Re: [Qemu-devel] [PATCH v2 12/33] target/mips: Implement emulation of nanoMIPS ROTX instruction

[Aleksandar Markovic]

> Subject: [PATCH v2 12/33] target/mips: Implement emulation of nanoMIPS ROTX 
> instruction
>
> From: Matthew Fortune <address@hidden>
>
> Added a helper for ROTX based on the pseudocode from the
> architecture spec. This instraction was not present in previous

instraction -> instruction

(this was my fault, since I wrote this commit message for v2)

> MIPS instruction sets.
>
> Signed-off-by: Yongbok Kim <address@hidden>
> Signed-off-by: Aleksandar Markovic <address@hidden>
> Signed-off-by: Stefan Markovic <address@hidden>
> ---
>  target/mips/helper.h    |  2 ++
>  target/mips/op_helper.c | 94 
> +++++++++++++++++++++++++++++++++++++++++++++++++
>  target/mips/translate.c | 15 ++++++++
>  3 files changed, 111 insertions(+)
>

Reviewed-by: Aleksandar Markovic <address@hidden>

... with a hint that, in future, an inline implementation should be considered.

> diff --git a/target/mips/helper.h b/target/mips/helper.h
> index 5f49234..b2a780a 100644
> --- a/target/mips/helper.h
> +++ b/target/mips/helper.h
> @@ -40,6 +40,8 @@ DEF_HELPER_FLAGS_1(bitswap, TCG_CALL_NO_RWG_SE, tl, tl)
>  DEF_HELPER_FLAGS_1(dbitswap, TCG_CALL_NO_RWG_SE, tl, tl)
>  #endif
>
> +DEF_HELPER_FLAGS_4(rotx, TCG_CALL_NO_RWG_SE, tl, tl, i32, i32, i32)
> +
>  #ifndef CONFIG_USER_ONLY
>  /* CP0 helpers */
>  DEF_HELPER_1(mfc0_mvpcontrol, tl, env)
> diff --git a/target/mips/op_helper.c b/target/mips/op_helper.c
> index 0b2663b..b3eef9f 100644
> --- a/target/mips/op_helper.c
> +++ b/target/mips/op_helper.c
> @@ -249,6 +249,100 @@ target_ulong helper_bitswap(target_ulong rt)
>      return (int32_t)bitswap(rt);
>  }
>
> +target_ulong helper_rotx(target_ulong rs, uint32_t shift, uint32_t shiftx,
> +                        uint32_t stripe)
> +{
> +    int i;
> +    uint64_t tmp0 = ((uint64_t)rs) << 32 | ((uint64_t)rs & 0xffffffff);
> +    uint64_t tmp1 = tmp0;
> +    for (i = 0; i <= 46; i++) {
> +        int s;
> +        if (i & 0x8) {
> +            s = shift;
> +        } else {
> +            s = shiftx;
> +        }
> +
> +        if (stripe != 0 && !(i & 0x4)) {
> +            s = ~s;
> +        }
> +        if (s & 0x10) {
> +            if (tmp0 & (1LL << (i + 16))) {
> +                tmp1 |= 1LL << i;
> +            } else {
> +                tmp1 &= ~(1LL << i);
> +            }
> +        }
> +    }
> +
> +    uint64_t tmp2 = tmp1;
> +    for (i = 0; i <= 38; i++) {
> +        int s;
> +        if (i & 0x4) {
> +            s = shift;
> +        } else {
> +            s = shiftx;
> +        }
> +
> +        if (s & 0x8) {
> +            if (tmp1 & (1LL << (i + 8))) {
> +                tmp2 |= 1LL << i;
> +            } else {
> +                tmp2 &= ~(1LL << i);
> +            }
> +        }
> +    }
> +
> +    uint64_t tmp3 = tmp2;
> +    for (i = 0; i <= 34; i++) {
> +        int s;
> +        if (i & 0x2) {
> +            s = shift;
> +        } else {
> +            s = shiftx;
> +        }
> +        if (s & 0x4) {
> +            if (tmp2 & (1LL << (i + 4))) {
> +                tmp3 |= 1LL << i;
> +            } else {
> +                tmp3 &= ~(1LL << i);
> +            }
> +        }
> +    }
> +
> +    uint64_t tmp4 = tmp3;
> +    for (i = 0; i <= 32; i++) {
> +        int s;
> +        if (i & 0x1) {
> +            s = shift;
> +        } else {
> +            s = shiftx;
> +        }
> +        if (s & 0x2) {
> +            if (tmp3 & (1LL << (i + 2))) {
> +                tmp4 |= 1LL << i;
> +            } else {
> +                tmp4 &= ~(1LL << i);
> +            }
> +        }
> +    }
> +
> +    uint64_t tmp5 = tmp4;
> +    for (i = 0; i <= 31; i++) {
> +        int s;
> +        s = shift;
> +        if (s & 0x1) {
> +            if (tmp4 & (1LL << (i + 1))) {
> +                tmp5 |= 1LL << i;
> +            } else {
> +                tmp5 &= ~(1LL << i);
> +            }
> +        }
> +    }
> +
> +    return (int64_t)(int32_t)(uint32_t)tmp5;
> +}
> +
>  #ifndef CONFIG_USER_ONLY
>
>  static inline hwaddr do_translate_address(CPUMIPSState *env,
> diff --git a/target/mips/translate.c b/target/mips/translate.c
> index 0a37f5a..944b40b 100644
> --- a/target/mips/translate.c
> +++ b/target/mips/translate.c
> @@ -17437,6 +17437,21 @@ static int decode_nanomips_32_48_opc(CPUMIPSState 
> *env, > DisasContext *ctx)
>          }
>              break;
>          case NM_P_ROTX:
> +            if (rt != 0) {
> +                TCGv t0 = tcg_temp_new();
> +                TCGv_i32 shift = tcg_const_i32(extract32(ctx->opcode, 0, 5));
> +                TCGv_i32 shiftx = tcg_const_i32(extract32(ctx->opcode, 7, 4)
> +                                                << 1);
> +                TCGv_i32 stripe = tcg_const_i32((ctx->opcode >> 6) & 1);
> +
> +                gen_load_gpr(t0, rs);
> +                gen_helper_rotx(cpu_gpr[rt], t0, shift, shiftx, stripe);
> +                tcg_temp_free(t0);
> +
> +                tcg_temp_free_i32(shift);
> +                tcg_temp_free_i32(shiftx);
> +                tcg_temp_free_i32(stripe);
> +            }
>              break;
>          case NM_P_INS:
>              switch (((ctx->opcode >> 10) & 2) | ((ctx->opcode >> 5) & 1)) {
> --
> 2.7.4
>
>