From 0a62cca4dd620d6f4c933d2d9e1ce0bd9915d124 Mon Sep 17 00:00:00 2001 From: lkcl Date: Thu, 25 Mar 2021 15:05:17 +0000 Subject: [PATCH] --- openpower/ISA_WG/Board_letter_26mar2021.mdwn | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/openpower/ISA_WG/Board_letter_26mar2021.mdwn b/openpower/ISA_WG/Board_letter_26mar2021.mdwn index 6bbd16ed0..a10836360 100644 --- a/openpower/ISA_WG/Board_letter_26mar2021.mdwn +++ b/openpower/ISA_WG/Board_letter_26mar2021.mdwn @@ -7,16 +7,33 @@ edit history: * 25mar2021 first revision +to be sent to: + +* OPF Board board@openpowerfoundation.org +* Tim Ansell blog@mithis.com +* Toshaan Bharvani +* James Kulina +* Mendy +* cc Alain Williams +* cc David Calderwood +* cc Paul Mackerras + # Contents Dear OPF Board, As you know the LibreSOC team have been working for over 3 years on a massive conceptual upgrade to the OpenPOWER ISA, based on Cray-Style Vectors, which will modernise it for today's 3D and VPU workloads, with an incidental side-effect of upgrading it for future supercomputing needs. RISC-V has RVV, ARM has SVE2, x86 has AVX512, whilst OpenPOWER has an out-of-date SIMD ISA. It goes without saying that over the decades, SIMD has been demonstrated to be harmful. + https://www.sigarch.org/simd-instructions-considered-harmful/ Normally, such huge ISA development efforts would be instigated, organised and funded through either Academia or an extremely large Corporation, or a Consortium combining multiple such entities. It is therefore without precedent across the Computing Industry for something of this magnitude of effort to come not only from a Libre background but from a Libre background that is funded by a Charitable Foundation with a mandate to fund "Works for the Public Good". -From reading the PowerISA v3.0C sections we have learned and taken on board that a "Sandbox" opcode exists (EXT22) which is intended for "small private extensions" to the OpenPOWER ISA. Our Bitmanipulation Extension, needed for Audio/Video and cryptographic workloads, struggles to fit into that space, and we have not yet added Custom 3D opcodes or the IEEE754 Transcendentals (SIN, COS) +From reading the PowerISA v3.0C sections we have learned and taken on board that a "Sandbox" opcode exists (EXT22) which is intended for "small private extensions" to the OpenPOWER ISA. Our Bitmanipulation Extension alone, needed for Audio/Video and cryptographic workloads, struggles to fit into that space, and we have not yet added Custom 3D opcodes or the IEEE754 Transcendentals (SIN, COS). + +http://libre-soc.org/openpower/bitmanip + +More than that, these are all "general-purpose" opcodes with uses far beyond LibreSOC's use-case: notwithstanding LibreSOC's use-case itself being by definition general-purpose. The instructions in the PowerISA v3.0C document therefore *require* us to contact the OpenPOWER Foundation, to initiae the process of including our opcodes, and SVP64, in the OpenPOWER ISA. + In speaking with various people (Toshaan, Paul and Hugh) we have pieced together the way that the Op -- 2.30.2