Copyright	(C) 2021-2024 QBayLogic B.V.
License	BSD2 (see the file LICENSE)
Maintainer	QBayLogic B.V. <devops@qbaylogic.com>
Safe Haskell	Trustworthy
Language	Haskell2010
Extensions	Cpp TemplateHaskell TemplateHaskellQuotes ScopedTypeVariables BangPatterns ViewPatterns DataKinds InstanceSigs StandaloneDeriving DeriveDataTypeable DeriveFunctor DeriveTraversable DeriveFoldable DeriveGeneric DefaultSignatures DeriveLift DerivingStrategies MagicHash KindSignatures PostfixOperators TupleSections TypeOperators ExplicitNamespaces ExplicitForAll BinaryLiterals TypeApplications

Clash.Explicit.BlockRam.Blob

Contents

Block RAMs initialized with a MemBlob
Creating and inspecting MemBlob
Internal

Description

Efficient bundling of initial RAM content with the compiled code

Leveraging Template Haskell, the initial content for the block RAM components in this module is stored alongside the compiled Haskell code. It covers use cases where passing the initial content as a Vec turns out to be problematically slow.

The data is stored efficiently, with very little overhead (worst-case 7%, often no overhead at all).

Unlike Clash.Explicit.BlockRam.File, Clash.Explicit.BlockRam.Blob generates practically the same HDL as Clash.Explicit.BlockRam and is compatible with all tools consuming the generated HDL.

Synopsis

blockRamBlob :: forall dom addr m n. (KnownDomain dom, Enum addr, NFDataX addr) => Clock dom -> Enable dom -> MemBlob n m -> Signal dom addr -> Signal dom (Maybe (addr, BitVector m)) -> Signal dom (BitVector m)
blockRamBlobPow2 :: forall dom m n. (KnownDomain dom, KnownNat n) => Clock dom -> Enable dom -> MemBlob (2 ^ n) m -> Signal dom (Unsigned n) -> Signal dom (Maybe (Unsigned n, BitVector m)) -> Signal dom (BitVector m)
data MemBlob (n :: Nat) (m :: Nat)
createMemBlob :: forall a f. (Foldable f, BitPack a) => String -> Maybe Bit -> f a -> DecsQ
memBlobTH :: forall a f. (Foldable f, BitPack a) => Maybe Bit -> f a -> ExpQ
unpackMemBlob :: forall n m. MemBlob n m -> [BitVector m]
blockRamBlob# :: forall dom m n. KnownDomain dom => Clock dom -> Enable dom -> MemBlob n m -> Signal dom Int -> Signal dom Bool -> Signal dom Int -> Signal dom (BitVector m) -> Signal dom (BitVector m)

Block RAMs initialized with a `MemBlob`

blockRamBlob Source #

Arguments

:: forall dom addr m n. (KnownDomain dom, Enum addr, NFDataX addr)
=> Clock dom	`Clock` to synchronize to
-> Enable dom	`Enable` line
-> MemBlob n m	Initial content of the BRAM, also determines the size, `n`, of the BRAM NB: MUST be a constant
-> Signal dom addr	Read address `r`
-> Signal dom (Maybe (addr, BitVector m))	(write address `w`, value to write)
-> Signal dom (BitVector m)	Value of the BRAM at address `r` from the previous clock cycle

Create a block RAM with space for n elements

NB: Read value is delayed by 1 cycle
NB: Initial output value is undefined, reading it will throw an XException

Creating and inspecting `MemBlob`

data MemBlob (n :: Nat) (m :: Nat) Source #

Efficient storage of memory content

It holds n words of BitVector m.

Instances

Instances details

Show (MemBlob n m) Source #
Instance details Defined in Clash.Explicit.BlockRam.Internal Methods showsPrec :: Int -> MemBlob n m -> ShowS Source # show :: MemBlob n m -> String Source # showList :: [MemBlob n m] -> ShowS Source #

createMemBlob Source #

Arguments

:: forall a f. (Foldable f, BitPack a)
=> String	Name of the binding to generate
-> Maybe Bit	Value to map don't care bits to. `Nothing` means throwing an error on don't care bits.
-> f a	The content for the `MemBlob`
-> DecsQ

Create a MemBlob binding from a list of values

Since this uses Template Haskell, nothing in the arguments given to createMemBlob can refer to something defined in the same module.

Example

Expand

createMemBlob "content" Nothing [15 :: Unsigned 8 .. 17]

ram clk en = blockRamBlob clk en content

The Maybe datatype has don't care bits, where the actual value does not matter. But the bits need a defined value in the memory. Either 0 or 1 can be used, and both are valid representations of the data.

>>> import qualified Prelude as P
>>> let es = [ Nothing, Just (7 :: Unsigned 8), Just 8 ]
>>> :{
createMemBlob "content0" (Just 0) es
createMemBlob "content1" (Just 1) es
x = 1
:}

>>> let pr = mapM_ (putStrLn . show)
>>> pr $ P.map pack es
0b0_...._....
0b1_0000_0111
0b1_0000_1000
>>> pr $ unpackMemBlob content0
0b0_0000_0000
0b1_0000_0111
0b1_0000_1000
>>> pr $ unpackMemBlob content1
0b0_1111_1111
0b1_0000_0111
0b1_0000_1000

>>> :{
createMemBlob "contentN" Nothing es
x = 1
:}

<interactive>:...: error:...
    packBVs: cannot convert don't care values. Please specify a mapping to a definite value.

Note how we hinted to clashi that our multi-line command was a list of declarations by including a dummy declaration x = 1. Without this trick, clashi would expect an expression and the Template Haskell would not work.

memBlobTH Source #

Arguments

:: forall a f. (Foldable f, BitPack a)
=> Maybe Bit	Value to map don't care bits to. `Nothing` means throwing an error on don't care bits.
-> f a	The content for the `MemBlob`
-> ExpQ

Create a MemBlob from a list of values

Since this uses Template Haskell, nothing in the arguments given to memBlobTH can refer to something defined in the same module.

Example

Expand

ram clk en = blockRamBlob clk en $(memBlobTH Nothing [15 :: Unsigned 8 .. 17])

The Maybe datatype has don't care bits, where the actual value does not matter. But the bits need a defined value in the memory. Either 0 or 1 can be used, and both are valid representations of the data.

>>> import qualified Prelude as P
>>> let es = [ Nothing, Just (7 :: Unsigned 8), Just 8 ]
>>> content0 = $(memBlobTH (Just 0) es)
>>> content1 = $(memBlobTH (Just 1) es)
>>> let pr = mapM_ (putStrLn . show)
>>> pr $ P.map pack es
0b0_...._....
0b1_0000_0111
0b1_0000_1000
>>> pr $ unpackMemBlob content0
0b0_0000_0000
0b1_0000_0111
0b1_0000_1000
>>> pr $ unpackMemBlob content1
0b0_1111_1111
0b1_0000_0111
0b1_0000_1000

>>> $(memBlobTH Nothing es)

<interactive>:...: error:...
    • packBVs: cannot convert don't care values. Please specify a mapping to a definite value.
    • In the untyped splice: $(memBlobTH Nothing es)

unpackMemBlob :: forall n m. MemBlob n m -> [BitVector m] Source #

Convert a MemBlob back to a list

NB: Not synthesizable

Internal

blockRamBlob# Source #

Arguments

:: forall dom m n. KnownDomain dom
=> Clock dom	`Clock` to synchronize to
-> Enable dom	`Enable` line
-> MemBlob n m	Initial content of the BRAM, also determines the size, `n`, of the BRAM NB: MUST be a constant
-> Signal dom Int	Read address `r`
-> Signal dom Bool	Write enable
-> Signal dom Int	Write address `w`
-> Signal dom (BitVector m)	Value to write (at address `w`)
-> Signal dom (BitVector m)	Value of the BRAM at address `r` from the previous clock cycle

blockRAMBlob primitive

Efficient bundling of initial RAM content with the compiled code

Block RAMs initialized with a `MemBlob`

See also:

See also:

Creating and inspecting `MemBlob`

Instances

Example

Example

Internal

:: forall dom m n. (KnownDomain dom, KnownNat n)
=> Clock dom	`Clock` to synchronize to
-> Enable dom	`Enable` line
-> MemBlob (2 ^ n) m	Initial content of the BRAM, also determines the size, 2^`n`, of the BRAM NB: MUST be a constant
-> Signal dom (Unsigned n)	Read address `r`
-> Signal dom (Maybe (Unsigned n, BitVector m))	(write address `w`, value to write)
-> Signal dom (BitVector m)	Value of the BRAM at address `r` from the previous clock cycle

Efficient bundling of initial RAM content with the compiled code

Block RAMs initialized with a MemBlob

See also:

See also:

Creating and inspecting MemBlob

Instances

Example

Example

Internal

Block RAMs initialized with a `MemBlob`

Creating and inspecting `MemBlob`