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Violators will be prosecuted for from ; Thu, 27 Oct 2016 16:02:59 -0200 Date: Thu, 27 Oct 2016 16:02:49 -0200 From: joserz@linux.vnet.ibm.com References: <1477487938-23921-1-git-send-email-joserz@linux.vnet.ibm.com> <1477487938-23921-4-git-send-email-joserz@linux.vnet.ibm.com> <20161027013519.GC19918@umbus.fritz.box> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20161027013519.GC19918@umbus.fritz.box> Message-Id: <20161027180249.GC19890@pacoca> Subject: Re: [Qemu-devel] [PATCH] 3/4] target-ppc: Implement bcdcfz. instruction List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Gibson Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.org, nikunj@linux.vnet.ibm.com, bharata@linux.vnet.ibm.com I'll send an improved version in v2. Thank you for reviewing it. On Thu, Oct 27, 2016 at 12:35:19PM +1100, David Gibson wrote: > On Wed, Oct 26, 2016 at 11:18:57AM -0200, Jose Ricardo Ziviani wrote: > > bcdcfz. converts from Zoned numeric format to BCD. 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 | 55 +++++++++++++++++++++++++++++++++++++ > > target-ppc/translate/vmx-impl.inc.c | 7 +++-- > > 3 files changed, 61 insertions(+), 2 deletions(-) > > > > diff --git a/target-ppc/helper.h b/target-ppc/helper.h > > index 92eaaf0..f460635 100644 > > --- a/target-ppc/helper.h > > +++ b/target-ppc/helper.h > > @@ -371,6 +371,7 @@ DEF_HELPER_4(bcdadd, i32, avr, avr, avr, i32) > > 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_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 cffe82c..8cbbdfc 100644 > > --- a/target-ppc/int_helper.c > > +++ b/target-ppc/int_helper.c > > @@ -2459,6 +2459,17 @@ static int bcd_preferred_sgn(int sgn, int ps) > > } > > } > > > > +static uint8_t get_nibble(ppc_avr_t *bcd, int n) > > +{ > > + uint8_t result; > > + if (!(n & 1)) { > > + result = bcd->u8[BCD_DIG_BYTE(n)] & 0xF; > > + } else { > > + result = bcd->u8[BCD_DIG_BYTE(n)] >> 4; > > + } > > + return result; > > +} > > This can be merged with bcd_get_digit() without too much effort. > > > static uint8_t bcd_get_digit(ppc_avr_t *bcd, int n, int *invalid) > > { > > uint8_t result; > > @@ -2713,6 +2724,50 @@ uint32_t helper_bcdctn(ppc_avr_t *r, ppc_avr_t *b) > > return cr; > > } > > > > +uint32_t helper_bcdcfz(ppc_avr_t *r, ppc_avr_t *b, uint32_t ps) > > +{ > > + int i; > > + int j = 0; > > + int cr = 0; > > + int invalid = 0; > > + int eq_flag = 0; > > + int zone_digit = 0; > > + ppc_avr_t ret = { .u64 = { 0, 0 } }; > > + int sgnb = get_nibble(b, 1); > > + > > + if (unlikely(((sgnb < 0xA) && ps) || > > + ((get_nibble(b, 0) > 0x9) && !ps))) { > > The second half of this condition doesn't belong here. It's a > requirement for both ps values, and would make more sense applied > along with the same test on the other digits. > > > + invalid = 1; > > + } > > + > > + for (i = 31, j = 16; i > 1; i -= 2, j--) { > > I don't see why you're doing this in reverse order. > > > + zone_digit = get_nibble(b, i); > > + if (unlikely((ps && zone_digit != 0xF) || > > + (!ps && zone_digit != 0x3))) { > > + invalid = 1; > > In this and the other instructions it would make sense to break out of > the function as soon as you detect an invalid encoding. > > > + } > > You never check for invalid encoding in the low input nibble > (i.e. value > 0x9). > > > + eq_flag += zone_digit; > > What?? How on earth does adding up the zone digits help you. For a > valid encoding the answer should always be either 0x2d (PS=0) or 0xe1 > (PS=1). > > > + bcd_put_digit(&ret, get_nibble(b, i - 1), j); > > + } > > + bcd_put_digit(&ret, get_nibble(b, 0), 1); > > + > > + if ((ps && (sgnb == 0xB || sgnb == 0xD)) || > > + (!ps && (sgnb & 0x4))) { > > + bcd_put_digit(&ret, BCD_NEG_PREF, 0); > > + cr = (!eq_flag) ? 1 << CRF_LT : 1 << CRF_EQ; > > + } else { > > + bcd_put_digit(&ret, BCD_PLUS_PREF_1, 0); > > + cr = (!eq_flag) ? 1 << CRF_GT : 1 << CRF_EQ; > > + } > > + > > + 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 4364881..9192f8f 100644 > > --- a/target-ppc/translate/vmx-impl.inc.c > > +++ b/target-ppc/translate/vmx-impl.inc.c > > @@ -917,6 +917,7 @@ GEN_BCD(bcdadd) > > GEN_BCD(bcdsub) > > GEN_BCD2(bcdcfn) > > GEN_BCD3(bcdctn) > > +GEN_BCD2(bcdcfz) > > > > static void gen_xpnd04_1(DisasContext *ctx) > > { > > @@ -931,7 +932,8 @@ static void gen_xpnd04_1(DisasContext *ctx) > > gen_bcdctn(ctx); > > break; > > case 6: > > - break; /* bcdcfz. */ > > + gen_bcdcfz(ctx); > > + break; > > case 7: > > gen_bcdcfn(ctx); > > break; > > @@ -952,7 +954,8 @@ static void gen_xpnd04_2(DisasContext *ctx) > > case 4: > > break; /* bcdctz. */ > > case 6: > > - break; /* bcdcfz. */ > > + gen_bcdcfz(ctx); > > + break; > > case 7: > > gen_bcdcfn(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