target-alpha: Implement call_pal without an exception

The destination of the call_pal, and the cpu state, is very predictable;
there's no need for exiting the cpu loop.
Signed-off-by: NRichard Henderson <rth@twiddle.net>

target-alpha/helper.h

@@ -99,6 +99,7 @@ DEF_HELPER_FLAGS_2(ieee_input_cmp, TCG_CALL_NO_WG, void, env, i64)
 
 #if !defined (CONFIG_USER_ONLY)
 DEF_HELPER_2(hw_ret, void, env, i64)
+DEF_HELPER_3(call_pal, void, env, i64, i64)
 
 DEF_HELPER_1(ldl_phys, i64, i64)
 DEF_HELPER_1(ldq_phys, i64, i64)

target-alpha/sys_helper.c

@@ -51,6 +51,17 @@ void helper_hw_ret(CPUAlphaState *env, uint64_t a)
     }
 }
 
+void helper_call_pal(CPUAlphaState *env, uint64_t pc, uint64_t entry_ofs)
+{
+    int pal_mode = env->pal_mode;
+    env->exc_addr = pc | pal_mode;
+    env->pc = env->palbr + entry_ofs;
+    if (!pal_mode) {
+        env->pal_mode = 1;
+        swap_shadow_regs(env);
+    }
+}
+
 void helper_tbia(CPUAlphaState *env)
 {
     tlb_flush(env, 1);
@@ -91,4 +102,5 @@ void helper_set_alarm(CPUAlphaState *env, uint64_t expire)
         qemu_del_timer(cpu->alarm_timer);
     }
 }
+
 #endif /* CONFIG_USER_ONLY */

target-alpha/translate.c

@@ -1521,7 +1521,8 @@ static ExitStatus gen_call_pal(DisasContext *ctx, int palcode)
             tcg_gen_mov_i64(cpu_unique, cpu_ir[IR_A0]);
             break;
         default:
-            return gen_excp(ctx, EXCP_CALL_PAL, palcode & 0xbf);
+            palcode &= 0xbf;
+            goto do_call_pal;
         }
         return NO_EXIT;
     }
@@ -1586,13 +1587,31 @@ static ExitStatus gen_call_pal(DisasContext *ctx, int palcode)
             break;
 
         default:
-            return gen_excp(ctx, EXCP_CALL_PAL, palcode & 0x3f);
+            palcode &= 0x3f;
+            goto do_call_pal;
         }
         return NO_EXIT;
     }
 #endif
-
     return gen_invalid(ctx);
+
+ do_call_pal:
+#ifdef CONFIG_USER_ONLY
+    return gen_excp(ctx, EXCP_CALL_PAL, palcode);
+#else
+    {
+        TCGv pc = tcg_const_i64(ctx->pc);
+        TCGv entry = tcg_const_i64(palcode & 0x80
+                                   ? 0x2000 + (palcode - 0x80) * 64
+                                   : 0x1000 + palcode * 64);
+
+        gen_helper_call_pal(cpu_env, pc, entry);
+
+        tcg_temp_free(entry);
+        tcg_temp_free(pc);
+        return EXIT_PC_UPDATED;
+    }
+#endif
 }
 
 #ifndef CONFIG_USER_ONLY