From: lkcl Date: Sat, 26 Dec 2020 23:12:06 +0000 (+0000) Subject: (no commit message) X-Git-Tag: convert-csv-opcode-to-binary~819 X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=dd87a654fbab858ceec570dbfe446c37df212a62;p=libreriscv.git --- diff --git a/openpower/sv/svp64.mdwn b/openpower/sv/svp64.mdwn index ff6a541e3..e6629d555 100644 --- a/openpower/sv/svp64.mdwn +++ b/openpower/sv/svp64.mdwn @@ -53,6 +53,8 @@ v3.0/1B instructions covered by the prefix are "unaltered". This is termed `scal Note that this is completely different from when VL=0. VL=0 turns all operations under its influence into `nops` (regardless of the prefix) whereas when VL=1 and the SV prefix is all zeros, the operation simply acts as if SV had not been applied at all to the instruction (an "identity operation"). +The significance of identity behaviour is that instructions added under svp64 to the 32 bit suffix are not only accessible to svp64: as long as implementors conform to identity behaviour (set the prefix to all zeros) they may use the instructions without needing to actually implement SV itself. + # Register Naming and size SV Registers are simply the INT, FP and CR register files extended