Re: [Qemu-arm] [PATCH 28/42] target/arm: Convert VMOV (imm) to decodetree

[Richard Henderson]

On 6/6/19 12:45 PM, Peter Maydell wrote:
> +    n = (a->imm4h << 28) & 0x80000000;
> +    i = ((a->imm4h << 4) & 0x70) | a->imm4l;
> +    if (i & 0x40) {
> +        i |= 0x780;
> +    } else {
> +        i |= 0x800;
> +    }
> +    n |= i << 19;

Can we reuse vfp_expand_imm here?  Given that you don't have pure code motion
from the old code (due to field extraction) it doesn't feel wrong to go ahead
and fix this wart now.


> +VMOV_imm_sp  ---- 1110 1.11 imm4h:4 .... 1010 0000 imm4l:4 \
> +             vd=%vd_sp

We should concatenate imm4h and imm4l here, so that trans_VMOV_imm_* only needs
to do "n = vfp_expand_imm(MO_32, a->imm);".

(We can't use !function to expand the whole float constant because the
decodetree fields are "int", and we'd need to store a "uint64_t" for dp.  C.f.
the SVE trans_FDUP.)


r~