RFR: 8333382: [s390x] Move population_count implementation out of ad file

[Amit Kumar]

On Sat, 1 Jun 2024 13:15:45 GMT, Amit Kumar <amitkumar at openjdk.org> wrote:

> We need to move popcnt instruction implementation out of s390.ad file as it is required to be required some methods present in [JDK-8331126.](https://bugs.openjdk.org/browse/JDK-8331126)
> 
> 
> When the miscellaneous-instruction-extensions facility 3 is not installed or bit 0 of the M3
>  field is zero, a count of the number of one bits in each of the eight bytes of general register
>  R2 is placed into the corresponding byte of general register R1. Each byte of general register 
> R1 is an 8-bit binary integer in the range of 0-8.
> 
> 
> 
> When the miscellaneous-instruction-extensions facility 3 is installed and bit 0 of the M3 field
> is one, a count of the total number of one bits in the 64-bit general register R2 is placed into 
> general register R1. The result is a 64-bit unsigned integer in the range 0 to 64.
> 
> 
> Performed tier1 test on fastdebug build and didn't see any regression.

src/hotspot/cpu/s390/macroAssembler_s390.cpp line 5814:

> 5812:   } else {
> 5813: 
> 5814:     z_illtrap(48); // fixme: remove

I'll remove this before making this PR ready for review. As of now I'm using z16 machine, So this is not producing any error.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/19509#discussion_r1625759934