Re: [Qemu-devel] [PATCH 23/40] Add vspltis{b,h,w} instructions.

[Aurelien Jarno]

On Wed, Jan 07, 2009 at 01:25:32PM -0800, Nathan Froyd wrote:
> On Sat, Jan 03, 2009 at 10:43:54PM +0100, Aurelien Jarno wrote:
> > On Tue, Dec 30, 2008 at 07:10:05PM -0800, Nathan Froyd wrote:
> > > +#define VSPLTI(suffix, element, splat_type)                     \
> > > +    void helper_vspltis##suffix (ppc_avr_t *r, uint32_t splat)  \
> > > +    {                                                           \
> > > +        splat_type x = (splat_type)splat;                       \
> > > +        int i;                                                  \
> > > +        /* 5-bit sign extension.  */                            \
> > > +        if (x & 0x10)                                           \
> > > +            x -= 0x20;                                          \
> > 
> > I don't really like this way of doing a sign extension. I would prefer
> > to avoid a test and do something like:
> > splat_type x = (int8_t)(splat << 3) >> 3;
> 
> Done thusly.

Thanks, applied.

> -Nathan
> 
> Use more obvious sequence for 5-bit sign extension.
> 
> Signed-off-by: Nathan Froyd <address@hidden>
> ---
>  target-ppc/helper.h    |    3 +++
>  target-ppc/op_helper.c |   14 ++++++++++++++
>  target-ppc/translate.c |   20 ++++++++++++++++++++
>  3 files changed, 37 insertions(+), 0 deletions(-)
> 
> diff --git a/target-ppc/helper.h b/target-ppc/helper.h
> index e15d6b0..755bfba 100644
> --- a/target-ppc/helper.h
> +++ b/target-ppc/helper.h
> @@ -188,6 +188,9 @@ DEF_HELPER_3(vrlw, void, avr, avr, avr)
>  DEF_HELPER_3(vsl, void, avr, avr, avr)
>  DEF_HELPER_3(vsr, void, avr, avr, avr)
>  DEF_HELPER_4(vsldoi, void, avr, avr, avr, i32)
> +DEF_HELPER_2(vspltisb, void, avr, i32)
> +DEF_HELPER_2(vspltish, void, avr, i32)
> +DEF_HELPER_2(vspltisw, void, avr, i32)
>  DEF_HELPER_3(vspltb, void, avr, avr, i32)
>  DEF_HELPER_3(vsplth, void, avr, avr, i32)
>  DEF_HELPER_3(vspltw, void, avr, avr, i32)
> diff --git a/target-ppc/op_helper.c b/target-ppc/op_helper.c
> index 81abd63..dc8ddfe 100644
> --- a/target-ppc/op_helper.c
> +++ b/target-ppc/op_helper.c
> @@ -2609,6 +2609,20 @@ VSPLT(w, u32)
>  #undef SPLAT_ELEMENT
>  #undef _SPLAT_MASKED
>  
> +#define VSPLTI(suffix, element, splat_type)                     \
> +    void helper_vspltis##suffix (ppc_avr_t *r, uint32_t splat)  \
> +    {                                                           \
> +        splat_type x = (int8_t)(splat << 3) >> 3;               \
> +        int i;                                                  \
> +        for (i = 0; i < ARRAY_SIZE(r->element); i++) {          \
> +            r->element[i] = x;                                  \
> +        }                                                       \
> +    }
> +VSPLTI(b, s8, int8_t)
> +VSPLTI(h, s16, int16_t)
> +VSPLTI(w, s32, int32_t)
> +#undef VSPLTI
> +
>  #define VSR(suffix, element)                                            \
>      void helper_vsr##suffix (ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b)  \
>      {                                                                   \
> diff --git a/target-ppc/translate.c b/target-ppc/translate.c
> index 65a80f2..6bb81d2 100644
> --- a/target-ppc/translate.c
> +++ b/target-ppc/translate.c
> @@ -6404,6 +6404,26 @@ GEN_VXRFORM(vcmpgtub, 3, 8)
>  GEN_VXRFORM(vcmpgtuh, 3, 9)
>  GEN_VXRFORM(vcmpgtuw, 3, 10)
>  
> +#define GEN_VXFORM_SIMM(name, opc2, opc3)                               \
> +    GEN_HANDLER(name, 0x04, opc2, opc3, 0x00000000, PPC_ALTIVEC)        \
> +    {                                                                   \
> +        TCGv_ptr rd;                                                    \
> +        TCGv_i32 simm;                                                  \
> +        if (unlikely(!ctx->altivec_enabled)) {                          \
> +            gen_exception(ctx, POWERPC_EXCP_VPU);                       \
> +            return;                                                     \
> +        }                                                               \
> +        simm = tcg_const_i32(SIMM5(ctx->opcode));                       \
> +        rd = gen_avr_ptr(rD(ctx->opcode));                              \
> +        gen_helper_##name (rd, simm);                                   \
> +        tcg_temp_free_i32(simm);                                        \
> +        tcg_temp_free_ptr(rd);                                          \
> +    }
> +
> +GEN_VXFORM_SIMM(vspltisb, 6, 12);
> +GEN_VXFORM_SIMM(vspltish, 6, 13);
> +GEN_VXFORM_SIMM(vspltisw, 6, 14);
> +
>  #define GEN_VXFORM_NOA(name, opc2, opc3)                                \
>      GEN_HANDLER(name, 0x04, opc2, opc3, 0x001f0000, PPC_ALTIVEC)        \
>      {                                                                   \
> -- 
> 1.6.0.5
> 
> 
> 
> 

-- 
  .''`.  Aurelien Jarno             | GPG: 1024D/F1BCDB73
 : :' :  Debian developer           | Electrical Engineer
 `. `'   address@hidden         | address@hidden
   `-    people.debian.org/~aurel32 | www.aurel32.net