Re: [Qemu-devel] [PATCH 07/11] target/hppa: fix b,gate instruction

[Richard Henderson]

On 3/11/19 12:15 PM, Sven Schnelle wrote:
> b,gate does GR[t] ← cat(GR[t]{0..29},IAOQ_Front{30..31});
> instead of saving the link address to register t.
> 

Quite right.  Silly mistake.

>  #ifndef CONFIG_USER_ONLY
> +    TCGv_reg tmp;
>      if (ctx->tb_flags & PSW_C) {
>          CPUHPPAState *env = ctx->cs->env_ptr;
>          int type = hppa_artype_for_page(env, ctx->base.pc_next);
> @@ -3480,12 +3481,13 @@ static bool trans_b_gate(DisasContext *ctx, 
> arg_b_gate *a)
>          if (type >= 4 && type - 4 < ctx->privilege) {
>              dest = deposit32(dest, 0, 2, type - 4);
>          }
> +        tmp = dest_gpr(ctx, a->l);
> +        tcg_gen_deposit_reg(tmp, tmp, cpu_iaoq_f, 0, 2);
>      } else {
>          dest &= -4;  /* priv = 0 */
>      }
>  #endif
> -
> -    return do_dbranch(ctx, dest, a->l, a->n);
> +    return do_dbranch(ctx, dest, 0, a->n);

This change needs to be outside the CONFIG_USER_ONLY.  It needs to handle
nullification (which was previously all handled in do_dbranch).  I'm thinking
of something like the following.


r~


diff --git a/target/hppa/translate.c b/target/hppa/translate.c
index f3e78b8e22..6ac196804b 100644
--- a/target/hppa/translate.c
+++ b/target/hppa/translate.c
@@ -3446,6 +3446,8 @@ static bool trans_b_gate
 {
     target_ureg dest = iaoq_dest(ctx, a->disp);

+    nullify_over(ctx);
+
     /* Make sure the caller hasn't done something weird with the queue.
      * ??? This is not quite the same as the PSW[B] bit, which would be
      * expensive to track.  Real hardware will trap for
@@ -3483,7 +3485,16 @@ static bool trans_b_gate
     }
 #endif

-    return do_dbranch(ctx, dest, a->l, a->n);
+    if (a->l) {
+        TCGv_reg tmp = dest_gpr(ctx, a->l);
+        if (ctx->privilege < 3) {
+            tcg_gen_andi_reg(tmp, tmp, -4);
+        }
+        tcg_gen_ori_reg(tmp, tmp, ctx->privilege);
+        save_gpr(ctx, a->l, tmp);
+    }
+
+    return do_dbranch(ctx, dest, 0, a->n);
 }

 static bool trans_blr(DisasContext *ctx, arg_blr *a)