From aed74479fde702ea44888685ba10c84627aecfce Mon Sep 17 00:00:00 2001
From: joevt <joevt@shaw.ca>
Date: Sun, 12 Nov 2023 22:52:41 -0800
Subject: [PATCH] ppcmmu: Handle undefined mmu mode.

---
 cpu/ppc/ppcmmu.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/cpu/ppc/ppcmmu.cpp b/cpu/ppc/ppcmmu.cpp
index a317b83..a3031d8 100644
--- a/cpu/ppc/ppcmmu.cpp
+++ b/cpu/ppc/ppcmmu.cpp
@@ -389,6 +389,10 @@ void mmu_change_mode()
                 pCurITLB1 = &itlb1_mode2[0];
                 pCurITLB2 = &itlb2_mode2[0];
                 break;
+            case 1:
+                // user mode can't disable translations
+                LOG_F(ERROR, "instruction mmu mode 1 is invalid!");
+                mmu_mode = 3;
             case 3: // user mode with instruction translation enabled
                 pCurITLB1 = &itlb1_mode3[0];
                 pCurITLB2 = &itlb2_mode3[0];
@@ -410,6 +414,10 @@ void mmu_change_mode()
                 pCurDTLB1 = &dtlb1_mode2[0];
                 pCurDTLB2 = &dtlb2_mode2[0];
                 break;
+            case 1:
+                // user mode can't disable translations
+                LOG_F(ERROR, "data mmu mode 1 is invalid!");
+                mmu_mode = 3;
             case 3: // user mode with data translation enabled
                 pCurDTLB1 = &dtlb1_mode3[0];
                 pCurDTLB2 = &dtlb2_mode3[0];