From 59dfde62039fe4d37ebe17c4ecb0fe32f682afa5 Mon Sep 17 00:00:00 2001 From: Luke Kenneth Casson Leighton Date: Mon, 5 Aug 2019 04:46:12 +0100 Subject: [PATCH] move FATAN2PI and FATAN to top-level funct5 --- rv_major_opcode_1010011.mdwn | 99 +++++++++++++++++++++--------------- 1 file changed, 57 insertions(+), 42 deletions(-) diff --git a/rv_major_opcode_1010011.mdwn b/rv_major_opcode_1010011.mdwn index 934ddf58d..993b4493c 100644 --- a/rv_major_opcode_1010011.mdwn +++ b/rv_major_opcode_1010011.mdwn @@ -29,46 +29,60 @@ Notes: * Both dual and single argument FP operations that do not require "rounding mode" should go in one of the funct5 tables that already use "funct3". +* The rs2 field can be best used to sub-select a considerable number + of 1-op operations, with "rounding" in funct3 +* The funct3 field can be best used to sub-select a considerable number + of 2-op operations +* 1-op operations that do not need "rounding" have the best brownfield + availability: 8 bit sub-selection (rs2=5 + funct3=3). This however is + rare as most FP operations need "rounding" selection. * Be careful not to use encoding space for which FP16 has already been - reserved. + reserved (mostly FP conversion opcodes) [[!table data=""" -31..27 | 26..25 | 24..20 |19..15| 14...12| 11..7 | 6....0 | function | -funct5 | SDHQ | rs2 | rs1 | funct3 | rd | opcode | name | - 5 | 2 | 5 | 5 | 3 | 5 | 7 | | -00000 | xx | rs2 | rs1 | rm | rd | 1010011 | FADD.xx | -00001 | xx | rs2 | rs1 | rm | rd | 1010011 | FSUB.xx | -00010 | xx | rs2 | rs1 | rm | rd | 1010011 | FMUL.xx | -00011 | xx | rs2 | rs1 | rm | rd | 1010011 | FDIV.xx | -00100 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | -00101 | xx | rs2 | rs1 | yyy | rd | 1010011 | tb=00101 | -00110 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | -00111 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | -01000 | xx | rs2 | rs1 | yyy | rd | 1010011 | tb=01000 | -01001 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | -01010 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | -01011 | xx | xxxxx | rs1 | yyy | rd | 1010011 | tb=01011 | -01100 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | -01101 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | -01110 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | -01111 | xx | rs2 | rs1 | yyy | rd | 1010011 | **FPOW.xx** | -10000 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | -10001 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | -10010 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | -10011 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | -10100 | xx | rs2 | rs1 | yyy | rd | 1010011 | tb=10100 | -10101 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | -10110 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | -10111 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | -11000 | xx | xxxxx | rs1 | yyy | rd | 1010011 | tb=11000 | -11001 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | -11010 | xx | xxxxx | rs1 | yyy | rd | 1010011 | tb=11010 | -11100 | xx | xxxxx | rs1 | 000 | rd | 1010011 | tb=11100 | -11101 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | -11110 | xx | xxxxx | rs1 | 000 | rd | 1010011 | tb=11110 | -11111 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | +31..27 | 26..25 | 24..20 |19..15| 14...12| 11..7 | 6....0 | function | +funct5 | SDHQ | rs2 | rs1 | funct3 | rd | opcode | name | + 5 | 2 | 5 | 5 | 3 | 5 | 7 | | +00000 | xx | rs2 | rs1 | rm | rd | 1010011 | FADD.xx | +00001 | xx | rs2 | rs1 | rm | rd | 1010011 | FSUB.xx | +00010 | xx | rs2 | rs1 | rm | rd | 1010011 | FMUL.xx | +00011 | xx | rs2 | rs1 | rm | rd | 1010011 | FDIV.xx | +00100 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | +00101 | xx | rs2 | rs1 | yyy | rd | 1010011 | tb=00101 | +00110 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | +00111 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | +01000 | xx | rs2 | rs1 | yyy | rd | 1010011 | tb=01000 | +01001 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | +01010 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | +01011 | xx | xxxxx | rs1 | yyy | rd | 1010011 | tb=01011 | +01100 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | +01101 | xx | rs2 | rs1 | rm | rd | 1010011 | **FATAN2.xx** | +01110 | xx | rs2 | rs1 | rm | rd | 1010011 | **FATAN2PI.xx**| +01111 | xx | rs2 | rs1 | rm | rd | 1010011 | **FPOW.xx** | +10000 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | +10001 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | +10010 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | +10011 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | +10100 | xx | rs2 | rs1 | yyy | rd | 1010011 | tb=10100 | +10101 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | +10110 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | +10111 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | +11000 | xx | xxxxx | rs1 | yyy | rd | 1010011 | tb=11000 | +11001 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | +11010 | xx | xxxxx | rs1 | yyy | rd | 1010011 | tb=11010 | +11100 | xx | xxxxx | rs1 | yyy | rd | 1010011 | tb=11100 | +11101 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | +11110 | xx | xxxxx | rs1 | yyy | rd | 1010011 | tb=11110 | +11111 | xx | rs2 | rs1 | yyy | rd | 1010011 | ? | """]] +Code: + +* xx: Opcode format field "fmt" - Table 11.3 +* xxxxx: 5-bit selection field (usually 1-op selection) +* yyy: funct3 selection field (usually 2-op selection) +* rm: "rounding mode" + ## funct5 = 00000 - FADD No brownfield encodings available. @@ -192,7 +206,7 @@ funct5 | SDHQ | rs2 | rs1 | funct3 | rd | opcode | name | 01011 | xx | 00000 | rs1 | rm | rd | 1010011 | FSQRT.xx | 01011 | xx | 00001 | rs1 | rm | rd | 1010011 | **FRSQRT.xx** | 01011 | xx | 00010 | rs1 | rm | rd | 1010011 | **FRCP.xx** | -01011 | xx | 00011 | rs1 | rm | rd | 1010011 | **CBRT.xx** | +01011 | xx | 00011 | rs1 | rm | rd | 1010011 | **FCBRT.xx** | 01011 | xx | 00100 | rs1 | rm | rd | 1010011 | ? | 01011 | xx | 00101 | rs1 | rm | rd | 1010011 | ? | 01011 | xx | 00110 | rs1 | rm | rd | 1010011 | ? | @@ -208,11 +222,11 @@ funct5 | SDHQ | rs2 | rs1 | funct3 | rd | opcode | name | 01011 | xx | 10000 | rs1 | rm | rd | 1010011 | **FSIN.xx** | 01011 | xx | 10001 | rs1 | rm | rd | 1010011 | **FCOS.xx** | 01011 | xx | 10010 | rs1 | rm | rd | 1010011 | **FTAN.xx** | -01011 | xx | 10011 | rs1 | rm | rd | 1010011 | **FTAN2.xx** | +01011 | xx | 10011 | rs1 | rm | rd | 1010011 | ? | 01011 | xx | 10100 | rs1 | rm | rd | 1010011 | **FSINPI.xx** | 01011 | xx | 10101 | rs1 | rm | rd | 1010011 | **FCOSPI.xx** | 01011 | xx | 10110 | rs1 | rm | rd | 1010011 | **FTANPI.xx** | -01011 | xx | 10111 | rs1 | rm | rd | 1010011 | **FATAN2PI.xx**| +01011 | xx | 10111 | rs1 | rm | rd | 1010011 | ? | 01011 | xx | 11000 | rs1 | rm | rd | 1010011 | **FSINH.xx** | 01011 | xx | 11001 | rs1 | rm | rd | 1010011 | **FCOSH.xx** | 01011 | xx | 11010 | rs1 | rm | rd | 1010011 | **FTANH.xx** | @@ -227,13 +241,14 @@ funct5 | SDHQ | rs2 | rs1 | funct3 | rd | opcode | name | Brownfield encodings available. -## funct5 = 01101 - unused +## funct5 = 01101 - **FATAN2** -Brownfield encodings available. +Proposed for Zftrans - FATAN: "atan(rs1, rs2)" -## funct5 = 01110 - unused +## funct5 = 01110 - **FATAN2PI** -Brownfield encodings available. +Proposed for ZftransExt - FATAN2PI: "atan2(rs1, rs2) * PI". +Rationale: Gives better accuracy than if using FMUL with the constant, PI. ## funct5 = 01111 - **FPOW** -- 2.30.2