Re: [PATCH v2 09/22] target/loongarch: Add fixed point bit instruction translation

[Philippe Mathieu-Daudé]

On 7/21/21 11:53 AM, Song Gao wrote:
> This patch implement fixed point bit instruction translation.
> 
> This includes:
> - EXT.W.{B/H}
> - CL{O/Z}.{W/D}, CT{O/Z}.{W/D}
> - BYTEPICK.{W/D}
> - REVB.{2H/4H/2W/D}
> - REVH.{2W/D}
> - BITREV.{4B/8B}, BITREV.{W/D}
> - BSTRINS.{W/D}, BSTRPICK.{W/D}
> - MASKEQZ, MASKNEZ
> 
> Signed-off-by: Song Gao <gaosong@loongson.cn>
> ---
>  target/loongarch/helper.h     |  10 +
>  target/loongarch/insns.decode |  45 +++
>  target/loongarch/op_helper.c  | 119 ++++++++
>  target/loongarch/trans.inc.c  | 665 
> ++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 839 insertions(+)

> diff --git a/target/loongarch/op_helper.c b/target/loongarch/op_helper.c
> index b2cbdd7..07c3d52 100644
> --- a/target/loongarch/op_helper.c
> +++ b/target/loongarch/op_helper.c
> @@ -25,3 +25,122 @@ void helper_raise_exception(CPULoongArchState *env, 
> uint32_t exception)
>  {
>      do_raise_exception(env, exception, GETPC());
>  }
> +
> +target_ulong helper_cto_w(CPULoongArchState *env, target_ulong rj)
> +{
> +    uint32_t v = (uint32_t)rj;
> +    int temp = 0;
> +
> +    while ((v & 0x1) == 1) {
> +        temp++;
> +        v = v >> 1;
> +    }

Why not use cto32() from "qemu/host-utils.h"

> +
> +    return (target_ulong)temp;
> +}
> +
> +target_ulong helper_ctz_w(CPULoongArchState *env, target_ulong rj)
> +{
> +    uint32_t v = (uint32_t)rj;
> +
> +    if (v == 0) {
> +        return 32;
> +    }
> +
> +    int temp = 0;
> +    while ((v & 0x1) == 0) {
> +        temp++;
> +        v = v >> 1;
> +    }

ctz32

> +
> +    return (target_ulong)temp;
> +}
> +
> +target_ulong helper_cto_d(CPULoongArchState *env, target_ulong rj)
> +{
> +    uint64_t v = rj;
> +    int temp = 0;
> +
> +    while ((v & 0x1) == 1) {
> +        temp++;
> +        v = v >> 1;
> +    }

cto64

> +
> +    return (target_ulong)temp;
> +}
> +
> +target_ulong helper_ctz_d(CPULoongArchState *env, target_ulong rj)
> +{
> +    uint64_t v = rj;
> +
> +    if (v == 0) {
> +        return 64;
> +    }
> +
> +    int temp = 0;
> +    while ((v & 0x1) == 0) {
> +        temp++;
> +        v = v >> 1;
> +    }

and ctz64?

> +
> +    return (target_ulong)temp;
> +}
> +
> +target_ulong helper_bitrev_w(CPULoongArchState *env, target_ulong rj)
> +{
> +    int32_t v = (int32_t)rj;
> +    const int SIZE = 32;
> +    uint8_t bytes[SIZE];
> +
> +    int i;
> +    for (i = 0; i < SIZE; i++) {
> +        bytes[i] = v & 0x1;
> +        v = v >> 1;
> +    }
> +    /* v == 0 */
> +    for (i = 0; i < SIZE; i++) {
> +        v = v | ((uint32_t)bytes[i] << (SIZE - 1 - i));
> +    }
> +
> +    return (target_ulong)(int32_t)v;
> +}
> +
> +target_ulong helper_bitrev_d(CPULoongArchState *env, target_ulong rj)
> +{
> +    uint64_t v = rj;
> +    const int SIZE = 64;
> +    uint8_t bytes[SIZE];
> +
> +    int i;
> +    for (i = 0; i < SIZE; i++) {
> +        bytes[i] = v & 0x1;
> +        v = v >> 1;
> +    }
> +    /* v == 0 */
> +    for (i = 0; i < SIZE; i++) {
> +        v = v | ((uint64_t)bytes[i] << (SIZE - 1 - i));
> +    }
> +
> +    return (target_ulong)v;
> +}
> +
> +static inline target_ulong bitswap(target_ulong v)
> +{
> +    v = ((v >> 1) & (target_ulong)0x5555555555555555ULL) |
> +        ((v & (target_ulong)0x5555555555555555ULL) << 1);
> +    v = ((v >> 2) & (target_ulong)0x3333333333333333ULL) |
> +        ((v & (target_ulong)0x3333333333333333ULL) << 2);
> +    v = ((v >> 4) & (target_ulong)0x0F0F0F0F0F0F0F0FULL) |
> +        ((v & (target_ulong)0x0F0F0F0F0F0F0F0FULL) << 4);
> +    return v;

Is this revbit64?

> +}
> +
> +target_ulong helper_loongarch_dbitswap(target_ulong rj)
> +{
> +    return bitswap(rj);
> +}
> +
> +target_ulong helper_loongarch_bitswap(target_ulong rt)
> +{
> +    return (int32_t)bitswap(rt);
> +}