cvs commit: fptools/ghc/compiler/prelude primops.txt.pp fptools/ghc/includes PrimOps.h fptools/ghc/lib/std PrelBase.lhs PrelBits.lhs PrelGHC.hi-boot.pp PrelInt.lhs PrelWord.lhs fptools/ghc/lib/std/cbits longlong.c

[Julian Seward]

sewardj     2001/12/07 03:34:48 PST

  Modified files:
    ghc/compiler/prelude primops.txt.pp 
    ghc/includes         PrimOps.h 
    ghc/lib/std          PrelBase.lhs PrelBits.lhs 
                         PrelGHC.hi-boot.pp PrelInt.lhs 
                         PrelWord.lhs 
    ghc/lib/std/cbits    longlong.c 
  Log:
  Change the story on shifting primops: SllOp, SrlOp, ISllOp, ISraOp, ISrlOp.
  
  In the old primop story, these were implemented by C macros which
  checked that the shift amount did not exceed the word size, and if so
  returns a suitable value (0 or -1).  This gives consistent, defined
  behaviour for any shift amount.  However, these checks were not
  implemented on the NCG route, an inconsistency.
  
  New story: these primops do NOT check their args; they just do the shift.
  Shift values >= word size give undefined results.  To reflect this, their
  Haskell names have been prefixed with 'unchecked'.
  
  The checks are now done on the Bits instances in the Prelude.  This means
  all code generation routes are consistently checked, and hopefully the
  simplifier will remove the checks for literal shift amounts.
  
  I have tried to fix up the implementation for 64-bit platforms too, but
  not having one to hand, I don't know if it will work as-is.
  
  Revision  Changes    Path
  1.11      +16 -11    fptools/ghc/compiler/prelude/primops.txt.pp
  1.87      +6 -6      fptools/ghc/includes/PrimOps.h
  1.56      +7 -7      fptools/ghc/lib/std/PrelBase.lhs
  1.6       +13 -7     fptools/ghc/lib/std/PrelBits.lhs
  1.10      +5 -5      fptools/ghc/lib/std/PrelGHC.hi-boot.pp
  1.23      +50 -32    fptools/ghc/lib/std/PrelInt.lhs
  1.19      +52 -33    fptools/ghc/lib/std/PrelWord.lhs
  1.5       +8 -7      fptools/ghc/lib/std/cbits/longlong.c