[Vm-dev] VM Maker: VMMaker.oscog-nice.2717.mcz

[commits at source.squeak.org]

Nicolas Cellier uploaded a new version of VMMaker to project VM Maker:
http://source.squeak.org/VMMaker/VMMaker.oscog-nice.2717.mcz

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

Name: VMMaker.oscog-nice.2717
Author: nice
Time: 22 February 2020, 9:27:55.723238 am
UUID: 7e488f00-892c-4569-b600-422064393682
Ancestors: VMMaker.oscog-eem.2716

Fix the BitBlt bug for convex shape fill.

The problem is that we are taking source one word too early (thus from previous row).
This happens when taking hdir=-1 and it is related to preload (again!!).

To guess if we must preload, we have to take the endBits when the direction is reversed due to overlap (hDir = -1)
	endBits := (sx + bbW - 1 bitAnd: pixPerM1) + 1
First error above: checkSourceOverlap has already done that:
	sx := sx + bbW - 1.
So it must be:
	endBits := (sx bitAnd: pixPerM1) + 1
	
Then we build mask1:
	m1 := destMSB = (hDir > 0)
		ifTrue: [AllOnes >> (32 - (startBits * destDepth))]
		ifFalse: [AllOnes << (32 - (startBits * destDepth)) bitAnd: AllOnes].
Second error above: if we have reversed direction (hDir = -1), then we		 must build mask2:
	destMSB
		ifTrue: [mask2 := AllOnes << (32 - (endBits * destDepth)) bitAnd: AllOnes]
		ifFalse: [mask2 := AllOnes >> (32 - (endBits * destDepth))].
Replace mask2 by m1 and endBits by startBits (because startBits contains endBits if hDir=-1)
And you see that the conditions destMSB is reversed...

Last thing: on 64bits, mask1 and mask2 have been declared int64...
But we only want 32 bits mask.
That is why I have protected with the bitAnd: AllOnes
(and thus removed the cCode:inSmalltalk: simulation guard)

=============== Diff against VMMaker.oscog-eem.2716 ===============

Item was changed:
  ----- Method: BitBltSimulation>>destMaskAndPointerInit (in category 'setup') -----
  destMaskAndPointerInit
  	"Compute masks for left and right destination words"
  	| startBits pixPerM1 endBits |
  	<inline: true>
  	pixPerM1 := destPPW - 1.  "A mask, assuming power of two"
  	"how many pixels in first word"
  	startBits := destPPW - (dx bitAnd: pixPerM1).
  	"how many pixels in last word"
  	endBits := (dx + bbW - 1 bitAnd: pixPerM1) + 1.
  	destMSB
  		ifTrue:
  			[mask1 := AllOnes >> (32 - (startBits * destDepth)).
+ 			 mask2 := AllOnes << (32 - (endBits * destDepth)) bitAnd: AllOnes] 
- 			 mask2 := AllOnes << (32 - (endBits * destDepth))] 
  		ifFalse:
+ 			[mask1 := AllOnes << (32 - (startBits * destDepth)) bitAnd: AllOnes.
- 			[mask1 := AllOnes << (32 - (startBits * destDepth)).
  			 mask2 := AllOnes >> (32 - (endBits * destDepth))].
- 	self cCode: [] inSmalltalk:
- 		[mask1 := mask1 bitAnd: 16rFFFFFFFF.
- 		 mask2 := mask2 bitAnd: 16rFFFFFFFF].
  
  	"determine number of words stored per line; merge masks if only 1"
  	bbW <= startBits
  		ifTrue: [mask1 := mask1 bitAnd: mask2.
  				mask2 := 0.
  				nWords := 1]
  		ifFalse: [nWords := bbW - startBits + pixPerM1 // destPPW + 1].
  	hDir := vDir := 1. "defaults for no overlap with source"
  
  	"calculate byte addr and delta, based on first word of data"
  	"Note pitch is bytes and nWords is longs, not bytes"
  	destIndex := destBits + (dy * destPitch) + ((dx // destPPW) * 4).
  	destDelta := destPitch * vDir - (4 * (nWords * hDir)) "byte addr delta"!

Item was changed:
  ----- Method: BitBltSimulation>>sourceSkewAndPointerInit (in category 'setup') -----
  sourceSkewAndPointerInit
  	"This is only used when source and dest are same depth,
  	ie, when the barrel-shift copy loop is used."
  	| sxLowBits dxLowBits pixPerM1 startBits m1 |
  	<inline: true>
  	<var: 'm1' type: #'unsigned int'>
  	self assert: (destPPW = sourcePPW and: [destMSB = sourceMSB and: [destDepth = sourceDepth]]).
  	pixPerM1 := destPPW - 1.  "A mask, assuming power of two"
  	sxLowBits := sx bitAnd: pixPerM1.
  	dxLowBits := dx bitAnd: pixPerM1.
  	"how many pixels in first word"
  	startBits := hDir > 0
  					ifTrue: [sourcePPW - (sx bitAnd: pixPerM1)]
+ 					ifFalse: [(sx bitAnd: pixPerM1) + 1].	
+ 	m1 := destMSB = (hDir > 0)
- 					ifFalse: [(sx + bbW - 1 bitAnd: pixPerM1) + 1].
- 	m1 := destMSB
  			ifTrue: [AllOnes >> (32 - (startBits * destDepth))] 
+ 			ifFalse: [AllOnes << (32 - (startBits * destDepth)) bitAnd: AllOnes].
- 			ifFalse: [AllOnes << (32 - (startBits * destDepth))].
  	preload := bbW > startBits and: [(m1 bitAnd: mask1) ~= mask1]. "i.e. there are some missing bits"
  
  	"calculate right-shift skew from source to dest"
  	skew := destDepth * (sourceMSB ifTrue: [sxLowBits - dxLowBits] ifFalse: [dxLowBits - sxLowBits]).  " -32..32 "
  	preload ifTrue: 
  		[skew := skew < 0 ifTrue: [skew + 32] ifFalse: [skew - 32]].
  
  	"Calc byte addr and delta from longWord info"
+ 	sourceIndex := sourceBits + (sy * sourcePitch) + ((sx // sourcePPW) * 4).
- 	sourceIndex := sourceBits + (sy * sourcePitch) + ((sx // (32 // sourceDepth)) * 4).
  	"calculate increments from end of 1 line to start of next"
  	sourceDelta := (sourcePitch * vDir) - (4 * (nWords * hDir)).
  
  	preload ifTrue: "Compensate for extra source word fetched"
  		[sourceDelta := sourceDelta - (4 * hDir)].
  
  	self deny: (preload and: [skew = 0]).
  	self assert: (skew between: -31 and: 31)!