From: Luke Kenneth Casson Leighton Date: Mon, 17 Jun 2019 11:08:16 +0000 (+0100) Subject: explain VL=1 X-Git-Tag: convert-csv-opcode-to-binary~4615 X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=d6832b4f97f570247e5f0eef38db742b173e0d2d;p=libreriscv.git explain VL=1 --- diff --git a/simple_v_extension/specification.mdwn b/simple_v_extension/specification.mdwn index d2a323e27..70c82d501 100644 --- a/simple_v_extension/specification.mdwn +++ b/simple_v_extension/specification.mdwn @@ -270,8 +270,11 @@ exactly as standard CSRs, and contains more than just VL. One interesting side-effect of using CSRRWI to set VL is that this may be done with a single instruction, useful particularly for a -context-load/save. There are however limitations: CSRWWI's immediate -is limited to 0-31. +context-load/save. There are however limitations: CSRWI's immediate +is limited to 0-31 (representing VL=1-32). + +Note that when VL is set to 1, all parallel operations cease: the +hardware loop is reduced to a single element: scalar operations. ## STATE