diff --git a/libc/string/lib_vikmemcpy.c b/libc/string/lib_vikmemcpy.c
index 41ab3ecf37..598672aac1 100644
--- a/libc/string/lib_vikmemcpy.c
+++ b/libc/string/lib_vikmemcpy.c
@@ -240,9 +240,9 @@
 
 #define COPY_SHIFT(shift)                                         \
 {                                                                 \
-  UIntN* dstN  = (UIntN*)((((UIntN)dst8) PRE_LOOP_ADJUST) &       \
+  UIntN* dstN  = (UIntN*)((((uintptr_t)dst8) PRE_LOOP_ADJUST) &   \
                            ~(TYPE_WIDTH - 1));                    \
-  UIntN* srcN  = (UIntN*)((((UIntN)src8) PRE_LOOP_ADJUST) &       \
+  UIntN* srcN  = (UIntN*)((((uintptr_t)src8) PRE_LOOP_ADJUST) &   \
                            ~(TYPE_WIDTH - 1));                    \
   size_t length  = count / TYPE_WIDTH;                            \
   UIntN srcWord = INC_VAL(srcN);                                  \
@@ -324,13 +324,13 @@ FAR void *memcpy(FAR void *dest, FAR const void *src, size_t count)
   START_VAL(dst8);
   START_VAL(src8);
 
-  while (((UIntN)dst8 & (TYPE_WIDTH - 1)) != WHILE_DEST_BREAK)
+  while (((uintptr_t)dst8 & (TYPE_WIDTH - 1)) != WHILE_DEST_BREAK)
     {
       INC_VAL(dst8) = INC_VAL(src8);
       count--;
     }
 
-  switch ((((UIntN)src8) PRE_SWITCH_ADJUST) & (TYPE_WIDTH - 1))
+  switch ((((uintptr_t)src8) PRE_SWITCH_ADJUST) & (TYPE_WIDTH - 1))
     {
     case 0: COPY_NO_SHIFT(); break;
     case 1: COPY_SHIFT(1);   break;