diff --git a/src/base_core.h b/src/base_core.h
index d1542d9..8a5f7b7 100644
--- a/src/base_core.h
+++ b/src/base_core.h
@@ -104,12 +104,43 @@ typedef unsigned __int128 U128;
     (const type *)((const void *)(const unsigned char *)__mptr - offsetof(const type, member));                     \
   })
 
-// align needs to be pow2
-#define AlignUp(val, align)     (((val) + (align) - 1UL) & ~((align) - 1UL))
-#define AlignDown(val, align)   ((val) & ~((align) - 1UL))
-#define IsPow2(x)                   ((x) && !((x) & ((x) - 1UL)))
-#define IsPow2OrZero(x)             (!((x) & ((x) - 1UL)))
-#define IsAlignedTo(x, align)           (IsPow2(align) && !((x) & ((align) - 1UL)))
+// `align` must be a power of two.
+//
+// These keep the result in the *same integer type as the first argument*
+#define AlignUp(val, align)                                                \
+  ({                                                                       \
+    __typeof__(val) AlignUp_v_ = (val);                                    \
+    __typeof__(val) AlignUp_a_ = (__typeof__(val))(align);                 \
+    (__typeof__(val))((AlignUp_v_ + (AlignUp_a_ - 1)) &                    \
+                      ~(__typeof__(val))(AlignUp_a_ - 1));                 \
+  })
+
+#define AlignDown(val, align)                                              \
+  ({                                                                       \
+    __typeof__(val) AlignDown_v_ = (val);                                  \
+    __typeof__(val) AlignDown_a_ = (__typeof__(val))(align);               \
+    (__typeof__(val))(AlignDown_v_ & ~(__typeof__(val))(AlignDown_a_ - 1));\
+  })
+
+#define IsPow2(x)                                                          \
+  ({                                                                       \
+    __typeof__(x) IsPow2_x_ = (x);                                         \
+    IsPow2_x_ && !(IsPow2_x_ & (__typeof__(x))(IsPow2_x_ - 1));            \
+  })
+
+#define IsPow2OrZero(x)                                                    \
+  ({                                                                       \
+    __typeof__(x) IsPow2OrZero_x_ = (x);                                   \
+    !(IsPow2OrZero_x_ & (__typeof__(x))(IsPow2OrZero_x_ - 1));             \
+  })
+
+#define IsAlignedTo(x, align)                                              \
+  ({                                                                       \
+    __typeof__(x) IsAlignedTo_x_ = (x);                                    \
+    __typeof__(x) IsAlignedTo_a_ = (__typeof__(x))(align);                 \
+    IsPow2(IsAlignedTo_a_) &&                                              \
+        !(IsAlignedTo_x_ & (__typeof__(x))(IsAlignedTo_a_ - 1));           \
+  })
 
 #define GetBit(val, idx) (((val) >> (idx)) & 1)
 // Get n_bits starting at idx going left