diff --git a/src/arch/arm/abi.zig b/src/arch/arm/abi.zig
index 9659ca13d72414e8babaa01f71c010222a3a8af8..13424fd9fa9bd4c3be76a76f710b8df5d86b5b54 100644
--- a/src/arch/arm/abi.zig
+++ b/src/arch/arm/abi.zig
@@ -11,7 +11,7 @@ pub const Class = union(enum) {
     i64_array: u8,
 
     fn arrSize(total_size: u64, arr_size: u64) Class {
-        const count = @intCast(u8, std.mem.alignForward(total_size, arr_size) / arr_size);
+        const count = @intCast(u8, std.mem.alignForwardGeneric(u64, total_size, arr_size) / arr_size);
         if (arr_size == 32) {
             return .{ .i32_array = count };
         } else {