diff --git a/cpu/mpc8xxx/ddr/ddr3_dimm_params.c b/cpu/mpc8xxx/ddr/ddr3_dimm_params.c
index 8d686ac5d9191e881d1e1d2e23dc73f148fc3a44..13d234e9331542eb8d56780cf971ac0bdd26ead0 100644
--- a/cpu/mpc8xxx/ddr/ddr3_dimm_params.c
+++ b/cpu/mpc8xxx/ddr/ddr3_dimm_params.c
@@ -68,7 +68,7 @@ compute_ranksize(const ddr3_spd_eeprom_t *spd)
 	if ((spd->organization & 0x7) < 4)
 		nbit_sdram_width = (spd->organization & 0x7) + 2;
 
-	bsize = 1 << (nbit_sdram_cap_bsize - 3
+	bsize = 1ULL << (nbit_sdram_cap_bsize - 3
 		    + nbit_primary_bus_width - nbit_sdram_width);
 
 	debug("DDR: DDR III rank density = 0x%08x\n", bsize);