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 - Transcendentals (FSIN, FCOS, FATAN, FPOW, FEXP, FLOG, FRCP)
  14   <http://bugs.libre-riscv.org/show_bug.cgi?id=127>
  15 * Extension of formats to cover FP16 (RISC-V ISA Manual Table 11.3 "fmt field")
  16 * HI-half FP MV - <https://github.com/riscv/riscv-isa-manual/pull/301>
  17   <https://groups.google.com/a/groups.riscv.org/forum/m/#!topic/isa-dev/kXgfFqgBv-c>
  18 * (Add new entries here: Zextname - Description and URL)
  19
  20 [[!toc levels=2]]
  21
  22 # Main FP opcode 1010011 table
  23
  24 Notes:
  25
  26 * Proposed new encodings in **bold**.
  27 * *Use funct5 sparingly!* - 2-operand functions only.
  28 * Single-argument FP operations should go under one of the funct5 tables
  29 * Both dual and single argument FP operations that do not require
  30   "rounding mode" should go in one of the funct5 tables that already use
  31   "funct3".
  32 * The rs2 field can be best used to sub-select a considerable number
  33   of 1-op operations, with "rounding" in funct3
  34 * The funct3 field can be best used to sub-select a considerable number
  35   of 2-op operations
  36 * 1-op operations that do not need "rounding" have the best brownfield
  37   availability: 8 bit sub-selection (rs2=5 + funct3=3).  This however is
  38   rare as most FP operations need "rounding" selection.
  39 * Be careful not to use encoding space for which FP16 has already been
  40   reserved (mostly FP conversion opcodes)
  41
  42 [[!table  data="""
  43 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function       |
  44 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name           |
  45  5      | 2       | 5      | 5    | 3      | 5     |   7     |                |
  46 00000   | xx      | rs2    | rs1  | rm     | rd    | 1010011 | FADD.xx        |
  47 00001   | xx      | rs2    | rs1  | rm     | rd    | 1010011 | FSUB.xx        |
  48 00010   | xx      | rs2    | rs1  | rm     | rd    | 1010011 | FMUL.xx        |
  49 00011   | xx      | rs2    | rs1  | rm     | rd    | 1010011 | FDIV.xx        |
  50 00100   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  51 00101   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | tb=00101       |
  52 00110   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  53 00111   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  54 01000   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | tb=01000       |
  55 01001   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  56 01010   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  57 01011   | xx      | xxxxx  | rs1  | yyy    | rd    | 1010011 | tb=01011       |
  58 01100   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  59 01101   | xx      | rs2    | rs1  | rm     | rd    | 1010011 | **FATAN2.xx**  |
  60 01110   | xx      | rs2    | rs1  | rm     | rd    | 1010011 | **FATAN2PI.xx**|
  61 01111   | xx      | rs2    | rs1  | rm     | rd    | 1010011 | **FPOW.xx**    |
  62 10000   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | **FROOT.xx**   |
  63 10001   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  64 10010   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  65 10011   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  66 10100   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | tb=10100       |
  67 10101   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  68 10110   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  69 10111   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  70 11000   | xx      | xxxxx  | rs1  | yyy    | rd    | 1010011 | tb=11000       |
  71 11001   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  72 11010   | xx      | xxxxx  | rs1  | yyy    | rd    | 1010011 | tb=11010       |
  73 11100   | xx      | xxxxx  | rs1  | yyy    | rd    | 1010011 | tb=11100       |
  74 11101   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  75 11110   | xx      | xxxxx  | rs1  | yyy    | rd    | 1010011 | tb=11110       |
  76 11111   | xx      | rs2    | rs1  | yyy    | rd    | 1010011 | ?              |
  77 """]]
  78
  79 Code:
  80
  81 * xx: Opcode format field "fmt" - Table 11.3
  82 * xxxxx: 5-bit selection field (usually 1-op selection)
  83 * yyy: funct3 selection field (usually 2-op selection)
  84 * rm: "rounding mode"
  85
  86 ## funct5 = 00000 - FADD
  87
  88 No brownfield encodings available.
  89
  90 ## funct5 = 00001 - FSUB
  91
  92 No brownfield encodings available.
  93
  94 ## funct5 = 00010 - FMUL
  95
  96 No brownfield encodings available.
  97
  98 ## funct5 = 00011 - FDIV
  99
 100 No brownfield encodings available.
 101
 102 ## funct5 = 00100 - unused
 103
 104 Brownfield encodings available.
 105
 106 ## funct5 = 00100
 107
 108 This table uses funct3 for encoding 2-operand FP operations
 109
 110 [[!table  data="""
 111 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function    |
 112 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name        |
 113  5      | 2       | 5      | 5    | 3      | 5     |   7     |             |
 114 00100   | xx      | rs2    | rs1  | 000    | rd    | 1010011 | FSGNJ.xx    |
 115 00100   | xx      | rs2    | rs1  | 001    | rd    | 1010011 | FSGNJN.xx   |
 116 00100   | xx      | rs2    | rs1  | 010    | rd    | 1010011 | FSGNJX.xx   |
 117 00100   | xx      | rs2    | rs1  | 011    | rd    | 1010011 | ?f3=011     |
 118 00100   | xx      | rs2    | rs1  | 100    | rd    | 1010011 | ?f3=100     |
 119 00100   | xx      | rs2    | rs1  | 101    | rd    | 1010011 | ?f3=101     |
 120 00100   | xx      | rs2    | rs1  | 110    | rd    | 1010011 | ?f3=110     |
 121 00100   | xx      | rs2    | rs1  | 111    | rd    | 1010011 | ?f3=111     |
 122 """]]
 123
 124 ## funct5 = 00101
 125
 126 This table uses funct3 for encoding 2-operand FP operations where the result
 127 register is a **floating-point** value.
 128
 129 [[!table  data="""
 130 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function    |
 131 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name        |
 132  5      | 2       | 5      | 5    | 3      | 5     |   7     |             |
 133 00101   | xx      | rs2    | rs1  | 000    | rd    | 1010011 | FMIN.S      |
 134 00101   | xx      | rs2    | rs1  | 001    | rd    | 1010011 | FMAX.S      |
 135 00101   | xx      | rs2    | rs1  | 010    | rd    | 1010011 | ?f3=010     |
 136 00101   | xx      | rs2    | rs1  | 011    | rd    | 1010011 | ?f3=011     |
 137 00101   | xx      | rs2    | rs1  | 100    | rd    | 1010011 | ?f3=100     |
 138 00101   | xx      | rs2    | rs1  | 101    | rd    | 1010011 | ?f3=101     |
 139 00101   | xx      | rs2    | rs1  | 110    | rd    | 1010011 | ?f3=110     |
 140 00101   | xx      | rs2    | rs1  | 111    | rd    | 1010011 | ?f3=111     |
 141 """]]
 142
 143 ## funct5 = 00110 - unused
 144
 145 Brownfield encodings available.
 146
 147 ## funct5 = 00111 - unused
 148
 149 Brownfield encodings available.
 150
 151 ## funct5 = 01000
 152
 153 This table uses rs2 for encoding 1-operand FP operations, using
 154 funct3 to specify the "rounding" mode
 155
 156 Notes:
 157
 158 * FP16 logically deduced from fmt field encoding (bits 25-26)
 159
 160 [[!table  data="""
 161 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function    |
 162 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name        |
 163  5      | 2       | 5      | 5    | 3      | 5     |   7     |             |
 164 01000   | 00      | 00000  | rs1  | rm     | rd    | 1010011 | ????????    |
 165 01000   | 00      | 00001  | rs1  | rm     | rd    | 1010011 | FCVT.S.D    |
 166 01000   | 00      | 00010  | rs1  | rm     | rd    | 1010011 | **FCVT.S.H**|
 167 01000   | 00      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.S.Q    |
 168 01000   | 00      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 169 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 170 01000   | 01      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.D.S    |
 171 01000   | 01      | 00001  | rs1  | rm     | rd    | 1010011 | ????????    |
 172 01000   | 01      | 00010  | rs1  | rm     | rd    | 1010011 | **FCVT.D.H**|
 173 01000   | 01      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.D.Q    |
 174 01000   | 01      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 175 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 176 01000   | 10      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.H.S    |
 177 01000   | 10      | 00001  | rs1  | rm     | rd    | 1010011 | **FCVT.H.D**|
 178 01000   | 10      | 00010  | rs1  | rm     | rd    | 1010011 | ????????    |
 179 01000   | 10      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.H.Q    |
 180 01000   | 10      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 181 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 182 01000   | 11      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.Q.S    |
 183 01000   | 11      | 00001  | rs1  | rm     | rd    | 1010011 | FCVT.Q.D    |
 184 01000   | 11      | 00010  | rs1  | rm     | rd    | 1010011 | **FCVT.Q.H**|
 185 01000   | 11      | 00011  | rs1  | rm     | rd    | 1010011 | ????????    |
 186 01000   | 11      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 187 """]]
 188
 189 ## funct5 = 01001 - unused
 190
 191 Brownfield encodings available.
 192
 193 ## funct5 = 01010 - unused
 194
 195 Brownfield encodings available.
 196
 197 ## funct5 = 01011 - 1-op Transcendentals <a name="transcendentals_1op"></a>
 198
 199 This table uses rs2 for encoding 1-operand FP operations, using
 200 funct3 to specify the "rounding" mode
 201
 202 [[!table  data="""
 203 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function      |
 204 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name          |
 205  5      | 2       | 5      | 5    | 3      | 5     |   7     |               |
 206 01011   | xx      | 00000  | rs1  | rm     | rd    | 1010011 | FSQRT.xx      |
 207 01011   | xx      | 00001  | rs1  | rm     | rd    | 1010011 | **FRSQRT.xx** |
 208 01011   | xx      | 00010  | rs1  | rm     | rd    | 1010011 | **FRCP.xx**   |
 209 01011   | xx      | 00011  | rs1  | rm     | rd    | 1010011 | **FCBRT.xx**  |
 210 01011   | xx      | 00100  | rs1  | rm     | rd    | 1010011 | **FEXP2.xx**  |
 211 01011   | xx      | 00101  | rs1  | rm     | rd    | 1010011 | **FLOG2.xx**  |
 212 01011   | xx      | 00110  | rs1  | rm     | rd    | 1010011 | **FEXPM1.xx** |
 213 01011   | xx      | 00111  | rs1  | rm     | rd    | 1010011 | **FLOGP1.xx** |
 214 01011   | xx      | 01000  | rs1  | rm     | rd    | 1010011 | **FEXP.xx**   |
 215 01011   | xx      | 01001  | rs1  | rm     | rd    | 1010011 | **FLOG.xx**   |
 216 01011   | xx      | 01010  | rs1  | rm     | rd    | 1010011 | **FEXP10.xx** |
 217 01011   | xx      | 01011  | rs1  | rm     | rd    | 1010011 | **FLOG10.xx** |
 218 01011   | xx      | 01100  | rs1  | rm     | rd    | 1010011 | **FASINH.xx** |
 219 01011   | xx      | 01101  | rs1  | rm     | rd    | 1010011 | **FACOSH.xx** |
 220 01011   | xx      | 01110  | rs1  | rm     | rd    | 1010011 | **FATANH.xx** |
 221 01011   | xx      | 01111  | rs1  | rm     | rd    | 1010011 | ?             |
 222 01011   | xx      | 10000  | rs1  | rm     | rd    | 1010011 | **FSIN.xx**   |
 223 01011   | xx      | 10001  | rs1  | rm     | rd    | 1010011 | **FASIN.xx**  |
 224 01011   | xx      | 10010  | rs1  | rm     | rd    | 1010011 | **FSINPI.xx** |
 225 01011   | xx      | 10011  | rs1  | rm     | rd    | 1010011 | **FASINPI.xx**|
 226 01011   | xx      | 10100  | rs1  | rm     | rd    | 1010011 | **FCOS.xx**   |
 227 01011   | xx      | 10101  | rs1  | rm     | rd    | 1010011 | **FACOS.xx**  |
 228 01011   | xx      | 10110  | rs1  | rm     | rd    | 1010011 | **FCOSPI.xx** |
 229 01011   | xx      | 10111  | rs1  | rm     | rd    | 1010011 | **FACOSPI.xx**|
 230 01011   | xx      | 11000  | rs1  | rm     | rd    | 1010011 | **FTAN.xx**   |
 231 01011   | xx      | 11001  | rs1  | rm     | rd    | 1010011 | **FATAN.xx**  |
 232 01011   | xx      | 11010  | rs1  | rm     | rd    | 1010011 | **FTANPI.xx** |
 233 01011   | xx      | 11011  | rs1  | rm     | rd    | 1010011 | **FATANPI.xx**|
 234 01011   | xx      | 11100  | rs1  | rm     | rd    | 1010011 | **FSINH.xx**  |
 235 01011   | xx      | 11101  | rs1  | rm     | rd    | 1010011 | **FCOSH.xx**  |
 236 01011   | xx      | 11110  | rs1  | rm     | rd    | 1010011 | **FTANH.xx**  |
 237 01011   | xx      | 11111  | rs1  | rm     | rd    | 1010011 | ?             |
 238 """]]
 239
 240
 241
 242
 243
 244
 245
 246 ## funct5 = 01100 - unused
 247
 248 Brownfield encodings available.
 249
 250 ## funct5 = 01101 - **FATAN2**
 251
 252 Proposed for Zftrans - FATAN: "atan(rs1, rs2)"
 253
 254 ## funct5 = 01110 - **FATAN2PI**
 255
 256 Proposed for ZftransExt - FATAN2PI: "atan2(rs1, rs2) * PI".
 257 Rationale: Gives better accuracy than if using FMUL with the constant, PI.
 258
 259 ## funct5 = 01111 - **FPOW**
 260
 261 Proposed for ZftransAdv - FPOW: "FP rs1 to the power of rs2"
 262
 263 ## funct5 = 10000 - **FROOT**
 264
 265 Proposed for ZftransAdv - FPROOT: "FP rs1 to the power of (1/rs2)"
 266
 267 ## funct5 = 10000 - unused
 268
 269 Brownfield encodings available.
 270
 271 ## funct5 = 10001 - unused
 272
 273 Brownfield encodings available.
 274
 275 ## funct5 = 10010 - unused
 276
 277 Brownfield encodings available.
 278
 279 ## funct5 = 10011 - unused
 280
 281 Brownfield encodings available.
 282
 283 ## funct5 = 10100
 284
 285 This table uses funct3 for encoding 2-operand FP "comparison" operations
 286 where the result register is an **integer**
 287
 288 Notes:
 289
 290 * FNE missing?
 291
 292 [[!table  data="""
 293 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function    |
 294 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name        |
 295  5      | 2       | 5      | 5    | 3      | 5     |   7     |             |
 296 10100   | xx      | rs2    | rs1  | 000    | rd    | 1010011 | FLE.xx      |
 297 10100   | xx      | rs2    | rs1  | 001    | rd    | 1010011 | FLT.xx      |
 298 10100   | xx      | rs2    | rs1  | 010    | rd    | 1010011 | FEQ.xx      |
 299 10100   | xx      | rs2    | rs1  | 011    | rd    | 1010011 | ?f3=011     |
 300 10100   | xx      | rs2    | rs1  | 100    | rd    | 1010011 | ?f3=100     |
 301 10100   | xx      | rs2    | rs1  | 101    | rd    | 1010011 | ?f3=101     |
 302 10100   | xx      | rs2    | rs1  | 110    | rd    | 1010011 | ?f3=110     |
 303 10100   | xx      | rs2    | rs1  | 111    | rd    | 1010011 | ?f3=111     |
 304 """]]
 305
 306 ## funct5 = 10101 - unused
 307
 308 Brownfield encodings available.
 309
 310 ## funct5 = 10110 - unused
 311
 312 Brownfield encodings available.
 313
 314 ## funct5 = 10111 - unused
 315
 316 Brownfield encodings available.
 317
 318 ## funct5 = 11000
 319
 320 This table uses rs2 for encoding 1-operand FP operations, using
 321 funct3 to specify the "rounding" mode
 322
 323 Notes:
 324
 325 * FP16 logically deduced from fmt field (bits 25-26)
 326
 327 [[!table  data="""
 328 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function    |
 329 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name        |
 330  5      | 2       | 5      | 5    | 3      | 5     |   7     |             |
 331 11000   | 00      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.W.S    |
 332 11000   | 00      | 00001  | rs1  | rm     | rd    | 1010011 | FCVT.WU.S   |
 333 11000   | 00      | 00010  | rs1  | rm     | rd    | 1010011 | FCVT.L.S    |
 334 11000   | 00      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.LU.S   |
 335 11000   | 00      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 336 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 337 11000   | 01      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.W.D    |
 338 11000   | 01      | 00001  | rs1  | rm     | rd    | 1010011 | FCVT.WU.D   |
 339 11000   | 01      | 00010  | rs1  | rm     | rd    | 1010011 | FCVT.L.D    |
 340 11000   | 01      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.LU.D   |
 341 11000   | 01      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 342 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 343 11000   | 10      | 00000  | rs1  | rm     | rd    | 1010011 |**FCVT.W.H** |
 344 11000   | 10      | 00001  | rs1  | rm     | rd    | 1010011 |**FCVT.WU.H**|
 345 11000   | 10      | 00010  | rs1  | rm     | rd    | 1010011 |**FCVT.L.H** |
 346 11000   | 10      | 00011  | rs1  | rm     | rd    | 1010011 |**FCVT.LU.H**|
 347 11000   | 10      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 348 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 349 11000   | 11      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.W.Q    |
 350 11000   | 11      | 00001  | rs1  | rm     | rd    | 1010011 | FCVT.WU.Q   |
 351 11000   | 11      | 00010  | rs1  | rm     | rd    | 1010011 | FCVT.L.Q    |
 352 11000   | 11      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.LU.Q   |
 353 11000   | 11      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 354 """]]
 355
 356 ## funct5 = 11001 - unused
 357
 358 Brownfield encodings available.
 359
 360 ## funct5 = 11010
 361
 362 This table uses rs2 for encoding 1-operand FP operations, using
 363 funct3 to specify the "rounding" mode
 364
 365 * FP16 logically deduced from fmt field (bits 25-26)
 366
 367 [[!table  data="""
 368 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function    |
 369 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name        |
 370  5      | 2       | 5      | 5    | 3      | 5     |   7     |             |
 371 11010   | 00      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.S.W    |
 372 11010   | 00      | 00001  | rs1  | rm     | rd    | 1010011 | FCVT.S.WU   |
 373 11010   | 00      | 00010  | rs1  | rm     | rd    | 1010011 | FCVT.S.L    |
 374 11010   | 00      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.S.LU   |
 375 11010   | 00      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 376 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 377 11010   | 01      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.D.W    |
 378 11010   | 01      | 00001  | rs1  | rm     | rd    | 1010011 | FCVT.D.WU   |
 379 11010   | 01      | 00010  | rs1  | rm     | rd    | 1010011 | FCVT.D.L    |
 380 11010   | 01      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.D.LU   |
 381 11010   | 01      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 382 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 383 11010   | 10      | 00000  | rs1  | rm     | rd    | 1010011 |**FCVT.H.W** |
 384 11010   | 10      | 00001  | rs1  | rm     | rd    | 1010011 |**FCVT.H.WU**|
 385 11010   | 10      | 00010  | rs1  | rm     | rd    | 1010011 |**FCVT.H.L** |
 386 11010   | 10      | 00011  | rs1  | rm     | rd    | 1010011 |**FCVT.H.LU**|
 387 11010   | 10      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 388 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 389 11010   | 11      | 00000  | rs1  | rm     | rd    | 1010011 | FCVT.Q.W    |
 390 11010   | 11      | 00001  | rs1  | rm     | rd    | 1010011 | FCVT.Q.WU   |
 391 11010   | 11      | 00010  | rs1  | rm     | rd    | 1010011 | FCVT.Q.L    |
 392 11010   | 11      | 00011  | rs1  | rm     | rd    | 1010011 | FCVT.Q.LU   |
 393 11010   | 11      | xxxxx  | rs1  | rm     | rd    | 1010011 | rs2?        |
 394 """]]
 395
 396 ## funct5 = 11100
 397
 398 This table uses *both* rs2 *and* funct3 for encoding 1-operand FP operations.
 399
 400 Notes:
 401
 402 * FMV.X.Q is missing (alias of FMVH.X.D if it existed)
 403 * FP16 logically deduced from fmt field (bits 25-26)
 404 * FMVH.X.HW (half-word) missing?
 405
 406 [[!table  data="""
 407 31..27| 26..25| 24..20 |19..15|14...12| 11..7 | 6....0  | function    |
 408 funct5| SDHQ  | rs2    | rs1  |funct3 | rd    | opcode  | name        |
 409  5    | 2     | 5      | 5    | 3     | 5     |   7     |             |
 410 11100 | 00    | 00000  | rs1  | 000   | rd    | 1010011 | FMV.X.W     |
 411 11100 | 00    | 00000  | rs1  | 001   | rd    | 1010011 | FCLASS.S    |
 412 11100 | 00    | xxxxx  | rs1  | yyy   | rd    | 1010011 | rs2? f3?    |
 413 ------| ----- | -----  | -----| ----- | ----- | ------- | --------    |
 414 11100 | 01    | 00000  | rs1  | 000   | rd    | 1010011 | FMV.X.D **FMVH.X.W** |
 415 11100 | 01    | 00000  | rs1  | 001   | rd    | 1010011 | FCLASS.D    |
 416 11100 | 01    | xxxxx  | rs1  | yyy   | rd    | 1010011 | rs2? f3?    |
 417 ------| ----- | -----  | -----| ----- | ----- | ------- | --------    |
 418 11100 | 10    | 00000  | rs1  | 000   | rd    | 1010011 |**FMV.X.H**  |
 419 11100 | 10    | 00000  | rs1  | 001   | rd    | 1010011 |**FCLASS.H** |
 420 11100 | 10    | xxxxx  | rs1  | yyy   | rd    | 1010011 | rs2? f3?    |
 421 ------| ----- | -----  | -----| ----- | ----- | ------- | --------    |
 422 11100 | 11    | 00000  | rs1  | 000   | rd    | 1010011 | **FMVH.X.D** |
 423 11100 | 11    | 00000  | rs1  | 001   | rd    | 1010011 | FCLASS.Q    |
 424 11100 | xx    | xxxxx  | rs1  | yyy   | rd    | 1010011 | rs2? f3?    |
 425 """]]
 426
 427 ## funct5 = 11101 - unused
 428
 429 Brownfield encodings available.
 430
 431 ## funct5 = 11110
 432
 433 This table uses *both* rs2 *and* funct3 for encoding 1-operand FP operations.
 434
 435 Notes:
 436
 437 * FMV.Q.X is missing (as is FMVH.D.X)
 438 * FMVH.W.X is missing (alias of FMV.D.X)
 439 * FP16 logically deduced from fmt field (bits 25-26)
 440 * FMVH.HW.X (half-word) missing?
 441
 442 [[!table  data="""
 443 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function    |
 444 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name        |
 445  5      | 2       | 5      | 5    | 3      | 5     |   7     |             |
 446 11110   | 00      | 00000  | rs1  | 000    | rd    | 1010011 | FMV.W.X     |
 447 11110   | 00      | xxxxx  | rs1  | yyy    | rd    | 1010011 | rs2? f3?    |
 448 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 449 11110   | 01      | 00000  | rs1  | 000    | rd    | 1010011 | FMV.D.X     |
 450 11110   | 01      | xxxxx  | rs1  | yyy    | rd    | 1010011 | rs2? f3?    |
 451 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 452 11110   | 10      | 00000  | rs1  | 000    | rd    | 1010011 |**FMV.H.X**  |
 453 11110   | 10      | xxxxx  | rs1  | yyy    | rd    | 1010011 | rs2? f3?    |
 454 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 455 11110   | 11      | 00000  | rs1  | 000    | rd    | 1010011 | ?           |
 456 11110   | 11      | xxxxx  | rs1  | yyy    | rd    | 1010011 | rs2? f3?    |
 457 """]]
 458
 459 ## funct5 = 11111 - unused
 460
 461 Brownfield encodings available.
 462
 463 ## funct5 = ????? (table template)
 464
 465 This table acts as a cut/paste template for creating brownfield encodings
 466
 467 [[!table  data="""
 468 31..27  | 26..25  | 24..20 |19..15| 14...12| 11..7 | 6....0  | function    |
 469 funct5  | SDHQ    | rs2    | rs1  | funct3 | rd    | opcode  | name        |
 470  5      | 2       | 5      | 5    | 3      | 5     |   7     |             |
 471 ------  | -----   | -----  | -----| -----  | ----- | ------- | --------    |
 472 """]]
 473