-----------------------------------------------------------------------
--- $Id: primops.txt.pp,v 1.12 2001/12/10 14:07:30 simonmar Exp $
+-- $Id: primops.txt.pp,v 1.21 2002/06/26 08:18:38 stolz Exp $
--
-- Primitive Operations
--
-- strictness attributes, whether it is defined as a macro
-- or as out-of-line code, etc.)
--
--- - ghc/lib/std/PrelGHC.hi-boot, to declare the primop
---
-- - if the primop is inline (i.e. a macro), then:
--- ghc/includes/PrimOps.h
--- ghc/compiler/nativeGen/StixPrim.lhs
--- ghc/compiler/nativeGen/MachCode.lhs (if implementation is machine-dependent)
+-- ghc/compiler/AbsCUtils.lhs (dscCOpStmt)
+-- defines the translation of the primop into simpler
+-- abstract C operations.
--
-- - or, for an out-of-line primop:
-- ghc/includes/PrimOps.h (just add the declaration)
-- ghc/rts/PrimOps.hc (define it here)
+-- ghc/rts/Linker.c (declare the symbol for GHCi)
--
-- - the User's Guide
--
primop IntMulOp "*#"
Dyadic Int# -> Int# -> Int#
+ {Low word of signed integer multiply.}
+ with commutable = True
+
+primop IntMulMayOfloOp "mulIntMayOflo#"
+ Dyadic 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.
+ }
with commutable = True
primop IntQuotOp "quotInt#" Dyadic
primop IntNegOp "negateInt#" Monadic Int# -> Int#
primop IntAddCOp "addIntC#" GenPrimOp Int# -> Int# -> (# Int#, Int# #)
- {Add with carry. First member of result is (wrapped) sum; second member is 0 iff no overflow occured.}
+ {Add with carry. First member of result is (wrapped) sum;
+ second member is 0 iff no overflow occured.}
primop IntSubCOp "subIntC#" GenPrimOp Int# -> Int# -> (# Int#, Int# #)
- {Subtract with carry. First member of result is (wrapped) difference; second member is 0 iff no overflow occured.}
-primop IntMulCOp "mulIntC#" GenPrimOp Int# -> Int# -> (# Int#, Int# #)
- {Multiply with carry. First member of result is (wrapped) product; second member is 0 iff no overflow occured.}
+ {Subtract with carry. First member of result is (wrapped) difference;
+ second member is 0 iff no overflow occured.}
+
primop IntGtOp ">#" Compare Int# -> Int# -> Bool
primop IntGeOp ">=#" Compare Int# -> Int# -> Bool
with out_of_line = True
primop ISllOp "uncheckedIShiftL#" GenPrimOp Int# -> Int# -> Int#
- {Shift left. Result undefined if shift amount equals
- or exceeds word size.}
+ {Shift left. Result undefined if shift amount is not
+ in the range 0 to word size - 1 inclusive.}
primop ISraOp "uncheckedIShiftRA#" GenPrimOp Int# -> Int# -> Int#
- {Shift right arithmetic. Result undefined if shift amount equals
- or exceeds word size.}
+ {Shift right arithmetic. Result undefined if shift amount is not
+ in the range 0 to word size - 1 inclusive.}
primop ISrlOp "uncheckedIShiftRL#" GenPrimOp Int# -> Int# -> Int#
- {Shift right logical. Result undefined if shift amount equals
- or exceeds word size.}
+ {Shift right logical. Result undefined if shift amount is not
+ in the range 0 to word size - 1 inclusive.}
------------------------------------------------------------------------
section "Word#"
primop NotOp "not#" Monadic Word# -> Word#
primop SllOp "uncheckedShiftL#" GenPrimOp Word# -> Int# -> Word#
- {Shift left logical. Result undefined if shift amount equals
- or exceeds word size.}
+ {Shift left logical. Result undefined if shift amount is not
+ in the range 0 to word size - 1 inclusive.}
primop SrlOp "uncheckedShiftRL#" GenPrimOp Word# -> Int# -> Word#
- {Shift right logical. Result undefined if shift amount equals
- or exceeds word size.}
+ {Shift right logical. Result undefined if shift amount is not
+ in the range 0 to word size - 1 inclusive.}
primop Word2IntOp "word2Int#" GenPrimOp Word# -> Int#
has_side_effects = True
out_of_line = True
+primop ForkProcessOp "forkProcess#" GenPrimOp
+ State# RealWorld -> (# State# RealWorld, Int# #)
+ with
+ has_side_effects = True
+ out_of_line = True
+
primop KillThreadOp "killThread#" GenPrimOp
ThreadId# -> a -> State# RealWorld -> State# RealWorld
with
with
out_of_line = True
+primop LabelThreadOp "labelThread#" GenPrimOp
+ ThreadId# -> Addr# -> State# RealWorld -> State# RealWorld
+ with
+ has_side_effects = True
+ out_of_line = True
+
------------------------------------------------------------------------
section "Weak pointers"
------------------------------------------------------------------------
usage = { mangle StableNameToIntOp [mkP] mkR }
------------------------------------------------------------------------
-section "Parallelism"
+section "Unsafe pointer equality"
+-- (#1 Bad Guy: Alistair Reid :)
------------------------------------------------------------------------
-primop SeqOp "seq#" GenPrimOp
- a -> Int#
+primop ReallyUnsafePtrEqualityOp "reallyUnsafePtrEquality#" GenPrimOp
+ a -> a -> Int#
with
- usage = { mangle SeqOp [mkO] mkR }
- strictness = { \ arity -> mkStrictSig (mkTopDmdType [evalDmd] TopRes) }
- -- Seq is strict in its argument; see notes in ConFold.lhs
- has_side_effects = True
+ usage = { mangle ReallyUnsafePtrEqualityOp [mkZ, mkZ] mkR }
+
+------------------------------------------------------------------------
+section "Parallelism"
+------------------------------------------------------------------------
primop ParOp "par#" GenPrimOp
a -> Int#
------------------------------------------------------------------------
section "Coercion"
- {{\tt unsafeCoerce# :: a -> b} is not a primop, but is defined in MkId.lhs.}
+ {{\tt unsafeCoerce\# :: a -> b} is not a primop, but is defined in MkId.lhs.}
------------------------------------------------------------------------
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