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
8 A primary critical use-case for extending FP is for 3D and supercomputing.
10 Publicly-known FP proposals:
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)
25 # Main FP opcode 1010011 table
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
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
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)
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 | **FROOT.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 | ? |
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)
89 ## funct5 = 00000 - FADD
91 No brownfield encodings available.
93 ## funct5 = 00001 - FSUB
95 No brownfield encodings available.
97 ## funct5 = 00010 - FMUL
99 No brownfield encodings available.
101 ## funct5 = 00011 - FDIV
103 No brownfield encodings available.
105 ## funct5 = 00100 - unused
107 Brownfield encodings available.
109 ## funct5 = 00100 - FSGN
111 This table uses funct3 for encoding 2-operand FP operations
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 |
127 ## funct5 = 00101 - FMIN/MAX
129 This table uses funct3 for encoding 2-operand FP operations where the result
130 register is a **floating-point** value.
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 |
146 ## funct5 = 00110 - unused
148 Brownfield encodings available.
150 ## funct5 = 00111 - unused
152 Brownfield encodings available.
154 ## funct5 = 01000 - FCVT
156 This table uses rs2 for encoding 1-operand FP operations, using
157 funct3 to specify the "rounding" mode
161 * FP16 logically deduced from fmt field encoding (bits 25-26)
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? |
192 ## funct5 = 01001 - unused
194 Brownfield encodings available.
196 ## funct5 = 01010 - unused
198 Brownfield encodings available.
200 ## funct5 = 01011 - 1-op Transcendentals <a name="transcendentals_1op"></a>
202 This table uses rs2 for encoding 1-operand FP operations, using
203 funct3 to specify the "rounding" mode
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 | ? |
243 ## funct5 = 01100 - **FHYPOT**
245 Proposed for Zftrans - FHYPOT: "sqrt(rs1 * rs1 + rs2 * rs2)"
247 ## funct5 = 01101 - **FATAN2**
249 Proposed for Zftrans - FATAN: "atan(rs1, rs2)"
251 ## funct5 = 01110 - **FATAN2PI**
253 Proposed for ZftransExt - FATAN2PI: "atan2(rs1, rs2) * PI".
254 Rationale: Gives better accuracy than if using FMUL with the constant, PI.
256 ## funct5 = 01111 - **FPOW**
258 Proposed for ZftransAdv - FPOW: "FP rs1 to the power of rs2"
260 ## funct5 = 10000 - **FROOT**
262 Proposed for ZftransAdv - FPROOT: "FP rs1 to the power of (1/rs2)"
264 ## funct5 = 10000 - unused
266 Brownfield encodings available.
268 ## funct5 = 10001 - unused
270 Brownfield encodings available.
272 ## funct5 = 10010 - unused
274 Brownfield encodings available.
276 ## funct5 = 10011 - unused
278 Brownfield encodings available.
280 ## funct5 = 10100 - FP comparisons
282 This table uses funct3 for encoding 2-operand FP "comparison" operations
283 where the result register is an **integer**
290 31..27 | 26..25 | 24..20 |19..15| 14...12| 11..7 | 6....0 | function |
291 funct5 | SDHQ | rs2 | rs1 | funct3 | rd | opcode | name |
292 5 | 2 | 5 | 5 | 3 | 5 | 7 | |
293 10100 | xx | rs2 | rs1 | 000 | rd | 1010011 | FLE.xx |
294 10100 | xx | rs2 | rs1 | 001 | rd | 1010011 | FLT.xx |
295 10100 | xx | rs2 | rs1 | 010 | rd | 1010011 | FEQ.xx |
296 10100 | xx | rs2 | rs1 | 011 | rd | 1010011 | ?f3=011 |
297 10100 | xx | rs2 | rs1 | 100 | rd | 1010011 | ?f3=100 |
298 10100 | xx | rs2 | rs1 | 101 | rd | 1010011 | ?f3=101 |
299 10100 | xx | rs2 | rs1 | 110 | rd | 1010011 | ?f3=110 |
300 10100 | xx | rs2 | rs1 | 111 | rd | 1010011 | ?f3=111 |
303 ## funct5 = 10101 - unused
305 Brownfield encodings available.
307 ## funct5 = 10110 - unused
309 Brownfield encodings available.
311 ## funct5 = 10111 - unused
313 Brownfield encodings available.
315 ## funct5 = 11000 - FCVT
317 This table uses rs2 for encoding 1-operand FP operations, using
318 funct3 to specify the "rounding" mode
322 * FP16 logically deduced from fmt field (bits 25-26)
325 31..27 | 26..25 | 24..20 |19..15| 14...12| 11..7 | 6....0 | function |
326 funct5 | SDHQ | rs2 | rs1 | funct3 | rd | opcode | name |
327 5 | 2 | 5 | 5 | 3 | 5 | 7 | |
328 11000 | 00 | 00000 | rs1 | rm | rd | 1010011 | FCVT.W.S |
329 11000 | 00 | 00001 | rs1 | rm | rd | 1010011 | FCVT.WU.S |
330 11000 | 00 | 00010 | rs1 | rm | rd | 1010011 | FCVT.L.S |
331 11000 | 00 | 00011 | rs1 | rm | rd | 1010011 | FCVT.LU.S |
332 11000 | 00 | xxxxx | rs1 | rm | rd | 1010011 | rs2? |
333 ------ | ----- | ----- | -----| ----- | ----- | ------- | -------- |
334 11000 | 01 | 00000 | rs1 | rm | rd | 1010011 | FCVT.W.D |
335 11000 | 01 | 00001 | rs1 | rm | rd | 1010011 | FCVT.WU.D |
336 11000 | 01 | 00010 | rs1 | rm | rd | 1010011 | FCVT.L.D |
337 11000 | 01 | 00011 | rs1 | rm | rd | 1010011 | FCVT.LU.D |
338 11000 | 01 | xxxxx | rs1 | rm | rd | 1010011 | rs2? |
339 ------ | ----- | ----- | -----| ----- | ----- | ------- | -------- |
340 11000 | 10 | 00000 | rs1 | rm | rd | 1010011 |**FCVT.W.H** |
341 11000 | 10 | 00001 | rs1 | rm | rd | 1010011 |**FCVT.WU.H**|
342 11000 | 10 | 00010 | rs1 | rm | rd | 1010011 |**FCVT.L.H** |
343 11000 | 10 | 00011 | rs1 | rm | rd | 1010011 |**FCVT.LU.H**|
344 11000 | 10 | xxxxx | rs1 | rm | rd | 1010011 | rs2? |
345 ------ | ----- | ----- | -----| ----- | ----- | ------- | -------- |
346 11000 | 11 | 00000 | rs1 | rm | rd | 1010011 | FCVT.W.Q |
347 11000 | 11 | 00001 | rs1 | rm | rd | 1010011 | FCVT.WU.Q |
348 11000 | 11 | 00010 | rs1 | rm | rd | 1010011 | FCVT.L.Q |
349 11000 | 11 | 00011 | rs1 | rm | rd | 1010011 | FCVT.LU.Q |
350 11000 | 11 | xxxxx | rs1 | rm | rd | 1010011 | rs2? |
353 ## funct5 = 11001 - unused
355 Brownfield encodings available.
357 ## funct5 = 11010 - FCVT
359 This table uses rs2 for encoding 1-operand FP operations, using
360 funct3 to specify the "rounding" mode
362 * FP16 logically deduced from fmt field (bits 25-26)
365 31..27 | 26..25 | 24..20 |19..15| 14...12| 11..7 | 6....0 | function |
366 funct5 | SDHQ | rs2 | rs1 | funct3 | rd | opcode | name |
367 5 | 2 | 5 | 5 | 3 | 5 | 7 | |
368 11010 | 00 | 00000 | rs1 | rm | rd | 1010011 | FCVT.S.W |
369 11010 | 00 | 00001 | rs1 | rm | rd | 1010011 | FCVT.S.WU |
370 11010 | 00 | 00010 | rs1 | rm | rd | 1010011 | FCVT.S.L |
371 11010 | 00 | 00011 | rs1 | rm | rd | 1010011 | FCVT.S.LU |
372 11010 | 00 | xxxxx | rs1 | rm | rd | 1010011 | rs2? |
373 ------ | ----- | ----- | -----| ----- | ----- | ------- | -------- |
374 11010 | 01 | 00000 | rs1 | rm | rd | 1010011 | FCVT.D.W |
375 11010 | 01 | 00001 | rs1 | rm | rd | 1010011 | FCVT.D.WU |
376 11010 | 01 | 00010 | rs1 | rm | rd | 1010011 | FCVT.D.L |
377 11010 | 01 | 00011 | rs1 | rm | rd | 1010011 | FCVT.D.LU |
378 11010 | 01 | xxxxx | rs1 | rm | rd | 1010011 | rs2? |
379 ------ | ----- | ----- | -----| ----- | ----- | ------- | -------- |
380 11010 | 10 | 00000 | rs1 | rm | rd | 1010011 |**FCVT.H.W** |
381 11010 | 10 | 00001 | rs1 | rm | rd | 1010011 |**FCVT.H.WU**|
382 11010 | 10 | 00010 | rs1 | rm | rd | 1010011 |**FCVT.H.L** |
383 11010 | 10 | 00011 | rs1 | rm | rd | 1010011 |**FCVT.H.LU**|
384 11010 | 10 | xxxxx | rs1 | rm | rd | 1010011 | rs2? |
385 ------ | ----- | ----- | -----| ----- | ----- | ------- | -------- |
386 11010 | 11 | 00000 | rs1 | rm | rd | 1010011 | FCVT.Q.W |
387 11010 | 11 | 00001 | rs1 | rm | rd | 1010011 | FCVT.Q.WU |
388 11010 | 11 | 00010 | rs1 | rm | rd | 1010011 | FCVT.Q.L |
389 11010 | 11 | 00011 | rs1 | rm | rd | 1010011 | FCVT.Q.LU |
390 11010 | 11 | xxxxx | rs1 | rm | rd | 1010011 | rs2? |
393 ## funct5 = 11100 - FMV, FCLASS
395 This table uses *both* rs2 *and* funct3 for encoding 1-operand FP operations.
399 * FMV.X.Q is missing (alias of FMVH.X.D if it existed)
400 * FP16 logically deduced from fmt field (bits 25-26)
401 * FMVH.X.HW (half-word) missing?
404 31..27| 26..25| 24..20 |19..15|14...12| 11..7 | 6....0 | function |
405 funct5| SDHQ | rs2 | rs1 |funct3 | rd | opcode | name |
406 5 | 2 | 5 | 5 | 3 | 5 | 7 | |
407 11100 | 00 | 00000 | rs1 | 000 | rd | 1010011 | FMV.X.W |
408 11100 | 00 | 00000 | rs1 | 001 | rd | 1010011 | FCLASS.S |
409 11100 | 00 | xxxxx | rs1 | yyy | rd | 1010011 | rs2? f3? |
410 ------| ----- | ----- | -----| ----- | ----- | ------- | -------- |
411 11100 | 01 | 00000 | rs1 | 000 | rd | 1010011 | FMV.X.D **FMVH.X.W** |
412 11100 | 01 | 00000 | rs1 | 001 | rd | 1010011 | FCLASS.D |
413 11100 | 01 | xxxxx | rs1 | yyy | rd | 1010011 | rs2? f3? |
414 ------| ----- | ----- | -----| ----- | ----- | ------- | -------- |
415 11100 | 10 | 00000 | rs1 | 000 | rd | 1010011 |**FMV.X.H** |
416 11100 | 10 | 00000 | rs1 | 001 | rd | 1010011 |**FCLASS.H** |
417 11100 | 10 | xxxxx | rs1 | yyy | rd | 1010011 | rs2? f3? |
418 ------| ----- | ----- | -----| ----- | ----- | ------- | -------- |
419 11100 | 11 | 00000 | rs1 | 000 | rd | 1010011 | **FMVH.X.D** |
420 11100 | 11 | 00000 | rs1 | 001 | rd | 1010011 | FCLASS.Q |
421 11100 | xx | xxxxx | rs1 | yyy | rd | 1010011 | rs2? f3? |
424 ## funct5 = 11101 - unused
426 Brownfield encodings available.
428 ## funct5 = 11110 - FMV
430 This table uses *both* rs2 *and* funct3 for encoding 1-operand FP operations.
434 * FMV.Q.X is missing (as is FMVH.D.X)
435 * FMVH.W.X is missing (alias of FMV.D.X)
436 * FP16 logically deduced from fmt field (bits 25-26)
437 * FMVH.HW.X (half-word) missing?
440 31..27 | 26..25 | 24..20 |19..15| 14...12| 11..7 | 6....0 | function |
441 funct5 | SDHQ | rs2 | rs1 | funct3 | rd | opcode | name |
442 5 | 2 | 5 | 5 | 3 | 5 | 7 | |
443 11110 | 00 | 00000 | rs1 | 000 | rd | 1010011 | FMV.W.X |
444 11110 | 00 | xxxxx | rs1 | yyy | rd | 1010011 | rs2? f3? |
445 ------ | ----- | ----- | -----| ----- | ----- | ------- | -------- |
446 11110 | 01 | 00000 | rs1 | 000 | rd | 1010011 | FMV.D.X |
447 11110 | 01 | xxxxx | rs1 | yyy | rd | 1010011 | rs2? f3? |
448 ------ | ----- | ----- | -----| ----- | ----- | ------- | -------- |
449 11110 | 10 | 00000 | rs1 | 000 | rd | 1010011 |**FMV.H.X** |
450 11110 | 10 | xxxxx | rs1 | yyy | rd | 1010011 | rs2? f3? |
451 ------ | ----- | ----- | -----| ----- | ----- | ------- | -------- |
452 11110 | 11 | 00000 | rs1 | 000 | rd | 1010011 | ? |
453 11110 | 11 | xxxxx | rs1 | yyy | rd | 1010011 | rs2? f3? |
456 ## funct5 = 11111 - unused
458 Brownfield encodings available.
460 ## funct5 = ????? (table template)
462 This table acts as a cut/paste template for creating brownfield encodings
465 31..27 | 26..25 | 24..20 |19..15| 14...12| 11..7 | 6....0 | function |
466 funct5 | SDHQ | rs2 | rs1 | funct3 | rd | opcode | name |
467 5 | 2 | 5 | 5 | 3 | 5 | 7 | |
468 ------ | ----- | ----- | -----| ----- | ----- | ------- | -------- |