Re: [RFC PATCH 4/7] target/ppc: Implemented xvf*ger*

[Richard Henderson]

On 4/26/22 05:50, Lucas Mateus Castro(alqotel) wrote:
> +#define VSXGER(NAME, TYPE, EL)                                          \
> +    void NAME(CPUPPCState *env, uint32_t a_r, uint32_t b_r,             \
> +              uint32_t  at_r, uint32_t mask, uint32_t packed_flags)     \
> +    {                                                                   \
> +        ppc_vsr_t *a, *b, *at;                                          \
> +        TYPE aux_acc, va, vb;                                           \
> +        int i, j, xmsk_bit, ymsk_bit, op_flags;                         \
> +        uint8_t xmsk = mask & 0x0F;                                     \
> +        uint8_t ymsk = (mask >> 4) & 0x0F;                              \
> +        int ymax = MIN(4, 128 / (sizeof(TYPE) * 8));                    \
> +        b = cpu_vsr_ptr(env, b_r);                                      \
> +        float_status *excp_ptr = &env->fp_status;                       \
> +        bool acc = ger_acc_flag(packed_flags);                          \
> +        bool neg_acc = ger_neg_acc_flag(packed_flags);                  \
> +        bool neg_mul = ger_neg_mul_flag(packed_flags);                  \
> +        helper_reset_fpstatus(env);                                     \
> +        for (i = 0, xmsk_bit = 1 << 3; i < 4; i++, xmsk_bit >>= 1) {    \
> +            a = cpu_vsr_ptr(env, a_r + i / ymax);                       \
> +            at = cpu_vsr_ptr(env, at_r + i);                            \
> +            for (j = 0, ymsk_bit = 1 << (ymax - 1); j < ymax;           \
> +                 j++, ymsk_bit >>= 1) {                                 \
> +                if ((xmsk_bit & xmsk) && (ymsk_bit & ymsk)) {           \
> +                    op_flags = (neg_acc ^ neg_mul) ?                    \
> +                                          float_muladd_negate_c : 0;    \
> +                    op_flags |= (neg_mul) ?                             \
> +                                     float_muladd_negate_result : 0;    \

There's no need to compute op_flags in the inner loop.
Indeed, probably better to compute it in translation.

This macro is trickier than the integer to turn into a function, however,

> +                    va = a->Vsr##EL(i % ymax);                          \
> +                    vb = b->Vsr##EL(j);                                 \
> +                    aux_acc = at->Vsr##EL(j);                           \
> +                    if (acc) {                                          \
> +                        at->Vsr##EL(j) = TYPE##_muladd(va, vb, aux_acc, \
> +                                                       op_flags,        \
> +                                                       excp_ptr);       \
> +                    } else {                                            \
> +                        at->Vsr##EL(j) = TYPE##_mul(va, vb, excp_ptr);  \
> +                    }                                                   \
> +                } else {                                                \
> +                    at->Vsr##EL(j) = 0;                                 \
> +                }                                                       \

static void vsxger_zero_f(ppc_vsr_t *a, int j)
{
    a->VsrSF(i) = float32_zero;
}

static uint64_t vsxger_mul_f(ppc_vsr_t *d, ppc_vsr_t *a, ppc_vsr_t *b,
                             int i, int j, int flags, float_status *s)
{
    float32 af = a->VsrSF(i);
    float32 bf = b->VsrSF(j);
    d->VsrSF(j) = float32_mul(af, bf, s);
}

static uint64_t vsxger_mac_f(ppc_vsr_t *d, ppc_vsr_t *a, ppc_vsr_t *b,
                             int i, int j, int flags, float_status *s)
{
    float32 af = a->VsrSF(i);
    float32 bf = b->VsrSF(j);
    float32 cf = d->VsrSF(j);
    d->VsrSF(j) = float32_muladd(af, bf, cf, flags, s);
}

is probably a good place to start for callbacks.


r~