target/riscv: add Zicbop cbo.prefetch{i, r, m} placeholder

The cmo.prefetch instructions are nops for QEMU (no emulation of the
memory hierarchy, no illegal instructions, no permission faults, no
traps).

Add a comment noting where they would be decoded in case cbo.prefetch
instructions become relevant in the future.

Co-developed-by: Philipp Tomsich <philipp.tomsich@vrull.eu>
Signed-off-by: Christoph Muellner <cmuellner@linux.com>
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Message-ID: <20230224132536.552293-5-dbarboza@ventanamicro.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Christoph Muellner 2023-02-24 10:25:36 -03:00 committed by Palmer Dabbelt
parent e05da09b7c
commit 59cb29d6a5
No known key found for this signature in database
GPG Key ID: 2E1319F35FBB1889

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@ -134,6 +134,7 @@ addi ............ ..... 000 ..... 0010011 @i
slti ............ ..... 010 ..... 0010011 @i slti ............ ..... 010 ..... 0010011 @i
sltiu ............ ..... 011 ..... 0010011 @i sltiu ............ ..... 011 ..... 0010011 @i
xori ............ ..... 100 ..... 0010011 @i xori ............ ..... 100 ..... 0010011 @i
# cbo.prefetch_{i,r,m} instructions are ori with rd=x0 and not decoded.
ori ............ ..... 110 ..... 0010011 @i ori ............ ..... 110 ..... 0010011 @i
andi ............ ..... 111 ..... 0010011 @i andi ............ ..... 111 ..... 0010011 @i
slli 00000. ...... ..... 001 ..... 0010011 @sh slli 00000. ...... ..... 001 ..... 0010011 @sh