From: Christoph Muellner <cmuellner@linux.com>

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>
---
 target/riscv/insn32.decode | 1 +
 1 file changed, 1 insertion(+)

diff --git a/target/riscv/insn32.decode b/target/riscv/insn32.decode
index 3788f86528..1aebd37572 100644
--- a/target/riscv/insn32.decode
+++ b/target/riscv/insn32.decode
@@ -134,6 +134,7 @@ addi     ............     ..... 000 ..... 0010011 @i
 slti     ............     ..... 010 ..... 0010011 @i
 sltiu    ............     ..... 011 ..... 0010011 @i
 xori     ............     ..... 100 ..... 0010011 @i
+# cbo.prefetch_{i,r,m} instructions are ori with rd=x0 and not decoded.
 ori      ............     ..... 110 ..... 0010011 @i
 andi     ............     ..... 111 ..... 0010011 @i
 slli     00000. ......    ..... 001 ..... 0010011 @sh
-- 
2.39.1

On 2/15/23 10:59, Daniel Henrique Barboza wrote:
> From: Christoph Muellner<cmuellner@linux.com>
> 
> 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>
> ---
>   target/riscv/insn32.decode | 1 +
>   1 file changed, 1 insertion(+)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~