rv_major_opcode_1010011.mdwn

   1 # Summary FP Opcodes
   2
   3 This page aids and assists in the development of FP proposals,
   4 by identifying and listing in full both publicly-known proposals
   5 and the full brownfield encoding space available in the 0b010011
   6 major opcode.
   7
   8 A primary critical use-case for extending FP is for 3D and supercomputing.
   9
  10 Publicly-known FP proposals:
  11
  12 * Zfrsqrt - Reciprocal SQRT <http://bugs.libre-riscv.org/show_bug.cgi?id=110>
  13 * Zftrans - see [[ztrans_proposal]]: Transcendentals
  14   (FPOW, FEXP, FLOG, FCBRT)
  15   <http://bugs.libre-riscv.org/show_bug.cgi?id=127>
  16 * Ztrig\* - see [[ztrans_proposal]]: Trigonometriics
  17   (FSIN, FCOS, FTAN, arc-variants, hypotenuse-variants)
  18 * Extension of formats to cover FP16 (RISC-V ISA Manual Table 11.3 "fmt field")
  19 * HI-half FP MV - <https://github.com/riscv/riscv-isa-manual/pull/301>
  20   <https://groups.google.com/a/groups.riscv.org/forum/m/#!topic/isa-dev/kXgfFqgBv-c>
  21 * (Add new entries here: Zextname - Description and URL)
  22
  23 [[!toc levels=2]]
  24
  25 # Main FP opcode 1010011 table
  26
  27 Notes:
  28
  29 * Proposed new encodings in **bold**.
  30 * *Use funct5 sparingly!* - 2-operand functions only.
  31 * Single-argument FP operations should go under one of the funct5 tables
  32 * Both dual and single argument FP operations that do not require
  33   "rounding mode" should go in one of the funct5 tables that already use
  34   "funct3".
  35 * The rs2 field can be best used to sub-select a considerable number
  36   of 1-op operations, with "rounding" in funct3
  37 * The funct3 field can be best used to sub-select a considerable number
  38   of 2-op operations
  39 * 1-op operations that do not need "rounding" have the best brownfield
  40   availability: 8 bit sub-selection (rs2=5 + funct3=3).  This however is
  41   rare as most FP operations need "rounding" selection.
  42 * Be careful not to use encoding space for which FP16 has already been
  43   reserved (mostly FP conversion opcodes)
  44
  45 [[!table  data="""
  46 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function       |
  47 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name           |
  48  5      | 2       | 5      | 5    | 3      | 5     |   7     |                |
  49 00000   | xx      | rs2    | rs1  | rm     | rd    | 1010011 | FADD.xx        |
  50 00001   | xx      | rs2    | rs1  | rm     | rd    | 1010011 | FSUB.xx        |
  51 00010   | xx      | rs2    | rs1  | rm     | rd    | 1010011 | FMUL.xx        |
  52 00011   | xx      | rs2    | rs1  | rm     | rd    | 1010011 | FDIV.xx        |
  53 00100   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  54 00101   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | tb=00101       |
  55 00110   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  56 00111   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  57 01000   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | tb=01000       |
  58 01001   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  59 01010   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  60 01011   | xx      | xxxxx  | rs1  | yyy    | rd    | 1010011 | tb=01011       |
  61 01100   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | **FHYPOT.xx**  |
  62 01101   | xx      | rs2    | rs1  | rm     | rd    | 1010011 | **FATAN2.xx**  |
  63 01110   | xx      | rs2    | rs1  | rm     | rd    | 1010011 | **FATAN2PI.xx**|
  64 01111   | xx      | rs2    | rs1  | rm     | rd    | 1010011 | **FPOW.xx**    |
  65 10000   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | **FROOTN.xx**  |
  66 10001   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  67 10010   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  68 10011   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  69 10100   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | tb=10100       |
  70 10101   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  71 10110   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  72 10111   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  73 11000   | xx      | xxxxx  | rs1  | yyy    | rd    | 1010011 | tb=11000       |
  74 11001   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  75 11010   | xx      | xxxxx  | rs1  | yyy    | rd    | 1010011 | tb=11010       |
  76 11100   | xx      | xxxxx  | rs1  | yyy    | rd    | 1010011 | tb=11100       |
  77 11101   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  78 11110   | xx      | xxxxx  | rs1  | yyy    | rd    | 1010011 | tb=11110       |
  79 11111   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  80 """]]
  81
  82 Code:
  83
  84 * xx: Opcode format field "fmt" - Table 11.3
  85 * xxxxx: 5-bit selection field (usually 1-op selection)
  86 * yyy: funct3 selection field (usually 2-op selection)
  87 * rm: "rounding mode"
  88
  89 ## funct5 = 00000 - FADD
  90
  91 No brownfield encodings available.
  92
  93 ## funct5 = 00001 - FSUB
  94
  95 No brownfield encodings available.
  96
  97 ## funct5 = 00010 - FMUL
  98
  99 No brownfield encodings available.
 100
 101 ## funct5 = 00011 - FDIV
 102
 103 No brownfield encodings available.
 104
 105 ## funct5 = 00100 - unused
 106
 107 Brownfield encodings available.
 108
 109 ## funct5 = 00100 - FSGN
 110
 111 This table uses funct3 for encoding 2-operand FP operations
 112
 113 [[!table  data="""
 114 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function    |
 115 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name        |
 116  5      | 2       | 5      | 5    | 3      | 5     |   7     |             |
 117 00100   | xx      | rs2    | rs1  | 000    | rd    | 1010011 | FSGNJ.xx    |
 118 00100   | xx      | rs2    | rs1  | 001    | rd    | 1010011 | FSGNJN.xx   |
 119 00100   | xx      | rs2    | rs1  | 010    | rd    | 1010011 | FSGNJX.xx   |
 120 00100   | xx      | rs2    | rs1  | 011    | rd    | 1010011 | ?f3=011     |
 121 00100   | xx      | rs2    | rs1  | 100    | rd    | 1010011 | ?f3=100     |
 122 00100   | xx      | rs2    | rs1  | 101    | rd    | 1010011 | ?f3=101     |
 123 00100   | xx      | rs2    | rs1  | 110    | rd    | 1010011 | ?f3=110     |
 124 00100   | xx      | rs2    | rs1  | 111    | rd    | 1010011 | ?f3=111     |
 125 """]]
 126
 127 ## funct5 = 00101 - FMIN/MAX
 128
 129 This table uses funct3 for encoding 2-operand FP operations where the result
 130 register is a **floating-point** value.
 131
 132 [[!table  data="""
 133 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function    |
 134 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name        |
 135  5      | 2       | 5      | 5    | 3      | 5     |   7     |             |
 136 00101   | xx      | rs2    | rs1  | 000    | rd    | 1010011 | FMIN.S      |
 137 00101   | xx      | rs2    | rs1  | 001    | rd    | 1010011 | FMAX.S      |
 138 00101   | xx      | rs2    | rs1  | 010    | rd    | 1010011 | ?f3=010     |
 139 00101   | xx      | rs2    | rs1  | 011    | rd    | 1010011 | ?f3=011     |
 140 00101   | xx      | rs2    | rs1  | 100    | rd    | 1010011 | ?f3=100     |
 141 00101   | xx      | rs2    | rs1  | 101    | rd    | 1010011 | ?f3=101     |
 142 00101   | xx      | rs2    | rs1  | 110    | rd    | 1010011 | ?f3=110     |
 143 00101   | xx      | rs2    | rs1  | 111    | rd    | 1010011 | ?f3=111     |
 144 """]]
 145
 146 ## funct5 = 00110 - unused
 147
 148 Brownfield encodings available.
 149
 150 ## funct5 = 00111 - unused
 151
 152 Brownfield encodings available.
 153
 154 ## funct5 = 01000 - FCVT
 155
 156 This table uses rs2 for encoding 1-operand FP operations, using
 157 funct3 to specify the "rounding" mode
 158
 159 Notes:
 160
 161 * FP16 logically deduced from fmt field encoding (bits 25-26)
 162
 163 [[!table  data="""
 164 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function    |
 165 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name        |
 166  5      | 2       | 5      | 5    | 3      | 5     |   7     |             |
 167 01000   | 00      | 00000  | rs1  | rm     | rd    | 1010011 | ????????    |
 168 01000   | 00      | 00001  | rs1  | rm     | rd    | 1010011 | FCVT.S.D    |
 169 01000   | 00      | 00010  | rs1  | rm     | rd    | 1010011 | **FCVT.S.H**|
 170 01000   | 00      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.S.Q    |
 171 01000   | 00      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 172 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 173 01000   | 01      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.D.S    |
 174 01000   | 01      | 00001  | rs1  | rm     | rd    | 1010011 | ????????    |
 175 01000   | 01      | 00010  | rs1  | rm     | rd    | 1010011 | **FCVT.D.H**|
 176 01000   | 01      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.D.Q    |
 177 01000   | 01      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 178 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 179 01000   | 10      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.H.S    |
 180 01000   | 10      | 00001  | rs1  | rm     | rd    | 1010011 | **FCVT.H.D**|
 181 01000   | 10      | 00010  | rs1  | rm     | rd    | 1010011 | ????????    |
 182 01000   | 10      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.H.Q    |
 183 01000   | 10      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 184 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 185 01000   | 11      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.Q.S    |
 186 01000   | 11      | 00001  | rs1  | rm     | rd    | 1010011 | FCVT.Q.D    |
 187 01000   | 11      | 00010  | rs1  | rm     | rd    | 1010011 | **FCVT.Q.H**|
 188 01000   | 11      | 00011  | rs1  | rm     | rd    | 1010011 | ????????    |
 189 01000   | 11      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 190 """]]
 191
 192 ## funct5 = 01001 - unused
 193
 194 Brownfield encodings available.
 195
 196 ## funct5 = 01010 - unused
 197
 198 Brownfield encodings available.
 199
 200 ## funct5 = 01011 - 1-op Transcendentals <a name="transcendentals_1op"></a>
 201
 202 This table uses rs2 for encoding 1-operand FP operations, using
 203 funct3 to specify the "rounding" mode
 204
 205 [[!table  data="""
 206 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function      |
 207 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name          |
 208  5      | 2       | 5      | 5    | 3      | 5     |   7     |               |
 209 01011   | xx      | 00000  | rs1  | rm     | rd    | 1010011 | FSQRT.xx      |
 210 01011   | xx      | 00001  | rs1  | rm     | rd    | 1010011 | **FRSQRT.xx** |
 211 01011   | xx      | 00010  | rs1  | rm     | rd    | 1010011 | **FRECIP.xx** |
 212 01011   | xx      | 00011  | rs1  | rm     | rd    | 1010011 | **FCBRT.xx**  |
 213 01011   | xx      | 00100  | rs1  | rm     | rd    | 1010011 | **FEXP2.xx**  |
 214 01011   | xx      | 00101  | rs1  | rm     | rd    | 1010011 | **FLOG2.xx**  |
 215 01011   | xx      | 00110  | rs1  | rm     | rd    | 1010011 | **FEXPM1.xx** |
 216 01011   | xx      | 00111  | rs1  | rm     | rd    | 1010011 | **FLOGP1.xx** |
 217 01011   | xx      | 01000  | rs1  | rm     | rd    | 1010011 | **FEXP.xx**   |
 218 01011   | xx      | 01001  | rs1  | rm     | rd    | 1010011 | **FLOG.xx**   |
 219 01011   | xx      | 01010  | rs1  | rm     | rd    | 1010011 | **FEXP10.xx** |
 220 01011   | xx      | 01011  | rs1  | rm     | rd    | 1010011 | **FLOG10.xx** |
 221 01011   | xx      | 01100  | rs1  | rm     | rd    | 1010011 | **FASINH.xx** |
 222 01011   | xx      | 01101  | rs1  | rm     | rd    | 1010011 | **FACOSH.xx** |
 223 01011   | xx      | 01110  | rs1  | rm     | rd    | 1010011 | **FATANH.xx** |
 224 01011   | xx      | 01111  | rs1  | rm     | rd    | 1010011 | ?             |
 225 01011   | xx      | 10000  | rs1  | rm     | rd    | 1010011 | **FSIN.xx**   |
 226 01011   | xx      | 10001  | rs1  | rm     | rd    | 1010011 | **FSINPI.xx**  |
 227 01011   | xx      | 10010  | rs1  | rm     | rd    | 1010011 | **FASIN.xx** |
 228 01011   | xx      | 10011  | rs1  | rm     | rd    | 1010011 | **FASINPI.xx**|
 229 01011   | xx      | 10100  | rs1  | rm     | rd    | 1010011 | **FCOS.xx**   |
 230 01011   | xx      | 10101  | rs1  | rm     | rd    | 1010011 | **FCOSPI.xx**  |
 231 01011   | xx      | 10110  | rs1  | rm     | rd    | 1010011 | **FACOS.xx** |
 232 01011   | xx      | 10111  | rs1  | rm     | rd    | 1010011 | **FACOSPI.xx**|
 233 01011   | xx      | 11000  | rs1  | rm     | rd    | 1010011 | **FTAN.xx**   |
 234 01011   | xx      | 11001  | rs1  | rm     | rd    | 1010011 | **FTANPI.xx** |
 235 01011   | xx      | 11010  | rs1  | rm     | rd    | 1010011 | **FATAN.xx**  |
 236 01011   | xx      | 11011  | rs1  | rm     | rd    | 1010011 | **FATANPI.xx**|
 237 01011   | xx      | 11100  | rs1  | rm     | rd    | 1010011 | **FSINH.xx**  |
 238 01011   | xx      | 11101  | rs1  | rm     | rd    | 1010011 | **FCOSH.xx**  |
 239 01011   | xx      | 11110  | rs1  | rm     | rd    | 1010011 | **FTANH.xx**  |
 240 01011   | xx      | 11111  | rs1  | rm     | rd    | 1010011 | ?             |
 241 """]]
 242
 243 ## funct5 = 01100 - **FHYPOT**
 244
 245 Proposed for Zftrans - FHYPOT: "sqrt(rs1 * rs1 + rs2 * rs2)"
 246
 247 ## funct5 = 01101 - **FATAN2**
 248
 249 Proposed for Zftrans - FATAN: "atan(rs1, rs2)"
 250
 251 ## funct5 = 01110 - **FATAN2PI**
 252
 253 Proposed for ZftransExt - FATAN2PI: "atan2(rs1, rs2) * PI".
 254 Rationale: Gives better accuracy than if using FMUL with the constant, PI.
 255
 256 ## funct5 = 01111 - **FPOW**
 257
 258 Proposed for ZftransAdv - FPOW: "FP rs1 to the power of rs2"
 259
 260 ## funct5 = 10000 - **FROOTN**
 261
 262 Proposed for ZftransAdv - FPROOTN: "FP rs1 to the power of (1/rs2)".
 263 rs1 is FP, rs2 is **integer**.
 264
 265 ## funct5 = 10000 - unused
 266
 267 Brownfield encodings available.
 268
 269 ## funct5 = 10001 - unused
 270
 271 Brownfield encodings available.
 272
 273 ## funct5 = 10010 - unused
 274
 275 Brownfield encodings available.
 276
 277 ## funct5 = 10011 - unused
 278
 279 Brownfield encodings available.
 280
 281 ## funct5 = 10100 - FP comparisons
 282
 283 This table uses funct3 for encoding 2-operand FP "comparison" operations
 284 where the result register is an **integer**
 285
 286 Notes:
 287
 288 * FNE missing?
 289
 290 [[!table  data="""
 291 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function    |
 292 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name        |
 293  5      | 2       | 5      | 5    | 3      | 5     |   7     |             |
 294 10100   | xx      | rs2    | rs1  | 000    | rd    | 1010011 | FLE.xx      |
 295 10100   | xx      | rs2    | rs1  | 001    | rd    | 1010011 | FLT.xx      |
 296 10100   | xx      | rs2    | rs1  | 010    | rd    | 1010011 | FEQ.xx      |
 297 10100   | xx      | rs2    | rs1  | 011    | rd    | 1010011 | ?f3=011     |
 298 10100   | xx      | rs2    | rs1  | 100    | rd    | 1010011 | ?f3=100     |
 299 10100   | xx      | rs2    | rs1  | 101    | rd    | 1010011 | ?f3=101     |
 300 10100   | xx      | rs2    | rs1  | 110    | rd    | 1010011 | ?f3=110     |
 301 10100   | xx      | rs2    | rs1  | 111    | rd    | 1010011 | ?f3=111     |
 302 """]]
 303
 304 ## funct5 = 10101 - unused
 305
 306 Brownfield encodings available.
 307
 308 ## funct5 = 10110 - unused
 309
 310 Brownfield encodings available.
 311
 312 ## funct5 = 10111 - unused
 313
 314 Brownfield encodings available.
 315
 316 ## funct5 = 11000 - FCVT
 317
 318 This table uses rs2 for encoding 1-operand FP operations, using
 319 funct3 to specify the "rounding" mode
 320
 321 Notes:
 322
 323 * FP16 logically deduced from fmt field (bits 25-26)
 324
 325 [[!table  data="""
 326 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function    |
 327 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name        |
 328  5      | 2       | 5      | 5    | 3      | 5     |   7     |             |
 329 11000   | 00      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.W.S    |
 330 11000   | 00      | 00001  | rs1  | rm     | rd    | 1010011 | FCVT.WU.S   |
 331 11000   | 00      | 00010  | rs1  | rm     | rd    | 1010011 | FCVT.L.S    |
 332 11000   | 00      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.LU.S   |
 333 11000   | 00      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 334 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 335 11000   | 01      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.W.D    |
 336 11000   | 01      | 00001  | rs1  | rm     | rd    | 1010011 | FCVT.WU.D   |
 337 11000   | 01      | 00010  | rs1  | rm     | rd    | 1010011 | FCVT.L.D    |
 338 11000   | 01      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.LU.D   |
 339 11000   | 01      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 340 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 341 11000   | 10      | 00000  | rs1  | rm     | rd    | 1010011 |**FCVT.W.H** |
 342 11000   | 10      | 00001  | rs1  | rm     | rd    | 1010011 |**FCVT.WU.H**|
 343 11000   | 10      | 00010  | rs1  | rm     | rd    | 1010011 |**FCVT.L.H** |
 344 11000   | 10      | 00011  | rs1  | rm     | rd    | 1010011 |**FCVT.LU.H**|
 345 11000   | 10      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 346 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 347 11000   | 11      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.W.Q    |
 348 11000   | 11      | 00001  | rs1  | rm     | rd    | 1010011 | FCVT.WU.Q   |
 349 11000   | 11      | 00010  | rs1  | rm     | rd    | 1010011 | FCVT.L.Q    |
 350 11000   | 11      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.LU.Q   |
 351 11000   | 11      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 352 """]]
 353
 354 ## funct5 = 11001 - unused
 355
 356 Brownfield encodings available.
 357
 358 ## funct5 = 11010 - FCVT
 359
 360 This table uses rs2 for encoding 1-operand FP operations, using
 361 funct3 to specify the "rounding" mode
 362
 363 * FP16 logically deduced from fmt field (bits 25-26)
 364
 365 [[!table  data="""
 366 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function    |
 367 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name        |
 368  5      | 2       | 5      | 5    | 3      | 5     |   7     |             |
 369 11010   | 00      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.S.W    |
 370 11010   | 00      | 00001  | rs1  | rm     | rd    | 1010011 | FCVT.S.WU   |
 371 11010   | 00      | 00010  | rs1  | rm     | rd    | 1010011 | FCVT.S.L    |
 372 11010   | 00      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.S.LU   |
 373 11010   | 00      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 374 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 375 11010   | 01      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.D.W    |
 376 11010   | 01      | 00001  | rs1  | rm     | rd    | 1010011 | FCVT.D.WU   |
 377 11010   | 01      | 00010  | rs1  | rm     | rd    | 1010011 | FCVT.D.L    |
 378 11010   | 01      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.D.LU   |
 379 11010   | 01      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 380 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 381 11010   | 10      | 00000  | rs1  | rm     | rd    | 1010011 |**FCVT.H.W** |
 382 11010   | 10      | 00001  | rs1  | rm     | rd    | 1010011 |**FCVT.H.WU**|
 383 11010   | 10      | 00010  | rs1  | rm     | rd    | 1010011 |**FCVT.H.L** |
 384 11010   | 10      | 00011  | rs1  | rm     | rd    | 1010011 |**FCVT.H.LU**|
 385 11010   | 10      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 386 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 387 11010   | 11      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.Q.W    |
 388 11010   | 11      | 00001  | rs1  | rm     | rd    | 1010011 | FCVT.Q.WU   |
 389 11010   | 11      | 00010  | rs1  | rm     | rd    | 1010011 | FCVT.Q.L    |
 390 11010   | 11      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.Q.LU   |
 391 11010   | 11      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 392 """]]
 393
 394 ## funct5 = 11100 - FMV, FCLASS
 395
 396 This table uses *both* rs2 *and* funct3 for encoding 1-operand FP operations.
 397
 398 Notes:
 399
 400 * FMV.X.Q is missing (alias of FMVH.X.D if it existed)
 401 * FP16 logically deduced from fmt field (bits 25-26)
 402 * FMVH.X.HW (half-word) missing?
 403
 404 [[!table  data="""
 405 31..27| 26..25| 24..20 |19..15|14...12| 11..7 | 6....0  | function    |
 406 funct5| SDHQ  | rs2    | rs1  |funct3 | rd    | opcode  | name        |
 407  5    | 2     | 5      | 5    | 3     | 5     |   7     |             |
 408 11100 | 00    | 00000  | rs1  | 000   | rd    | 1010011 | FMV.X.W     |
 409 11100 | 00    | 00000  | rs1  | 001   | rd    | 1010011 | FCLASS.S    |
 410 11100 | 00    | xxxxx  | rs1  | yyy   | rd    | 1010011 | rs2? f3?    |
 411 ------| ----- | -----  | -----| ----- | ----- | ------- | --------    |
 412 11100 | 01    | 00000  | rs1  | 000   | rd    | 1010011 | FMV.X.D **FMVH.X.W** |
 413 11100 | 01    | 00000  | rs1  | 001   | rd    | 1010011 | FCLASS.D    |
 414 11100 | 01    | xxxxx  | rs1  | yyy   | rd    | 1010011 | rs2? f3?    |
 415 ------| ----- | -----  | -----| ----- | ----- | ------- | --------    |
 416 11100 | 10    | 00000  | rs1  | 000   | rd    | 1010011 |**FMV.X.H**  |
 417 11100 | 10    | 00000  | rs1  | 001   | rd    | 1010011 |**FCLASS.H** |
 418 11100 | 10    | xxxxx  | rs1  | yyy   | rd    | 1010011 | rs2? f3?    |
 419 ------| ----- | -----  | -----| ----- | ----- | ------- | --------    |
 420 11100 | 11    | 00000  | rs1  | 000   | rd    | 1010011 | **FMVH.X.D** |
 421 11100 | 11    | 00000  | rs1  | 001   | rd    | 1010011 | FCLASS.Q    |
 422 11100 | xx    | xxxxx  | rs1  | yyy   | rd    | 1010011 | rs2? f3?    |
 423 """]]
 424
 425 ## funct5 = 11101 - unused
 426
 427 Brownfield encodings available.
 428
 429 ## funct5 = 11110 - FMV
 430
 431 This table uses *both* rs2 *and* funct3 for encoding 1-operand FP operations.
 432
 433 Notes:
 434
 435 * FMV.Q.X is missing (as is FMVH.D.X)
 436 * FMVH.W.X is missing (alias of FMV.D.X)
 437 * FP16 logically deduced from fmt field (bits 25-26)
 438 * FMVH.HW.X (half-word) missing?
 439
 440 [[!table  data="""
 441 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function    |
 442 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name        |
 443  5      | 2       | 5      | 5    | 3      | 5     |   7     |             |
 444 11110   | 00      | 00000  | rs1  | 000    | rd    | 1010011 | FMV.W.X     |
 445 11110   | 00      | xxxxx  | rs1  | yyy    | rd    | 1010011 | rs2? f3?    |
 446 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 447 11110   | 01      | 00000  | rs1  | 000    | rd    | 1010011 | FMV.D.X     |
 448 11110   | 01      | xxxxx  | rs1  | yyy    | rd    | 1010011 | rs2? f3?    |
 449 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 450 11110   | 10      | 00000  | rs1  | 000    | rd    | 1010011 |**FMV.H.X**  |
 451 11110   | 10      | xxxxx  | rs1  | yyy    | rd    | 1010011 | rs2? f3?    |
 452 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 453 11110   | 11      | 00000  | rs1  | 000    | rd    | 1010011 | ?           |
 454 11110   | 11      | xxxxx  | rs1  | yyy    | rd    | 1010011 | rs2? f3?    |
 455 """]]
 456
 457 ## funct5 = 11111 - unused
 458
 459 Brownfield encodings available.
 460
 461 ## funct5 = ????? (table template)
 462
 463 This table acts as a cut/paste template for creating brownfield encodings
 464
 465 [[!table  data="""
 466 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function    |
 467 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name        |
 468  5      | 2       | 5      | 5    | 3      | 5     |   7     |             |
 469 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 470 """]]
 471