[Vm-dev] Re: VM Maker: VMMaker.oscog-tfel.1862.mcz

[timfelgentreff]

Sorry, I wasn't careful here and got confused by the method name and comment,
thinking we're talking platform integers here. I updated the method to
truncate to 32-bit.


Eliot Miranda-2 wrote
> On Thu, May 19, 2016 at 7:04 AM, Nicolas Cellier <

> nicolas.cellier.aka.nice@

>> wrote:
> 
>>
>>
>>
>> 2016-05-19 9:49 GMT+02:00 &lt;

> commits at .squeak

> &gt;:
>>
>>>
>>> Tim Felgentreff uploaded a new version of VMMaker to project VM Maker:
>>> http://source.squeak.org/VMMaker/VMMaker.oscog-tfel.1862.mcz
>>>
>>> ==================== Summary ====================
>>>
>>> Name: VMMaker.oscog-tfel.1862
>>> Author: tfel
>>> Time: 19 May 2016, 9:49:06.672041 am
>>> UUID: ee2580a0-a9df-a945-ab7d-26865d302201
>>> Ancestors: VMMaker.oscog-tfel.1861
>>>
>>> Use SmallInteger maxVal and minVal in Integer>>signedIntFromLong for the
>>> benefit of VMs that can fit more than 30bit into a signed integer
>>>
>>> =============== Diff against VMMaker.oscog-eem.1860 ===============
>>>
>>> Item was changed:
>>>   ----- Method: Integer>>signedIntFromLong (in category
>>> '*VMMaker-interpreter simulator') -----
>>>   signedIntFromLong
>>>         "Self is a signed or unsigned 32-bit integer"
>>>
>>>         | bits |
>>> +       (self >= SmallInteger minVal and: [self <= SmallInteger maxVal])
>>> ifTrue: "These are known to be SmallIntegers..."
>>> -       (self >= -1073741824 and: [self <= 1073741823]) ifTrue: "These
>>> are known to be SmallIntegers..."
>>>
>>
>> Hi Tim,
>> this does not look correct to me.
>> if maxVal is 1<<60-1, and self is 1<<40, then self won't be truncated to
>> 32 low bits as it should...
>>
> 
> +1.
> 
> 
>> Above test is just a fast-up.
>>
>>
>>>                 [^self].
>>>         bits := self bitAnd: 16rFFFFFFFF.
>>>         (bits digitAt: 4) <= 16r7F ifTrue: [^bits].
>>>         ^bits - 16r100000000!
>>>
>>
> _,,,^..^,,,_
> best, Eliot





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