Re: [Qemu-ppc] [Qemu-devel] [PATCH v5 2/5] target-ppc: add vector extract instructions

[Rajalakshmi Srinivasaraghavan]

On 09/01/2016 09:38 PM, Richard Henderson wrote:
> On 08/31/2016 11:36 PM, Rajalakshmi Srinivasaraghavan wrote:
> > +#if defined(HOST_WORDS_BIGENDIAN)
> > +#define VEXTRACT(suffix, 
> > element)                                            \
> > +    void helper_vextract##suffix(ppc_avr_t *r, ppc_avr_t *b, 
> > uint32_t index) \
> > + { \
> > +        r->u64[0] = r->u64[1] = 
> > 0;                                           \
> > +        memmove(&r->u8[8 - sizeof(r->element)], 
> > &b->u8[index],               \
> > + sizeof(r->element[0])); \
>
> Again, you must consider R == B.  I made this same comment wrt v2, 
> when you still had a memcpy here.
>
> This is trivial:
>
>   (1) Use memmove to set first sizeof(r->element[0]) bytes,
>   (2) Use memset 0 to clean last (16 - sizeof(r->element[0]) bytes.
Ack. So I have to call memset twice to clean initial and last bytes.

#if defined(HOST_WORDS_BIGENDIAN)
#define VEXTRACT(suffix, 
element)                                            \
    void helper_vextract##suffix(ppc_avr_t *r, ppc_avr_t *b, uint32_t 
index) \
{ \
        uint32_t es = 
sizeof(r->element[0]);                                 \
        memmove(&r->u8[8 - es], &b->u8[index], 
es);                          \
        memset(&r->u8[8], 0, 
8);                                             \
        memset(&r->u8[0], 0, 8 - 
es);                                        \
    }
#else
#define VEXTRACT(suffix, 
element)                                            \
    void helper_vextract##suffix(ppc_avr_t *r, ppc_avr_t *b, uint32_t 
index) \
{ \
        uint32_t es = 
sizeof(r->element[0]);                                 \
        uint32_t s = (16 - index) - 
es;                                      \
        memmove(&r->u8[8], &b->u8[s], 
es);                                   \
        memset(&r->u8[0], 0, 
8);                                             \
        memset(&r->u8[8 + es], 0, 8 - 
es);                                   \
    }
#endif

> You have some test cases for these insns, don't you?
>
>
> r~

--
Thanks
Rajalakshmi S