From: lkcl Date: Wed, 8 Jun 2022 23:39:48 +0000 (+0100) Subject: (no commit message) X-Git-Tag: opf_rfc_ls005_v1~1906 X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=2f464237ffa1e574bc46bf1bfac1dbedc631875a;p=libreriscv.git --- diff --git a/openpower/sv/compliancy_levels.mdwn b/openpower/sv/compliancy_levels.mdwn index 809de7f4a..adadccb21 100644 --- a/openpower/sv/compliancy_levels.mdwn +++ b/openpower/sv/compliancy_levels.mdwn @@ -48,7 +48,7 @@ permitted to declare meeting the 3D/Advanced Level unless implementing # Ultra-Embedded Level This level exists as an entry-level into SVP64, most suited to resource -constrained soft cores, or Hardware implementations where cost is a +constrained soft cores, or Hardware implementations where cost is a much higher priority than execution speed. This level sets the bare minimum requirements, where everything with the @@ -91,8 +91,9 @@ to the required total 128. Another important aspect is that when Rc=1 is set, CR Field Vector co-results are produced. Should these exceed CR7 (CR8-CR127) and the number of CR Fields has not been increased to 128 then an Illegal Instruction Trap must be -raised. In practical terms, to avoid this scenario, MAXVL should not -exceed 8 for Arithmetic or Logical operations, when Rc=1. +raised. In practical terms, to avoid this occurrence in software, +MAXVL should not +exceed 8 for Arithmetic or Logical operations with Rc=1. Zeroing on source and destination for Predicates must also be supported (sz, dz) however @@ -101,9 +102,11 @@ Iteration/Reduction) are entirely optional. Implementation of Element-Width Overrides is also optional. One of the important side-benefits of this SV Compliancy Level is that it -brings Hardware-level support for Predication to the entire Scalar Power +brings Hardware-level support for Scalar Predication (VL=MAXVL=1) +to the entire Scalar Power ISA, completely without -modifying the Scalar Power ISA. The cost is that instructions are Prefixed +modifying the Scalar Power ISA. The cost in software is that Predicated +instructions are Prefixed to 64-bit. # DSP / Audio / Video Level @@ -120,3 +123,15 @@ assist with Audio/Video. It is not mandatory for this Level to have DCT/FFT REMAP Capability but due to the high prevalence of DCT and FFT in Audio, Video and DSP workloads it is strongly recommended. + +# 3D / Advanced / Supercomputing + +This Compliancy Level is for highest performance and energy efficiency. +All aspects of SVP64 must be entirely implemented, in full, in Hardware. +How that is achieved is entirely at the discretion of the implementor: +there are no hard requirements of any kind on the level of performance, +just as there are none in the Vulkan Specification. Throughout the SV +Specification however there are hints to Micro-Architects: byte-level +write-enable lines on Register Files is strongly recommended, for +example. +