From 7547c640eff4826d799c7839194bf09e0fe10b8b Mon Sep 17 00:00:00 2001 From: Luke Kenneth Casson Leighton Date: Wed, 26 Jun 2019 09:12:38 +0100 Subject: [PATCH] add sv.setvl exploration --- .../specification/sv.setvl.mdwn | 51 +++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 simple_v_extension/specification/sv.setvl.mdwn diff --git a/simple_v_extension/specification/sv.setvl.mdwn b/simple_v_extension/specification/sv.setvl.mdwn new file mode 100644 index 000000000..c32623bff --- /dev/null +++ b/simple_v_extension/specification/sv.setvl.mdwn @@ -0,0 +1,51 @@ +# SV setvl exploration + +Formats for Vector Configuration Instructions under OP-V major opcode: + +| 31|30 25|24 20|19 15|14 12|11 7|6 0| name | +|---|------------------------|----------|-------|---------|-------|---------| +| 0 | zimm[10:6] |imm[4:0] | rs1 | 1 1 1 | rd |1010111| vsetvli | +| 1 | 000000 | rs2 | rs1 | 1 1 1 | rd |1010111| vsetvl | +| 1 | 6 | 5 | 5 | 3 | 5 | 7 | | + +Requirement: fit MVL into this format. + +| 31|30 25|24 20|19 15|14 12|11 7|6 0| name | +|---|-------------|----------|----------|-------|---------|-------|---------| +| 0 | zimm[10:6] |imm[4:0] | rs1 | 1 1 1 | rd |1010111| vsetvli | +| 1 | imm[5:0] | rs2 | rs1 | 1 1 1 | rd |1010111| vsetvl | +| 1 | 6 | 5 | 5 | 3 | 5 | 7 | | + +where: +* when bit 31==0, both MVL and VL are set to imm(5:0) - plus one to + get it out of the "NOP" scenario. +* when bit 31==1, MVL is set to imm(5:0) plus one. + +hang on... no, that's a 4-argument setvl! what about this? + + +| 31 25|24 20|19 15|14 12|11 7|6 0| name | variant# - | +|-----------------|----------|----------|-------|---------|-------|---------|------------| +| 0 | imm[5:0] | 0b00000 | rs1 | 1 1 1 | rd |1010111| vsetvli | 1 | +| 0 | imm[5:0] | 0b00000 | 0b00000 | 1 1 1 | rd |1010111| vsetvli | 2 | +| 0 | imm[5:0] | rs2!=x0 | rs1 | 1 1 1 | rd |1010111| vsetvli | 3 | +| 0 | imm[5:0] | rs2!=x0 | 0b00000 | 1 1 1 | rd |1010111| vsetvli | 4 | +| 1 | imm[5:0] | 0b00000 | rs1 | 1 1 1 | rd |1010111| vsetvl | 5 | +| 1 | imm[5:0] | 0b00000 | 0b00000 | 1 1 1 | rd |1010111| vsetvl | 6 | +| 1 | imm[5:0] | rs2!=x0 | rs1 | 1 1 1 | rd |1010111| vsetvl | 7 | +| 1 | imm[5:0] | rs2!=x0 | 0b00000 | 1 1 1 | rd |1010111| vsetvl | 8 | +| 1 | 6 | 5 | 5 | 3 | 5 | 7 | | | + +i think those are the 8 permutations: what can those be used for? + +| name | variant# - | purpose | +|---------|------------|------------------------------------------------| +| vsetvli | 1 | TBD | +| vsetvli | 2 | TBD | +| vsetvli | 3 | TBD | +| vsetvli | 4 | TBD | +| vsetvl | 5 | TBD | +| vsetvl | 6 | TBD | +| vsetvl | 7 | TBD | +| vsetvl | 8 | TBD | + -- 2.30.2