Re: [Qemu-devel] [PATCH v3 7/8] target-arm: A64: add support for 3 src data proc insns

[Claudio Fontana]

Hello Peter,

On 13.12.2013 20:18, Peter Maydell wrote:
> From: Alexander Graf <address@hidden>
> 
> This patch adds emulation for the "Data-processing (3 source)"
> family of instructions, namely MADD, MSUB, SMADDL, SMSUBL, SMULH,
> UMADDL, UMSUBL, UMULH.
> 
> Signed-off-by: Alexander Graf <address@hidden>
> Signed-off-by: Alex Bennée <address@hidden>
> Signed-off-by: Peter Maydell <address@hidden>
> ---
>  target-arm/translate-a64.c | 91 
> +++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 89 insertions(+), 2 deletions(-)
> 
> diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c
> index a6f1945..b3e9449 100644
> --- a/target-arm/translate-a64.c
> +++ b/target-arm/translate-a64.c
> @@ -2125,10 +2125,97 @@ static void disas_add_sub_reg(DisasContext *s, 
> uint32_t insn)
>      tcg_temp_free_i64(tcg_result);
>  }
>  
> -/* Data-processing (3 source) */
> +/* C3.5.9 Data-processing (3 source)
> +
> +   31 30  29 28       24 23 21  20  16  15  14  10 9    5 4    0
> +  +--+------+-----------+------+------+----+------+------+------+
> +  |sf| op54 | 1 1 0 1 1 | op31 |  Rm  | o0 |  Ra  |  Rn  |  Rd  |
> +  +--+------+-----------+------+------+----+------+------+------+
> +
> + */
>  static void disas_data_proc_3src(DisasContext *s, uint32_t insn)
>  {
> -    unsupported_encoding(s, insn);
> +    int rd = extract32(insn, 0, 5);
> +    int rn = extract32(insn, 5, 5);
> +    int ra = extract32(insn, 10, 5);
> +    int rm = extract32(insn, 16, 5);
> +    int op_id = (extract32(insn, 29, 3) << 4) |
> +        (extract32(insn, 21, 3) << 1) |
> +        extract32(insn, 15, 1);
> +    bool is_32bit = !extract32(insn, 31, 1);

we have used "sf" everywhere else..

> +    bool is_sub = extract32(op_id, 0, 1);
> +    bool is_high = extract32(op_id, 2, 1);
> +    bool is_signed = false;
> +    TCGv_i64 tcg_op1;
> +    TCGv_i64 tcg_op2;
> +    TCGv_i64 tcg_tmp;
> +
> +    /* Note that op_id is sf:op54:op31:o0 so it includes the 32/64 size flag 
> */
> +    switch (op_id) {
> +    case 0x42: /* SMADDL */
> +    case 0x43: /* SMSUBL */
> +    case 0x44: /* SMULH */
> +        is_signed = true;
> +        break;
> +    case 0x0: /* MADD (32bit) */
> +    case 0x1: /* MSUB (32bit) */
> +    case 0x40: /* MADD (64bit) */
> +    case 0x41: /* MSUB (64bit) */
> +    case 0x4a: /* UMADDL */
> +    case 0x4b: /* UMSUBL */
> +    case 0x4c: /* UMULH */
> +        break;
> +    default:
> +        unallocated_encoding(s);
> +    }
> +
> +    if (is_high) {
> +        TCGv_i64 low_bits = tcg_temp_new_i64(); /* low bits discarded */
> +        TCGv_i64 tcg_rd = cpu_reg(s, rd);
> +        TCGv_i64 tcg_rn = cpu_reg(s, rn);
> +        TCGv_i64 tcg_rm = cpu_reg(s, rm);
> +
> +        if (is_signed) {
> +            tcg_gen_muls2_i64(low_bits, tcg_rd, tcg_rn, tcg_rm);
> +        } else {
> +            tcg_gen_mulu2_i64(low_bits, tcg_rd, tcg_rn, tcg_rm);
> +        }
> +
> +        tcg_temp_free(low_bits);

should this be tcg_temp_free_i64()?

> +        return;
> +    }
> +
> +    tcg_op1 = tcg_temp_new_i64();
> +    tcg_op2 = tcg_temp_new_i64();
> +    tcg_tmp = tcg_temp_new_i64();
> +
> +    if (op_id < 0x42) {
> +        tcg_gen_mov_i64(tcg_op1, cpu_reg(s, rn));
> +        tcg_gen_mov_i64(tcg_op2, cpu_reg(s, rm));
> +    } else {
> +        if (is_signed) {
> +            tcg_gen_ext32s_i64(tcg_op1, cpu_reg(s, rn));
> +            tcg_gen_ext32s_i64(tcg_op2, cpu_reg(s, rm));
> +        } else {
> +            tcg_gen_ext32u_i64(tcg_op1, cpu_reg(s, rn));
> +            tcg_gen_ext32u_i64(tcg_op2, cpu_reg(s, rm));
> +        }
> +    }
> +
> +    tcg_gen_mul_i64(tcg_tmp, tcg_op1, tcg_op2);
> +    if (is_sub) {
> +        tcg_gen_sub_i64(cpu_reg(s, rd), cpu_reg(s, ra), tcg_tmp);
> +    } else {
> +        tcg_gen_add_i64(cpu_reg(s, rd), cpu_reg(s, ra), tcg_tmp);
> +    }
> +
> +    if (is_32bit) {
> +        tcg_gen_ext32u_i64(cpu_reg(s, rd), cpu_reg(s, rd));
> +    }
> +
> +    tcg_temp_free_i64(tcg_op1);
> +    tcg_temp_free_i64(tcg_op2);
> +    tcg_temp_free_i64(tcg_tmp);
>  }
>  
>  /* Add/subtract (with carry) */
> 

Ciao,

Claudio