diff --git a/src/northbridge/intel/i945/northbridge.c b/src/northbridge/intel/i945/northbridge.c
index 514f88c..719a795 100644
--- a/src/northbridge/intel/i945/northbridge.c
+++ b/src/northbridge/intel/i945/northbridge.c
@@ -104,18 +104,8 @@
 	/* Note: subtract IGD device and TSEG */
 	reg16 = pci_read_config16(dev_find_slot(0, PCI_DEVFN(0, 0)), GGC);
 	if (!(reg16 & 2)) {
-		int uma_size = 0;
 		printk(BIOS_DEBUG, "IGD decoded, subtracting ");
-		reg16 >>= 4;
-		reg16 &= 7;
-		switch (reg16) {
-		case 1:
-			uma_size = 1024;
-			break;
-		case 3:
-			uma_size = 8192;
-			break;
-		}
+		int uma_size = decode_igd_memory_size((reg16 >> 4) & 7);
 
 		printk(BIOS_DEBUG, "%dM UMA\n", uma_size >> 10);
 		tomk_stolen -= uma_size;