diff --git a/src/northbridge/intel/i945/ram_calc.c b/src/northbridge/intel/i945/ram_calc.c
index b161431..4349d19 100644
--- a/src/northbridge/intel/i945/ram_calc.c
+++ b/src/northbridge/intel/i945/ram_calc.c
@@ -19,6 +19,7 @@
 #include <arch/io.h>
 #include <cbmem.h>
 #include "i945.h"
+#include <console/console.h>
 
 static uintptr_t smm_region_start(void)
 {
@@ -56,3 +57,15 @@
 {
 	return (void *) smm_region_start();
 }
+
+/** Decodes used Graphics Mode Select (GMS) to kilobytes. */
+u32 decode_igd_memory_size(const u32 gms)
+{
+	static const u16 ggc2uma[] = { 0, 1, 4, 8, 16, 32,
+			48, 64 };
+
+	if (gms > ARRAY_SIZE(ggc2uma))
+		die("Bad Graphics Mode Select (GMS) setting.\n");
+
+	return ggc2uma[gms] << 10;
+}