[Qemu-devel] [PULL 047/118] target-ppc: Introduce DFP Decode DPD to BCD

[Alexander Graf <agraf@suse.de>]

From: Tom Musta <tommusta@gmail.com>

Add emulation of the Power PC Decimal Floating Point Decode
Densely Packed Decimal to Binary Coded Decimal instructions
ddedpd[q][.].

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
 target-ppc/dfp_helper.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++
 target-ppc/helper.h     |  2 ++
 target-ppc/translate.c  |  4 +++
 3 files changed, 72 insertions(+)

diff --git a/target-ppc/dfp_helper.c b/target-ppc/dfp_helper.c
index 24de5a7..df40da7 100644
--- a/target-ppc/dfp_helper.c
+++ b/target-ppc/dfp_helper.c
@@ -983,3 +983,69 @@ void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *b)                  \
 
 DFP_HELPER_CTFIX(dctfix, 64)
 DFP_HELPER_CTFIX(dctfixq, 128)
+
+static inline void dfp_set_bcd_digit_64(uint64_t *t, uint8_t digit,
+                                            unsigned n)
+{
+    *t |= ((uint64_t)(digit & 0xF) << (n << 2));
+}
+
+static inline void dfp_set_bcd_digit_128(uint64_t *t, uint8_t digit,
+                                             unsigned n)
+{
+    t[(n & 0x10) ? HI_IDX : LO_IDX] |=
+        ((uint64_t)(digit & 0xF) << ((n & 15) << 2));
+}
+
+static inline void dfp_set_sign_64(uint64_t *t, uint8_t sgn)
+{
+    *t <<= 4;
+    *t |= (sgn & 0xF);
+}
+
+static inline void dfp_set_sign_128(uint64_t *t, uint8_t sgn)
+{
+    t[HI_IDX] <<= 4;
+    t[HI_IDX] |= (t[LO_IDX] >> 60);
+    t[LO_IDX] <<= 4;
+    t[LO_IDX] |= (sgn & 0xF);
+}
+
+#define DFP_HELPER_DEDPD(op, size)                                        \
+void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *b, uint32_t sp) \
+{                                                                         \
+    struct PPC_DFP dfp;                                                   \
+    uint8_t digits[34];                                                   \
+    int i, N;                                                             \
+                                                                          \
+    dfp_prepare_decimal##size(&dfp, 0, b, env);                           \
+                                                                          \
+    decNumberGetBCD(&dfp.b, digits);                                      \
+    dfp.t64[0] = dfp.t64[1] = 0;                                          \
+    N = dfp.b.digits;                                                     \
+                                                                          \
+    for (i = 0; (i < N) && (i < (size)/4); i++) {                         \
+        dfp_set_bcd_digit_##size(dfp.t64, digits[N-i-1], i);              \
+    }                                                                     \
+                                                                          \
+    if (sp & 2) {                                                         \
+        uint8_t sgn;                                                      \
+                                                                          \
+        if (decNumberIsNegative(&dfp.b)) {                                \
+            sgn = 0xD;                                                    \
+        } else {                                                          \
+            sgn = ((sp & 1) ? 0xF : 0xC);                                 \
+        }                                                                 \
+        dfp_set_sign_##size(dfp.t64, sgn);                                \
+    }                                                                     \
+                                                                          \
+    if (size == 64) {                                                     \
+        t[0] = dfp.t64[0];                                                \
+    } else if (size == 128) {                                             \
+        t[0] = dfp.t64[HI_IDX];                                           \
+        t[1] = dfp.t64[LO_IDX];                                           \
+    }                                                                     \
+}
+
+DFP_HELPER_DEDPD(ddedpd, 64)
+DFP_HELPER_DEDPD(ddedpdq, 128)
diff --git a/target-ppc/helper.h b/target-ppc/helper.h
index 69c0a1d..d4e73f2 100644
--- a/target-ppc/helper.h
+++ b/target-ppc/helper.h
@@ -654,3 +654,5 @@ DEF_HELPER_3(dcffix, void, env, fprp, fprp)
 DEF_HELPER_3(dcffixq, void, env, fprp, fprp)
 DEF_HELPER_3(dctfix, void, env, fprp, fprp)
 DEF_HELPER_3(dctfixq, void, env, fprp, fprp)
+DEF_HELPER_4(ddedpd, void, env, fprp, fprp, i32)
+DEF_HELPER_4(ddedpdq, void, env, fprp, fprp, i32)
diff --git a/target-ppc/translate.c b/target-ppc/translate.c
index cc7af45..0de657a 100644
--- a/target-ppc/translate.c
+++ b/target-ppc/translate.c
@@ -8393,6 +8393,8 @@ GEN_DFP_T_B_Rc(dcffix)
 GEN_DFP_T_B_Rc(dcffixq)
 GEN_DFP_T_B_Rc(dctfix)
 GEN_DFP_T_B_Rc(dctfixq)
+GEN_DFP_T_FPR_I32_Rc(ddedpd, rB, SP)
+GEN_DFP_T_FPR_I32_Rc(ddedpdq, rB, SP)
 /***                           SPE extension                               ***/
 /* Register moves */
 
@@ -11358,6 +11360,8 @@ GEN_DFP_T_B_Rc(dcffix, 0x02, 0x19),
 GEN_DFP_Tp_B_Rc(dcffixq, 0x02, 0x19),
 GEN_DFP_T_B_Rc(dctfix, 0x02, 0x09),
 GEN_DFP_T_Bp_Rc(dctfixq, 0x02, 0x09),
+GEN_DFP_SP_T_B_Rc(ddedpd, 0x02, 0x0a),
+GEN_DFP_SP_Tp_Bp_Rc(ddedpdq, 0x02, 0x0a),
 #undef GEN_SPE
 #define GEN_SPE(name0, name1, opc2, opc3, inval0, inval1, type) \
     GEN_OPCODE_DUAL(name0##_##name1, 0x04, opc2, opc3, inval0, inval1, type, PPC_NONE)
-- 
1.8.1.4