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(svn r22284) -Codechange [FS#4564]: cast values to uint before computing modulus in direction_func.h, so compiler can generate superior code (adf88)

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smatz
2011-04-01 12:17:23 +00:00
parent 22bc18cc71
commit 0bbfed084f
1 changed files with 9 additions and 4 deletions
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13
src/direction_func.h
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@@ -35,7 +35,9 @@ static inline Direction ReverseDir(Direction d)
*/ */
static inline DirDiff DirDifference(Direction d0, Direction d1) static inline DirDiff DirDifference(Direction d0, Direction d1)
{ {
return (DirDiff)((d0 + 8 - d1) % 8); /* Cast to uint so compiler can use bitmask. If the difference is negative
* and we used int instead of uint, further "+ 8" would have to be added. */
return (DirDiff)((uint)(d0 - d1) % 8);
} }
/** /**
@@ -51,7 +53,8 @@ static inline DirDiff DirDifference(Direction d0, Direction d1)
*/ */
static inline DirDiff ChangeDirDiff(DirDiff d, DirDiff delta) static inline DirDiff ChangeDirDiff(DirDiff d, DirDiff delta)
{ {
return (DirDiff)((d + delta) % 8); /* Cast to uint so compiler can use bitmask. Result can never be negative. */
return (DirDiff)((uint)(d + delta) % 8);
} }
/** /**
@@ -66,7 +69,8 @@ static inline DirDiff ChangeDirDiff(DirDiff d, DirDiff delta)
*/ */
static inline Direction ChangeDir(Direction d, DirDiff delta) static inline Direction ChangeDir(Direction d, DirDiff delta)
{ {
return (Direction)((d + delta) % 8); /* Cast to uint so compiler can use bitmask. Result can never be negative. */
return (Direction)((uint)(d + delta) % 8);
} }
@@ -94,7 +98,8 @@ static inline DiagDirection ReverseDiagDir(DiagDirection d)
*/ */
static inline DiagDirection ChangeDiagDir(DiagDirection d, DiagDirDiff delta) static inline DiagDirection ChangeDiagDir(DiagDirection d, DiagDirDiff delta)
{ {
return (DiagDirection)((d + delta) % 4); /* Cast to uint so compiler can use bitmask. Result can never be negative. */
return (DiagDirection)((uint)(d + delta) % 4);
} }
/** /**