target-alpha: Merge HW_REI and HW_RET implementations.

Signed-off-by: Richard Henderson <rth@twiddle.net>
diff --git a/target-alpha/helper.h b/target-alpha/helper.h
index f4f693a..de86ff2 100644
--- a/target-alpha/helper.h
+++ b/target-alpha/helper.h
@@ -100,7 +100,6 @@
 DEF_HELPER_1(ieee_input_s, i64, i64)
 
 #if !defined (CONFIG_USER_ONLY)
-DEF_HELPER_0(hw_rei, void)
 DEF_HELPER_1(hw_ret, void, i64)
 DEF_HELPER_2(mfpr, i64, int, i64)
 DEF_HELPER_2(mtpr, void, int, i64)
diff --git a/target-alpha/op_helper.c b/target-alpha/op_helper.c
index a90c7a6..ea11cd2 100644
--- a/target-alpha/op_helper.c
+++ b/target-alpha/op_helper.c
@@ -1156,22 +1156,12 @@
 
 /* PALcode support special instructions */
 #if !defined (CONFIG_USER_ONLY)
-void helper_hw_rei (void)
-{
-    env->pc = env->ipr[IPR_EXC_ADDR] & ~3;
-    env->ipr[IPR_EXC_ADDR] = env->ipr[IPR_EXC_ADDR] & 1;
-    env->intr_flag = 0;
-    env->lock_addr = -1;
-    /* XXX: re-enable interrupts and memory mapping */
-}
-
 void helper_hw_ret (uint64_t a)
 {
     env->pc = a & ~3;
     env->ipr[IPR_EXC_ADDR] = a & 1;
     env->intr_flag = 0;
     env->lock_addr = -1;
-    /* XXX: re-enable interrupts and memory mapping */
 }
 
 uint64_t helper_mfpr (int iprn, uint64_t val)
diff --git a/target-alpha/translate.c b/target-alpha/translate.c
index 2c0b9c2..2559814 100644
--- a/target-alpha/translate.c
+++ b/target-alpha/translate.c
@@ -2876,25 +2876,22 @@
         break;
 #endif
     case 0x1E:
-        /* HW_REI (PALcode) */
+        /* HW_RET (PALcode) */
 #if defined (CONFIG_USER_ONLY)
         goto invalid_opc;
 #else
         if (!ctx->pal_mode)
             goto invalid_opc;
         if (rb == 31) {
-            /* "Old" alpha */
-            gen_helper_hw_rei();
-        } else {
-            TCGv tmp;
-
-            if (ra != 31) {
-                tmp = tcg_temp_new();
-                tcg_gen_addi_i64(tmp, cpu_ir[rb], (((int64_t)insn << 51) >> 51));
-            } else
-                tmp = tcg_const_i64(((int64_t)insn << 51) >> 51);
+            /* Pre-EV6 CPUs interpreted this as HW_REI, loading the return
+               address from EXC_ADDR.  This turns out to be useful for our
+               emulation PALcode, so continue to accept it.  */
+            TCGv tmp = tcg_temp_new();
+            tcg_gen_ld_i64(tmp, cpu_env, offsetof(CPUState, ipr[IPR_EXC_ADDR]));
             gen_helper_hw_ret(tmp);
             tcg_temp_free(tmp);
+        } else {
+            gen_helper_hw_ret(cpu_ir[rb]);
         }
         ret = EXIT_PC_UPDATED;
         break;