Re: [PATCH 05/11] tcg/riscv: Use ADD.UW for guest address generation

[Alistair Francis]

On Wed, May 3, 2023 at 6:58 PM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> The instruction is a combined zero-extend and add.
> Use it for exactly that.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

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

Alistair

> ---
>  tcg/riscv/tcg-target.c.inc | 33 ++++++++++++++++++++++-----------
>  1 file changed, 22 insertions(+), 11 deletions(-)
>
> diff --git a/tcg/riscv/tcg-target.c.inc b/tcg/riscv/tcg-target.c.inc
> index 53a7f97b29..f64eaa8515 100644
> --- a/tcg/riscv/tcg-target.c.inc
> +++ b/tcg/riscv/tcg-target.c.inc
> @@ -1039,14 +1039,18 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext 
> *s, TCGReg *pbase,
>      tcg_out_opc_branch(s, OPC_BNE, TCG_REG_TMP0, TCG_REG_TMP1, 0);
>
>      /* TLB Hit - translate address using addend.  */
> -    addr_adj = addr_reg;
> -    if (TARGET_LONG_BITS == 32) {
> -        addr_adj = TCG_REG_TMP0;
> -        tcg_out_ext32u(s, addr_adj, addr_reg);
> +    if (TARGET_LONG_BITS == 64) {
> +        tcg_out_opc_reg(s, OPC_ADD, TCG_REG_TMP0, addr_reg, TCG_REG_TMP2);
> +    } else if (have_zba) {
> +        tcg_out_opc_reg(s, OPC_ADD_UW, TCG_REG_TMP0, addr_reg, TCG_REG_TMP2);
> +    } else {
> +        tcg_out_ext32u(s, TCG_REG_TMP0, addr_reg);
> +        tcg_out_opc_reg(s, OPC_ADD, TCG_REG_TMP0, TCG_REG_TMP0, 
> TCG_REG_TMP2);
>      }
> -    tcg_out_opc_reg(s, OPC_ADD, TCG_REG_TMP0, TCG_REG_TMP2, addr_adj);
>      *pbase = TCG_REG_TMP0;
>  #else
> +    TCGReg base;
> +
>      if (a_mask) {
>          ldst = new_ldst_label(s);
>          ldst->is_ld = is_ld;
> @@ -1061,14 +1065,21 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext 
> *s, TCGReg *pbase,
>          tcg_out_opc_branch(s, OPC_BNE, TCG_REG_TMP1, TCG_REG_ZERO, 0);
>      }
>
> -    TCGReg base = addr_reg;
> -    if (TARGET_LONG_BITS == 32) {
> -        tcg_out_ext32u(s, TCG_REG_TMP0, base);
> -        base = TCG_REG_TMP0;
> -    }
>      if (guest_base != 0) {
> -        tcg_out_opc_reg(s, OPC_ADD, TCG_REG_TMP0, TCG_GUEST_BASE_REG, base);
>          base = TCG_REG_TMP0;
> +        if (TARGET_LONG_BITS == 64) {
> +            tcg_out_opc_reg(s, OPC_ADD, base, addr_reg, TCG_GUEST_BASE_REG);
> +        } else if (have_zba) {
> +            tcg_out_opc_reg(s, OPC_ADD_UW, base, addr_reg, 
> TCG_GUEST_BASE_REG);
> +        } else {
> +            tcg_out_ext32u(s, base, addr_reg);
> +            tcg_out_opc_reg(s, OPC_ADD, base, base, TCG_GUEST_BASE_REG);
> +        }
> +    } else if (TARGET_LONG_BITS == 64) {
> +        base = addr_reg;
> +    } else {
> +        base = TCG_REG_TMP0;
> +        tcg_out_ext32u(s, base, addr_reg);
>      }
>      *pbase = base;
>  #endif
> --
> 2.34.1
>
>