1 files changed, 88 insertions, 0 deletions
diff --git a/target/nios2/op_helper.c b/target/nios2/op_helper.c
index caa885f7b4..2e30d0a908 100644
--- a/target/nios2/op_helper.c
+++ b/target/nios2/op_helper.c
@@ -30,3 +30,91 @@ void helper_raise_exception(CPUNios2State *env, uint32_t index)
     cs->exception_index = index;
     cpu_loop_exit(cs);
 }
+
+void nios2_cpu_loop_exit_advance(CPUNios2State *env, uintptr_t retaddr)
+{
+    CPUState *cs = env_cpu(env);
+
+    /*
+     * Note that PC is advanced for all hardware exceptions.
+     * Do this here, rather than in restore_state_to_opc(),
+     * lest we affect QEMU internal exceptions, like EXCP_DEBUG.
+     */
+    cpu_restore_state(cs, retaddr, true);
+    env->pc += 4;
+    cpu_loop_exit(cs);
+}
+
+static void maybe_raise_div(CPUNios2State *env, uintptr_t ra)
+{
+    Nios2CPU *cpu = env_archcpu(env);
+    CPUState *cs = env_cpu(env);
+
+    if (cpu->diverr_present) {
+        cs->exception_index = EXCP_DIV;
+        nios2_cpu_loop_exit_advance(env, ra);
+    }
+}
+
+int32_t helper_divs(CPUNios2State *env, int32_t num, int32_t den)
+{
+    if (unlikely(den == 0) || unlikely(den == -1 && num == INT32_MIN)) {
+        maybe_raise_div(env, GETPC());
+        return num; /* undefined */
+    }
+    return num / den;
+}
+
+uint32_t helper_divu(CPUNios2State *env, uint32_t num, uint32_t den)
+{
+    if (unlikely(den == 0)) {
+        maybe_raise_div(env, GETPC());
+        return num; /* undefined */
+    }
+    return num / den;
+}
+
+#ifndef CONFIG_USER_ONLY
+void helper_eret(CPUNios2State *env, uint32_t new_status, uint32_t new_pc)
+{
+    Nios2CPU *cpu = env_archcpu(env);
+    CPUState *cs = env_cpu(env);
+
+    if (unlikely(new_pc & 3)) {
+        env->ctrl[CR_BADADDR] = new_pc;
+        cs->exception_index = EXCP_UNALIGND;
+        nios2_cpu_loop_exit_advance(env, GETPC());
+    }
+
+    /*
+     * None of estatus, bstatus, or sstatus have constraints on write;
+     * do not allow reserved fields in status to be set.
+     * When shadow registers are enabled, eret *does* restore CRS.
+     * Rather than testing eic_present to decide, mask CRS out of
+     * the set of readonly fields.
+     */
+    new_status &= cpu->cr_state[CR_STATUS].writable |
+                  (cpu->cr_state[CR_STATUS].readonly & R_CR_STATUS_CRS_MASK);
+
+    env->ctrl[CR_STATUS] = new_status;
+    env->pc = new_pc;
+    nios2_update_crs(env);
+    cpu_loop_exit(cs);
+}
+
+/*
+ * RDPRS and WRPRS are implemented out of line so that if PRS == CRS,
+ * all of the tcg global temporaries are synced back to ENV.
+ */
+uint32_t helper_rdprs(CPUNios2State *env, uint32_t regno)
+{
+    unsigned prs = FIELD_EX32(env->ctrl[CR_STATUS], CR_STATUS, PRS);
+    return env->shadow_regs[prs][regno];
+}
+
+void helper_wrprs(CPUNios2State *env, uint32_t regno, uint32_t val)
+{
+    unsigned prs = FIELD_EX32(env->ctrl[CR_STATUS], CR_STATUS, PRS);
+    env->shadow_regs[prs][regno] = val;
+}
+#endif /* !CONFIG_USER_ONLY */