RFR: 8348561: Add aarch64 intrinsics for ML-DSA [v5]

[Ferenc Rakoczi]

On Tue, 25 Feb 2025 09:36:49 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> @ferakocz This also really needs addressing before committing the patch. Perhaps @theRealAph can advise on how to circumvent the problems you found when trying to update the python script?
>
>> You might have to use an assembler from the latest binutils build (if the system default isn't the latest) and add the path to the assembler in the "AS" variable. Also you can run it something like - `python aarch64-asmtest.py | expand > asmtest.out.h`. Please let me know if you still face problems.
> 
> People have been running this script for a decade now.
> 
> Let's look at just one of these:
> 
> 
> aarch64ops.s:357:20: error: expected 'sxtx' 'uxtx' or 'lsl' with optional integer in range [0, 4]
> sub x1, x10, x23, sxth #2
> 
> 
> From the AArch64 manual:
> 
> SUB (extended register)
> SUB <Xd|SP>, <Xn|SP>, <R><m>{, <extend> {#<amount>}}
> 
>  It thinks this is a SUB (shifted register), bit it's really a SUB (extended register).
> 
> 
> fedora:aarch64 $ cat t.s
> sub x1, x10, x23, sxth #2
> fedora:aarch64 $ as t.s
> fedora:aarch64 $ objdump -D a.out
> Disassembly of section .text:
> 
> 0000000000000000 <.text>:
>    0:	cb37a941 	sub	x1, x10, w23, sxth #2
> 
> 
> So perhaps binutils expects w23 here, not x23. But the manual (ARM DDI 0487K.a) says x23 should be just fine, and, what's more, gives the x form preferred status.

@theRealAlph, maybe we are not reading the same manual (ARM DDI 0487K.a). In my copy:
SUB (extended register) is defined as
SUB <Xd|SP>, <Xn|SP>, <R><m>{, <extend> {#<amount>}}
and <R> should be W when <extend> is SXTH
and the as I have enforces this: 

ferakocz at ferakocz-mac aarch64 % cat t.s  
sub x1, x10, w23, sxth #2
ferakocz at ferakocz-mac aarch64 % cat > t1.s
sub x1, x10, x23, sxth #2
ferakocz at ferakocz-mac aarch64 % cat t.s
sub x1, x10, w23, sxth #2
ferakocz at ferakocz-mac aarch64 % cat t1.s
sub x1, x10, x23, sxth #2
ferakocz at ferakocz-mac aarch64 % as --version
Apple clang version 16.0.0 (clang-1600.0.26.6)
Target: arm64-apple-darwin24.3.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin
ferakocz at ferakocz-mac aarch64 % as t.s
ferakocz at ferakocz-mac aarch64 % objdump -D t.o

t.o:	file format mach-o arm64

Disassembly of section __TEXT,__text:

0000000000000000 <ltmp0>:
       0: cb37a941     	sub	x1, x10, w23, sxth #2
ferakocz at ferakocz-mac aarch64 % as t1.s
t1.s:1:19: error: expected 'sxtx' 'uxtx' or 'lsl' with optional integer in range [0, 4]
sub x1, x10, x23, sxth #2
                    ^

I have not found the place in the manual where it allows/encourages the use of x<n> instead of w<n>, but I admit I haven't read through all of the 14568 pages.

So I'm stuck for now. What 'as' are you using?

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PR Review Comment: https://git.openjdk.org/jdk/pull/23300#discussion_r1969561791