[Qemu-devel] [PATCH 6/6] target-ppc: Implement mulldo with TCG

[Tom Musta <tommusta@gmail.com>]

Optimize mulldo by using the muls2_i64 operation rather than a helper.  Eliminate
the obsolete helper code.

Signed-off-by: Tom Musta <tommusta@gmail.com>
Suggested-by: Richard Henderson <rth@twiddle.net>
---
 target-ppc/helper.h     |    1 -
 target-ppc/int_helper.c |   27 ---------------------------
 target-ppc/translate.c  |   16 ++++++++++++++--
 3 files changed, 14 insertions(+), 30 deletions(-)

diff --git a/target-ppc/helper.h b/target-ppc/helper.h
index 509eae5..0cfdc8a 100644
--- a/target-ppc/helper.h
+++ b/target-ppc/helper.h
@@ -28,7 +28,6 @@ DEF_HELPER_2(icbi, void, env, tl)
 DEF_HELPER_5(lscbx, tl, env, tl, i32, i32, i32)
 
 #if defined(TARGET_PPC64)
-DEF_HELPER_3(mulldo, i64, env, i64, i64)
 DEF_HELPER_4(divdeu, i64, env, i64, i64, i32)
 DEF_HELPER_4(divde, i64, env, i64, i64, i32)
 #endif
diff --git a/target-ppc/int_helper.c b/target-ppc/int_helper.c
index e5b103b..713d777 100644
--- a/target-ppc/int_helper.c
+++ b/target-ppc/int_helper.c
@@ -24,33 +24,6 @@
 #include "helper_regs.h"
 /*****************************************************************************/
 /* Fixed point operations helpers */
-#if defined(TARGET_PPC64)
-
-uint64_t helper_mulldo(CPUPPCState *env, uint64_t arg1, uint64_t arg2)
-{
-    int64_t th;
-    uint64_t tl;
-
-    muls64(&tl, (uint64_t *)&th, arg1, arg2);
-
-    /* th should either contain all 1 bits or all 0 bits and should
-     * match the sign bit of tl; otherwise we have overflowed. */
-
-    if ((int64_t)tl < 0) {
-        if (likely(th == -1LL)) {
-            env->ov = 0;
-        } else {
-            env->so = env->ov = 1;
-        }
-    } else if (likely(th == 0LL)) {
-        env->ov = 0;
-    } else {
-        env->so = env->ov = 1;
-    }
-
-    return (int64_t)tl;
-}
-#endif
 
 target_ulong helper_divweu(CPUPPCState *env, target_ulong ra, target_ulong rb,
                            uint32_t oe)
diff --git a/target-ppc/translate.c b/target-ppc/translate.c
index 1062634..d03daea 100644
--- a/target-ppc/translate.c
+++ b/target-ppc/translate.c
@@ -1215,8 +1215,20 @@ static void gen_mulld(DisasContext *ctx)
 /* mulldo  mulldo. */
 static void gen_mulldo(DisasContext *ctx)
 {
-    gen_helper_mulldo(cpu_gpr[rD(ctx->opcode)], cpu_env,
-                      cpu_gpr[rA(ctx->opcode)], cpu_gpr[rB(ctx->opcode)]);
+    TCGv_i64 t0 = tcg_temp_new_i64();
+    TCGv_i64 t1 = tcg_temp_new_i64();
+
+    tcg_gen_muls2_i64(t0, t1, cpu_gpr[rA(ctx->opcode)],
+                      cpu_gpr[rB(ctx->opcode)]);
+    tcg_gen_mov_i64(cpu_gpr[rD(ctx->opcode)], t0);
+
+    tcg_gen_sari_i64(t0, t0, 63);
+    tcg_gen_setcond_i64(TCG_COND_NE, cpu_ov, t0, t1);
+    tcg_gen_or_tl(cpu_so, cpu_so, cpu_ov);
+
+    tcg_temp_free_i64(t0);
+    tcg_temp_free_i64(t1);
+
     if (unlikely(Rc(ctx->opcode) != 0)) {
         gen_set_Rc0(ctx, cpu_gpr[rD(ctx->opcode)]);
     }
-- 
1.7.1