[commit: ghc] master: Clarify documentation of addIntC#, subIntC# (e83e873)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/e83e873dabb5c2b9280782a4ae3a6fab528c5214/ghc

>---------------------------------------------------------------

commit e83e873dabb5c2b9280782a4ae3a6fab528c5214
Author: Reid Barton <rwbarton at gmail.com>
Date:   Sat Aug 9 19:24:12 2014 -0400

    Clarify documentation of addIntC#, subIntC#


>---------------------------------------------------------------

e83e873dabb5c2b9280782a4ae3a6fab528c5214
 compiler/prelude/primops.txt.pp | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/compiler/prelude/primops.txt.pp b/compiler/prelude/primops.txt.pp
index 19cd812..0c33233 100644
--- a/compiler/prelude/primops.txt.pp
+++ b/compiler/prelude/primops.txt.pp
@@ -247,13 +247,19 @@ primop   NotIOp   "notI#"   Monadic   Int# -> Int#
 
 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 signed integers reporting overflow.
+          First member of result is the sum truncated to an {\tt Int#};
+          second member is zero if the true sum fits in an {\tt Int#},
+          nonzero if overflow occurred (the sum is either too large
+          or too small to fit in an {\tt Int#}).}
    with code_size = 2
 
 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.}
+         {Subtract signed integers reporting overflow.
+          First member of result is the difference truncated to an {\tt Int#};
+          second member is zero if the true difference fits in an {\tt Int#},
+          nonzero if overflow occurred (the difference is either too large
+          or too small to fit in an {\tt Int#}).}
    with code_size = 2
 
 primop   IntGtOp  ">#"   Compare   Int# -> Int# -> Int#