Re: [Qemu-devel] [PATCH v3 64/69] target/arm: Convert T16, shift immediate

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 8/28/19 9:04 PM, Richard Henderson wrote:
> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> ---
>  target/arm/translate.c | 26 ++------------------------
>  target/arm/t16.decode  |  8 ++++++++
>  2 files changed, 10 insertions(+), 24 deletions(-)
> 
> diff --git a/target/arm/translate.c b/target/arm/translate.c
> index 5fb0e2066b..dd292b3042 100644
> --- a/target/arm/translate.c
> +++ b/target/arm/translate.c
> @@ -10731,7 +10731,7 @@ static void disas_thumb2_insn(DisasContext *s, uint32_t insn)
>  
>  static void disas_thumb_insn(DisasContext *s, uint32_t insn)
>  {
> -    uint32_t val, op, rm, rd, shift;
> +    uint32_t val, rd;
>      int32_t offset;
>      TCGv_i32 tmp;
>      TCGv_i32 tmp2;
> @@ -10743,29 +10743,7 @@ static void disas_thumb_insn(DisasContext *s, uint32_t insn)
>      /* fall back to legacy decoder */
>  
>      switch (insn >> 12) {
> -    case 0: case 1:
> -
> -        rd = insn & 7;
> -        op = (insn >> 11) & 3;
> -        if (op == 3) {
> -            /*
> -             * 0b0001_1xxx_xxxx_xxxx
> -             *  - Add, subtract (three low registers)
> -             *  - Add, subtract (two low registers and immediate)
> -             * In decodetree.
> -             */
> -            goto illegal_op;
> -        } else {
> -            /* shift immediate */
> -            rm = (insn >> 3) & 7;
> -            shift = (insn >> 6) & 0x1f;
> -            tmp = load_reg(s, rm);
> -            gen_arm_shift_im(tmp, op, shift, s->condexec_mask == 0);
> -            if (!s->condexec_mask)
> -                gen_logic_CC(tmp);
> -            store_reg(s, rd, tmp);
> -        }
> -        break;
> +    case 0: case 1: /* add/sub (3reg, 2reg imm), shift imm; in decodetree */
>      case 2: case 3: /* add, sub, cmp, mov (reg, imm), in decodetree */
>          goto illegal_op;
>      case 4:
> diff --git a/target/arm/t16.decode b/target/arm/t16.decode
> index f128110dee..79a1d66d6c 100644
> --- a/target/arm/t16.decode
> +++ b/target/arm/t16.decode
> @@ -126,6 +126,14 @@ ADD_rri         10101 rd:3 ........ \
>  STM             11000 ... ........              @ldstm
>  LDM_t16         11001 ... ........              @ldstm
>  
> +# Shift (immediate)
> +
> +@shift_i        ..... shim:5 rm:3 rd:3          &s_rrr_shi %s rn=%reg_0
> +
> +MOV_rxri        000 00 ..... ... ...            @shift_i shty=0  # LSL
> +MOV_rxri        000 01 ..... ... ...            @shift_i shty=1  # LSR
> +MOV_rxri        000 10 ..... ... ...            @shift_i shty=2  # ASR
> +
>  # Add/subtract (three low registers)
>  
>  @addsub_3       ....... rm:3 rn:3 rd:3 \
>