VM Maker: VMMaker.oscog- nice.2281.mcz

 
Nicolas Cellier uploaded a new version of VMMaker to project VM Maker:
http://source.squeak.org/VMMaker/VMMaker.oscog- nice.2281.mcz

==================== Summary ====================

Name: VMMaker.oscog- nice.2281
Author:  nice
Time: 24 November 2017, 10:59:40.883312 am
UUID: 4beeaee7-567e-1a4b-b0fb-bd95ce302516
Ancestors: VMMaker.oscog-eem.2280

Fix type inference of variable unskew in BitBlt >> copyLoop

unskew is a signed bitShift and must remain signed.

=============== Diff against VMMaker.oscog-eem.2280 ===============

Item was changed:
  ----- Method: BitBltSimulation>>copyLoop (in category 'inner loop') -----
  copyLoop
  | prevWord thisWord skewWord halftoneWord mergeWord hInc y unskew skewMask notSkewMask mergeFnwith destWord |
  "This version of the inner loop assumes noSource = false."
  <inline: false>
  <var: #mergeFnwith declareC: 'unsigned int (*mergeFnwith)(unsigned int, unsigned int)'>
  <var: #prevWord type: #'unsigned int'>
  <var: #thisWord type: #'unsigned int'>
  <var: #skewWord type: #'unsigned int'>
  <var: #halftoneWord type: #'unsigned int'>
  <var: #mergeWord type: #'unsigned int'>
  <var: #destWord type: #'unsigned int'>
  <var: #skewMask type: #'unsigned int'>
  <var: #notSkewMask type: #'unsigned int'>
  mergeFnwith := self cCoerce: (opTable at: combinationRule+1) to: 'unsigned int (*)(unsigned int, unsigned int)'.
  mergeFnwith.  "null ref for compiler"
 
  hInc := hDir*4.  "Byte delta"
  "degenerate skew fixed for Sparc. 10/20/96 ikp"
  skew == -32
+ ifTrue:
+ ["Beware: separate skewMask initialization to avoid bad type inference.
+ Indeed, unskew is a bitShift and MUST remain signed, while skewMask is unsigned"
+ skew := unskew := 0.
+ skewMask := 0]
- ifTrue: [skew := unskew := skewMask := 0]
  ifFalse: [skew < 0
  ifTrue:
  [unskew := skew+32.
  skewMask := AllOnes << (0-skew)]
  ifFalse:
  [skew = 0
  ifTrue:
  [unskew := 0.
  skewMask := AllOnes]
  ifFalse:
  [unskew := skew-32.
  skewMask := AllOnes >> skew]]].
  notSkewMask := skewMask bitInvert32.
  noHalftone
  ifTrue: [halftoneWord := AllOnes.  halftoneHeight := 0]
  ifFalse: [halftoneWord := self halftoneAt: 0].
 
  y := dy.
  1 to: bbH do: "here is the vertical loop"
  [ :i |
  halftoneHeight > 1 ifTrue:  "Otherwise, its always the same"
  [halftoneWord := self halftoneAt: y.
  y := y + vDir].
  preload ifTrue:
  ["load the 64-bit shifter"
  prevWord := self srcLongAt: sourceIndex.
  self incSrcIndex: hInc]
  ifFalse:
  [prevWord := 0].
 
  "Note: the horizontal loop has been expanded into three parts for speed:"
 
  "This first section requires masking of the destination store..."
  destMask := mask1.
  thisWord := self srcLongAt: sourceIndex.  "pick up next word"
  self incSrcIndex: hInc.
  skewWord := ((prevWord bitAnd: notSkewMask) bitShift: unskew)
  bitOr:  "32-bit rotate"
  ((thisWord bitAnd: skewMask) bitShift: skew).
  prevWord := thisWord.
  destWord := self dstLongAt: destIndex.
  mergeWord := self mergeFn: (skewWord bitAnd: halftoneWord) with: destWord.
  destWord := (destMask bitAnd: mergeWord) bitOr:
  (destWord bitAnd: destMask bitInvert32).
  self dstLongAt: destIndex put: destWord.
  self incDestIndex: hInc.
 
  "This central horizontal loop requires no store masking"
  destMask := AllOnes.
  combinationRule = 3
  ifTrue: [(skew = 0) & (halftoneWord = AllOnes)
  ifTrue:
  ["Very special inner loop for STORE mode with no skew -- just move words"
  hDir = -1
  ifTrue: ["Woeful patch: revert to older code for hDir = -1"
  2 to: nWords-1 do:
  [ :word |
  thisWord := self srcLongAt: sourceIndex.
  self incSrcIndex: hInc.
  self dstLongAt: destIndex put: thisWord.
  self incDestIndex: hInc]]
  ifFalse: [2 to: nWords-1 do:
  [ :word |  "Note loop starts with prevWord loaded (due to preload)"
  self dstLongAt: destIndex put: prevWord.
  self incDestIndex: hInc.
  prevWord := self srcLongAt: sourceIndex.
  self incSrcIndex: hInc]]]
  ifFalse:
  ["Special inner loop for STORE mode -- no need to call merge"
  2 to: nWords-1 do:
  [ :word |
  thisWord := self srcLongAt: sourceIndex.
  self incSrcIndex: hInc.
  skewWord := ((prevWord bitAnd: notSkewMask) bitShift: unskew)
  bitOr:  "32-bit rotate"
  ((thisWord bitAnd: skewMask) bitShift: skew).
  prevWord := thisWord.
  self dstLongAt: destIndex put: (skewWord bitAnd: halftoneWord).
  self incDestIndex: hInc]]
  ] ifFalse: [2 to: nWords-1 do: "Normal inner loop does merge:"
  [ :word |
  thisWord := self srcLongAt: sourceIndex.  "pick up next word"
  self incSrcIndex: hInc.
  skewWord := ((prevWord bitAnd: notSkewMask) bitShift: unskew)
  bitOr:  "32-bit rotate"
  ((thisWord bitAnd: skewMask) bitShift: skew).
  prevWord := thisWord.
  mergeWord := self mergeFn: (skewWord bitAnd: halftoneWord)
  with: (self dstLongAt: destIndex).
  self dstLongAt: destIndex put: mergeWord.
  self incDestIndex: hInc]
  ].
 
  "This last section, if used, requires masking of the destination store..."
  nWords > 1 ifTrue:
  [destMask := mask2.
  thisWord := self srcLongAt: sourceIndex.  "pick up next word"
  self incSrcIndex: hInc.
  skewWord := ((prevWord bitAnd: notSkewMask) bitShift: unskew)
  bitOr:  "32-bit rotate"
  ((thisWord bitAnd: skewMask) bitShift: skew).
  destWord := self dstLongAt: destIndex.
  mergeWord := self mergeFn: (skewWord bitAnd: halftoneWord) with: destWord.
  destWord := (destMask bitAnd: mergeWord) bitOr:
  (destWord bitAnd: destMask bitInvert32).
  self dstLongAt: destIndex put: destWord.
  self incDestIndex: hInc].
 
  self incSrcIndex: sourceDelta.
  self incDestIndex: destDelta]!