RFR(S): 8231612: 100% cpu on arm32 in Service Thread

[Kim Barrett]

> On Dec 10, 2019, at 9:05 AM, Aleksei Voitylov <aleksei.voitylov at bell-sw.com> wrote:
> 
> Kim,
> 
> thank you for the suggestions. Here is an updated webrev:
> 
> http://cr.openjdk.java.net/~avoitylov/webrev.8231612.04/
> 
> The assembly generated with inline functions is equivalent to that with
> the macros, and the testing passed as well.

This is mostly good.

However, the new function names don't follow usual HotSpot style,
which is lower case with underscore word separators.  (Yes, there
are *many* counterexamples.)

Also, the minimal parenthesizing in SetByteInInt requires one to think
about operator precedence order more than I would like.  What's there
is correct, but would be easier to read as

 855   return (n & ~(0xff << bitsIdx)) | (b << bitsIdx);

(We have some functions in globalDefinitions.hpp to supposedly help
with these kinds of calculations, but the supported types are often
wrong (as here), and there are missing operations (again, as here).)