[Qemu-devel] [PATCH v3 3/4] target-ppc: Implement bcdcfz. instruction

[Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>]

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 <joserz@linux.vnet.ibm.com>
---
 target-ppc/helper.h                 |  1 +
 target-ppc/int_helper.c             | 48 +++++++++++++++++++++++++++++++++++++
 target-ppc/translate/vmx-impl.inc.c |  7 ++++--
 3 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/target-ppc/helper.h b/target-ppc/helper.h
index 33286c6..8546bb9 100644
--- a/target-ppc/helper.h
+++ b/target-ppc/helper.h
@@ -373,6 +373,7 @@ 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_3(bcdctn, i32, avr, avr, i32)
+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 aaaf642..6581887 100644
--- a/target-ppc/int_helper.c
+++ b/target-ppc/int_helper.c
@@ -2727,6 +2727,54 @@ uint32_t helper_bcdctn(ppc_avr_t *r, ppc_avr_t *b, uint32_t ps)
     return cr;
 }
 
+uint32_t helper_bcdcfz(ppc_avr_t *r, ppc_avr_t *b, uint32_t ps)
+{
+    int i;
+    int j;
+    int cr = 0;
+    int invalid = 0;
+    int neq_flag = 0;
+    int zone_digit = 0;
+    int zone_lead = ps ? 0xF : 0x3;
+    int digit = 0;
+    ppc_avr_t ret = { .u64 = { 0, 0 } };
+    int sgnb = b->u8[BCD_DIG_BYTE(0)] >> 4;
+
+    if (unlikely((sgnb < 0xA) && ps)) {
+        invalid = 1;
+    }
+
+    for (i = 0, j = 1; i < 31; i += 2, j++) {
+        zone_digit = (i) ? b->u8[BCD_DIG_BYTE(i)] >> 4 : zone_lead;
+        digit = b->u8[BCD_DIG_BYTE(i)] & 0xF;
+
+        if (unlikely(zone_digit != zone_lead || digit > 0x9)) {
+            invalid = 1;
+            break;
+        }
+
+        neq_flag += (digit != 0);
+        bcd_put_digit(&ret, digit, j);
+    }
+
+    if ((ps && (sgnb == 0xB || sgnb == 0xD)) ||
+            (!ps && (sgnb & 0x4))) {
+        bcd_put_digit(&ret, BCD_NEG_PREF, 0);
+        cr = (neq_flag) ? 1 << CRF_LT : 1 << CRF_EQ;
+    } else {
+        bcd_put_digit(&ret, BCD_PLUS_PREF_1, 0);
+        cr = (neq_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 301088e..ecf0e54 100644
--- a/target-ppc/translate/vmx-impl.inc.c
+++ b/target-ppc/translate/vmx-impl.inc.c
@@ -972,6 +972,7 @@ GEN_BCD(bcdadd)
 GEN_BCD(bcdsub)
 GEN_BCD2(bcdcfn)
 GEN_BCD2(bcdctn)
+GEN_BCD2(bcdcfz)
 
 static void gen_xpnd04_1(DisasContext *ctx)
 {
@@ -986,7 +987,8 @@ 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;
@@ -1008,7 +1010,8 @@ 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