Do upcoming double byte strings require Spur? (was: The Trunk: Kernel-eem.980.mcz)

> Eliot Miranda uploaded a new version of Kernel to project The Trunk:
> http://source.squeak.org/trunk/Kernel-eem.980.mcz
>
> ==================== Summary ====================
>
> Name: Kernel-eem.980
> Author: eem
> Time: 18 January 2016, 7:32:08.6746 pm
> UUID: 95543c3e-e2d1-4ec8-8ad2-a90fca9a2b06
> Ancestors: Kernel-tpr.979
>
> Lay the ground work for double-byte strings (and possibly a 64-bit indexable bits type).
>
> Test shallowCopy's error code and report primitive failure if it has failed for other than being out of memory (which may simply imply the need for a GC).
>
> =============== Diff against Kernel-tpr.979 ===============
>
> Item was changed:
>   ----- Method: Behavior>>format (in category 'accessing') -----
>   format
>   "Answer an Integer that encodes the kinds and numbers of variables of
> + instances of the receiver.  The format is (currently) composed of two fields,
> + a 16-bit instSize, in the least significant bits, specifying the number of named
> + inst vars, if any, and a 5-bit format field, describing the kind of class.  c.f. instSpec.
> + (msb)<5 bit format><16 bit #fixed fields>(lsb)"
> - instances of the receiver."
>  
>   ^format!
>
> Item was changed:
>   ----- Method: Behavior>>instSpec (in category 'testing') -----
>   instSpec
>   "Answer the instance specification part of the format that defines what kind of object
>   an instance of the receiver is.  The formats are
>   0 = 0 sized objects (UndefinedObject True False et al)
>   1 = non-indexable objects with inst vars (Point et al)
>   2 = indexable objects with no inst vars (Array et al)
>   3 = indexable objects with inst vars (MethodContext AdditionalMethodState et al)
>   4 = weak indexable objects with inst vars (WeakArray et al)
>   5 = weak non-indexable objects with inst vars (ephemerons) (Ephemeron)
>   6 = unused
>   7 = immediates (SmallInteger, Character)
>   8 = unused
>   9 = 64-bit indexable
> + 10-11 = 32-bit indexable (Bitmap) (plus one odd bit, unused in 32-bits)
> + 12-15 = 16-bit indexable (plus two odd bits, one unused in 32-bits)
> + 16-23 = 8-bit indexable (plus three odd bits, one unused in 32-bits)
> + 24-31 = compiled methods (CompiledMethod) (plus three odd bits, one unused in 32-bits)
> + Note that in the VM instances also have a 5 bit format field that relates to their class's format.
> + Formats 11, 13-15, 17-23 & 25-31 are unused in classes but used in instances to define the
> + number of elements missing up to the slot size.  For example, a 2-byte ByteString instance
> + has format 18 in 32-bits, since its size is one 32-bit slot - 2 bytes ((18 bitAnd: 3) = 2), and
> + 22 in 64 bits, since its size is one 64-bit slot - 6 bytes ((22 bitAnd: 7) = 6)."
> - 10-11 = 32-bit indexable (Bitmap)
> - 12-15 = 16-bit indexable
> - 16-23 = 8-bit indexable
> - 24-31 = compiled methods (CompiledMethod)"
>   ^(format bitShift: -16) bitAnd: 16r1F!
>
> Item was changed:
>   ----- Method: Behavior>>kindOfSubclass (in category 'testing class hierarchy') -----
>   kindOfSubclass
>   "Answer a String that is the keyword that describes the receiver's kind of subclass,
>   either a regular subclass, a variableSubclass, a variableByteSubclass,
>   a variableWordSubclass, a weakSubclass, an ephemeronSubclass or an immediateSubclass.
> + c.f. typeOfClass & instSpec"
> + ^(#(' subclass: '
> + ' subclass: '
> + ' variableSubclass: '
> + ' variableSubclass: '
> + ' weakSubclass: '
> + ' ephemeronSubclass: '
> + nil
> + ' immediateSubclass: '
> + nil
> + ' variableDoubleWordSubclass: '
> + ' variableWordSubclass: ' nil
> + ' variableDoubleByteSubclass: ' nil nil nil
> + ' variableByteSubclass: ' nil nil nil nil nil nil nil
> + ' variableByteSubclass: ' nil nil nil nil nil nil nil )
> + at: self instSpec + 1) ifNil:
> + [self error: 'invalid class type']!
> - c.f. typeOfClass"
> - ^self isVariable
> - ifTrue:
> - [self isBits
> - ifTrue:
> - [self isBytes
> - ifTrue: [' variableByteSubclass: ']
> - ifFalse: [' variableWordSubclass: ']]
> - ifFalse:
> - [self isWeak
> - ifTrue: [' weakSubclass: ']
> - ifFalse: [' variableSubclass: ']]]
> - ifFalse:
> - [self isImmediateClass
> - ifTrue: [' immediateSubclass: ']
> - ifFalse:
> - [self isEphemeronClass
> - ifTrue: [' ephemeronSubclass: ']
> - ifFalse: [' subclass: ']]]!
>
> Item was changed:
>   ----- Method: Behavior>>typeOfClass (in category 'accessing') -----
>   typeOfClass
> + "Answer a symbol uniquely describing the type of the receiver. c.f. kindOfSubclass, instSpec"
> + ^(#(normal
> + normal
> + variable
> + variable
> + weak
> + ephemeron
> + nil
> + immediate
> + nil
> + longs
> + words nil
> + shorts nil nil nil
> + bytes nil nil nil nil nil nil nil
> + compiledMethod nil nil nil nil nil nil nil)
> + at: self instSpec + 1) ifNil:
> + [self error: 'invalid class type']!
> - "Answer a symbol uniquely describing the type of the receiver. c.f. kindOfSubclass"
> - self isBytes ifTrue:
> - [^self instSpec = CompiledMethod instSpec
> - ifTrue: [#compiledMethod] "Very special!!"
> - ifFalse: [#bytes]].
> - (self isWords and: [self isPointers not]) ifTrue:
> - [^self instSpec = SmallInteger instSpec
> - ifTrue: [#immediate] "Very special!!"
> - ifFalse: [#words]].
> - self isWeak ifTrue: [^#weak].
> - self isVariable ifTrue: [^#variable].
> - self isEphemeronClass ifTrue: [^#ephemeron].
> - ^#normal!
>
> Item was changed:
>   ----- Method: ClassBuilder>>computeFormat:instSize:forSuper: (in category 'class format') -----
>   computeFormat: type instSize: newInstSize forSuper: newSuper
>   "Compute the new format for making oldClass a subclass of newSuper.
>   Answer the format or nil if there is any problem."
> + | instSize isVar isPointers isWeak bitsUnitSize |
> - | instSize isVar isWords isPointers isWeak |
>   type == #compiledMethod ifTrue:
>   [newInstSize > 0 ifTrue:
>   [self error: 'A compiled method class cannot have named instance variables'.
>   ^nil].
>   ^CompiledMethod format].
>   instSize := newInstSize + (newSuper ifNil:[0] ifNotNil:[newSuper instSize]).
>   instSize > 65535 ifTrue:
>   [self error: 'Class has too many instance variables (', instSize printString,')'.
>   ^nil].
> + type == #normal ifTrue:[isVar := isWeak := false. isPointers := true].
> + type == #bytes ifTrue:[isVar := true. bitsUnitSize := 1. isPointers := isWeak := false].
> + type == #shorts ifTrue:[isVar := true. bitsUnitSize := 2. isPointers := isWeak := false].
> + type == #words ifTrue:[isVar := true. bitsUnitSize := 4. isPointers := isWeak := false].
> + type == #longs ifTrue:[isVar := true. bitsUnitSize := 8. isPointers := isWeak := false].
> + type == #variable ifTrue:[isVar := isPointers := true. isWeak := false].
> + type == #weak ifTrue:[isVar := isWeak := isPointers := true].
> + type == #ephemeron ifTrue:[isVar := false. isWeak := isPointers := true].
> + type == #immediate ifTrue:[isVar := isWeak := isPointers := false].
> - type == #normal ifTrue:[isVar := isWeak := false. isWords := isPointers := true].
> - type == #bytes ifTrue:[isVar := true. isWords := isPointers := isWeak := false].
> - type == #words ifTrue:[isVar := isWords := true. isPointers := isWeak := false].
> - type == #variable ifTrue:[isVar := isPointers := isWords := true. isWeak := false].
> - type == #weak ifTrue:[isVar := isWeak := isWords := isPointers := true].
> - type == #ephemeron ifTrue:[isVar := false. isWeak := isWords := isPointers := true].
> - type == #immediate ifTrue:[isVar := isWeak := isPointers := false. isWords := true].
>   (isPointers not and: [instSize > 0]) ifTrue:
>   [self error: 'A non-pointer class cannot have named instance variables'.
>   ^nil].
> + ^self format: instSize variable: isVar bitsUnitSize: bitsUnitSize pointers: isPointers weak: isWeak!
> - ^self format: instSize variable: isVar words: isWords pointers: isPointers weak: isWeak!
>
> Item was added:
> + ----- Method: ClassBuilder>>format:variable:bitsUnitSize:pointers:weak: (in category 'class format') -----
> + format: nInstVars variable: isVar bitsUnitSize: bitsUnitSize pointers: isPointers weak: isWeak
> + "Compute the format for the given instance specfication.
> + Above Cog Spur the class format is
> + <5 bits inst spec><16 bits inst size>
> + where the 5-bit inst spec is
> + 0 = 0 sized objects (UndefinedObject True False et al)
> + 1 = non-indexable objects with inst vars (Point et al)
> + 2 = indexable objects with no inst vars (Array et al)
> + 3 = indexable objects with inst vars (MethodContext AdditionalMethodState et al)
> + 4 = weak indexable objects with inst vars (WeakArray et al)
> + 5 = weak non-indexable objects with inst vars (ephemerons) (Ephemeron)
> + 6 = unused
> + 7 = immediates (SmallInteger, Character, SmallFloat64)
> + 8 = unused
> + 9 = 64-bit indexable
> + 10-11 = 32-bit indexable (Bitmap, WideString)
> + 12-15 = 16-bit indexable
> + 16-23 = 8-bit indexable (ByteString)
> + 24-31 = compiled methods (CompiledMethod)"
> + | instSpec |
> + instSpec := isWeak
> + ifTrue:
> + [isVar
> + ifTrue: [4]
> + ifFalse: [5]]
> + ifFalse:
> + [isPointers
> + ifTrue:
> + [isVar
> + ifTrue: [nInstVars > 0 ifTrue: [3] ifFalse: [2]]
> + ifFalse: [nInstVars > 0 ifTrue: [1] ifFalse: [0]]]
> + ifFalse:
> + [isVar
> + ifTrue: [bitsUnitSize caseOf: {
> + [1] -> [16].
> + [2] -> [12].
> + [4] -> [10].
> + [8] -> [9] }]
> + ifFalse: [7]]].
> + ^(instSpec bitShift: 16) + nInstVars!
>
> Item was changed:
>   ----- Method: Object>>shallowCopy (in category 'copying') -----
>   shallowCopy
>   "Answer a copy of the receiver which shares the receiver's instance variables."
>   | class newObject index |
> + <primitive: 148 error: ec>
> + ec == #'insufficient object memory' ifFalse:
> + [^self primitiveFailed].
> - <primitive: 148>
>   class := self class.
>   class isVariable
>   ifTrue:
>   [index := self basicSize.
> + newObject := class basicNew: index.
> + [index > 0] whileTrue:
> + [newObject basicAt: index put: (self basicAt: index).
> + index := index - 1]]
> - newObject := class basicNew: index.
> - [index > 0]
> - whileTrue:
> - [newObject basicAt: index put: (self basicAt: index).
> - index := index - 1]]
>   ifFalse: [newObject := class basicNew].
>   index := class instSize.
> + [index > 0] whileTrue:
> + [newObject instVarAt: index put: (self instVarAt: index).
> + index := index - 1].
> + ^newObject!
> - [index > 0]
> - whileTrue:
> - [newObject instVarAt: index put: (self instVarAt: index).
> - index := index - 1].
> - ^ newObject!
>

>
>
>> On Mon, Jan 18, 2016 at 03:32:21AM +0000, [hidden email] wrote:
>> Eliot Miranda uploaded a new version of Kernel to project The Trunk:
>> http://source.squeak.org/trunk/Kernel-eem.980.mcz
>>
>> ==================== Summary ====================
>>
>> Name: Kernel-eem.980
>> Author: eem
>> Time: 18 January 2016, 7:32:08.6746 pm
>> UUID: 95543c3e-e2d1-4ec8-8ad2-a90fca9a2b06
>> Ancestors: Kernel-tpr.979
>>
>> Lay the ground work for double-byte strings (and possibly a 64-bit indexable bits type).
>>
>> Test shallowCopy's error code and report primitive failure if it has failed for other than being out of memory (which may simply imply the need for a GC).
>>
>> =============== Diff against Kernel-tpr.979 ===============
>>
>> Item was changed:
>>  ----- Method: Behavior>>format (in category 'accessing') -----
>>  format
>>      "Answer an Integer that encodes the kinds and numbers of variables of
>> +     instances of the receiver.  The format is (currently) composed of two fields,
>> +     a 16-bit instSize, in the least significant bits, specifying the number of named
>> +     inst vars, if any, and a 5-bit format field, describing the kind of class.  c.f. instSpec.
>> +        (msb)<5 bit format><16 bit #fixed fields>(lsb)"
>> -    instances of the receiver."
>>
>>      ^format!
>>
>> Item was changed:
>>  ----- Method: Behavior>>instSpec (in category 'testing') -----
>>  instSpec
>>      "Answer the instance specification part of the format that defines what kind of object
>>       an instance of the receiver is.  The formats are
>>              0    = 0 sized objects (UndefinedObject True False et al)
>>              1    = non-indexable objects with inst vars (Point et al)
>>              2    = indexable objects with no inst vars (Array et al)
>>              3    = indexable objects with inst vars (MethodContext AdditionalMethodState et al)
>>              4    = weak indexable objects with inst vars (WeakArray et al)
>>              5    = weak non-indexable objects with inst vars (ephemerons) (Ephemeron)
>>              6    = unused
>>              7    = immediates (SmallInteger, Character)
>>              8    = unused
>>              9    = 64-bit indexable
>> +        10-11    = 32-bit indexable (Bitmap)                    (plus one odd bit, unused in 32-bits)
>> +        12-15    = 16-bit indexable                            (plus two odd bits, one unused in 32-bits)
>> +        16-23    = 8-bit indexable                            (plus three odd bits, one unused in 32-bits)
>> +        24-31    = compiled methods (CompiledMethod)    (plus three odd bits, one unused in 32-bits)
>> +     Note that in the VM instances also have a 5 bit format field that relates to their class's format.
>> +     Formats 11, 13-15, 17-23 & 25-31 are unused in classes but used in instances to define the
>> +     number of elements missing up to the slot size.  For example, a 2-byte ByteString instance
>> +     has format 18 in 32-bits, since its size is one 32-bit slot - 2 bytes ((18 bitAnd: 3) = 2), and
>> +     22 in 64 bits, since its size is one 64-bit slot - 6 bytes ((22 bitAnd: 7) = 6)."
>> -        10-11    = 32-bit indexable (Bitmap)
>> -        12-15    = 16-bit indexable
>> -        16-23    = 8-bit indexable
>> -        24-31    = compiled methods (CompiledMethod)"
>>      ^(format bitShift: -16) bitAnd: 16r1F!
>>
>> Item was changed:
>>  ----- Method: Behavior>>kindOfSubclass (in category 'testing class hierarchy') -----
>>  kindOfSubclass
>>      "Answer a String that is the keyword that describes the receiver's kind of subclass,
>>       either a regular subclass, a variableSubclass, a variableByteSubclass,
>>       a variableWordSubclass, a weakSubclass, an ephemeronSubclass or an immediateSubclass.
>> +     c.f. typeOfClass & instSpec"
>> +    ^(#(' subclass: '
>> +        ' subclass: '
>> +        ' variableSubclass: '
>> +        ' variableSubclass: '
>> +        ' weakSubclass: '
>> +        ' ephemeronSubclass: '
>> +        nil
>> +        ' immediateSubclass: '
>> +        nil
>> +        ' variableDoubleWordSubclass: '
>> +        ' variableWordSubclass: '        nil
>> +        ' variableDoubleByteSubclass: '    nil nil nil
>> +        ' variableByteSubclass: '        nil nil nil nil nil nil nil
>> +        ' variableByteSubclass: '        nil nil nil nil nil nil nil )
>> +            at: self instSpec + 1) ifNil:
>> +                [self error: 'invalid class type']!
>> -     c.f. typeOfClass"
>> -    ^self isVariable
>> -        ifTrue:
>> -            [self isBits
>> -                ifTrue:
>> -                    [self isBytes
>> -                        ifTrue: [' variableByteSubclass: ']
>> -                        ifFalse: [' variableWordSubclass: ']]
>> -                ifFalse:
>> -                    [self isWeak
>> -                        ifTrue: [' weakSubclass: ']
>> -                        ifFalse: [' variableSubclass: ']]]
>> -        ifFalse:
>> -            [self isImmediateClass
>> -                ifTrue: [' immediateSubclass: ']
>> -                ifFalse:
>> -                    [self isEphemeronClass
>> -                        ifTrue: [' ephemeronSubclass: ']
>> -                        ifFalse: [' subclass: ']]]!
>>
>> Item was changed:
>>  ----- Method: Behavior>>typeOfClass (in category 'accessing') -----
>>  typeOfClass
>> +    "Answer a symbol uniquely describing the type of the receiver. c.f. kindOfSubclass, instSpec"
>> +    ^(#(normal
>> +        normal
>> +        variable
>> +        variable
>> +        weak
>> +        ephemeron
>> +        nil
>> +        immediate
>> +        nil
>> +        longs
>> +        words                nil
>> +        shorts                nil nil nil
>> +        bytes                nil nil nil nil nil nil nil
>> +        compiledMethod    nil nil nil nil nil nil nil)
>> +            at: self instSpec + 1) ifNil:
>> +                [self error: 'invalid class type']!
>> -    "Answer a symbol uniquely describing the type of the receiver. c.f. kindOfSubclass"
>> -    self isBytes ifTrue:
>> -        [^self instSpec = CompiledMethod instSpec
>> -            ifTrue: [#compiledMethod] "Very special!!"
>> -            ifFalse: [#bytes]].
>> -    (self isWords and: [self isPointers not]) ifTrue:
>> -        [^self instSpec = SmallInteger instSpec
>> -            ifTrue: [#immediate] "Very special!!"
>> -            ifFalse: [#words]].
>> -    self isWeak ifTrue: [^#weak].
>> -    self isVariable ifTrue: [^#variable].
>> -    self isEphemeronClass ifTrue: [^#ephemeron].
>> -    ^#normal!
>>
>> Item was changed:
>>  ----- Method: ClassBuilder>>computeFormat:instSize:forSuper: (in category 'class format') -----
>>  computeFormat: type instSize: newInstSize forSuper: newSuper
>>      "Compute the new format for making oldClass a subclass of newSuper.
>>       Answer the format or nil if there is any problem."
>> +    | instSize isVar isPointers isWeak bitsUnitSize |
>> -    | instSize isVar isWords isPointers isWeak |
>>      type == #compiledMethod ifTrue:
>>          [newInstSize > 0 ifTrue:
>>              [self error: 'A compiled method class cannot have named instance variables'.
>>              ^nil].
>>          ^CompiledMethod format].
>>      instSize := newInstSize + (newSuper ifNil:[0] ifNotNil:[newSuper instSize]).
>>      instSize > 65535 ifTrue:
>>          [self error: 'Class has too many instance variables (', instSize printString,')'.
>>          ^nil].
>> +    type == #normal ifTrue:[isVar := isWeak := false. isPointers := true].
>> +    type == #bytes ifTrue:[isVar := true. bitsUnitSize := 1. isPointers := isWeak := false].
>> +    type == #shorts ifTrue:[isVar := true. bitsUnitSize := 2. isPointers := isWeak := false].
>> +    type == #words ifTrue:[isVar := true. bitsUnitSize := 4. isPointers := isWeak := false].
>> +    type == #longs ifTrue:[isVar := true. bitsUnitSize := 8. isPointers := isWeak := false].
>> +    type == #variable ifTrue:[isVar := isPointers := true. isWeak := false].
>> +    type == #weak ifTrue:[isVar := isWeak := isPointers := true].
>> +    type == #ephemeron ifTrue:[isVar := false. isWeak := isPointers := true].
>> +    type == #immediate ifTrue:[isVar := isWeak := isPointers := false].
>> -    type == #normal ifTrue:[isVar := isWeak := false. isWords := isPointers := true].
>> -    type == #bytes ifTrue:[isVar := true. isWords := isPointers := isWeak := false].
>> -    type == #words ifTrue:[isVar := isWords := true. isPointers := isWeak := false].
>> -    type == #variable ifTrue:[isVar := isPointers := isWords := true. isWeak := false].
>> -    type == #weak ifTrue:[isVar := isWeak := isWords := isPointers := true].
>> -    type == #ephemeron ifTrue:[isVar := false. isWeak := isWords := isPointers := true].
>> -    type == #immediate ifTrue:[isVar := isWeak := isPointers := false. isWords := true].
>>      (isPointers not and: [instSize > 0]) ifTrue:
>>          [self error: 'A non-pointer class cannot have named instance variables'.
>>          ^nil].
>> +    ^self format: instSize variable: isVar bitsUnitSize: bitsUnitSize pointers: isPointers weak: isWeak!
>> -    ^self format: instSize variable: isVar words: isWords pointers: isPointers weak: isWeak!
>>
>> Item was added:
>> + ----- Method: ClassBuilder>>format:variable:bitsUnitSize:pointers:weak: (in category 'class format') -----
>> + format: nInstVars variable: isVar bitsUnitSize: bitsUnitSize pointers: isPointers weak: isWeak
>> +    "Compute the format for the given instance specfication.
>> +     Above Cog Spur the class format is
>> +        <5 bits inst spec><16 bits inst size>
>> +     where the 5-bit inst spec is
>> +            0    = 0 sized objects (UndefinedObject True False et al)
>> +            1    = non-indexable objects with inst vars (Point et al)
>> +            2    = indexable objects with no inst vars (Array et al)
>> +            3    = indexable objects with inst vars (MethodContext AdditionalMethodState et al)
>> +            4    = weak indexable objects with inst vars (WeakArray et al)
>> +            5    = weak non-indexable objects with inst vars (ephemerons) (Ephemeron)
>> +            6    = unused
>> +            7    = immediates (SmallInteger, Character, SmallFloat64)
>> +            8    = unused
>> +            9    = 64-bit indexable
>> +        10-11    = 32-bit indexable (Bitmap, WideString)
>> +        12-15    = 16-bit indexable
>> +        16-23    = 8-bit indexable (ByteString)
>> +        24-31    = compiled methods (CompiledMethod)"
>> +    | instSpec |
>> +    instSpec := isWeak
>> +                    ifTrue:
>> +                        [isVar
>> +                            ifTrue: [4]
>> +                            ifFalse: [5]]
>> +                    ifFalse:
>> +                        [isPointers
>> +                            ifTrue:
>> +                                [isVar
>> +                                    ifTrue: [nInstVars > 0 ifTrue: [3] ifFalse: [2]]
>> +                                    ifFalse: [nInstVars > 0 ifTrue: [1] ifFalse: [0]]]
>> +                            ifFalse:
>> +                                [isVar
>> +                                    ifTrue: [bitsUnitSize caseOf: {
>> +                                            [1] -> [16].
>> +                                            [2] -> [12].
>> +                                            [4] -> [10].
>> +                                            [8] -> [9] }]
>> +                                    ifFalse: [7]]].
>> +    ^(instSpec bitShift: 16) + nInstVars!
>>
>> Item was changed:
>>  ----- Method: Object>>shallowCopy (in category 'copying') -----
>>  shallowCopy
>>      "Answer a copy of the receiver which shares the receiver's instance variables."
>>      | class newObject index |
>> +    <primitive: 148 error: ec>
>> +    ec == #'insufficient object memory' ifFalse:
>> +        [^self primitiveFailed].
>> -    <primitive: 148>
>>      class := self class.
>>      class isVariable
>>          ifTrue:
>>              [index := self basicSize.
>> +             newObject := class basicNew: index.
>> +             [index > 0] whileTrue:
>> +                [newObject basicAt: index put: (self basicAt: index).
>> +                 index := index - 1]]
>> -            newObject := class basicNew: index.
>> -            [index > 0]
>> -                whileTrue:
>> -                    [newObject basicAt: index put: (self basicAt: index).
>> -                    index := index - 1]]
>>          ifFalse: [newObject := class basicNew].
>>      index := class instSize.
>> +    [index > 0] whileTrue:
>> +        [newObject instVarAt: index put: (self instVarAt: index).
>> +         index := index - 1].
>> +    ^newObject!
>> -    [index > 0]
>> -        whileTrue:
>> -            [newObject instVarAt: index put: (self instVarAt: index).
>> -            index := index - 1].
>> -    ^ newObject!
>

> Hi David,
>
>
>> On Jan 26, 2016, at 3:13 PM, David T. Lewis <[hidden email]> wrote:
>>
>> Do the upcoming changes for double-byte strings require the Spur object
>> format, or are they something that would also work on a V3 object
>> memory?
>
> Well, it would be possible to implement them in a different way, by
> adding 16-bit character access primitives, but it can't be done
> "naturally".  The V3 object representation has a 4 bit format field in
> every object (it is also in the class's format field, the instSpec
> subfield).  This is organized as follows:
>
> ObjectMemory methods for object access
> formatOf: oop
> "       0      no fields
>         1      fixed fields only (all containing pointers)
>         2      indexable fields only (all containing pointers)
>         3      both fixed and indexable fields (all containing pointers)
>         4      both fixed and indexable weak fields (all containing
> pointers).
>
>         5      unused (reserved for ephemerons?)
>         6      indexable word fields only (no pointers)
>         7      indexable long (64-bit) fields (only in 64-bit images)
>
>     8-11      indexable byte fields only (no pointers) (low 2 bits are
> low 2 bits of size)
>    12-15     compiled methods:
>                    # of literal oops specified in method header,
>                    followed by indexable bytes (same interpretation of
> low 2 bits as above)
> "
> <inline: true>
> ^((self baseHeader: oop) >> self instFormatFieldLSB) bitAnd: 16rF
>
> The low two bits of formats 8-11 and 12-15 are subtracted from the
> object's slot size to derive the size in bytes.  So there is only one
> unused format, 7, and that isn't enough to express two short formats,
> one with the lsb set to indicate subtracting 2 bytes from the size.
>
> When I designed the Spur format field I made sure it would scale to
> 64-bits and provide 8- 16- 32- and 64-bit indexing.  It is organized
> as follows:
>
> SpurMemoryManager methods for object access
> formatOf: objOop
> "               0 = 0 sized objects (UndefinedObject True False et al)
>                 1 = non-indexable objects with inst vars (Point et al)
>                 2 = indexable objects with no inst vars (Array et al)
>                 3 = indexable objects with inst vars (MethodContext
> AdditionalMethodState et al)
>                 4 = weak indexable objects with inst vars (WeakArray et
> al)
>                 5 = weak non-indexable objects with inst vars
> (ephemerons) (Ephemeron)
>                 6 unused, reserved for exotic pointer objects?
>                 7 Forwarded Object, 1st field is pointer, rest of
> fields are ignored
>                 8 unused, reserved for exotic non-pointer objects?
>                 9 (?) 64-bit indexable
>        10 - 11 32-bit indexable (11 unused in 32 bits)
>        12 - 15 16-bit indexable (14 & 15 unused in 32-bits)
>        16 - 23 byte indexable (20-23 unused in 32-bits)
>        24 - 31 compiled method (28-31 unused in 32-bits)"
>     ^(self longAt: objOop) >> self formatShift bitAnd: self formatMask
>
>
> So this makes it natural to have the at:[put:] primitives in both
> normal (60 & 61, objects for pointer objects or integers for bits
> objects) and string (63 & 64, characters for bits objects) variations.
> And indeed when I finally get round to building new Spur VMs the
> primitives do already access 16-bits, and extending the ClassBuilder
> to allow specifying those classes is straight-forward.
>
>> Thanks,
>> Dave
>
> _,,,^..^,,,_
> Eliot
>
>>
>>
>>> On Mon, Jan 18, 2016 at 03:32:21AM +0000, [hidden email]
>>> wrote:
>>> Eliot Miranda uploaded a new version of Kernel to project The Trunk:
>>> http://source.squeak.org/trunk/Kernel-eem.980.mcz
>>>
>>> ==================== Summary ====================
>>>
>>> Name: Kernel-eem.980
>>> Author: eem
>>> Time: 18 January 2016, 7:32:08.6746 pm
>>> UUID: 95543c3e-e2d1-4ec8-8ad2-a90fca9a2b06
>>> Ancestors: Kernel-tpr.979
>>>
>>> Lay the ground work for double-byte strings (and possibly a 64-bit
>>> indexable bits type).
>>>
>>> Test shallowCopy's error code and report primitive failure if it has
>>> failed for other than being out of memory (which may simply imply the
>>> need for a GC).
>>>
>>> =============== Diff against Kernel-tpr.979 ===============
>>>
>>> Item was changed:
>>>  ----- Method: Behavior>>format (in category 'accessing') -----
>>>  format
>>>      "Answer an Integer that encodes the kinds and numbers of variables
>>> of
>>> +     instances of the receiver.  The format is (currently) composed of
>>> two fields,
>>> +     a 16-bit instSize, in the least significant bits, specifying the
>>> number of named
>>> +     inst vars, if any, and a 5-bit format field, describing the kind
>>> of class.  c.f. instSpec.
>>> +        (msb)<5 bit format><16 bit #fixed fields>(lsb)"
>>> -    instances of the receiver."
>>>
>>>      ^format!
>>>
>>> Item was changed:
>>>  ----- Method: Behavior>>instSpec (in category 'testing') -----
>>>  instSpec
>>>      "Answer the instance specification part of the format that defines
>>> what kind of object
>>>       an instance of the receiver is.  The formats are
>>>              0    = 0 sized objects (UndefinedObject True False et al)
>>>              1    = non-indexable objects with inst vars (Point et al)
>>>              2    = indexable objects with no inst vars (Array et al)
>>>              3    = indexable objects with inst vars (MethodContext
>>> AdditionalMethodState et al)
>>>              4    = weak indexable objects with inst vars (WeakArray et
>>> al)
>>>              5    = weak non-indexable objects with inst vars
>>> (ephemerons) (Ephemeron)
>>>              6    = unused
>>>              7    = immediates (SmallInteger, Character)
>>>              8    = unused
>>>              9    = 64-bit indexable
>>> +        10-11    = 32-bit indexable (Bitmap)                    (plus
>>> one odd bit, unused in 32-bits)
>>> +        12-15    = 16-bit indexable                            (plus
>>> two odd bits, one unused in 32-bits)
>>> +        16-23    = 8-bit indexable                            (plus
>>> three odd bits, one unused in 32-bits)
>>> +        24-31    = compiled methods (CompiledMethod)    (plus three
>>> odd bits, one unused in 32-bits)
>>> +     Note that in the VM instances also have a 5 bit format field that
>>> relates to their class's format.
>>> +     Formats 11, 13-15, 17-23 & 25-31 are unused in classes but used
>>> in instances to define the
>>> +     number of elements missing up to the slot size.  For example, a
>>> 2-byte ByteString instance
>>> +     has format 18 in 32-bits, since its size is one 32-bit slot - 2
>>> bytes ((18 bitAnd: 3) = 2), and
>>> +     22 in 64 bits, since its size is one 64-bit slot - 6 bytes ((22
>>> bitAnd: 7) = 6)."
>>> -        10-11    = 32-bit indexable (Bitmap)
>>> -        12-15    = 16-bit indexable
>>> -        16-23    = 8-bit indexable
>>> -        24-31    = compiled methods (CompiledMethod)"
>>>      ^(format bitShift: -16) bitAnd: 16r1F!
>>>
>>> Item was changed:
>>>  ----- Method: Behavior>>kindOfSubclass (in category 'testing class
>>> hierarchy') -----
>>>  kindOfSubclass
>>>      "Answer a String that is the keyword that describes the receiver's
>>> kind of subclass,
>>>       either a regular subclass, a variableSubclass, a
>>> variableByteSubclass,
>>>       a variableWordSubclass, a weakSubclass, an ephemeronSubclass or
>>> an immediateSubclass.
>>> +     c.f. typeOfClass & instSpec"
>>> +    ^(#(' subclass: '
>>> +        ' subclass: '
>>> +        ' variableSubclass: '
>>> +        ' variableSubclass: '
>>> +        ' weakSubclass: '
>>> +        ' ephemeronSubclass: '
>>> +        nil
>>> +        ' immediateSubclass: '
>>> +        nil
>>> +        ' variableDoubleWordSubclass: '
>>> +        ' variableWordSubclass: '        nil
>>> +        ' variableDoubleByteSubclass: '    nil nil nil
>>> +        ' variableByteSubclass: '        nil nil nil nil nil nil nil
>>> +        ' variableByteSubclass: '        nil nil nil nil nil nil nil )
>>> +            at: self instSpec + 1) ifNil:
>>> +                [self error: 'invalid class type']!
>>> -     c.f. typeOfClass"
>>> -    ^self isVariable
>>> -        ifTrue:
>>> -            [self isBits
>>> -                ifTrue:
>>> -                    [self isBytes
>>> -                        ifTrue: [' variableByteSubclass: ']
>>> -                        ifFalse: [' variableWordSubclass: ']]
>>> -                ifFalse:
>>> -                    [self isWeak
>>> -                        ifTrue: [' weakSubclass: ']
>>> -                        ifFalse: [' variableSubclass: ']]]
>>> -        ifFalse:
>>> -            [self isImmediateClass
>>> -                ifTrue: [' immediateSubclass: ']
>>> -                ifFalse:
>>> -                    [self isEphemeronClass
>>> -                        ifTrue: [' ephemeronSubclass: ']
>>> -                        ifFalse: [' subclass: ']]]!
>>>
>>> Item was changed:
>>>  ----- Method: Behavior>>typeOfClass (in category 'accessing') -----
>>>  typeOfClass
>>> +    "Answer a symbol uniquely describing the type of the receiver.
>>> c.f. kindOfSubclass, instSpec"
>>> +    ^(#(normal
>>> +        normal
>>> +        variable
>>> +        variable
>>> +        weak
>>> +        ephemeron
>>> +        nil
>>> +        immediate
>>> +        nil
>>> +        longs
>>> +        words                nil
>>> +        shorts                nil nil nil
>>> +        bytes                nil nil nil nil nil nil nil
>>> +        compiledMethod    nil nil nil nil nil nil nil)
>>> +            at: self instSpec + 1) ifNil:
>>> +                [self error: 'invalid class type']!
>>> -    "Answer a symbol uniquely describing the type of the receiver.
>>> c.f. kindOfSubclass"
>>> -    self isBytes ifTrue:
>>> -        [^self instSpec = CompiledMethod instSpec
>>> -            ifTrue: [#compiledMethod] "Very special!!"
>>> -            ifFalse: [#bytes]].
>>> -    (self isWords and: [self isPointers not]) ifTrue:
>>> -        [^self instSpec = SmallInteger instSpec
>>> -            ifTrue: [#immediate] "Very special!!"
>>> -            ifFalse: [#words]].
>>> -    self isWeak ifTrue: [^#weak].
>>> -    self isVariable ifTrue: [^#variable].
>>> -    self isEphemeronClass ifTrue: [^#ephemeron].
>>> -    ^#normal!
>>>
>>> Item was changed:
>>>  ----- Method: ClassBuilder>>computeFormat:instSize:forSuper: (in
>>> category 'class format') -----
>>>  computeFormat: type instSize: newInstSize forSuper: newSuper
>>>      "Compute the new format for making oldClass a subclass of
>>> newSuper.
>>>       Answer the format or nil if there is any problem."
>>> +    | instSize isVar isPointers isWeak bitsUnitSize |
>>> -    | instSize isVar isWords isPointers isWeak |
>>>      type == #compiledMethod ifTrue:
>>>          [newInstSize > 0 ifTrue:
>>>              [self error: 'A compiled method class cannot have named
>>> instance variables'.
>>>              ^nil].
>>>          ^CompiledMethod format].
>>>      instSize := newInstSize + (newSuper ifNil:[0] ifNotNil:[newSuper
>>> instSize]).
>>>      instSize > 65535 ifTrue:
>>>          [self error: 'Class has too many instance variables (',
>>> instSize printString,')'.
>>>          ^nil].
>>> +    type == #normal ifTrue:[isVar := isWeak := false. isPointers :=
>>> true].
>>> +    type == #bytes ifTrue:[isVar := true. bitsUnitSize := 1.
>>> isPointers := isWeak := false].
>>> +    type == #shorts ifTrue:[isVar := true. bitsUnitSize := 2.
>>> isPointers := isWeak := false].
>>> +    type == #words ifTrue:[isVar := true. bitsUnitSize := 4.
>>> isPointers := isWeak := false].
>>> +    type == #longs ifTrue:[isVar := true. bitsUnitSize := 8.
>>> isPointers := isWeak := false].
>>> +    type == #variable ifTrue:[isVar := isPointers := true. isWeak :=
>>> false].
>>> +    type == #weak ifTrue:[isVar := isWeak := isPointers := true].
>>> +    type == #ephemeron ifTrue:[isVar := false. isWeak := isPointers :=
>>> true].
>>> +    type == #immediate ifTrue:[isVar := isWeak := isPointers :=
>>> false].
>>> -    type == #normal ifTrue:[isVar := isWeak := false. isWords :=
>>> isPointers := true].
>>> -    type == #bytes ifTrue:[isVar := true. isWords := isPointers :=
>>> isWeak := false].
>>> -    type == #words ifTrue:[isVar := isWords := true. isPointers :=
>>> isWeak := false].
>>> -    type == #variable ifTrue:[isVar := isPointers := isWords := true.
>>> isWeak := false].
>>> -    type == #weak ifTrue:[isVar := isWeak := isWords := isPointers :=
>>> true].
>>> -    type == #ephemeron ifTrue:[isVar := false. isWeak := isWords :=
>>> isPointers := true].
>>> -    type == #immediate ifTrue:[isVar := isWeak := isPointers := false.
>>> isWords := true].
>>>      (isPointers not and: [instSize > 0]) ifTrue:
>>>          [self error: 'A non-pointer class cannot have named instance
>>> variables'.
>>>          ^nil].
>>> +    ^self format: instSize variable: isVar bitsUnitSize: bitsUnitSize
>>> pointers: isPointers weak: isWeak!
>>> -    ^self format: instSize variable: isVar words: isWords pointers:
>>> isPointers weak: isWeak!
>>>
>>> Item was added:
>>> + ----- Method:
>>> ClassBuilder>>format:variable:bitsUnitSize:pointers:weak: (in category
>>> 'class format') -----
>>> + format: nInstVars variable: isVar bitsUnitSize: bitsUnitSize
>>> pointers: isPointers weak: isWeak
>>> +    "Compute the format for the given instance specfication.
>>> +     Above Cog Spur the class format is
>>> +        <5 bits inst spec><16 bits inst size>
>>> +     where the 5-bit inst spec is
>>> +            0    = 0 sized objects (UndefinedObject True False et al)
>>> +            1    = non-indexable objects with inst vars (Point et al)
>>> +            2    = indexable objects with no inst vars (Array et al)
>>> +            3    = indexable objects with inst vars (MethodContext
>>> AdditionalMethodState et al)
>>> +            4    = weak indexable objects with inst vars (WeakArray et
>>> al)
>>> +            5    = weak non-indexable objects with inst vars
>>> (ephemerons) (Ephemeron)
>>> +            6    = unused
>>> +            7    = immediates (SmallInteger, Character, SmallFloat64)
>>> +            8    = unused
>>> +            9    = 64-bit indexable
>>> +        10-11    = 32-bit indexable (Bitmap, WideString)
>>> +        12-15    = 16-bit indexable
>>> +        16-23    = 8-bit indexable (ByteString)
>>> +        24-31    = compiled methods (CompiledMethod)"
>>> +    | instSpec |
>>> +    instSpec := isWeak
>>> +                    ifTrue:
>>> +                        [isVar
>>> +                            ifTrue: [4]
>>> +                            ifFalse: [5]]
>>> +                    ifFalse:
>>> +                        [isPointers
>>> +                            ifTrue:
>>> +                                [isVar
>>> +                                    ifTrue: [nInstVars > 0 ifTrue: [3]
>>> ifFalse: [2]]
>>> +                                    ifFalse: [nInstVars > 0 ifTrue:
>>> [1] ifFalse: [0]]]
>>> +                            ifFalse:
>>> +                                [isVar
>>> +                                    ifTrue: [bitsUnitSize caseOf: {
>>> +                                            [1] -> [16].
>>> +                                            [2] -> [12].
>>> +                                            [4] -> [10].
>>> +                                            [8] -> [9] }]
>>> +                                    ifFalse: [7]]].
>>> +    ^(instSpec bitShift: 16) + nInstVars!
>>>
>>> Item was changed:
>>>  ----- Method: Object>>shallowCopy (in category 'copying') -----
>>>  shallowCopy
>>>      "Answer a copy of the receiver which shares the receiver's
>>> instance variables."
>>>      | class newObject index |
>>> +    <primitive: 148 error: ec>
>>> +    ec == #'insufficient object memory' ifFalse:
>>> +        [^self primitiveFailed].
>>> -    <primitive: 148>
>>>      class := self class.
>>>      class isVariable
>>>          ifTrue:
>>>              [index := self basicSize.
>>> +             newObject := class basicNew: index.
>>> +             [index > 0] whileTrue:
>>> +                [newObject basicAt: index put: (self basicAt: index).
>>> +                 index := index - 1]]
>>> -            newObject := class basicNew: index.
>>> -            [index > 0]
>>> -                whileTrue:
>>> -                    [newObject basicAt: index put: (self basicAt:
>>> index).
>>> -                    index := index - 1]]
>>>          ifFalse: [newObject := class basicNew].
>>>      index := class instSize.
>>> +    [index > 0] whileTrue:
>>> +        [newObject instVarAt: index put: (self instVarAt: index).
>>> +         index := index - 1].
>>> +    ^newObject!
>>> -    [index > 0]
>>> -        whileTrue:
>>> -            [newObject instVarAt: index put: (self instVarAt: index).
>>> -            index := index - 1].
>>> -    ^ newObject!
>>
>