target/riscv: Add rev8 instruction, removing grev/grevi
The 1.0.0 version of Zbb does not contain grev/grevi. Instead, a
rev8 instruction (equivalent to the rev8 pseudo-instruction built on
grevi from pre-0.93 draft-B) is available.
This commit adds the new rev8 instruction and removes grev/grevi.
Note that there is no W-form of this instruction (both a
sign-extending and zero-extending 32-bit version can easily be
synthesized by following rev8 with either a srai or srli instruction
on RV64) and that the opcode encodings for rev8 in RV32 and RV64 are
different.
Signed-off-by: Philipp Tomsich <philipp.tomsich@vrull.eu>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20210911140016.834071-14-philipp.tomsich@vrull.eu
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
diff --git a/target/riscv/insn32.decode b/target/riscv/insn32.decode
index 5920219..901a66c 100644
--- a/target/riscv/insn32.decode
+++ b/target/riscv/insn32.decode
@@ -683,6 +683,9 @@
minu 0000101 .......... 101 ..... 0110011 @r
orc_b 001010 000111 ..... 101 ..... 0010011 @r2
orn 0100000 .......... 110 ..... 0110011 @r
+# The encoding for rev8 differs between RV32 and RV64.
+# rev8_32 denotes the RV32 variant.
+rev8_32 011010 011000 ..... 101 ..... 0010011 @r2
rol 0110000 .......... 001 ..... 0110011 @r
ror 0110000 .......... 101 ..... 0110011 @r
rori 01100 ............ 101 ..... 0010011 @sh
@@ -694,6 +697,10 @@
clzw 0110000 00000 ..... 001 ..... 0011011 @r2
ctzw 0110000 00001 ..... 001 ..... 0011011 @r2
cpopw 0110000 00010 ..... 001 ..... 0011011 @r2
+# The encoding for rev8 differs between RV32 and RV64.
+# When executing on RV64, the encoding used in RV32 is an illegal
+# instruction, so we use different handler functions to differentiate.
+rev8_64 011010 111000 ..... 101 ..... 0010011 @r2
rolw 0110000 .......... 001 ..... 0111011 @r
roriw 0110000 .......... 101 ..... 0011011 @sh5
rorw 0110000 .......... 101 ..... 0111011 @r
@@ -702,15 +709,10 @@
pack 0000100 .......... 100 ..... 0110011 @r
packu 0100100 .......... 100 ..... 0110011 @r
packh 0000100 .......... 111 ..... 0110011 @r
-grev 0110100 .......... 101 ..... 0110011 @r
-grevi 01101. ........... 101 ..... 0010011 @sh
# *** RV64B Standard Extension (in addition to RV32B) ***
packw 0000100 .......... 100 ..... 0111011 @r
packuw 0100100 .......... 100 ..... 0111011 @r
-grevw 0110100 .......... 101 ..... 0111011 @r
-
-greviw 0110100 .......... 101 ..... 0011011 @sh5
# *** RV32 Zbc Standard Extension ***
clmul 0000101 .......... 001 ..... 0110011 @r
