Re: [Qemu-devel] [PATCH] 4/4] target-ppc: Implement bcdctz. instruction

[joserz]

Everything will be fixed in v2.

Thanks for reviewing it!

On Thu, Oct 27, 2016 at 12:47:34PM +1100, David Gibson wrote:
> On Wed, Oct 26, 2016 at 11:18:58AM -0200, Jose Ricardo Ziviani wrote:
> > bcdctz. converts from BCD to Zoned numeric format. Zoned format uses
> > a byte to represent a digit where the most significant nibble is 0x3
> > or 0xf, depending on the preferred signal.
> > 
> > Signed-off-by: Jose Ricardo Ziviani 
> > ---
> >  target-ppc/helper.h |  1 +
> >  target-ppc/int_helper.c | 54 
> > +
> >  target-ppc/translate/vmx-impl.inc.c |  7 +++--
> >  3 files changed, 60 insertions(+), 2 deletions(-)
> > 
> > diff --git a/target-ppc/helper.h b/target-ppc/helper.h
> > index f460635..3b928b8 100644
> > --- a/target-ppc/helper.h
> > +++ b/target-ppc/helper.h
> > @@ -372,6 +372,7 @@ DEF_HELPER_4(bcdsub, i32, avr, avr, avr, i32)
> >  DEF_HELPER_3(bcdcfn, i32, avr, avr, i32)
> >  DEF_HELPER_2(bcdctn, i32, avr, avr)
> >  DEF_HELPER_3(bcdcfz, i32, avr, avr, i32)
> > +DEF_HELPER_3(bcdctz, 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 8cbbdfc..e0a84bb 100644
> > --- a/target-ppc/int_helper.c
> > +++ b/target-ppc/int_helper.c
> > @@ -2768,6 +2768,60 @@ uint32_t helper_bcdcfz(ppc_avr_t *r, ppc_avr_t *b, 
> > uint32_t ps)
> >  *r = ret;
> >  return cr;
> >  }
> > +
> > +uint32_t helper_bcdctz(ppc_avr_t *r, ppc_avr_t *b, uint32_t ps)
> > +{
> > +int i;
> > +int j;
> > +int cr = 0;
> > +int invalid = 0;
> > +uint8_t digit = 0;
> > +int sgnb = bcd_get_sgn(b);
> > +int zone_lead = (ps) ? 0xF0 : 0x30;
> > +ppc_avr_t ret = { .u64 = { 0, 0 } };
> > +
> > +int eq_flag = (b->u64[HI_IDX] == 0) && ((b->u64[LO_IDX] >> 4) == 0);
> > +int ox_flag = (b->u64[HI_IDX] != 0);
> 
> This doesn't look right.  The zoned format can accomodate 16 digits.
> The low word of the packed format can accomodate 15 digits + sign.  So
> it should be possible to convert a packed for with a value in the low
> nibble of the upper word.
> 
> > +for (i = 31, j = 16; i > 1; i -= 2, j--) {
> 
> Again not seeing any point for the reverse order.
> 
> > +digit = get_nibble(b, j);
> > +ret.u8[BCD_DIG_BYTE(i)] = zone_lead + digit;
> > +
> > +if (unlikely(digit > 9)) {
> > +invalid = 1;
> > +}
> > +}
> > +
> > +if (unlikely(!sgnb)) {
> > +sgnb = (!get_nibble(b, 0)) ? 1 : -1;
> > +}
> 
> Doesn't bcd_get_sgn() returning 0 indicate a badly encoded sign
> point.  In which case you should set invalid, rather than making up a
> sign according to this apparently arbitrary scheme.
> 
> > +
> > +if (ps) {
> > +bcd_put_digit(, (sgnb == 1) ? 0xC : 0xD, 1);
> > +} else {
> > +bcd_put_digit(, (sgnb == 1) ? 0x3 : 0x7, 1);
> > +}
> > +bcd_put_digit(, get_nibble(b, 1), 0);
> > +
> > +if (!eq_flag) {
> > +cr = (sgnb == 1) ? 1 << CRF_GT : 1 << CRF_LT;
> > +} else {
> > +cr = 1 << CRF_EQ;
> > +}
> > +
> > +if (ox_flag) {
> > +cr |= 1 << CRF_SO;
> > +}
> > +
> > +if (unlikely(invalid)) {
> > +cr = 1 << CRF_SO;
> > +}
> > +
> > +*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 9192f8f..62c44f0 100644
> > --- a/target-ppc/translate/vmx-impl.inc.c
> > +++ b/target-ppc/translate/vmx-impl.inc.c
> > @@ -918,6 +918,7 @@ GEN_BCD(bcdsub)
> >  GEN_BCD2(bcdcfn)
> >  GEN_BCD3(bcdctn)
> >  GEN_BCD2(bcdcfz)
> > +GEN_BCD2(bcdctz)
> >  
> >  static void gen_xpnd04_1(DisasContext *ctx)
> >  {
> > @@ -927,7 +928,8 @@ static void gen_xpnd04_1(DisasContext *ctx)
> >  case 2:
> >  break; /* bcdcfsq. */
> >  case 4:
> > -break; /* bcdctz. */
> > +gen_bcdctz(ctx);
> > +break;
> >  case 5:
> >  gen_bcdctn(ctx);
> >  break;
> > @@ -952,7 +954,8 @@ static void gen_xpnd04_2(DisasContext *ctx)
> >  case 2:
> >  break; /* bcdcfsq. */
> >  case 4:
> > -break; /* bcdctz. */
> > +gen_bcdctz(ctx);
> > +break;
> >  case 6:
> >  gen_bcdcfz(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

Re: [Qemu-devel] [PATCH] 4/4] target-ppc: Implement bcdctz. instruction

[David Gibson]

On Wed, Oct 26, 2016 at 11:18:58AM -0200, Jose Ricardo Ziviani wrote:
> bcdctz. converts from BCD to Zoned numeric format. Zoned format uses
> a byte to represent a digit where the most significant nibble is 0x3
> or 0xf, depending on the preferred signal.
> 
> Signed-off-by: Jose Ricardo Ziviani 
> ---
>  target-ppc/helper.h |  1 +
>  target-ppc/int_helper.c | 54 
> +
>  target-ppc/translate/vmx-impl.inc.c |  7 +++--
>  3 files changed, 60 insertions(+), 2 deletions(-)
> 
> diff --git a/target-ppc/helper.h b/target-ppc/helper.h
> index f460635..3b928b8 100644
> --- a/target-ppc/helper.h
> +++ b/target-ppc/helper.h
> @@ -372,6 +372,7 @@ DEF_HELPER_4(bcdsub, i32, avr, avr, avr, i32)
>  DEF_HELPER_3(bcdcfn, i32, avr, avr, i32)
>  DEF_HELPER_2(bcdctn, i32, avr, avr)
>  DEF_HELPER_3(bcdcfz, i32, avr, avr, i32)
> +DEF_HELPER_3(bcdctz, 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 8cbbdfc..e0a84bb 100644
> --- a/target-ppc/int_helper.c
> +++ b/target-ppc/int_helper.c
> @@ -2768,6 +2768,60 @@ uint32_t helper_bcdcfz(ppc_avr_t *r, ppc_avr_t *b, 
> uint32_t ps)
>  *r = ret;
>  return cr;
>  }
> +
> +uint32_t helper_bcdctz(ppc_avr_t *r, ppc_avr_t *b, uint32_t ps)
> +{
> +int i;
> +int j;
> +int cr = 0;
> +int invalid = 0;
> +uint8_t digit = 0;
> +int sgnb = bcd_get_sgn(b);
> +int zone_lead = (ps) ? 0xF0 : 0x30;
> +ppc_avr_t ret = { .u64 = { 0, 0 } };
> +
> +int eq_flag = (b->u64[HI_IDX] == 0) && ((b->u64[LO_IDX] >> 4) == 0);
> +int ox_flag = (b->u64[HI_IDX] != 0);

This doesn't look right.  The zoned format can accomodate 16 digits.
The low word of the packed format can accomodate 15 digits + sign.  So
it should be possible to convert a packed for with a value in the low
nibble of the upper word.

> +for (i = 31, j = 16; i > 1; i -= 2, j--) {

Again not seeing any point for the reverse order.

> +digit = get_nibble(b, j);
> +ret.u8[BCD_DIG_BYTE(i)] = zone_lead + digit;
> +
> +if (unlikely(digit > 9)) {
> +invalid = 1;
> +}
> +}
> +
> +if (unlikely(!sgnb)) {
> +sgnb = (!get_nibble(b, 0)) ? 1 : -1;
> +}

Doesn't bcd_get_sgn() returning 0 indicate a badly encoded sign
point.  In which case you should set invalid, rather than making up a
sign according to this apparently arbitrary scheme.

> +
> +if (ps) {
> +bcd_put_digit(, (sgnb == 1) ? 0xC : 0xD, 1);
> +} else {
> +bcd_put_digit(, (sgnb == 1) ? 0x3 : 0x7, 1);
> +}
> +bcd_put_digit(, get_nibble(b, 1), 0);
> +
> +if (!eq_flag) {
> +cr = (sgnb == 1) ? 1 << CRF_GT : 1 << CRF_LT;
> +} else {
> +cr = 1 << CRF_EQ;
> +}
> +
> +if (ox_flag) {
> +cr |= 1 << CRF_SO;
> +}
> +
> +if (unlikely(invalid)) {
> +cr = 1 << CRF_SO;
> +}
> +
> +*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 9192f8f..62c44f0 100644
> --- a/target-ppc/translate/vmx-impl.inc.c
> +++ b/target-ppc/translate/vmx-impl.inc.c
> @@ -918,6 +918,7 @@ GEN_BCD(bcdsub)
>  GEN_BCD2(bcdcfn)
>  GEN_BCD3(bcdctn)
>  GEN_BCD2(bcdcfz)
> +GEN_BCD2(bcdctz)
>  
>  static void gen_xpnd04_1(DisasContext *ctx)
>  {
> @@ -927,7 +928,8 @@ static void gen_xpnd04_1(DisasContext *ctx)
>  case 2:
>  break; /* bcdcfsq. */
>  case 4:
> -break; /* bcdctz. */
> +gen_bcdctz(ctx);
> +break;
>  case 5:
>  gen_bcdctn(ctx);
>  break;
> @@ -952,7 +954,8 @@ static void gen_xpnd04_2(DisasContext *ctx)
>  case 2:
>  break; /* bcdcfsq. */
>  case 4:
> -break; /* bcdctz. */
> +gen_bcdctz(ctx);
> +break;
>  case 6:
>  gen_bcdcfz(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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[Qemu-devel] [PATCH] 4/4] target-ppc: Implement bcdctz. instruction

[Jose Ricardo Ziviani]

bcdctz. converts from BCD to Zoned numeric format. Zoned format uses
a byte to represent a digit where the most significant nibble is 0x3
or 0xf, depending on the preferred signal.

Signed-off-by: Jose Ricardo Ziviani 
---
 target-ppc/helper.h |  1 +
 target-ppc/int_helper.c | 54 +
 target-ppc/translate/vmx-impl.inc.c |  7 +++--
 3 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/target-ppc/helper.h b/target-ppc/helper.h
index f460635..3b928b8 100644
--- a/target-ppc/helper.h
+++ b/target-ppc/helper.h
@@ -372,6 +372,7 @@ DEF_HELPER_4(bcdsub, i32, avr, avr, avr, i32)
 DEF_HELPER_3(bcdcfn, i32, avr, avr, i32)
 DEF_HELPER_2(bcdctn, i32, avr, avr)
 DEF_HELPER_3(bcdcfz, i32, avr, avr, i32)
+DEF_HELPER_3(bcdctz, 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 8cbbdfc..e0a84bb 100644
--- a/target-ppc/int_helper.c
+++ b/target-ppc/int_helper.c
@@ -2768,6 +2768,60 @@ uint32_t helper_bcdcfz(ppc_avr_t *r, ppc_avr_t *b, 
uint32_t ps)
 *r = ret;
 return cr;
 }
+
+uint32_t helper_bcdctz(ppc_avr_t *r, ppc_avr_t *b, uint32_t ps)
+{
+int i;
+int j;
+int cr = 0;
+int invalid = 0;
+uint8_t digit = 0;
+int sgnb = bcd_get_sgn(b);
+int zone_lead = (ps) ? 0xF0 : 0x30;
+ppc_avr_t ret = { .u64 = { 0, 0 } };
+
+int eq_flag = (b->u64[HI_IDX] == 0) && ((b->u64[LO_IDX] >> 4) == 0);
+int ox_flag = (b->u64[HI_IDX] != 0);
+
+for (i = 31, j = 16; i > 1; i -= 2, j--) {
+digit = get_nibble(b, j);
+ret.u8[BCD_DIG_BYTE(i)] = zone_lead + digit;
+
+if (unlikely(digit > 9)) {
+invalid = 1;
+}
+}
+
+if (unlikely(!sgnb)) {
+sgnb = (!get_nibble(b, 0)) ? 1 : -1;
+}
+
+if (ps) {
+bcd_put_digit(, (sgnb == 1) ? 0xC : 0xD, 1);
+} else {
+bcd_put_digit(, (sgnb == 1) ? 0x3 : 0x7, 1);
+}
+bcd_put_digit(, get_nibble(b, 1), 0);
+
+if (!eq_flag) {
+cr = (sgnb == 1) ? 1 << CRF_GT : 1 << CRF_LT;
+} else {
+cr = 1 << CRF_EQ;
+}
+
+if (ox_flag) {
+cr |= 1 << CRF_SO;
+}
+
+if (unlikely(invalid)) {
+cr = 1 << CRF_SO;
+}
+
+*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 9192f8f..62c44f0 100644
--- a/target-ppc/translate/vmx-impl.inc.c
+++ b/target-ppc/translate/vmx-impl.inc.c
@@ -918,6 +918,7 @@ GEN_BCD(bcdsub)
 GEN_BCD2(bcdcfn)
 GEN_BCD3(bcdctn)
 GEN_BCD2(bcdcfz)
+GEN_BCD2(bcdctz)
 
 static void gen_xpnd04_1(DisasContext *ctx)
 {
@@ -927,7 +928,8 @@ static void gen_xpnd04_1(DisasContext *ctx)
 case 2:
 break; /* bcdcfsq. */
 case 4:
-break; /* bcdctz. */
+gen_bcdctz(ctx);
+break;
 case 5:
 gen_bcdctn(ctx);
 break;
@@ -952,7 +954,8 @@ static void gen_xpnd04_2(DisasContext *ctx)
 case 2:
 break; /* bcdcfsq. */
 case 4:
-break; /* bcdctz. */
+gen_bcdctz(ctx);
+break;
 case 6:
 gen_bcdcfz(ctx);
 break;
-- 
2.7.4