline at end of file
diff --git a/clash-prelude/src/Clash/Explicit/BlockRam.hs b/clash-prelude/src/Clash/Explicit/BlockRam.hs
index a52084fbe9..4591442b30 100644
--- a/clash-prelude/src/Clash/Explicit/BlockRam.hs
+++ b/clash-prelude/src/Clash/Explicit/BlockRam.hs
@@ -854,9 +854,9 @@ blockRamPow2 = \clk en cnt rd wrM -> withFrozenCallStack
   (blockRam clk en cnt rd wrM)
 {-# INLINE blockRamPow2 #-}
 
-data ResetStrategy (r :: Bool) where
-  ClearOnReset :: ResetStrategy 'True
-  NoClearOnReset :: ResetStrategy 'False
+data ResetStrategy (r :: Bool) a where
+  ClearOnReset :: a -> ResetStrategy 'True a
+  NoClearOnReset :: ResetStrategy 'False a
 
 -- | A version of 'blockRam' that has no default values set. May be cleared to
 -- an arbitrary state using a reset function.
@@ -875,25 +875,28 @@ blockRamU
   -- for the BRAM to be reset to its initial state.
   -> Enable dom
   -- ^ 'Enable' line
-  -> ResetStrategy r
+  -> ResetStrategy r (Index n -> a)
   -- ^ Whether to clear BRAM on asserted reset ('ClearOnReset') or
   -- not ('NoClearOnReset'). The reset needs to be asserted for at least /n/
   -- cycles to clear the BRAM.
   -> SNat n
   -- ^ Number of elements in BRAM
-  -> (Index n -> a)
-  -- ^ If applicable (see 'ResetStrategy' argument), reset BRAM using this function
   -> Signal dom addr
   -- ^ Read address @r@
   -> Signal dom (Maybe (addr, a))
   -- ^ (write address @w@, value to write)
   -> Signal dom a
   -- ^ Value of the BRAM at address @r@ from the previous clock cycle
-blockRamU clk rst0 en rstStrategy n@SNat initF rd0 mw0 =
+blockRamU clk rst0 en rstStrategy n@SNat rd0 mw0 =
   case rstStrategy of
-    ClearOnReset ->
+    ClearOnReset initF ->
       -- Use reset infrastructure
       blockRamU# clk en n rd1 we1 wa1 w1
+      where
+        rd1 = mux rstBool 0 (fromEnum <$> rd0)
+        we1 = mux rstBool (pure True) we0
+        wa1 = mux rstBool (fromInteger . toInteger <$> waCounter) (fromEnum <$> wa0)
+        w1  = mux rstBool (initF <$> waCounter) w0
     NoClearOnReset ->
       -- Ignore reset infrastructure, pass values unchanged
       blockRamU# clk en n
@@ -912,11 +915,6 @@ blockRamU clk rst0 en rstStrategy n@SNat initF rd0 mw0 =
   w0  = snd . fromJustX <$> mw0
   we0 = isJust <$> mw0
 
-  rd1 = mux rstBool 0 (fromEnum <$> rd0)
-  we1 = mux rstBool (pure True) we0
-  wa1 = mux rstBool (fromInteger . toInteger <$> waCounter) (fromEnum <$> wa0)
-  w1  = mux rstBool (initF <$> waCounter) w0
-
 -- | blockRAMU primitive
 blockRamU#
   :: forall n dom a
@@ -968,7 +966,7 @@ blockRam1
   -- for the BRAM to be reset to its initial state.
   -> Enable dom
   -- ^ 'Enable' line
-  -> ResetStrategy r
+  -> ResetStrategy r a
   -- ^ Whether to clear BRAM on asserted reset ('ClearOnReset') or
   -- not ('NoClearOnReset'). The reset needs to be asserted for at least /n/
   -- cycles to clear the BRAM.
@@ -984,9 +982,14 @@ blockRam1
   -- ^ Value of the BRAM at address @r@ from the previous clock cycle
 blockRam1 clk rst0 en rstStrategy n@SNat a rd0 mw0 =
   case rstStrategy of
-    ClearOnReset ->
+    ClearOnReset a' ->
       -- Use reset infrastructure
       blockRam1# clk en n a rd1 we1 wa1 w1
+      where
+        rd1 = mux rstBool 0 (fromEnum <$> rd0)
+        we1 = mux rstBool (pure True) we0
+        wa1 = mux rstBool (fromInteger . toInteger <$> waCounter) (fromEnum <$> wa0)
+        w1  = mux rstBool (pure a') w0
     NoClearOnReset ->
       -- Ignore reset infrastructure, pass values unchanged
       blockRam1# clk en n a
@@ -1005,11 +1008,6 @@ blockRam1 clk rst0 en rstStrategy n@SNat a rd0 mw0 =
   w0  = snd . fromJustX <$> mw0
   we0 = isJust <$> mw0
 
-  rd1 = mux rstBool 0 (fromEnum <$> rd0)
-  we1 = mux rstBool (pure True) we0
-  wa1 = mux rstBool (fromInteger . toInteger <$> waCounter) (fromEnum <$> wa0)
-  w1  = mux rstBool (pure a) w0
-
 -- | blockRAM1 primitive
 blockRam1#
   :: forall n dom a
diff --git a/clash-prelude/src/Clash/Prelude/BlockRam.hs b/clash-prelude/src/Clash/Prelude/BlockRam.hs
index db58c6d3c7..d8b68637c1 100644
--- a/clash-prelude/src/Clash/Prelude/BlockRam.hs
+++ b/clash-prelude/src/Clash/Prelude/BlockRam.hs
@@ -741,14 +741,12 @@ blockRamU
      , Enum addr
      , NFDataX addr
      , 1 <= n )
-  => E.ResetStrategy r
+  => E.ResetStrategy r (Index n -> a)
   -- ^ Whether to clear BRAM on asserted reset ('Clash.Explicit.BlockRam.ClearOnReset')
   -- or not ('Clash.Explicit.BlockRam.NoClearOnReset'). The reset needs to be
   -- asserted for at least /n/ cycles to clear the BRAM.
   -> SNat n
   -- ^ Number of elements in BRAM
-  -> (Index n -> a)
-  -- ^ If applicable (see first argument), reset BRAM using this function
   -> Signal dom addr
   -- ^ Read address @r@
   -> Signal dom (Maybe (addr, a))
@@ -756,8 +754,8 @@ blockRamU
   -> Signal dom a
   -- ^ Value of the BRAM at address @r@ from the previous clock cycle
 blockRamU =
-  \rstStrategy cnt initF rd wrM -> withFrozenCallStack
-    (hideClockResetEnable E.blockRamU) rstStrategy cnt initF rd wrM
+  \rstStrategy cnt rd wrM -> withFrozenCallStack
+    (hideClockResetEnable E.blockRamU) rstStrategy cnt rd wrM
 {-# INLINE blockRamU #-}
 
 -- | A version of 'blockRam' that is initialized with the same value on all
@@ -770,7 +768,7 @@ blockRam1
      , Enum addr
      , NFDataX addr
      , 1 <= n )
-  => E.ResetStrategy r
+  => E.ResetStrategy r a
   -- ^ Whether to clear BRAM on asserted reset ('Clash.Explicit.BlockRam.ClearOnReset')
   -- or not ('Clash.Explicit.BlockRam.NoClearOnReset'). The reset needs to be
   -- asserted for at least /n/ cycles to clear the BRAM.