[v5,10/14] target/mips: Add emulation of MXU instruction S8LDD

From: Craig Janeczek <jancraig@amazon.com>

Add support for emulating the S8LDD MXU instruction.

Signed-off-by: Craig Janeczek <jancraig@amazon.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
---
 target/mips/translate.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 87 insertions(+), 3 deletions(-)

> From: Aleksandar Markovic <aleksandar.markovic@rt-rk.com>
> Sent: Friday, October 19, 2018 6:33 PM
> Subject: [PATCH v5 10/14] target/mips: Add emulation of MXU instruction S8LDD
> 
> From: Craig Janeczek <jancraig@amazon.com>
> 
> Add support for emulating the S8LDD MXU instruction.
> 
> Signed-off-by: Craig Janeczek <jancraig@amazon.com>
> Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
> ---
>  target/mips/translate.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 87 insertions(+), 3 deletions(-)
> 
> diff --git a/target/mips/translate.c b/target/mips/translate.c
> index c2b3463..71a6533 100644
> --- a/target/mips/translate.c
> +++ b/target/mips/translate.c
> @@ -23410,6 +23410,92 @@ static void gen_mxu_s32m2i(DisasContext *ctx)
>      tcg_temp_free(t0);
>  }
> 
> +/*
> + * S8LDD XRa, Rb, s8, optn3 - Load a byte from memory to XRF
> + */
> +static void gen_mxu_s8ldd(DisasContext *ctx)
> +{
> +    TCGv t0, t1;
> +    TCGLabel *l0;
> +    uint32_t XRa, Rb, s8, optn3;
> +
> +    t0 = tcg_temp_new();
> +    t1 = tcg_temp_new();
> +
> +    l0 = gen_new_label();
> +
> +    XRa = extract32(ctx->opcode, 6, 4);
> +    s8 = extract32(ctx->opcode, 10, 8);
> +    optn3 = extract32(ctx->opcode, 18, 3);
> +    Rb = extract32(ctx->opcode, 21, 5);
> +
> +    gen_load_mxu_cr(t0);
> +    tcg_gen_andi_tl(t0, t0, MXU_CR_MXU_EN);
> +    tcg_gen_brcondi_tl(TCG_COND_NE, t0, MXU_CR_MXU_EN, l0);
> +

Is there any way to move MXU_CR_MXU_EN check to the one level higher function, to avoid repetition?

I think all MXU instructions need this check, except S32I2M, S32M2I, and non-MXU MUL.

Thanks,
Aleksandar

> +    gen_load_gpr(t0, Rb);
> +    tcg_gen_addi_tl(t0, t0, (int8_t)s8);
> +
> +    switch (optn3) {
> +    /* XRa[7:0] = tmp8 */
> +    case MXU_OPTN3_PTN0:
> +        tcg_gen_qemu_ld_tl(t1, t0, ctx->mem_idx, MO_UB);
> +        gen_load_mxu_gpr(t0, XRa);
> +        tcg_gen_deposit_tl(t0, t0, t1, 0, 8);
> +        break;
> +    /* XRa[15:8] = tmp8 */
> +    case MXU_OPTN3_PTN1:
> +        tcg_gen_qemu_ld_tl(t1, t0, ctx->mem_idx, MO_UB);
> +        gen_load_mxu_gpr(t0, XRa);
> +        tcg_gen_deposit_tl(t0, t0, t1, 8, 8);
> +        break;
> +    /* XRa[23:16] = tmp8 */
> +    case MXU_OPTN3_PTN2:
> +        tcg_gen_qemu_ld_tl(t1, t0, ctx->mem_idx, MO_UB);
> +        gen_load_mxu_gpr(t0, XRa);
> +        tcg_gen_deposit_tl(t0, t0, t1, 16, 8);
> +        break;
> +    /* XRa[31:24] = tmp8 */
> +    case MXU_OPTN3_PTN3:
> +        tcg_gen_qemu_ld_tl(t1, t0, ctx->mem_idx, MO_UB);
> +        gen_load_mxu_gpr(t0, XRa);
> +        tcg_gen_deposit_tl(t0, t0, t1, 24, 8);
> +        break;
> +    /* XRa = {8'b0, tmp8, 8'b0, tmp8} */
> +    case MXU_OPTN3_PTN4:
> +        tcg_gen_qemu_ld_tl(t1, t0, ctx->mem_idx, MO_UB);
> +        tcg_gen_deposit_tl(t0, t1, t1, 16, 16);
> +        break;
> +    /* XRa = {tmp8, 8'b0, tmp8, 8'b0} */
> +    case MXU_OPTN3_PTN5:
> +        tcg_gen_qemu_ld_tl(t1, t0, ctx->mem_idx, MO_UB);
> +        tcg_gen_shli_tl(t1, t1, 8);
> +        tcg_gen_deposit_tl(t0, t1, t1, 16, 16);
> +        break;
> +    /* XRa = {{8{sign of tmp8}}, tmp8, {8{sign of tmp8}}, tmp8} */
> +    case MXU_OPTN3_PTN6:
> +        tcg_gen_qemu_ld_tl(t1, t0, ctx->mem_idx, MO_SB);
> +        tcg_gen_mov_tl(t0, t1);
> +        tcg_gen_andi_tl(t0, t0, 0xFF00FFFF);
> +        tcg_gen_shli_tl(t1, t1, 16);
> +        tcg_gen_or_tl(t0, t0, t1);
> +        break;
> +    /* XRa = {tmp8, tmp8, tmp8, tmp8} */
> +    case MXU_OPTN3_PTN7:
> +        tcg_gen_qemu_ld_tl(t1, t0, ctx->mem_idx, MO_UB);
> +        tcg_gen_deposit_tl(t1, t1, t1, 8, 8);
> +        tcg_gen_deposit_tl(t0, t1, t1, 16, 16);
> +        break;
> +    }
> +
> +    gen_store_mxu_gpr(t0, XRa);
> +
> +    gen_set_label(l0);
> +
> +    tcg_temp_free(t0);
> +    tcg_temp_free(t1);
> +}
> +
> 
>  /*
>   * Decoding engine for MXU
> @@ -24469,9 +24555,7 @@ static void decode_opc_mxu(CPUMIPSState *env, DisasContext *ctx)
>          generate_exception_end(ctx, EXCP_RI);
>          break;
>      case OPC_MXU_S8LDD:
> -        /* TODO: Implement emulation of S8LDD instruction. */
> -        MIPS_INVAL("OPC_MXU_S8LDD");
> -        generate_exception_end(ctx, EXCP_RI);
> +        gen_mxu_s8ldd(ctx);
>          break;
>      case OPC_MXU_S8STD:
>          /* TODO: Implement emulation of S8STD instruction. */
> --
> 2.7.4
>