32 bit float endian conversion... how?

>  I thought i had a method to convert squeak floats to 32 bit little endian,
> but apparently it no longer works (if it ever did).
>
> Is there an accepted conversion utility/strategy/algorithm for doing this
> kind of thing? I've got my Second Life client working to the point where an
> amorphous cloud appears in-world with the correct name-tag, but its probably
> not facing the right way because I can't send a little-endian float value.
> Since much of SL is based on 3D coordinates and such, this will be a problem
> for sure if I try to do anything more sophisticated than floating in mid air
> as a white cloud (the non-rendering avatar default appearance).
>
>
>
> Lawson
>
>
>
>
>

> 2010/10/12 Lawson English<[hidden email]>:
>>   I thought i had a method to convert squeak floats to 32 bit little endian,
>> but apparently it no longer works (if it ever did).
>>
>> Is there an accepted conversion utility/strategy/algorithm for doing this
>> kind of thing? I've got my Second Life client working to the point where an
>> amorphous cloud appears in-world with the correct name-tag, but its probably
>> not facing the right way because I can't send a little-endian float value.
>> Since much of SL is based on 3D coordinates and such, this will be a problem
>> for sure if I try to do anything more sophisticated than floating in mid air
>> as a white cloud (the non-rendering avatar default appearance).
>>
>>
>>
>> Lawson
>>
>>
>>
>>
>>
>

>  On 10/12/10 3:29 AM, Nicolas Cellier wrote:
> >I think these two are bigEdian
> >
> >Float pi asIEEE32BitWord.
> >FloatArray with: Float pi.
> >
> Converts it to a 31-bit int, which is not compatible with swapping
> endianness because you can't index it.
>
> I'm sure I can eventually analyze what the asIEEE32BitWord is doing and
> put it into a 4 byte array instead of an int, but I was hoping that
> someone else had already solved the problem.
>

> On Tue, Oct 12, 2010 at 05:18:40AM -0700, Lawson English wrote:
>>  On 10/12/10 3:29 AM, Nicolas Cellier wrote:
>> >I think these two are bigEdian
>> >
>> >Float pi asIEEE32BitWord.
>> >FloatArray with: Float pi.
>> >
>> Converts it to a 31-bit int, which is not compatible with swapping
>> endianness because you can't index it.
>>
>> I'm sure I can eventually analyze what the asIEEE32BitWord is doing and
>> put it into a 4 byte array instead of an int, but I was hoping that
>> someone else had already solved the problem.
>>
>
> (FloatArray with: Float pi) basicAt: 1
>
> This gives you the value as a LargePositiveInteger. If you are running
> on a little-endian machine, the value should already be in the byte
> order you want. If you need to swap bytes (Smalltalk endianness = #big)
> you can use #bitAnd: and shift operators, etc.
>
> Dave
>
>

> 2010/10/12 David T. Lewis <[hidden email]>:
>> On Tue, Oct 12, 2010 at 05:18:40AM -0700, Lawson English wrote:
>>>  On 10/12/10 3:29 AM, Nicolas Cellier wrote:
>>> >I think these two are bigEdian
>>> >
>>> >Float pi asIEEE32BitWord.
>>> >FloatArray with: Float pi.
>>> >
>>> Converts it to a 31-bit int, which is not compatible with swapping
>>> endianness because you can't index it.
>>>
>>> I'm sure I can eventually analyze what the asIEEE32BitWord is doing and
>>> put it into a 4 byte array instead of an int, but I was hoping that
>>> someone else had already solved the problem.
>>>
>>
>> (FloatArray with: Float pi) basicAt: 1
>>
>> This gives you the value as a LargePositiveInteger. If you are running
>> on a little-endian machine, the value should already be in the byte
>> order you want. If you need to swap bytes (Smalltalk endianness = #big)
>> you can use #bitAnd: and shift operators, etc.
>>
>> Dave
>>
>>
>
> And to make a ByteArray from an Integer between:0 and: 1<<32-1, you
> have a license to be hackish:
>
> (ByteArray newFrom: (Float pi asIEEE32BitWord + 16r100000000))
>        copyFrom: 2 to: 5
>
> Nicolas
>

> 2010/10/12 Nicolas Cellier <[hidden email]>:
>> 2010/10/12 David T. Lewis <[hidden email]>:
>>> On Tue, Oct 12, 2010 at 05:18:40AM -0700, Lawson English wrote:
>>>>  On 10/12/10 3:29 AM, Nicolas Cellier wrote:
>>>> >I think these two are bigEdian
>>>> >
>>>> >Float pi asIEEE32BitWord.
>>>> >FloatArray with: Float pi.
>>>> >
>>>> Converts it to a 31-bit int, which is not compatible with swapping
>>>> endianness because you can't index it.
>>>>
>>>> I'm sure I can eventually analyze what the asIEEE32BitWord is doing and
>>>> put it into a 4 byte array instead of an int, but I was hoping that
>>>> someone else had already solved the problem.
>>>>
>>>
>>> (FloatArray with: Float pi) basicAt: 1
>>>
>>> This gives you the value as a LargePositiveInteger. If you are running
>>> on a little-endian machine, the value should already be in the byte
>>> order you want. If you need to swap bytes (Smalltalk endianness = #big)
>>> you can use #bitAnd: and shift operators, etc.
>>>
>>> Dave
>>>
>>>
>>
>> And to make a ByteArray from an Integer between:0 and: 1<<32-1, you
>> have a license to be hackish:
>>
>> (ByteArray newFrom: (Float pi asIEEE32BitWord + 16r100000000))
>>        copyFrom: 2 to: 5
>>
>> Nicolas
>>
>
> Oops no, it's rather
> (ByteArray newFrom: (Float pi asIEEE32BitWord + 16r100000000)) first: 4
>
> Nicolas
>