[Qemu-devel] [PATCH] 3/4] target-ppc: Implement bcdcfz. instruction

[Jose Ricardo Ziviani]

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 <address@hidden>
---
 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;
+}
+
 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))) {
+        invalid = 1;
+    }
+
+    for (i = 31, j = 16; i > 1; i -= 2, j--) {
+        zone_digit = get_nibble(b, i);
+        if (unlikely((ps && zone_digit != 0xF) ||
+                    (!ps && zone_digit != 0x3))) {
+            invalid = 1;
+        }
+
+        eq_flag += zone_digit;
+        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;
-- 
2.7.4