diff --git a/include/ata.h b/include/ata.h
index 9d6f59c..dde377c 100644
--- a/include/ata.h
+++ b/include/ata.h
@@ -126,7 +126,7 @@
 
 #define ATA_BLOCKSIZE	512	/* bytes */
 #define ATA_BLOCKSHIFT	9	/* 2 ^ ATA_BLOCKSIZESHIFT = 512 */
-#define ATA_SECTORWORDS	(512 / sizeof(unsigned long))
+#define ATA_SECTORWORDS	(512 / sizeof(uint32_t))
 
 #ifndef ATA_RESET_TIME
 #define ATA_RESET_TIME	60	/* spec allows up to 31 seconds */