diff --git a/src/devices/cpu/mips/mips1.cpp b/src/devices/cpu/mips/mips1.cpp
index 05e3996d96f..57c0c151d55 100644
--- a/src/devices/cpu/mips/mips1.cpp
+++ b/src/devices/cpu/mips/mips1.cpp
@@ -156,12 +156,14 @@ void mips1core_device_base::device_add_mconfig(machine_config &config)
 
 void mips1core_device_base::icache_map(address_map &map)
 {
-	map(0, m_icache_size - 1).ram().mirror(~(m_icache_size - 1));
+	if (m_icache_size)
+		map(0, m_icache_size - 1).ram().mirror(~(m_icache_size - 1));
 }
 
 void mips1core_device_base::dcache_map(address_map &map)
 {
-	map(0, m_dcache_size - 1).ram().mirror(~(m_dcache_size - 1));
+	if (m_dcache_size)
+		map(0, m_dcache_size - 1).ram().mirror(~(m_dcache_size - 1));
 }
 
 void mips1core_device_base::device_start()