ppc: Implement bcdsr. instruction

bcdsr.: Decimal shift and round. This instruction works like bcds. however, when performing right shift, 1 will be added to the result if the last digit was >= 5. Signed-off-by: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
qemu · Jan 30, 2017 · a54238a · a54238a
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diff --git a/target/ppc/helper.h b/target/ppc/helper.h
@@ -395,6 +395,7 @@ DEF_HELPER_4(bcdcpsgn, i32, avr, avr, avr, i32)
 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_2(xsadddp, void, env, i32)
 DEF_HELPER_2(xsaddqp, void, env, i32)

diff --git a/target/ppc/int_helper.c b/target/ppc/int_helper.c
@@ -3143,6 +3143,54 @@ uint32_t helper_bcdus(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, uint32_t ps)
     return cr;
 }
 
+uint32_t helper_bcdsr(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, uint32_t ps)
+{
+    int cr;
+    int unused = 0;
+    int invalid = 0;
+    bool ox_flag = false;
+    int sgnb = bcd_get_sgn(b);
+    ppc_avr_t ret = *b;
+    ret.u64[LO_IDX] &= ~0xf;
+
+#if defined(HOST_WORDS_BIGENDIAN)
+    int i = a->s8[7];
+    ppc_avr_t bcd_one = { .u64 = { 0, 0x10 } };
+#else
+    int i = a->s8[8];
+    ppc_avr_t bcd_one = { .u64 = { 0x10, 0 } };
+#endif
+
+    if (bcd_is_valid(b) == false) {
+        return CRF_SO;
+    }
+
+    if (unlikely(i > 31)) {
+        i = 31;
+    } else if (unlikely(i < -31)) {
+        i = -31;
+    }
+
+    if (i > 0) {
+        ulshift(&ret.u64[LO_IDX], &ret.u64[HI_IDX], i * 4, &ox_flag);
+    } else {
+        urshift(&ret.u64[LO_IDX], &ret.u64[HI_IDX], -i * 4);
+
+        if (bcd_get_digit(&ret, 0, &invalid) >= 5) {
+            bcd_add_mag(&ret, &ret, &bcd_one, &invalid, &unused);
+        }
+    }
+    bcd_put_digit(&ret, bcd_preferred_sgn(sgnb, ps), 0);
+
+    cr = bcd_cmp_zero(&ret);
+    if (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
@@ -1018,6 +1018,7 @@ GEN_BCD2(bcdsetsgn)
 GEN_BCD(bcdcpsgn);
 GEN_BCD(bcds);
 GEN_BCD(bcdus);
+GEN_BCD(bcdsr);
 
 static void gen_xpnd04_1(DisasContext *ctx)
 {

diff --git a/target/ppc/translate/vmx-ops.inc.c b/target/ppc/translate/vmx-ops.inc.c
@@ -132,6 +132,8 @@ GEN_HANDLER_E_2(vprtybd, 0x4, 0x1, 0x18, 9, 0, PPC_NONE, PPC2_ISA300),
 GEN_HANDLER_E_2(vprtybq, 0x4, 0x1, 0x18, 10, 0, PPC_NONE, PPC2_ISA300),
 
 GEN_VXFORM_DUAL(vsubcuw, xpnd04_1, 0, 22, PPC_ALTIVEC, PPC_NONE),
+GEN_VXFORM_300(bcdsr, 0, 23),
+GEN_VXFORM_300(bcdsr, 0, 31),
 GEN_VXFORM_DUAL(vaddubs, vmul10uq, 0, 8, PPC_ALTIVEC, PPC_NONE),
 GEN_VXFORM_DUAL(vadduhs, vmul10euq, 0, 9, PPC_ALTIVEC, PPC_NONE),
 GEN_VXFORM(vadduws, 0, 10),