[Qemu-devel] [PATCH v2 6/7] target-ppc: Implement bcdtrunc. instruction

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

bcdtrunc.: Decimal integer truncate. Given a BCD number in vrb and the
number of bytes to truncate in vra, the return register will have vrb
with such bits truncated.

Signed-off-by: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>
---
 target-ppc/helper.h                 |  1 +
 target-ppc/int_helper.c             | 43 +++++++++++++++++++++++++++++++++++++
 target-ppc/translate/vmx-impl.inc.c |  5 +++++
 target-ppc/translate/vmx-ops.inc.c  |  4 ++--
 4 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/target-ppc/helper.h b/target-ppc/helper.h
index d9528eb..49965b0 100644
--- a/target-ppc/helper.h
+++ b/target-ppc/helper.h
@@ -395,6 +395,7 @@ DEF_HELPER_3(bcdsetsgn, i32, avr, avr, i32)
 DEF_HELPER_4(bcds, i32, avr, avr, avr, i32)
 DEF_HELPER_4(bcdus, i32, avr, avr, avr, i32)
 DEF_HELPER_4(bcdsr, i32, avr, avr, avr, i32)
+DEF_HELPER_4(bcdtrunc, i32, avr, 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 cfef25f..faf34c1 100644
--- a/target-ppc/int_helper.c
+++ b/target-ppc/int_helper.c
@@ -3169,6 +3169,49 @@ uint32_t helper_bcdsr(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, uint32_t ps)
     return cr;
 }
 
+uint32_t helper_bcdtrunc(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, uint32_t ps)
+{
+    int i;
+    int cr;
+    int ox_flag;
+    uint8_t digit;
+    uint8_t trunc;
+    int invalid = 0;
+    int sgnb = bcd_get_sgn(b);
+    ppc_avr_t ret = *b;
+
+#if defined(HOST_WORDS_BIGENDIAN)
+    int upper = ARRAY_SIZE(a->u16) - 1;
+#else
+    int upper = 0;
+#endif
+
+    trunc = 32 - (a->u16[upper] & 31);
+    for (i = 1; i < 32; i++) {
+        digit = bcd_get_digit(b, i, &invalid);
+
+        if (unlikely(invalid)) {
+            return CRF_SO;
+        }
+
+        if (i >= trunc) {
+            if (!ox_flag && digit > 0x0) {
+                ox_flag = 1;
+            }
+            bcd_put_digit(&ret, 0, i);
+        }
+    }
+    bcd_put_digit(&ret, bcd_preferred_sgn(sgnb, ps), 0);
+
+    cr = bcd_cmp_zero(&ret);
+    if (unlikely(ox_flag)) {
+        cr |= 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 451abb5..1683f42 100644
--- a/target-ppc/translate/vmx-impl.inc.c
+++ b/target-ppc/translate/vmx-impl.inc.c
@@ -1019,6 +1019,7 @@ GEN_BCD(bcdcpsgn);
 GEN_BCD(bcds);
 GEN_BCD(bcdus);
 GEN_BCD(bcdsr);
+GEN_BCD(bcdtrunc);
 
 static void gen_xpnd04_1(DisasContext *ctx)
 {
@@ -1097,6 +1098,10 @@ GEN_VXFORM_DUAL(vsubudm, PPC2_ALTIVEC_207, PPC_NONE, \
                 bcds, PPC_NONE, PPC2_ISA300)
 GEN_VXFORM_DUAL(vsubuwm, PPC_ALTIVEC, PPC_NONE, \
                 bcdus, PPC_NONE, PPC2_ISA300)
+GEN_VXFORM_DUAL(vsubsbs, PPC_ALTIVEC, PPC_NONE, \
+                bcdtrunc, PPC_NONE, PPC2_ISA300)
+GEN_VXFORM_DUAL(vsubuqm, PPC2_ALTIVEC_207, PPC_NONE, \
+                bcdtrunc, PPC_NONE, PPC2_ISA300)
 
 static void gen_vsbox(DisasContext *ctx)
 {
diff --git a/target-ppc/translate/vmx-ops.inc.c b/target-ppc/translate/vmx-ops.inc.c
index fa9c996..e6167a4 100644
--- a/target-ppc/translate/vmx-ops.inc.c
+++ b/target-ppc/translate/vmx-ops.inc.c
@@ -143,14 +143,14 @@ GEN_VXFORM(vaddsws, 0, 14),
 GEN_VXFORM_DUAL(vsububs, bcdadd, 0, 24, PPC_ALTIVEC, PPC_NONE),
 GEN_VXFORM_DUAL(vsubuhs, bcdsub, 0, 25, PPC_ALTIVEC, PPC_NONE),
 GEN_VXFORM(vsubuws, 0, 26),
-GEN_VXFORM(vsubsbs, 0, 28),
+GEN_VXFORM_DUAL(vsubsbs, bcdtrunc, 0, 28, PPC_NONE, PPC2_ISA300),
 GEN_VXFORM(vsubshs, 0, 29),
 GEN_VXFORM_DUAL(vsubsws, xpnd04_2, 0, 30, PPC_ALTIVEC, PPC_NONE),
 GEN_VXFORM_207(vadduqm, 0, 4),
 GEN_VXFORM_207(vaddcuq, 0, 5),
 GEN_VXFORM_DUAL(vaddeuqm, vaddecuq, 30, 0xFF, PPC_NONE, PPC2_ALTIVEC_207),
-GEN_VXFORM_207(vsubuqm, 0, 20),
 GEN_VXFORM_207(vsubcuq, 0, 21),
+GEN_VXFORM_DUAL(vsubuqm, bcdtrunc, 0, 20, PPC2_ALTIVEC_207, PPC2_ISA300),
 GEN_VXFORM_DUAL(vsubeuqm, vsubecuq, 31, 0xFF, PPC_NONE, PPC2_ALTIVEC_207),
 GEN_VXFORM(vrlb, 2, 0),
 GEN_VXFORM(vrlh, 2, 1),
-- 
2.7.4