RFR: 8288047: Accelerate Poly1305 on x86_64 using AVX512 instructions [v20]

[Volodymyr Paprotski]

On Wed, 16 Nov 2022 23:41:32 GMT, Volodymyr Paprotski <duke at openjdk.org> wrote:

>> Yes, please. And for the upper half of register file, just code it as a loop over register range:
>> 
>> for (int rxmm_num = 16; rxmm_num < 30; rxmm_num++) {
>>   XMMRegister rxmm = as_XMMRegister(rxmm_num);
>>   __ vpxorq(rxmm, rxmm, rxmm, Assembler::AVX_512bit);
>> }
>> 
>> or even
>> 
>> // Zeroes zmm16-zmm31. 
>> for (XMMRegister rxmm = xmm16; rxmm->is_valid(); rxmm = rxmm->successor()) {
>>   __ vpxorq(rxmm, rxmm, rxmm, Assembler::AVX_512bit);
>> }
>
> Will do.. ("loop" erm.. wow.. "duh, this isn't assembler!") Thanks!!

done
(Note: disassembler proof for vzeroall encoding

   0x7fffed0022f8:      vzeroall
   0x7fffed0022fb:      vpxorq zmm16,zmm16,zmm16
   0x7fffed002301:      vpxorq zmm17,zmm17,zmm17
   0x7fffed002307:      vpxorq zmm18,zmm18,zmm18
   0x7fffed00230d:      vpxorq zmm19,zmm19,zmm19
   0x7fffed002313:      vpxorq zmm20,zmm20,zmm20
   0x7fffed002319:      vpxorq zmm21,zmm21,zmm21
   0x7fffed00231f:      vpxorq zmm22,zmm22,zmm22
   0x7fffed002325:      vpxorq zmm23,zmm23,zmm23
   0x7fffed00232b:      vpxorq zmm24,zmm24,zmm24
   0x7fffed002331:      vpxorq zmm25,zmm25,zmm25
   0x7fffed002337:      vpxorq zmm26,zmm26,zmm26
   0x7fffed00233d:      vpxorq zmm27,zmm27,zmm27
   0x7fffed002343:      vpxorq zmm28,zmm28,zmm28
   0x7fffed002349:      vpxorq zmm29,zmm29,zmm29
   0x7fffed00234f:      vpxorq zmm30,zmm30,zmm30
   0x7fffed002355:      vpxorq zmm31,zmm31,zmm31
   0x7fffed00235b:      cmp    ebx,0x10
   0x7fffed00235e:      jl     0x7fffed0023e6

)

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PR: https://git.openjdk.org/jdk/pull/10582