Re: [PATCH v11 17/20] target/riscv: compressed encodings for sspush and sspopchk

[Alistair Francis]

On Thu, Aug 29, 2024 at 3:50 AM Deepak Gupta <debug@rivosinc.com> wrote:
>
> sspush/sspopchk have compressed encodings carved out of zcmops.
> compressed sspush is designated as c.mop.1 while compressed sspopchk
> is designated as c.mop.5.
>
> Note that c.sspush x1 exists while c.sspush x5 doesn't. Similarly
> c.sspopchk x5 exists while c.sspopchk x1 doesn't.
>
> Signed-off-by: Deepak Gupta <debug@rivosinc.com>
> Co-developed-by: Jim Shu <jim.shu@sifive.com>
> Co-developed-by: Andy Chiu <andy.chiu@sifive.com>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  target/riscv/insn16.decode | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/target/riscv/insn16.decode b/target/riscv/insn16.decode
> index 3953bcf82d..bf893d1c2e 100644
> --- a/target/riscv/insn16.decode
> +++ b/target/riscv/insn16.decode
> @@ -140,6 +140,10 @@ sw                110  ... ... .. ... 00 @cs_w
>  addi              000 .  .....  ..... 01 @ci
>  addi              010 .  .....  ..... 01 @c_li
>  {
> +  # c.sspush x1 carving out of zcmops
> +  sspush          011 0  00001  00000 01 &r2_s rs2=1 rs1=0
> +  # c.sspopchk x5 carving out of zcmops
> +  sspopchk        011 0  00101  00000 01 &r2 rs1=5 rd=0
>    c_mop_n         011 0 0 n:3 1 00000 01
>    illegal         011 0  -----  00000 01 # c.addi16sp and c.lui, RES nzimm=0
>    addi            011 .  00010  ..... 01 @c_addi16sp
> --
> 2.44.0
>
>