Re: [Qemu-devel] [PATCH v3 1/4] target-ppc: Implement bcdcfsq. instruction

[David Gibson <david@gibson.dropbear.id.au>]

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On Fri, Nov 25, 2016 at 01:53:30AM -0200, Jose Ricardo Ziviani wrote:
> bcdcfsq.: Decimal convert from signed quadword. It is not possible
> to convert values less than -10^31-1 or greater than 10^31-1 to be
> represented in packed decimal format.
> 
> Signed-off-by: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>
> ---
>  target-ppc/helper.h                 |  1 +
>  target-ppc/int_helper.c             | 38 +++++++++++++++++++++++++++++++++++++
>  target-ppc/translate/vmx-impl.inc.c |  7 +++++++
>  3 files changed, 46 insertions(+)
> 
> diff --git a/target-ppc/helper.h b/target-ppc/helper.h
> index 3b26678..efb384a 100644
> --- a/target-ppc/helper.h
> +++ b/target-ppc/helper.h
> @@ -382,6 +382,7 @@ DEF_HELPER_3(bcdcfn, i32, avr, avr, i32)
>  DEF_HELPER_3(bcdctn, i32, avr, avr, i32)
>  DEF_HELPER_3(bcdcfz, i32, avr, avr, i32)
>  DEF_HELPER_3(bcdctz, i32, avr, avr, i32)
> +DEF_HELPER_3(bcdcfsq, i32, avr, avr, i32)
>  
>  DEF_HELPER_2(xsadddp, void, env, i32)
>  DEF_HELPER_2(xssubdp, void, env, i32)
> diff --git a/target-ppc/int_helper.c b/target-ppc/int_helper.c
> index fbf477f..9d753e2 100644
> --- a/target-ppc/int_helper.c
> +++ b/target-ppc/int_helper.c
> @@ -2874,6 +2874,44 @@ uint32_t helper_bcdctz(ppc_avr_t *r, ppc_avr_t *b, uint32_t ps)
>      return cr;
>  }
>  
> +uint32_t helper_bcdcfsq(ppc_avr_t *r, ppc_avr_t *b, uint32_t ps)
> +{
> +    int i;
> +    int cr = 0;
> +    uint64_t lo_value;
> +    uint64_t hi_value;
> +    ppc_avr_t ret = { .u64 = { 0, 0 } };
> +
> +    if (b->s64[HI_IDX] < 0) {
> +        lo_value = -b->s64[LO_IDX];
> +        hi_value = ~b->u64[HI_IDX] + !lo_value;
> +        bcd_put_digit(&ret, 0xD, 0);
> +    } else {
> +        lo_value = b->u64[LO_IDX];
> +        hi_value = b->u64[HI_IDX];
> +        bcd_put_digit(&ret, bcd_preferred_sgn(0, ps), 0);
> +    }
> +
> +    if (divu128(&lo_value, &hi_value, 1000000000000000ULL) ||
> +            lo_value > 99999999999999999ULL) {

This is 10^17-1, but it should be 10^16-1.  I've corrected that in my
tree, but please try to be more careful in future.

> +        cr = CRF_SO;
> +    }
> +
> +    for (i = 1; i < 16; hi_value /= 10, i++) {
> +        bcd_put_digit(&ret, hi_value % 10, i);
> +    }
> +
> +    for (; i < 32; lo_value /= 10, i++) {
> +        bcd_put_digit(&ret, lo_value % 10, i);
> +    }
> +
> +    cr |= bcd_cmp_zero(&ret);
> +
> +    *r = ret;
> +
> +    return cr;
> +}
> +
>  void helper_vsbox(ppc_avr_t *r, ppc_avr_t *a)
>  {
>      int i;
> diff --git a/target-ppc/translate/vmx-impl.inc.c b/target-ppc/translate/vmx-impl.inc.c
> index 7143eb3..36141e5 100644
> --- a/target-ppc/translate/vmx-impl.inc.c
> +++ b/target-ppc/translate/vmx-impl.inc.c
> @@ -989,10 +989,14 @@ GEN_BCD2(bcdcfn)
>  GEN_BCD2(bcdctn)
>  GEN_BCD2(bcdcfz)
>  GEN_BCD2(bcdctz)
> +GEN_BCD2(bcdcfsq)
>  
>  static void gen_xpnd04_1(DisasContext *ctx)
>  {
>      switch (opc4(ctx->opcode)) {
> +    case 2:
> +        gen_bcdcfsq(ctx);
> +        break;
>      case 4:
>          gen_bcdctz(ctx);
>          break;
> @@ -1014,6 +1018,9 @@ static void gen_xpnd04_1(DisasContext *ctx)
>  static void gen_xpnd04_2(DisasContext *ctx)
>  {
>      switch (opc4(ctx->opcode)) {
> +    case 2:
> +        gen_bcdcfsq(ctx);
> +        break;
>      case 4:
>          gen_bcdctz(ctx);
>          break;

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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