diff --git a/target/hppa/helper.h b/target/hppa/helper.h
index 38d834ef6b..2d483aab58 100644
--- a/target/hppa/helper.h
+++ b/target/hppa/helper.h
@@ -17,6 +17,8 @@ DEF_HELPER_FLAGS_3(stby_b_parallel, TCG_CALL_NO_WG, void, env, tl, tr)
 DEF_HELPER_FLAGS_3(stby_e, TCG_CALL_NO_WG, void, env, tl, tr)
 DEF_HELPER_FLAGS_3(stby_e_parallel, TCG_CALL_NO_WG, void, env, tl, tr)
 
+DEF_HELPER_FLAGS_1(ldc_check, TCG_CALL_NO_RWG, void, tl)
+
 DEF_HELPER_FLAGS_4(probe, TCG_CALL_NO_WG, tr, env, tl, i32, i32)
 
 DEF_HELPER_FLAGS_1(loaded_fr0, TCG_CALL_NO_RWG, void, env)
diff --git a/target/hppa/op_helper.c b/target/hppa/op_helper.c
index f0516e81f1..7823706e9c 100644
--- a/target/hppa/op_helper.c
+++ b/target/hppa/op_helper.c
@@ -153,6 +153,15 @@ void HELPER(stby_e_parallel)(CPUHPPAState *env, target_ulong addr,
     do_stby_e(env, addr, val, true, GETPC());
 }
 
+void HELPER(ldc_check)(target_ulong addr)
+{
+    if (unlikely(addr & 0xf)) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "Undefined ldc to unaligned address mod 16: "
+                      TARGET_FMT_lx "\n", addr);
+    }
+}
+
 target_ureg HELPER(probe)(CPUHPPAState *env, target_ulong addr,
                           uint32_t level, uint32_t want)
 {
diff --git a/target/hppa/translate.c b/target/hppa/translate.c
index f25927aeca..52d7bea1ea 100644
--- a/target/hppa/translate.c
+++ b/target/hppa/translate.c
@@ -2942,7 +2942,7 @@ static bool trans_st(DisasContext *ctx, arg_ldst *a)
 
 static bool trans_ldc(DisasContext *ctx, arg_ldst *a)
 {
-    MemOp mop = MO_TEUL | MO_ALIGN_16 | a->size;
+    MemOp mop = MO_TE | MO_ALIGN | a->size;
     TCGv_reg zero, dest, ofs;
     TCGv_tl addr;
 
@@ -2958,8 +2958,21 @@ static bool trans_ldc(DisasContext *ctx, arg_ldst *a)
 
     form_gva(ctx, &addr, &ofs, a->b, a->x, a->scale ? a->size : 0,
              a->disp, a->sp, a->m, ctx->mmu_idx == MMU_PHYS_IDX);
+
+    /*
+     * For hppa1.1, LDCW is undefined unless aligned mod 16.
+     * However actual hardware succeeds with aligned mod 4.
+     * Detect this case and log a GUEST_ERROR.
+     *
+     * TODO: HPPA64 relaxes the over-alignment requirement
+     * with the ,co completer.
+     */
+    gen_helper_ldc_check(addr);
+
     zero = tcg_const_reg(0);
     tcg_gen_atomic_xchg_reg(dest, addr, zero, ctx->mmu_idx, mop);
+    tcg_temp_free(zero);
+
     if (a->m) {
         save_gpr(ctx, a->b, ofs);
     }