GHC.Prim

ghc-prim-0.2.0.0: GHC primitives

Portability | non-portable (GHC extensions)
Stability | internal
Maintainer | cvs-ghc@haskell.org

GHC.Prim

Contents

- The word size story.
- Char#
- Int#
- Word#
- Narrowings
- Double#
- Float#
- Arrays
- Byte Arrays
- Addr#
- Mutable variables
- Exceptions
- STM-accessible Mutable Variables
- Synchronized Mutable Variables
- Delay/wait operations
- Concurrency primitives
- Weak pointers
- Stable pointers and names
- Unsafe pointer equality
- Parallelism
- Tag to enum stuff
- Bytecode operations
- Misc
- Etc

Description

GHC's primitive types and operations. Use GHC.Exts from the base package instead of importing this module directly.

Synopsis

- data Char#
- gtChar# :: Char# -> Char# -> Bool
- geChar# :: Char# -> Char# -> Bool
- eqChar# :: Char# -> Char# -> Bool
- neChar# :: Char# -> Char# -> Bool
- ltChar# :: Char# -> Char# -> Bool
- leChar# :: Char# -> Char# -> Bool
- ord# :: Char# -> Int#
- data Int#
- (+#) :: Int# -> Int# -> Int#
- (-#) :: Int# -> Int# -> Int#
- (*#) :: Int# -> Int# -> Int#
- mulIntMayOflo# :: Int# -> Int# -> Int#
- quotInt# :: Int# -> Int# -> Int#
- remInt# :: Int# -> Int# -> Int#
- negateInt# :: Int# -> Int#
- addIntC# :: Int# -> Int# -> (#Int#, Int##)
- subIntC# :: Int# -> Int# -> (#Int#, Int##)
- (>#) :: Int# -> Int# -> Bool
- (>=#) :: Int# -> Int# -> Bool
- (==#) :: Int# -> Int# -> Bool
- (/=#) :: Int# -> Int# -> Bool
- (<#) :: Int# -> Int# -> Bool
- (<=#) :: Int# -> Int# -> Bool
- chr# :: Int# -> Char#
- int2Word# :: Int# -> Word#
- int2Float# :: Int# -> Float#
- int2Double# :: Int# -> Double#
- uncheckedIShiftL# :: Int# -> Int# -> Int#
- uncheckedIShiftRA# :: Int# -> Int# -> Int#
- uncheckedIShiftRL# :: Int# -> Int# -> Int#
- data Word#
- plusWord# :: Word# -> Word# -> Word#
- minusWord# :: Word# -> Word# -> Word#
- timesWord# :: Word# -> Word# -> Word#
- quotWord# :: Word# -> Word# -> Word#
- remWord# :: Word# -> Word# -> Word#
- and# :: Word# -> Word# -> Word#
- or# :: Word# -> Word# -> Word#
- xor# :: Word# -> Word# -> Word#
- not# :: Word# -> Word#
- uncheckedShiftL# :: Word# -> Int# -> Word#
- uncheckedShiftRL# :: Word# -> Int# -> Word#
- word2Int# :: Word# -> Int#
- gtWord# :: Word# -> Word# -> Bool
- geWord# :: Word# -> Word# -> Bool
- eqWord# :: Word# -> Word# -> Bool
- neWord# :: Word# -> Word# -> Bool
- ltWord# :: Word# -> Word# -> Bool
- leWord# :: Word# -> Word# -> Bool
- narrow8Int# :: Int# -> Int#
- narrow16Int# :: Int# -> Int#
- narrow32Int# :: Int# -> Int#
- narrow8Word# :: Word# -> Word#
- narrow16Word# :: Word# -> Word#
- narrow32Word# :: Word# -> Word#
- data Double#
- (>##) :: Double# -> Double# -> Bool
- (>=##) :: Double# -> Double# -> Bool
- (==##) :: Double# -> Double# -> Bool
- (/=##) :: Double# -> Double# -> Bool
- (<##) :: Double# -> Double# -> Bool
- (<=##) :: Double# -> Double# -> Bool
- (+##) :: Double# -> Double# -> Double#
- (-##) :: Double# -> Double# -> Double#
- (*##) :: Double# -> Double# -> Double#
- (/##) :: Double# -> Double# -> Double#
- negateDouble# :: Double# -> Double#
- double2Int# :: Double# -> Int#
- double2Float# :: Double# -> Float#
- expDouble# :: Double# -> Double#
- logDouble# :: Double# -> Double#
- sqrtDouble# :: Double# -> Double#
- sinDouble# :: Double# -> Double#
- cosDouble# :: Double# -> Double#
- tanDouble# :: Double# -> Double#
- asinDouble# :: Double# -> Double#
- acosDouble# :: Double# -> Double#
- atanDouble# :: Double# -> Double#
- sinhDouble# :: Double# -> Double#
- coshDouble# :: Double# -> Double#
- tanhDouble# :: Double# -> Double#
- (**##) :: Double# -> Double# -> Double#
- decodeDouble_2Int# :: Double# -> (#Int#, Word#, Word#, Int##)
- data Float#
- gtFloat# :: Float# -> Float# -> Bool
- geFloat# :: Float# -> Float# -> Bool
- eqFloat# :: Float# -> Float# -> Bool
- neFloat# :: Float# -> Float# -> Bool
- ltFloat# :: Float# -> Float# -> Bool
- leFloat# :: Float# -> Float# -> Bool
- plusFloat# :: Float# -> Float# -> Float#
- minusFloat# :: Float# -> Float# -> Float#
- timesFloat# :: Float# -> Float# -> Float#
- divideFloat# :: Float# -> Float# -> Float#
- negateFloat# :: Float# -> Float#
- float2Int# :: Float# -> Int#
- expFloat# :: Float# -> Float#
- logFloat# :: Float# -> Float#
- sqrtFloat# :: Float# -> Float#
- sinFloat# :: Float# -> Float#
- cosFloat# :: Float# -> Float#
- tanFloat# :: Float# -> Float#
- asinFloat# :: Float# -> Float#
- acosFloat# :: Float# -> Float#
- atanFloat# :: Float# -> Float#
- sinhFloat# :: Float# -> Float#
- coshFloat# :: Float# -> Float#
- tanhFloat# :: Float# -> Float#
- powerFloat# :: Float# -> Float# -> Float#
- float2Double# :: Float# -> Double#
- decodeFloat_Int# :: Float# -> (#Int#, Int##)
- data Array# a
- data MutableArray# s a
- newArray# :: Int# -> a -> State# s -> (#State# s, MutableArray# s a#)
- sameMutableArray# :: MutableArray# s a -> MutableArray# s a -> Bool
- readArray# :: MutableArray# s a -> Int# -> State# s -> (#State# s, a#)
- writeArray# :: MutableArray# s a -> Int# -> a -> State# s -> State# s
- indexArray# :: Array# a -> Int# -> (#a#)
- unsafeFreezeArray# :: MutableArray# s a -> State# s -> (#State# s, Array# a#)
- unsafeThawArray# :: Array# a -> State# s -> (#State# s, MutableArray# s a#)
- data ByteArray#
- data MutableByteArray# s
- newByteArray# :: Int# -> State# s -> (#State# s, MutableByteArray# s#)
- newPinnedByteArray# :: Int# -> State# s -> (#State# s, MutableByteArray# s#)
- newAlignedPinnedByteArray# :: Int# -> Int# -> State# s -> (#State# s, MutableByteArray# s#)
- byteArrayContents# :: ByteArray# -> Addr#
- sameMutableByteArray# :: MutableByteArray# s -> MutableByteArray# s -> Bool
- unsafeFreezeByteArray# :: MutableByteArray# s -> State# s -> (#State# s, ByteArray##)
- sizeofByteArray# :: ByteArray# -> Int#
- sizeofMutableByteArray# :: MutableByteArray# s -> Int#
- indexCharArray# :: ByteArray# -> Int# -> Char#
- indexWideCharArray# :: ByteArray# -> Int# -> Char#
- indexIntArray# :: ByteArray# -> Int# -> Int#
- indexWordArray# :: ByteArray# -> Int# -> Word#
- indexAddrArray# :: ByteArray# -> Int# -> Addr#
- indexFloatArray# :: ByteArray# -> Int# -> Float#
- indexDoubleArray# :: ByteArray# -> Int# -> Double#
- indexStablePtrArray# :: ByteArray# -> Int# -> StablePtr# a
- indexInt8Array# :: ByteArray# -> Int# -> Int#
- indexInt16Array# :: ByteArray# -> Int# -> Int#
- indexInt32Array# :: ByteArray# -> Int# -> Int#
- indexInt64Array# :: ByteArray# -> Int# -> Int#
- indexWord8Array# :: ByteArray# -> Int# -> Word#
- indexWord16Array# :: ByteArray# -> Int# -> Word#
- indexWord32Array# :: ByteArray# -> Int# -> Word#
- indexWord64Array# :: ByteArray# -> Int# -> Word#
- readCharArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Char##)
- readWideCharArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Char##)
- readIntArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Int##)
- readWordArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Word##)
- readAddrArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Addr##)
- readFloatArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Float##)
- readDoubleArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Double##)
- readStablePtrArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, StablePtr# a#)
- readInt8Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Int##)
- readInt16Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Int##)
- readInt32Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Int##)
- readInt64Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Int##)
- readWord8Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Word##)
- readWord16Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Word##)
- readWord32Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Word##)
- readWord64Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Word##)
- writeCharArray# :: MutableByteArray# s -> Int# -> Char# -> State# s -> State# s
- writeWideCharArray# :: MutableByteArray# s -> Int# -> Char# -> State# s -> State# s
- writeIntArray# :: MutableByteArray# s -> Int# -> Int# -> State# s -> State# s
- writeWordArray# :: MutableByteArray# s -> Int# -> Word# -> State# s -> State# s
- writeAddrArray# :: MutableByteArray# s -> Int# -> Addr# -> State# s -> State# s
- writeFloatArray# :: MutableByteArray# s -> Int# -> Float# -> State# s -> State# s
- writeDoubleArray# :: MutableByteArray# s -> Int# -> Double# -> State# s -> State# s
- writeStablePtrArray# :: MutableByteArray# s -> Int# -> StablePtr# a -> State# s -> State# s
- writeInt8Array# :: MutableByteArray# s -> Int# -> Int# -> State# s -> State# s
- writeInt16Array# :: MutableByteArray# s -> Int# -> Int# -> State# s -> State# s
- writeInt32Array# :: MutableByteArray# s -> Int# -> Int# -> State# s -> State# s
- writeInt64Array# :: MutableByteArray# s -> Int# -> Int# -> State# s -> State# s
- writeWord8Array# :: MutableByteArray# s -> Int# -> Word# -> State# s -> State# s
- writeWord16Array# :: MutableByteArray# s -> Int# -> Word# -> State# s -> State# s
- writeWord32Array# :: MutableByteArray# s -> Int# -> Word# -> State# s -> State# s
- writeWord64Array# :: MutableByteArray# s -> Int# -> Word# -> State# s -> State# s
- data Addr#
- nullAddr# :: Addr#
- plusAddr# :: Addr# -> Int# -> Addr#
- minusAddr# :: Addr# -> Addr# -> Int#
- remAddr# :: Addr# -> Int# -> Int#
- addr2Int# :: Addr# -> Int#
- int2Addr# :: Int# -> Addr#
- gtAddr# :: Addr# -> Addr# -> Bool
- geAddr# :: Addr# -> Addr# -> Bool
- eqAddr# :: Addr# -> Addr# -> Bool
- neAddr# :: Addr# -> Addr# -> Bool
- ltAddr# :: Addr# -> Addr# -> Bool
- leAddr# :: Addr# -> Addr# -> Bool
- indexCharOffAddr# :: Addr# -> Int# -> Char#
- indexWideCharOffAddr# :: Addr# -> Int# -> Char#
- indexIntOffAddr# :: Addr# -> Int# -> Int#
- indexWordOffAddr# :: Addr# -> Int# -> Word#
- indexAddrOffAddr# :: Addr# -> Int# -> Addr#
- indexFloatOffAddr# :: Addr# -> Int# -> Float#
- indexDoubleOffAddr# :: Addr# -> Int# -> Double#
- indexStablePtrOffAddr# :: Addr# -> Int# -> StablePtr# a
- indexInt8OffAddr# :: Addr# -> Int# -> Int#
- indexInt16OffAddr# :: Addr# -> Int# -> Int#
- indexInt32OffAddr# :: Addr# -> Int# -> Int#
- indexInt64OffAddr# :: Addr# -> Int# -> Int#
- indexWord8OffAddr# :: Addr# -> Int# -> Word#
- indexWord16OffAddr# :: Addr# -> Int# -> Word#
- indexWord32OffAddr# :: Addr# -> Int# -> Word#
- indexWord64OffAddr# :: Addr# -> Int# -> Word#
- readCharOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Char##)
- readWideCharOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Char##)
- readIntOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Int##)
- readWordOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Word##)
- readAddrOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Addr##)
- readFloatOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Float##)
- readDoubleOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Double##)
- readStablePtrOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, StablePtr# a#)
- readInt8OffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Int##)
- readInt16OffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Int##)
- readInt32OffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Int##)
- readInt64OffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Int##)
- readWord8OffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Word##)
- readWord16OffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Word##)
- readWord32OffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Word##)
- readWord64OffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Word##)
- writeCharOffAddr# :: Addr# -> Int# -> Char# -> State# s -> State# s
- writeWideCharOffAddr# :: Addr# -> Int# -> Char# -> State# s -> State# s
- writeIntOffAddr# :: Addr# -> Int# -> Int# -> State# s -> State# s
- writeWordOffAddr# :: Addr# -> Int# -> Word# -> State# s -> State# s
- writeAddrOffAddr# :: Addr# -> Int# -> Addr# -> State# s -> State# s
- writeFloatOffAddr# :: Addr# -> Int# -> Float# -> State# s -> State# s
- writeDoubleOffAddr# :: Addr# -> Int# -> Double# -> State# s -> State# s
- writeStablePtrOffAddr# :: Addr# -> Int# -> StablePtr# a -> State# s -> State# s
- writeInt8OffAddr# :: Addr# -> Int# -> Int# -> State# s -> State# s
- writeInt16OffAddr# :: Addr# -> Int# -> Int# -> State# s -> State# s
- writeInt32OffAddr# :: Addr# -> Int# -> Int# -> State# s -> State# s
- writeInt64OffAddr# :: Addr# -> Int# -> Int# -> State# s -> State# s
- writeWord8OffAddr# :: Addr# -> Int# -> Word# -> State# s -> State# s
- writeWord16OffAddr# :: Addr# -> Int# -> Word# -> State# s -> State# s
- writeWord32OffAddr# :: Addr# -> Int# -> Word# -> State# s -> State# s
- writeWord64OffAddr# :: Addr# -> Int# -> Word# -> State# s -> State# s
- data MutVar# s a
- newMutVar# :: a -> State# s -> (#State# s, MutVar# s a#)
- readMutVar# :: MutVar# s a -> State# s -> (#State# s, a#)
- writeMutVar# :: MutVar# s a -> a -> State# s -> State# s
- sameMutVar# :: MutVar# s a -> MutVar# s a -> Bool
- atomicModifyMutVar# :: MutVar# s a -> (a -> b) -> State# s -> (#State# s, c#)
- catch# :: (State# RealWorld -> (#State# RealWorld, a#)) -> (b -> State# RealWorld -> (#State# RealWorld, a#)) -> State# RealWorld -> (#State# RealWorld, a#)
- raise# :: a -> b
- raiseIO# :: a -> State# RealWorld -> (#State# RealWorld, b#)
- maskAsyncExceptions# :: (State# RealWorld -> (#State# RealWorld, a#)) -> State# RealWorld -> (#State# RealWorld, a#)
- maskUninterruptible# :: (State# RealWorld -> (#State# RealWorld, a#)) -> State# RealWorld -> (#State# RealWorld, a#)
- unmaskAsyncExceptions# :: (State# RealWorld -> (#State# RealWorld, a#)) -> State# RealWorld -> (#State# RealWorld, a#)
- getMaskingState# :: State# RealWorld -> (#State# RealWorld, Int##)
- data TVar# s a
- atomically# :: (State# RealWorld -> (#State# RealWorld, a#)) -> State# RealWorld -> (#State# RealWorld, a#)
- retry# :: State# RealWorld -> (#State# RealWorld, a#)
- catchRetry# :: (State# RealWorld -> (#State# RealWorld, a#)) -> (State# RealWorld -> (#State# RealWorld, a#)) -> State# RealWorld -> (#State# RealWorld, a#)
- catchSTM# :: (State# RealWorld -> (#State# RealWorld, a#)) -> (b -> State# RealWorld -> (#State# RealWorld, a#)) -> State# RealWorld -> (#State# RealWorld, a#)
- check# :: (State# RealWorld -> (#State# RealWorld, a#)) -> State# RealWorld -> (#State# RealWorld, ()#)
- newTVar# :: a -> State# s -> (#State# s, TVar# s a#)
- readTVar# :: TVar# s a -> State# s -> (#State# s, a#)
- readTVarIO# :: TVar# s a -> State# s -> (#State# s, a#)
- writeTVar# :: TVar# s a -> a -> State# s -> State# s
- sameTVar# :: TVar# s a -> TVar# s a -> Bool
- data MVar# s a
- newMVar# :: State# s -> (#State# s, MVar# s a#)
- takeMVar# :: MVar# s a -> State# s -> (#State# s, a#)
- tryTakeMVar# :: MVar# s a -> State# s -> (#State# s, Int#, a#)
- putMVar# :: MVar# s a -> a -> State# s -> State# s
- tryPutMVar# :: MVar# s a -> a -> State# s -> (#State# s, Int##)
- sameMVar# :: MVar# s a -> MVar# s a -> Bool
- isEmptyMVar# :: MVar# s a -> State# s -> (#State# s, Int##)
- delay# :: Int# -> State# s -> State# s
- waitRead# :: Int# -> State# s -> State# s
- waitWrite# :: Int# -> State# s -> State# s
- data State# s
- data RealWorld
- data ThreadId#
- fork# :: a -> State# RealWorld -> (#State# RealWorld, ThreadId##)
- forkOn# :: Int# -> a -> State# RealWorld -> (#State# RealWorld, ThreadId##)
- killThread# :: ThreadId# -> a -> State# RealWorld -> State# RealWorld
- yield# :: State# RealWorld -> State# RealWorld
- myThreadId# :: State# RealWorld -> (#State# RealWorld, ThreadId##)
- labelThread# :: ThreadId# -> Addr# -> State# RealWorld -> State# RealWorld
- isCurrentThreadBound# :: State# RealWorld -> (#State# RealWorld, Int##)
- noDuplicate# :: State# RealWorld -> State# RealWorld
- threadStatus# :: ThreadId# -> State# RealWorld -> (#State# RealWorld, Int##)
- data Weak# b
- mkWeak# :: o -> b -> c -> State# RealWorld -> (#State# RealWorld, Weak# b#)
- mkWeakForeignEnv# :: o -> b -> Addr# -> Addr# -> Int# -> Addr# -> State# RealWorld -> (#State# RealWorld, Weak# b#)
- deRefWeak# :: Weak# a -> State# RealWorld -> (#State# RealWorld, Int#, a#)
- finalizeWeak# :: Weak# a -> State# RealWorld -> (#State# RealWorld, Int#, State# RealWorld -> (#State# RealWorld, ()#)#)
- touch# :: o -> State# RealWorld -> State# RealWorld
- data StablePtr# a
- data StableName# a
- makeStablePtr# :: a -> State# RealWorld -> (#State# RealWorld, StablePtr# a#)
- deRefStablePtr# :: StablePtr# a -> State# RealWorld -> (#State# RealWorld, a#)
- eqStablePtr# :: StablePtr# a -> StablePtr# a -> Int#
- makeStableName# :: a -> State# RealWorld -> (#State# RealWorld, StableName# a#)
- eqStableName# :: StableName# a -> StableName# a -> Int#
- stableNameToInt# :: StableName# a -> Int#
- reallyUnsafePtrEquality# :: a -> a -> Int#
- par# :: a -> Int#
- getSpark# :: State# s -> (#State# s, Int#, a#)
- numSparks# :: State# s -> (#State# s, Int##)
- parGlobal# :: a -> Int# -> Int# -> Int# -> Int# -> b -> Int#
- parLocal# :: a -> Int# -> Int# -> Int# -> Int# -> b -> Int#
- parAt# :: b -> a -> Int# -> Int# -> Int# -> Int# -> c -> Int#
- parAtAbs# :: a -> Int# -> Int# -> Int# -> Int# -> Int# -> b -> Int#
- parAtRel# :: a -> Int# -> Int# -> Int# -> Int# -> Int# -> b -> Int#
- parAtForNow# :: b -> a -> Int# -> Int# -> Int# -> Int# -> c -> Int#
- dataToTag# :: a -> Int#
- tagToEnum# :: Int# -> a
- data BCO#
- addrToHValue# :: Addr# -> (#a#)
- mkApUpd0# :: BCO# -> (#a#)
- newBCO# :: ByteArray# -> ByteArray# -> Array# a -> Int# -> ByteArray# -> State# s -> (#State# s, BCO##)
- unpackClosure# :: a -> (#Addr#, Array# b, ByteArray##)
- getApStackVal# :: a -> Int# -> (#Int#, b#)
- traceCcs# :: a -> b -> b
- seq :: a -> b -> b
- inline :: a -> a
- lazy :: a -> a
- data Any a
- unsafeCoerce# :: a -> b
- traceEvent# :: Addr# -> State# s -> State# s

# The word size story.

Haskell98 specifies that signed integers (type `Int`) must contain at least 30 bits. GHC always implements `Int` using the primitive type `Int#`, whose size equals the `MachDeps.h` constant `WORD_SIZE_IN_BITS`. This is normally set based on the `config.h` parameter `SIZEOF_HSWORD`, i.e., 32 bits on 32-bit machines, 64 bits on 64-bit machines. However, it can also be explicitly set to a smaller number, e.g., 31 bits, to allow the possibility of using tag bits. Currently GHC itself has only 32-bit and 64-bit variants, but 30 or 31-bit code can be exported as an external core file for use in other back ends.

GHC also implements a primitive unsigned integer type `Word#` which always has the same number of bits as `Int#`.

In addition, GHC supports families of explicit-sized integers and words at 8, 16, 32, and 64 bits, with the usual arithmetic operations, comparisons, and a range of conversions. The 8-bit and 16-bit sizes are always represented as `Int#` and `Word#`, and the operations implemented in terms of the the primops on these types, with suitable range restrictions on the results (using the `narrow$n$Int#` and `narrow$n$Word#` families of primops. The 32-bit sizes are represented using `Int#` and `Word#` when `WORD_SIZE_IN_BITS` $geq$ 32; otherwise, these are represented using distinct primitive types `Int32#` and `Word32#`. These (when needed) have a complete set of corresponding operations; however, nearly all of these are implemented as external C functions rather than as primops. Exactly the same story applies to the 64-bit sizes. All of these details are hidden under the `PrelInt` and `PrelWord` modules, which use `#if`-defs to invoke the appropriate types and operators.

Word size also matters for the families of primops for indexing/reading/writing fixed-size quantities at offsets from an array base, address, or foreign pointer. Here, a slightly different approach is taken. The names of these primops are fixed, but their types vary according to the value of `WORD_SIZE_IN_BITS`. For example, if word size is at least 32 bits then an operator like `indexInt32Array#` has type `ByteArray# -> Int# -> Int#`; otherwise it has type `ByteArray# -> Int# -> Int32#`. This approach confines the necessary `#if`-defs to this file; no conditional compilation is needed in the files that expose these primops.

Finally, there are strongly deprecated primops for coercing between `Addr#`, the primitive type of machine addresses, and `Int#`. These are pretty bogus anyway, but will work on existing 32-bit and 64-bit GHC targets; they are completely bogus when tag bits are used in `Int#`, so are not available in this case.

# Char#

Operations on 31-bit characters.

data Char#

gtChar# :: Char# -> Char# -> Bool

geChar# :: Char# -> Char# -> Bool

eqChar# :: Char# -> Char# -> Bool

neChar# :: Char# -> Char# -> Bool

ltChar# :: Char# -> Char# -> Bool

leChar# :: Char# -> Char# -> Bool

ord# :: Char# -> Int#

# Int#

Operations on native-size integers (30+ bits).

data Int#

(+#) :: Int# -> Int# -> Int#

(-#) :: Int# -> Int# -> Int#

(*#) :: Int# -> Int# -> Int#

Low word of signed integer multiply.

mulIntMayOflo# :: Int# -> Int# -> Int#

Return non-zero if there is any possibility that the upper word of a signed integer multiply might contain useful information. Return zero only if you are completely sure that no overflow can occur. On a 32-bit platform, the recommmended implementation is to do a 32 x 32 -> 64 signed multiply, and subtract result[63:32] from (result[31] >>signed 31). If this is zero, meaning that the upper word is merely a sign extension of the lower one, no overflow can occur.

On a 64-bit platform it is not always possible to acquire the top 64 bits of the result. Therefore, a recommended implementation is to take the absolute value of both operands, and return 0 iff bits[63:31] of them are zero, since that means that their magnitudes fit within 31 bits, so the magnitude of the product must fit into 62 bits.

If in doubt, return non-zero, but do make an effort to create the correct answer for small args, since otherwise the performance of `(*) :: Integer -> Integer -> Integer` will be poor.

quotInt# :: Int# -> Int# -> Int#

Rounds towards zero.

remInt# :: Int# -> Int# -> Int#

Satisfies `(quotInt# x y) *# y +# (remInt# x y) == x`.

negateInt# :: Int# -> Int#

addIntC# :: Int# -> Int# -> (#Int#, Int##)

Add with carry. First member of result is (wrapped) sum; second member is 0 iff no overflow occured.

subIntC# :: Int# -> Int# -> (#Int#, Int##)

Subtract with carry. First member of result is (wrapped) difference; second member is 0 iff no overflow occured.

(>#) :: Int# -> Int# -> Bool

(>=#) :: Int# -> Int# -> Bool

(==#) :: Int# -> Int# -> Bool

(/=#) :: Int# -> Int# -> Bool

(<#) :: Int# -> Int# -> Bool

(<=#) :: Int# -> Int# -> Bool

chr# :: Int# -> Char#

int2Word# :: Int# -> Word#

int2Float# :: Int# -> Float#

int2Double# :: Int# -> Double#

uncheckedIShiftL# :: Int# -> Int# -> Int#

Shift left. Result undefined if shift amount is not in the range 0 to word size - 1 inclusive.

uncheckedIShiftRA# :: Int# -> Int# -> Int#

Shift right arithmetic. Result undefined if shift amount is not in the range 0 to word size - 1 inclusive.

uncheckedIShiftRL# :: Int# -> Int# -> Int#

Shift right logical. Result undefined if shift amount is not in the range 0 to word size - 1 inclusive.

# Word#

Operations on native-sized unsigned words (30+ bits).

data Word#

plusWord# :: Word# -> Word# -> Word#

minusWord# :: Word# -> Word# -> Word#

timesWord# :: Word# -> Word# -> Word#

quotWord# :: Word# -> Word# -> Word#

remWord# :: Word# -> Word# -> Word#

and# :: Word# -> Word# -> Word#

or# :: Word# -> Word# -> Word#

xor# :: Word# -> Word# -> Word#

not# :: Word# -> Word#

uncheckedShiftL# :: Word# -> Int# -> Word#

Shift left logical. Result undefined if shift amount is not in the range 0 to word size - 1 inclusive.

uncheckedShiftRL# :: Word# -> Int# -> Word#

Shift right logical. Result undefined if shift amount is not in the range 0 to word size - 1 inclusive.

word2Int# :: Word# -> Int#

gtWord# :: Word# -> Word# -> Bool

geWord# :: Word# -> Word# -> Bool

eqWord# :: Word# -> Word# -> Bool

neWord# :: Word# -> Word# -> Bool

ltWord# :: Word# -> Word# -> Bool

leWord# :: Word# -> Word# -> Bool

# Narrowings

Explicit narrowing of native-sized ints or words.

narrow8Int# :: Int# -> Int#

narrow16Int# :: Int# -> Int#

narrow32Int# :: Int# -> Int#

narrow8Word# :: Word# -> Word#

narrow16Word# :: Word# -> Word#

narrow32Word# :: Word# -> Word#

# Double#

Operations on double-precision (64 bit) floating-point numbers.

data Double#

(>##) :: Double# -> Double# -> Bool

(>=##) :: Double# -> Double# -> Bool

(==##) :: Double# -> Double# -> Bool

(/=##) :: Double# -> Double# -> Bool

(<##) :: Double# -> Double# -> Bool

(<=##) :: Double# -> Double# -> Bool

(+##) :: Double# -> Double# -> Double#

(-##) :: Double# -> Double# -> Double#

(*##) :: Double# -> Double# -> Double#

(/##) :: Double# -> Double# -> Double#

negateDouble# :: Double# -> Double#

double2Int# :: Double# -> Int#

Truncates a `Double`. Results are undefined if the truncation if truncation yields a value outside the range of `Int#`.

double2Float# :: Double# -> Float#

expDouble# :: Double# -> Double#

logDouble# :: Double# -> Double#

sqrtDouble# :: Double# -> Double#

sinDouble# :: Double# -> Double#

cosDouble# :: Double# -> Double#

tanDouble# :: Double# -> Double#

asinDouble# :: Double# -> Double#

acosDouble# :: Double# -> Double#

atanDouble# :: Double# -> Double#

sinhDouble# :: Double# -> Double#

coshDouble# :: Double# -> Double#

tanhDouble# :: Double# -> Double#

(**##) :: Double# -> Double# -> Double#

Exponentiation.

decodeDouble_2Int# :: Double# -> (#Int#, Word#, Word#, Int##)

Convert to integer. First component of the result is -1 or 1, indicating the sign of the mantissa. The next two are the high and low 32 bits of the mantissa respectively, and the last is the exponent.

# Float#

Operations on single-precision (32-bit) floating-point numbers.

data Float#

gtFloat# :: Float# -> Float# -> Bool

geFloat# :: Float# -> Float# -> Bool

eqFloat# :: Float# -> Float# -> Bool

neFloat# :: Float# -> Float# -> Bool

ltFloat# :: Float# -> Float# -> Bool

leFloat# :: Float# -> Float# -> Bool

plusFloat# :: Float# -> Float# -> Float#

minusFloat# :: Float# -> Float# -> Float#

timesFloat# :: Float# -> Float# -> Float#

divideFloat# :: Float# -> Float# -> Float#

negateFloat# :: Float# -> Float#

float2Int# :: Float# -> Int#

Truncates a `Float`. Results are undefined if the truncation if truncation yields a value outside the range of `Int#`.

expFloat# :: Float# -> Float#

logFloat# :: Float# -> Float#

sqrtFloat# :: Float# -> Float#

sinFloat# :: Float# -> Float#

cosFloat# :: Float# -> Float#

tanFloat# :: Float# -> Float#

asinFloat# :: Float# -> Float#

acosFloat# :: Float# -> Float#

atanFloat# :: Float# -> Float#

sinhFloat# :: Float# -> Float#

coshFloat# :: Float# -> Float#

tanhFloat# :: Float# -> Float#

powerFloat# :: Float# -> Float# -> Float#

float2Double# :: Float# -> Double#

decodeFloat_Int# :: Float# -> (#Int#, Int##)

Convert to integers. First `Int#` in result is the mantissa; second is the exponent.

# Arrays

Operations on `Array#`.

data Array# a

data MutableArray# s a

newArray# :: Int# -> a -> State# s -> (#State# s, MutableArray# s a#)

Create a new mutable array with the specified number of elements, in the specified state thread, with each element containing the specified initial value.

sameMutableArray# :: MutableArray# s a -> MutableArray# s a -> Bool

readArray# :: MutableArray# s a -> Int# -> State# s -> (#State# s, a#)

Read from specified index of mutable array. Result is not yet evaluated.

writeArray# :: MutableArray# s a -> Int# -> a -> State# s -> State# s

Write to specified index of mutable array.

indexArray# :: Array# a -> Int# -> (#a#)

Read from specified index of immutable array. Result is packaged into an unboxed singleton; the result itself is not yet evaluated.

unsafeFreezeArray# :: MutableArray# s a -> State# s -> (#State# s, Array# a#)

Make a mutable array immutable, without copying.

unsafeThawArray# :: Array# a -> State# s -> (#State# s, MutableArray# s a#)

Make an immutable array mutable, without copying.

# Byte Arrays

Operations on `ByteArray#`. A `ByteArray#` is a just a region of raw memory in the garbage-collected heap, which is not scanned for pointers. It carries its own size (in bytes). There are three sets of operations for accessing byte array contents: index for reading from immutable byte arrays, and read/write for mutable byte arrays. Each set contains operations for a range of useful primitive data types. Each operation takes an offset measured in terms of the size fo the primitive type being read or written.

data ByteArray#

data MutableByteArray# s

newByteArray# :: Int# -> State# s -> (#State# s, MutableByteArray# s#)

Create a new mutable byte array of specified size (in bytes), in the specified state thread.

newPinnedByteArray# :: Int# -> State# s -> (#State# s, MutableByteArray# s#)

Create a mutable byte array that the GC guarantees not to move.

newAlignedPinnedByteArray# :: Int# -> Int# -> State# s -> (#State# s, MutableByteArray# s#)

Create a mutable byte array, aligned by the specified amount, that the GC guarantees not to move.

byteArrayContents# :: ByteArray# -> Addr#

Intended for use with pinned arrays; otherwise very unsafe!

sameMutableByteArray# :: MutableByteArray# s -> MutableByteArray# s -> Bool

unsafeFreezeByteArray# :: MutableByteArray# s -> State# s -> (#State# s, ByteArray##)

Make a mutable byte array immutable, without copying.

sizeofByteArray# :: ByteArray# -> Int#

Return the size of the array in bytes.

sizeofMutableByteArray# :: MutableByteArray# s -> Int#

Return the size of the array in bytes.

indexCharArray# :: ByteArray# -> Int# -> Char#

Read 8-bit character; offset in bytes.

indexWideCharArray# :: ByteArray# -> Int# -> Char#

Read 31-bit character; offset in 4-byte words.

indexIntArray# :: ByteArray# -> Int# -> Int#

indexWordArray# :: ByteArray# -> Int# -> Word#

indexAddrArray# :: ByteArray# -> Int# -> Addr#

indexFloatArray# :: ByteArray# -> Int# -> Float#

indexDoubleArray# :: ByteArray# -> Int# -> Double#

indexStablePtrArray# :: ByteArray# -> Int# -> StablePtr# a

indexInt8Array# :: ByteArray# -> Int# -> Int#

indexInt16Array# :: ByteArray# -> Int# -> Int#

indexInt32Array# :: ByteArray# -> Int# -> Int#

indexInt64Array# :: ByteArray# -> Int# -> Int#

indexWord8Array# :: ByteArray# -> Int# -> Word#

indexWord16Array# :: ByteArray# -> Int# -> Word#

indexWord32Array# :: ByteArray# -> Int# -> Word#

indexWord64Array# :: ByteArray# -> Int# -> Word#

readCharArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Char##)

Read 8-bit character; offset in bytes.

readWideCharArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Char##)

Read 31-bit character; offset in 4-byte words.

readIntArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Int##)

readWordArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Word##)

readAddrArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Addr##)

readFloatArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Float##)

readDoubleArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Double##)

readStablePtrArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, StablePtr# a#)

readInt8Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Int##)

readInt16Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Int##)

readInt32Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Int##)

readInt64Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Int##)

readWord8Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Word##)

readWord16Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Word##)

readWord32Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Word##)

readWord64Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Word##)

writeCharArray# :: MutableByteArray# s -> Int# -> Char# -> State# s -> State# s

Write 8-bit character; offset in bytes.

writeWideCharArray# :: MutableByteArray# s -> Int# -> Char# -> State# s -> State# s

Write 31-bit character; offset in 4-byte words.

writeIntArray# :: MutableByteArray# s -> Int# -> Int# -> State# s -> State# s

writeWordArray# :: MutableByteArray# s -> Int# -> Word# -> State# s -> State# s

writeAddrArray# :: MutableByteArray# s -> Int# -> Addr# -> State# s -> State# s

writeFloatArray# :: MutableByteArray# s -> Int# -> Float# -> State# s -> State# s

writeDoubleArray# :: MutableByteArray# s -> Int# -> Double# -> State# s -> State# s

writeStablePtrArray# :: MutableByteArray# s -> Int# -> StablePtr# a -> State# s -> State# s

writeInt8Array# :: MutableByteArray# s -> Int# -> Int# -> State# s -> State# s

writeInt16Array# :: MutableByteArray# s -> Int# -> Int# -> State# s -> State# s

writeInt32Array# :: MutableByteArray# s -> Int# -> Int# -> State# s -> State# s

writeInt64Array# :: MutableByteArray# s -> Int# -> Int# -> State# s -> State# s

writeWord8Array# :: MutableByteArray# s -> Int# -> Word# -> State# s -> State# s

writeWord16Array# :: MutableByteArray# s -> Int# -> Word# -> State# s -> State# s

writeWord32Array# :: MutableByteArray# s -> Int# -> Word# -> State# s -> State# s

writeWord64Array# :: MutableByteArray# s -> Int# -> Word# -> State# s -> State# s

# Addr#

data Addr#

An arbitrary machine address assumed to point outside the garbage-collected heap.

nullAddr# :: Addr#

The null address.

plusAddr# :: Addr# -> Int# -> Addr#

minusAddr# :: Addr# -> Addr# -> Int#

Result is meaningless if two `Addr#`s are so far apart that their difference doesn't fit in an `Int#`.

remAddr# :: Addr# -> Int# -> Int#

Return the remainder when the `Addr#` arg, treated like an `Int#`, is divided by the `Int#` arg.

addr2Int# :: Addr# -> Int#

Coerce directly from address to int. Strongly deprecated.

int2Addr# :: Int# -> Addr#

Coerce directly from int to address. Strongly deprecated.

gtAddr# :: Addr# -> Addr# -> Bool

geAddr# :: Addr# -> Addr# -> Bool

eqAddr# :: Addr# -> Addr# -> Bool

neAddr# :: Addr# -> Addr# -> Bool

ltAddr# :: Addr# -> Addr# -> Bool

leAddr# :: Addr# -> Addr# -> Bool

indexCharOffAddr# :: Addr# -> Int# -> Char#

Reads 8-bit character; offset in bytes.

indexWideCharOffAddr# :: Addr# -> Int# -> Char#

Reads 31-bit character; offset in 4-byte words.

indexIntOffAddr# :: Addr# -> Int# -> Int#

indexWordOffAddr# :: Addr# -> Int# -> Word#

indexAddrOffAddr# :: Addr# -> Int# -> Addr#

indexFloatOffAddr# :: Addr# -> Int# -> Float#

indexDoubleOffAddr# :: Addr# -> Int# -> Double#

indexStablePtrOffAddr# :: Addr# -> Int# -> StablePtr# a

indexInt8OffAddr# :: Addr# -> Int# -> Int#

indexInt16OffAddr# :: Addr# -> Int# -> Int#

indexInt32OffAddr# :: Addr# -> Int# -> Int#

indexInt64OffAddr# :: Addr# -> Int# -> Int#

indexWord8OffAddr# :: Addr# -> Int# -> Word#

indexWord16OffAddr# :: Addr# -> Int# -> Word#

indexWord32OffAddr# :: Addr# -> Int# -> Word#

indexWord64OffAddr# :: Addr# -> Int# -> Word#

readCharOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Char##)

Reads 8-bit character; offset in bytes.

readWideCharOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Char##)

Reads 31-bit character; offset in 4-byte words.

readIntOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Int##)

readWordOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Word##)

readAddrOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Addr##)

readFloatOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Float##)

readDoubleOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Double##)

readStablePtrOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, StablePtr# a#)

readInt8OffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Int##)

readInt16OffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Int##)

readInt32OffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Int##)

readInt64OffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Int##)

readWord8OffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Word##)

readWord16OffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Word##)

readWord32OffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Word##)

readWord64OffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Word##)

writeCharOffAddr# :: Addr# -> Int# -> Char# -> State# s -> State# s

writeWideCharOffAddr# :: Addr# -> Int# -> Char# -> State# s -> State# s

writeIntOffAddr# :: Addr# -> Int# -> Int# -> State# s -> State# s

writeWordOffAddr# :: Addr# -> Int# -> Word# -> State# s -> State# s

writeAddrOffAddr# :: Addr# -> Int# -> Addr# -> State# s -> State# s

writeFloatOffAddr# :: Addr# -> Int# -> Float# -> State# s -> State# s

writeDoubleOffAddr# :: Addr# -> Int# -> Double# -> State# s -> State# s

writeStablePtrOffAddr# :: Addr# -> Int# -> StablePtr# a -> State# s -> State# s

writeInt8OffAddr# :: Addr# -> Int# -> Int# -> State# s -> State# s

writeInt16OffAddr# :: Addr# -> Int# -> Int# -> State# s -> State# s

writeInt32OffAddr# :: Addr# -> Int# -> Int# -> State# s -> State# s

writeInt64OffAddr# :: Addr# -> Int# -> Int# -> State# s -> State# s

writeWord8OffAddr# :: Addr# -> Int# -> Word# -> State# s -> State# s

writeWord16OffAddr# :: Addr# -> Int# -> Word# -> State# s -> State# s

writeWord32OffAddr# :: Addr# -> Int# -> Word# -> State# s -> State# s

writeWord64OffAddr# :: Addr# -> Int# -> Word# -> State# s -> State# s

# Mutable variables

Operations on MutVar#s.

data MutVar# s a

A `MutVar#` behaves like a single-element mutable array.

newMutVar# :: a -> State# s -> (#State# s, MutVar# s a#)

Create `MutVar#` with specified initial value in specified state thread.

readMutVar# :: MutVar# s a -> State# s -> (#State# s, a#)

Read contents of `MutVar#`. Result is not yet evaluated.

writeMutVar# :: MutVar# s a -> a -> State# s -> State# s

Write contents of `MutVar#`.

sameMutVar# :: MutVar# s a -> MutVar# s a -> Bool

atomicModifyMutVar# :: MutVar# s a -> (a -> b) -> State# s -> (#State# s, c#)

# Exceptions

catch# :: (State# RealWorld -> (#State# RealWorld, a#)) -> (b -> State# RealWorld -> (#State# RealWorld, a#)) -> State# RealWorld -> (#State# RealWorld, a#)

raise# :: a -> b

raiseIO# :: a -> State# RealWorld -> (#State# RealWorld, b#)

maskAsyncExceptions# :: (State# RealWorld -> (#State# RealWorld, a#)) -> State# RealWorld -> (#State# RealWorld, a#)

maskUninterruptible# :: (State# RealWorld -> (#State# RealWorld, a#)) -> State# RealWorld -> (#State# RealWorld, a#)

unmaskAsyncExceptions# :: (State# RealWorld -> (#State# RealWorld, a#)) -> State# RealWorld -> (#State# RealWorld, a#)

getMaskingState# :: State# RealWorld -> (#State# RealWorld, Int##)

# STM-accessible Mutable Variables

data TVar# s a

atomically# :: (State# RealWorld -> (#State# RealWorld, a#)) -> State# RealWorld -> (#State# RealWorld, a#)

retry# :: State# RealWorld -> (#State# RealWorld, a#)

catchRetry# :: (State# RealWorld -> (#State# RealWorld, a#)) -> (State# RealWorld -> (#State# RealWorld, a#)) -> State# RealWorld -> (#State# RealWorld, a#)

catchSTM# :: (State# RealWorld -> (#State# RealWorld, a#)) -> (b -> State# RealWorld -> (#State# RealWorld, a#)) -> State# RealWorld -> (#State# RealWorld, a#)

check# :: (State# RealWorld -> (#State# RealWorld, a#)) -> State# RealWorld -> (#State# RealWorld, ()#)

newTVar# :: a -> State# s -> (#State# s, TVar# s a#)

Create a new `TVar#` holding a specified initial value.

readTVar# :: TVar# s a -> State# s -> (#State# s, a#)

Read contents of `TVar#`. Result is not yet evaluated.

readTVarIO# :: TVar# s a -> State# s -> (#State# s, a#)

Read contents of `TVar#` outside an STM transaction

writeTVar# :: TVar# s a -> a -> State# s -> State# s

Write contents of `TVar#`.

sameTVar# :: TVar# s a -> TVar# s a -> Bool

# Synchronized Mutable Variables

Operations on `MVar#`s.

data MVar# s a

A shared mutable variable (not the same as a `MutVar#`!). (Note: in a non-concurrent implementation, `(MVar# a)` can be represented by `(MutVar# (Maybe a))`.)

newMVar# :: State# s -> (#State# s, MVar# s a#)

Create new `MVar#`; initially empty.

takeMVar# :: MVar# s a -> State# s -> (#State# s, a#)

If `MVar#` is empty, block until it becomes full. Then remove and return its contents, and set it empty.

tryTakeMVar# :: MVar# s a -> State# s -> (#State# s, Int#, a#)

If `MVar#` is empty, immediately return with integer 0 and value undefined. Otherwise, return with integer 1 and contents of `MVar#`, and set `MVar#` empty.

putMVar# :: MVar# s a -> a -> State# s -> State# s

If `MVar#` is full, block until it becomes empty. Then store value arg as its new contents.

tryPutMVar# :: MVar# s a -> a -> State# s -> (#State# s, Int##)

If `MVar#` is full, immediately return with integer 0. Otherwise, store value arg as `MVar#`'s new contents, and return with integer 1.

sameMVar# :: MVar# s a -> MVar# s a -> Bool

isEmptyMVar# :: MVar# s a -> State# s -> (#State# s, Int##)

Return 1 if `MVar#` is empty; 0 otherwise.

# Delay/wait operations

delay# :: Int# -> State# s -> State# s

Sleep specified number of microseconds.

waitRead# :: Int# -> State# s -> State# s

Block until input is available on specified file descriptor.

waitWrite# :: Int# -> State# s -> State# s

Block until output is possible on specified file descriptor.

# Concurrency primitives

data State# s

`State#` is the primitive, unlifted type of states. It has one type parameter, thus `State# RealWorld`, or `State# s`, where s is a type variable. The only purpose of the type parameter is to keep different state threads separate. It is represented by nothing at all.

data RealWorld

`RealWorld` is deeply magical. It is primitive, but it is not unlifted (hence `ptrArg`). We never manipulate values of type `RealWorld`; it's only used in the type system, to parameterise `State#`.

data ThreadId#

(In a non-concurrent implementation, this can be a singleton type, whose (unique) value is returned by `myThreadId#`. The other operations can be omitted.)

fork# :: a -> State# RealWorld -> (#State# RealWorld, ThreadId##)

forkOn# :: Int# -> a -> State# RealWorld -> (#State# RealWorld, ThreadId##)

killThread# :: ThreadId# -> a -> State# RealWorld -> State# RealWorld

yield# :: State# RealWorld -> State# RealWorld

myThreadId# :: State# RealWorld -> (#State# RealWorld, ThreadId##)

labelThread# :: ThreadId# -> Addr# -> State# RealWorld -> State# RealWorld

isCurrentThreadBound# :: State# RealWorld -> (#State# RealWorld, Int##)

noDuplicate# :: State# RealWorld -> State# RealWorld

threadStatus# :: ThreadId# -> State# RealWorld -> (#State# RealWorld, Int##)

# Weak pointers

data Weak# b

mkWeak# :: o -> b -> c -> State# RealWorld -> (#State# RealWorld, Weak# b#)

mkWeakForeignEnv# :: o -> b -> Addr# -> Addr# -> Int# -> Addr# -> State# RealWorld -> (#State# RealWorld, Weak# b#)

deRefWeak# :: Weak# a -> State# RealWorld -> (#State# RealWorld, Int#, a#)

finalizeWeak# :: Weak# a -> State# RealWorld -> (#State# RealWorld, Int#, State# RealWorld -> (#State# RealWorld, ()#)#)

touch# :: o -> State# RealWorld -> State# RealWorld

# Stable pointers and names

data StablePtr# a

data StableName# a

makeStablePtr# :: a -> State# RealWorld -> (#State# RealWorld, StablePtr# a#)

deRefStablePtr# :: StablePtr# a -> State# RealWorld -> (#State# RealWorld, a#)

eqStablePtr# :: StablePtr# a -> StablePtr# a -> Int#

makeStableName# :: a -> State# RealWorld -> (#State# RealWorld, StableName# a#)

eqStableName# :: StableName# a -> StableName# a -> Int#

stableNameToInt# :: StableName# a -> Int#

# Unsafe pointer equality

reallyUnsafePtrEquality# :: a -> a -> Int#

# Parallelism

par# :: a -> Int#

getSpark# :: State# s -> (#State# s, Int#, a#)

numSparks# :: State# s -> (#State# s, Int##)

Returns the number of sparks in the local spark pool.

parGlobal# :: a -> Int# -> Int# -> Int# -> Int# -> b -> Int#

parLocal# :: a -> Int# -> Int# -> Int# -> Int# -> b -> Int#

parAt# :: b -> a -> Int# -> Int# -> Int# -> Int# -> c -> Int#

parAtAbs# :: a -> Int# -> Int# -> Int# -> Int# -> Int# -> b -> Int#

parAtRel# :: a -> Int# -> Int# -> Int# -> Int# -> Int# -> b -> Int#

parAtForNow# :: b -> a -> Int# -> Int# -> Int# -> Int# -> c -> Int#

# Tag to enum stuff

Convert back and forth between values of enumerated types and small integers.

dataToTag# :: a -> Int#

tagToEnum# :: Int# -> a

# Bytecode operations

Support for the bytecode interpreter and linker.

data BCO#

Primitive bytecode type.

addrToHValue# :: Addr# -> (#a#)

Convert an `Addr#` to a followable type.

mkApUpd0# :: BCO# -> (#a#)

newBCO# :: ByteArray# -> ByteArray# -> Array# a -> Int# -> ByteArray# -> State# s -> (#State# s, BCO##)

unpackClosure# :: a -> (#Addr#, Array# b, ByteArray##)

getApStackVal# :: a -> Int# -> (#Int#, b#)

# Misc

These aren't nearly as wired in as Etc...

traceCcs# :: a -> b -> b

# Etc

Miscellaneous built-ins

seq :: a -> b -> b

Evaluates its first argument to head normal form, and then returns its second argument as the result.

inline :: a -> a

The call `(inline f)` arranges that f is inlined, regardless of its size. More precisely, the call `(inline f)` rewrites to the right-hand side of `f`'s definition. This allows the programmer to control inlining from a particular call site rather than the definition site of the function (c.f. `INLINE` pragmas in User's Guide, Section 7.10.3, "INLINE and NOINLINE pragmas").

This inlining occurs regardless of the argument to the call or the size of `f`'s definition; it is unconditional. The main caveat is that `f`'s definition must be visible to the compiler. That is, `f` must be `let`-bound in the current scope. If no inlining takes place, the `inline` function expands to the identity function in Phase zero; so its use imposes no overhead.

It is good practice to mark the function with an INLINABLE pragma at its definition, (a) so that GHC guarantees to expose its unfolding regardless of size, and (b) so that you have control over exactly what is inlined.

lazy :: a -> a

The `lazy` function restrains strictness analysis a little. The call `(lazy e)` means the same as `e`, but `lazy` has a magical property so far as strictness analysis is concerned: it is lazy in its first argument, even though its semantics is strict. After strictness analysis has run, calls to `lazy` are inlined to be the identity function.

This behaviour is occasionally useful when controlling evaluation order. Notably, `lazy` is used in the library definition of `Control.Parallel.par`:

    par :: a -> b -> b

    par x y = case (par# x) of _ -> lazy y

If `lazy` were not lazy, `par` would look strict in `y` which would defeat the whole purpose of `par`.

Like `seq`, the argument of `lazy` can have an unboxed type.

data Any a

The type constructor `Any` is type to which you can unsafely coerce any lifted type, and back.

- It is lifted, and hence represented by a pointer
- It does not claim to be a data type, and that's important for the code generator, because the code gen may enter a data value but never enters a function value.

It's also used to instantiate un-constrained type variables after type checking. For example

    length Any []

Annoyingly, we sometimes need `Any`s of other kinds, such as `(* -> *)` etc. This is a bit like tuples. We define a couple of useful ones here, and make others up on the fly. If any of these others end up being exported into interface files, we'll get a crash; at least until we add interface-file syntax to support them.

unsafeCoerce# :: a -> b

The function `unsafeCoerce#` allows you to side-step the typechecker entirely. That is, it allows you to coerce any type into any other type. If you use this function, you had better get it right, otherwise segmentation faults await. It is generally used when you want to write a program that you know is well-typed, but where Haskell's type system is not expressive enough to prove that it is well typed.

The following uses of `unsafeCoerce#` are supposed to work (i.e. not lead to spurious compile-time or run-time crashes):

- Casting any lifted type to `Any`
- Casting `Any` back to the real type
- Casting an unboxed type to another unboxed type of the same size (but not coercions between floating-point and integral types)
- Casting between two types that have the same runtime representation. One case is when the two types differ only in "phantom" type parameters, for example `Ptr Int` to `Ptr Float`, or `[Int]` to `[Float]` when the list is known to be empty. Also, a `newtype` of a type `T` has the same representation at runtime as `T`.

Other uses of `unsafeCoerce#` are undefined. In particular, you should not use `unsafeCoerce#` to cast a T to an algebraic data type D, unless T is also an algebraic data type. For example, do not cast `Int->Int` to `Bool`, even if you later cast that `Bool` back to `Int->Int` before applying it. The reasons have to do with GHC's internal representation details (for the congnoscenti, data values can be entered but function closures cannot). If you want a safe type to cast things to, use `Any`, which is not an algebraic data type.

traceEvent# :: Addr# -> State# s -> State# s

Emits an event via the RTS tracing framework. The contents of the event is the zero-terminated byte string passed as the first argument. The event will be emitted either to the .eventlog file, or to stderr, depending on the runtime RTS flags.