[Qemu-devel] [V4 PATCH 06/22] target-ppc: Add ISA 2.06 divwe[o] Instructions

[Tom Musta <tommusta@gmail.com>]

This patch addes the signed Divide Word Extended instructions
which were introduced in Power ISA 2.06B.

Signed-off-by: Tom Musta <tommusta@gmail.com>
---
V2: Eliminating extraneous code in the overflow case per comments
from Richard Henderson.  Fixed corner case bug in divweu (check
for (RA) >= (RB)).

V4: Using newly added PPC2_DIVE_ISA206 flag.  Converted to helper
per Richard Henderson's review.

 target-ppc/helper.h     |    1 +
 target-ppc/int_helper.c |   32 ++++++++++++++++++++++++++++++++
 target-ppc/translate.c  |    4 ++++
 3 files changed, 37 insertions(+), 0 deletions(-)

diff --git a/target-ppc/helper.h b/target-ppc/helper.h
index 41025c9..ae2e990 100644
--- a/target-ppc/helper.h
+++ b/target-ppc/helper.h
@@ -35,6 +35,7 @@ DEF_HELPER_4(divdeu, i64, env, i64, i64, i32)
 DEF_HELPER_4(divde, i64, env, i64, i64, i32)
 #endif
 DEF_HELPER_4(divweu, tl, env, tl, tl, i32)
+DEF_HELPER_4(divwe, tl, env, tl, tl, i32)
 
 DEF_HELPER_FLAGS_1(cntlzw, TCG_CALL_NO_RWG_SE, tl, tl)
 DEF_HELPER_FLAGS_1(popcntb, TCG_CALL_NO_RWG_SE, tl, tl)
diff --git a/target-ppc/int_helper.c b/target-ppc/int_helper.c
index 45586be..71db3fb 100644
--- a/target-ppc/int_helper.c
+++ b/target-ppc/int_helper.c
@@ -72,6 +72,38 @@ target_ulong helper_divweu(CPUPPCState *env, target_ulong ra, target_ulong rb,
     return (target_ulong)rt;
 }
 
+target_ulong helper_divwe(CPUPPCState *env, target_ulong ra, target_ulong rb,
+                          uint32_t oe)
+{
+    int64_t rt = 0;
+    int overflow = 0;
+
+    int64_t dividend = (int64_t)ra << 32;
+    int64_t divisor = (int64_t)((int32_t)rb);
+
+    if (unlikely((divisor == 0) ||
+                 ((divisor == -1ull) && (dividend == INT64_MIN)))) {
+        overflow = 1;
+    } else {
+        rt = dividend / divisor;
+        overflow = rt != (int32_t)rt;
+    }
+
+    if (unlikely(overflow)) {
+        rt = 0; /* Undefined */
+    }
+
+    if (oe) {
+        if (unlikely(overflow)) {
+            env->so = env->ov = 1;
+        } else {
+            env->ov = 0;
+        }
+    }
+
+    return (target_ulong)rt;
+}
+
 #if defined(TARGET_PPC64)
 
 uint64_t helper_divdeu(CPUPPCState *env, uint64_t ra, uint64_t rb, uint32_t oe)
diff --git a/target-ppc/translate.c b/target-ppc/translate.c
index a7d3295..d476d92 100644
--- a/target-ppc/translate.c
+++ b/target-ppc/translate.c
@@ -1000,6 +1000,8 @@ static void gen_##name(DisasContext *ctx)                                     \
 
 GEN_DIVE(divweu, divweu, 0);
 GEN_DIVE(divweuo, divweu, 1);
+GEN_DIVE(divwe, divwe, 0);
+GEN_DIVE(divweo, divwe, 1);
 
 #if defined(TARGET_PPC64)
 static inline void gen_op_arith_divd(DisasContext *ctx, TCGv ret, TCGv arg1,
@@ -9622,6 +9624,8 @@ GEN_INT_ARITH_DIVW(divwu, 0x0E, 0, 0),
 GEN_INT_ARITH_DIVW(divwuo, 0x1E, 0, 1),
 GEN_INT_ARITH_DIVW(divw, 0x0F, 1, 0),
 GEN_INT_ARITH_DIVW(divwo, 0x1F, 1, 1),
+GEN_HANDLER_E(divwe, 0x1F, 0x0B, 0x0D, 0, PPC_NONE, PPC2_DIVE_ISA206),
+GEN_HANDLER_E(divweo, 0x1F, 0x0B, 0x1D, 0, PPC_NONE, PPC2_DIVE_ISA206),
 GEN_HANDLER_E(divweu, 0x1F, 0x0B, 0x0C, 0, PPC_NONE, PPC2_DIVE_ISA206),
 GEN_HANDLER_E(divweuo, 0x1F, 0x0B, 0x1C, 0, PPC_NONE, PPC2_DIVE_ISA206),
 
-- 
1.7.1