Hi Chris, I think these methods belong in the image with the fastest
implementation we can do.

I implemented 64-bit unsigned access for Ma Serializer back in 2005.
I modeled my implementation after Andreas' original approach which
tries to avoid LI arithmetic.  I was curious whether your
implementations would be faster, because if they are then it could
benefit Magma.  After loading "Ma Serializer" 1.5 (or head) into a
trunk image, I used the following script to take comparison
measurements:

| smallN largeN maBa cbBa |  smallN := ((2 raisedTo: 13) to: (2
raisedTo: 14)) atRandom.
largeN := ((2 raisedTo: 63) to: (2 raisedTo: 64)) atRandom.
maBa := ByteArray new: 8.
cbBa := ByteArray new: 8.
maBa maUint: 64 at: 0 put: largeN.
cbBa unsignedLong64At: 1 put: largeN bigEndian: false.
self assert: (cbBa maUnsigned64At: 1) = (maBa unsignedLong64At: 1
bigEndian: false).
{ 'cbc smallN write' -> [ cbBa unsignedLong64At: 1 put: smallN
bigEndian: false] bench.
'ma smallN write' -> [cbBa maUint: 64 at: 0 put: smallN ] bench.
'cbc smallN access' -> [ cbBa unsignedLong64At: 1 bigEndian: false. ] bench.
'ma smallN access' -> [ cbBa maUnsigned64At: 1] bench.
'cbc largeN write' -> [ cbBa unsignedLong64At: 1 put: largeN
bigEndian: false] bench.
'ma largeN write' -> [cbBa maUint: 64 at: 0 put: largeN ] bench.
'cbc largeN access' -> [ cbBa unsignedLong64At: 1 bigEndian: false ] bench.
'ma largeN access' -> [ cbBa maUnsigned64At: 1] bench.
 }

Here are the results:

'cbc smallN write'->'3,110,000 per second.  322 nanoseconds per run.' .
'ma smallN write'->'4,770,000 per second.  210 nanoseconds per run.' .
'cbc smallN access'->'4,300,000 per second.  233 nanoseconds per run.' .
'ma smallN access'->'16,400,000 per second.  60.9 nanoseconds per run.' .
'cbc largeN write'->'907,000 per second.  1.1 microseconds per run.' .
'ma largeN write'->'6,620,000 per second.  151 nanoseconds per run.' .
'cbc largeN access'->'1,900,000 per second.  527 nanoseconds per run.' .
'ma largeN access'->'1,020,000 per second.  982 nanoseconds per run.'

It looks like your 64-bit access is 86% faster for accessing the
high-end of the 64-bit range, but slower in the other 3 metrics.
Noticeably, it was only 14% as fast for writing the high-end of the
64-bit range, and similarly as much slower for small-number access..


On Fri, Aug 28, 2015 at 6:01 PM, Chris Cunningham
<cunningham.cb at gmail.com> wrote:
> Hi.
>
> I've committed a change to the inbox with changes to allow getting/putting
> 64bit values to ByteArrays (similar to 32 and 16 bit accessors).  Could this
> be added to trunk?
>
> Also, first time I used the selective commit function - very nice!  the
> changes I didn't want committed didn't, in fact, get commited.  Just the
> desirable bits!
>
> -cbc
>
>
>