[Qemu-ppc] [PATCH v2 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 <address@hidden>
---
 target-ppc/helper.h                 |  1 +
 target-ppc/int_helper.c             | 51 +++++++++++++++++++++++++++++++++++++
 target-ppc/translate/vmx-impl.inc.c |  7 +++--
 3 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/target-ppc/helper.h b/target-ppc/helper.h
index a9ac28b..489a405 100644
--- a/target-ppc/helper.h
+++ b/target-ppc/helper.h
@@ -374,6 +374,7 @@ 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 19e6a3a..518824e 100644
--- a/target-ppc/int_helper.c
+++ b/target-ppc/int_helper.c
@@ -2774,6 +2774,57 @@ uint32_t helper_bcdcfz(ppc_avr_t *r, ppc_avr_t *b, 
uint32_t ps)
 
     return cr;
 }
+
+uint32_t helper_bcdctz(ppc_avr_t *r, ppc_avr_t *b, uint32_t ps)
+{
+    int i;
+    int j;
+    int cr = 0;
+    uint8_t digit = 0;
+    int sgnb = bcd_get_sgn(b);
+    int zone_lead = (ps) ? 0xF0 : 0x30;
+    int invalid = (sgnb == 0);
+    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] >> 4) != 0);
+
+    for (i = 0, j = 1; i < 32; i += 2, j++) {
+        digit = bcd_get_digit(b, j, &invalid);
+
+        if (unlikely(invalid)) {
+            break;
+        }
+
+        ret.u8[BCD_DIG_BYTE(i)] = zone_lead + digit;
+    }
+
+    if (ps) {
+        bcd_put_digit(&ret, (sgnb == 1) ? 0xC : 0xD, 1);
+    } else {
+        bcd_put_digit(&ret, (sgnb == 1) ? 0x3 : 0x7, 1);
+    }
+    bcd_put_digit(&ret, b->u8[BCD_DIG_BYTE(0)] >> 4, 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 6e54437..a868740 100644
--- a/target-ppc/translate/vmx-impl.inc.c
+++ b/target-ppc/translate/vmx-impl.inc.c
@@ -992,6 +992,7 @@ GEN_BCD(bcdsub)
 GEN_BCD2(bcdcfn)
 GEN_BCD3(bcdctn)
 GEN_BCD2(bcdcfz)
+GEN_BCD2(bcdctz)
 
 static void gen_xpnd04_1(DisasContext *ctx)
 {
@@ -1001,7 +1002,8 @@ 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;
@@ -1026,7 +1028,8 @@ 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