X-Git-Url: https://git.libre-soc.org/?a=blobdiff_plain;f=rv_major_opcode_1010011.mdwn;h=6383cf0c48f21b9b91aecbffef51b4da553e6847;hb=e4957db5becf5bdf2303588d31a324dce3d68443;hp=934ddf58d08715775a48a542f139f479cfef8c2a;hpb=3760fea33afdb9d57036719c19f69c21ab13f015;p=libreriscv.git diff --git a/rv_major_opcode_1010011.mdwn b/rv_major_opcode_1010011.mdwn index 934ddf58d..6383cf0c4 100644 --- a/rv_major_opcode_1010011.mdwn +++ b/rv_major_opcode_1010011.mdwn @@ -1,3 +1,5 @@ +**OBSOLETE**, superceded by [[openpower/transcendentals]] + # Summary FP Opcodes This page aids and assists in the development of FP proposals, @@ -10,9 +12,13 @@ A primary critical use-case for extending FP is for 3D and supercomputing. Publicly-known FP proposals: * Zfrsqrt - Reciprocal SQRT -* Zftrans - Transcendentals (FSIN, FCOS, FATAN, FPOW, FEXP, FLOG, FRCP) +* Zftrans - see [[ztrans_proposal]]: Transcendentals + (FPOW, FEXP, FLOG, FCBRT) +* Ztrig\* - see [[ztrans_proposal]]: Trigonometriics + (FSIN, FCOS, FTAN, arc-variants, hypotenuse-variants) * Extension of formats to cover FP16 (RISC-V ISA Manual Table 11.3 "fmt field") + * HI-half FP MV - * (Add new entries here: Zextname - Description and URL) @@ -29,46 +35,60 @@ 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 | **FHYPOT.xx** | +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 | **FROOTN.xx** | +10001 | xx | rs2 | rs1 | yyy | rd | 1010011 | **FPOWN.xx** | +10010 | xx | rs2 | rs1 | yyy | rd | 1010011 | **FPOWR.xx** | +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. @@ -89,7 +109,7 @@ No brownfield encodings available. Brownfield encodings available. -## funct5 = 00100 +## funct5 = 00100 - FSGN This table uses funct3 for encoding 2-operand FP operations @@ -107,7 +127,7 @@ funct5 | SDHQ | rs2 | rs1 | funct3 | rd | opcode | name | 00100 | xx | rs2 | rs1 | 111 | rd | 1010011 | ?f3=111 | """]] -## funct5 = 00101 +## funct5 = 00101 - FMIN/MAX This table uses funct3 for encoding 2-operand FP operations where the result register is a **floating-point** value. @@ -134,7 +154,7 @@ Brownfield encodings available. Brownfield encodings available. -## funct5 = 01000 +## funct5 = 01000 - FCVT This table uses rs2 for encoding 1-operand FP operations, using funct3 to specify the "rounding" mode @@ -191,61 +211,69 @@ funct5 | SDHQ | rs2 | rs1 | funct3 | rd | opcode | name | 5 | 2 | 5 | 5 | 3 | 5 | 7 | | 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 | 00100 | rs1 | rm | rd | 1010011 | ? | -01011 | xx | 00101 | rs1 | rm | rd | 1010011 | ? | -01011 | xx | 00110 | rs1 | rm | rd | 1010011 | ? | -01011 | xx | 00111 | rs1 | rm | rd | 1010011 | ? | -01011 | xx | 01000 | rs1 | rm | rd | 1010011 | **FEXP2.xx** | -01011 | xx | 01001 | rs1 | rm | rd | 1010011 | **FLOG2.xx** | -01011 | xx | 01010 | rs1 | rm | rd | 1010011 | **FEXPM1.xx** | -01011 | xx | 01011 | rs1 | rm | rd | 1010011 | **FLOGP1.xx** | -01011 | xx | 01100 | rs1 | rm | rd | 1010011 | **FEXP.xx** | -01011 | xx | 01101 | rs1 | rm | rd | 1010011 | **FLOG.xx** | -01011 | xx | 01110 | rs1 | rm | rd | 1010011 | **FEXP10.xx** | -01011 | xx | 01111 | rs1 | rm | rd | 1010011 | **FLOG10.xx** | +01011 | xx | 00010 | rs1 | rm | rd | 1010011 | **FRECIP.xx** | +01011 | xx | 00011 | rs1 | rm | rd | 1010011 | **FCBRT.xx** | +01011 | xx | 00100 | rs1 | rm | rd | 1010011 | **FEXP2.xx** | +01011 | xx | 00101 | rs1 | rm | rd | 1010011 | **FLOG2.xx** | +01011 | xx | 00110 | rs1 | rm | rd | 1010011 | **FEXPM1.xx** | +01011 | xx | 00111 | rs1 | rm | rd | 1010011 | **FLOGP1.xx** | +01011 | xx | 01000 | rs1 | rm | rd | 1010011 | **FEXP.xx** | +01011 | xx | 01001 | rs1 | rm | rd | 1010011 | **FLOG.xx** | +01011 | xx | 01010 | rs1 | rm | rd | 1010011 | **FEXP10.xx** | +01011 | xx | 01011 | rs1 | rm | rd | 1010011 | **FLOG10.xx** | +01011 | xx | 01100 | rs1 | rm | rd | 1010011 | **FASINH.xx** | +01011 | xx | 01101 | rs1 | rm | rd | 1010011 | **FACOSH.xx** | +01011 | xx | 01110 | rs1 | rm | rd | 1010011 | **FATANH.xx** | +01011 | xx | 01111 | rs1 | rm | rd | 1010011 | ? | 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 | 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 | 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** | -01011 | xx | 11011 | rs1 | rm | rd | 1010011 | ? | -01011 | xx | 11100 | rs1 | rm | rd | 1010011 | **FASINH.xx** | -01011 | xx | 11101 | rs1 | rm | rd | 1010011 | **FACOSH.xx** | -01011 | xx | 11110 | rs1 | rm | rd | 1010011 | **FATANH.xx** | +01011 | xx | 10001 | rs1 | rm | rd | 1010011 | **FSINPI.xx** | +01011 | xx | 10010 | rs1 | rm | rd | 1010011 | **FASIN.xx** | +01011 | xx | 10011 | rs1 | rm | rd | 1010011 | **FASINPI.xx**| +01011 | xx | 10100 | rs1 | rm | rd | 1010011 | **FCOS.xx** | +01011 | xx | 10101 | rs1 | rm | rd | 1010011 | **FCOSPI.xx** | +01011 | xx | 10110 | rs1 | rm | rd | 1010011 | **FACOS.xx** | +01011 | xx | 10111 | rs1 | rm | rd | 1010011 | **FACOSPI.xx**| +01011 | xx | 11000 | rs1 | rm | rd | 1010011 | **FTAN.xx** | +01011 | xx | 11001 | rs1 | rm | rd | 1010011 | **FTANPI.xx** | +01011 | xx | 11010 | rs1 | rm | rd | 1010011 | **FATAN.xx** | +01011 | xx | 11011 | rs1 | rm | rd | 1010011 | **FATANPI.xx**| +01011 | xx | 11100 | rs1 | rm | rd | 1010011 | **FSINH.xx** | +01011 | xx | 11101 | rs1 | rm | rd | 1010011 | **FCOSH.xx** | +01011 | xx | 11110 | rs1 | rm | rd | 1010011 | **FTANH.xx** | 01011 | xx | 11111 | rs1 | rm | rd | 1010011 | ? | """]] -## funct5 = 01100 - unused +## funct5 = 01100 - **FHYPOT** -Brownfield encodings available. +Proposed for Zftrans - FHYPOT: "sqrt(rs1 * rs1 + rs2 * rs2)" -## 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** -Proposed for Zftrans - FPOW: "FP rs2 to the power of rs1" +Proposed for ZftransAdv - FPOW: "FP rs1 to the power of rs2" -## funct5 = 10000 - unused +## funct5 = 10000 - **FROOTN** -Brownfield encodings available. +Proposed for ZftransAdv - FPROOTN: "FP rs1 to the power of (1/rs2)". +rs1 is FP, rs2 is **integer**. -## funct5 = 10001 - unused +## funct5 = 10000 - **FPOWN** -Brownfield encodings available. +Proposed for ZftransAdv - FPOW: "FP rs1 to the power of rs2" +rs1 is FP, rs2 is **integer**. + +## funct5 = 10001 - **FPOW** + +Proposed for ZftransAdv - FPOWN: "FP rs1 to the power of rs2, rs1 +ve" +rs1 and rs2 are FP, rs1 must be +ve. Equivalent to "exp(rs2 * log(rs1))" ## funct5 = 10010 - unused @@ -255,7 +283,7 @@ Brownfield encodings available. Brownfield encodings available. -## funct5 = 10100 +## funct5 = 10100 - FP comparisons This table uses funct3 for encoding 2-operand FP "comparison" operations where the result register is an **integer** @@ -290,7 +318,7 @@ Brownfield encodings available. Brownfield encodings available. -## funct5 = 11000 +## funct5 = 11000 - FCVT This table uses rs2 for encoding 1-operand FP operations, using funct3 to specify the "rounding" mode @@ -332,7 +360,7 @@ funct5 | SDHQ | rs2 | rs1 | funct3 | rd | opcode | name | Brownfield encodings available. -## funct5 = 11010 +## funct5 = 11010 - FCVT This table uses rs2 for encoding 1-operand FP operations, using funct3 to specify the "rounding" mode @@ -368,7 +396,7 @@ funct5 | SDHQ | rs2 | rs1 | funct3 | rd | opcode | name | 11010 | 11 | xxxxx | rs1 | rm | rd | 1010011 | rs2? | """]] -## funct5 = 11100 +## funct5 = 11100 - FMV, FCLASS This table uses *both* rs2 *and* funct3 for encoding 1-operand FP operations. @@ -403,7 +431,7 @@ funct5| SDHQ | rs2 | rs1 |funct3 | rd | opcode | name | Brownfield encodings available. -## funct5 = 11110 +## funct5 = 11110 - FMV This table uses *both* rs2 *and* funct3 for encoding 1-operand FP operations.