From: Xan Date: Wed, 25 Apr 2018 05:02:19 +0000 (+0100) Subject: (no commit message) X-Git-Tag: convert-csv-opcode-to-binary~5556 X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=99baa10e8dd6726657c41e91d8600d3911413f52;p=libreriscv.git --- diff --git a/A_Harmonised_RVV_and_Packed_SIMD.mdwn b/A_Harmonised_RVV_and_Packed_SIMD.mdwn index 77a23c33c..ff9b13807 100644 --- a/A_Harmonised_RVV_and_Packed_SIMD.mdwn +++ b/A_Harmonised_RVV_and_Packed_SIMD.mdwn @@ -32,7 +32,7 @@ Notes: ##### Default MVL -The default RVV MVL value (in absence of explicit VDCFG setup) is to be MVL = 2 on RV32I machines and MVL = 4 on RV64I machines. +The default RVV MVL value (in absence of explicit VCFG setup) is to be MVL = 2 on RV32I machines and MVL = 4 on RV64I machines. However, note RV32I registers can fit 4x INT8 elements. To preserve Andes SIMD behaviour, all VOP instructions should still operate on all “unused” elements in the register, regardless of MVL. (This is still compliant with the RVV spec, provided elements from VL..MVL-1 are set to zero). VMEM instructions however will only operate on VL elements, and so where full Andes SIMD compliance is required (without RVV forward compatibility), LW/LD and SW/SD are to be used instead of VLD and VST. ##### Alternative register "banks" and alternative MVL @@ -44,4 +44,4 @@ A programmer can configure VCFG with any mix of these alternative configurations * A lesser number of registers (