diff --git a/src/cs_gen.cc b/src/cs_gen.cc
index 2ed84dd..889c862 100644
--- a/src/cs_gen.cc
+++ b/src/cs_gen.cc
@@ -5,6 +5,7 @@
 #include <ctype.h>
 
 #include <ostd/memory.hh>
+#include <ostd/limits.hh>
 
 namespace cscript {
 
@@ -353,7 +354,7 @@ lookupid:
                                     numargs++;
                                     break;
                                 case 'b':
-                                    gs.gen_int(CsIntMin);
+                                    gs.gen_int(ostd::NumericLimitMin<CsInt>);
                                     numargs++;
                                     break;
                                 case 'f':
@@ -939,7 +940,7 @@ static void compile_cmd(
                     if (rep) {
                         break;
                     }
-                    gs.gen_int(CsIntMin);
+                    gs.gen_int(ostd::NumericLimitMin<CsInt>);
                     fakeargs++;
                 }
                 numargs++;
diff --git a/src/cs_util.hh b/src/cs_util.hh
index 0f32a61..827e54c 100644
--- a/src/cs_util.hh
+++ b/src/cs_util.hh
@@ -7,9 +7,6 @@
 
 namespace cscript {
 
-/* TODO: use actual numeric limits as soon as ostd has them */
-constexpr CsInt const CsIntMin = -(~(1ULL << (sizeof(CsInt) * CHAR_BIT - 1))) - 1;
-
 template<typename K, typename V>
 using CsMap = ostd::Map<K, V>;
 
diff --git a/src/cs_vm.cc b/src/cs_vm.cc
index fa8b77c..dd3d547 100644
--- a/src/cs_vm.cc
+++ b/src/cs_vm.cc
@@ -3,6 +3,7 @@
 #include "cs_util.hh"
 
 #include <ostd/memory.hh>
+#include <ostd/limits.hh>
 
 namespace cscript {
 
@@ -320,7 +321,7 @@ static inline void callcommand(
                     if (rep) {
                         break;
                     }
-                    args[i].set_int(CsIntMin);
+                    args[i].set_int(ostd::NumericLimitMin<CsInt>);
                     fakeargs++;
                 } else {
                     args[i].force_int();
diff --git a/src/lib_math.cc b/src/lib_math.cc
index ca8fd2c..2c08445 100644
--- a/src/lib_math.cc
+++ b/src/lib_math.cc
@@ -1,5 +1,3 @@
-#include <limits.h>
-
 /* c++ versions for overloaded math */
 #include <stdlib.h>
 #include <math.h>
@@ -309,7 +307,7 @@ void cs_init_lib_math(CsState &cs) {
     cs.new_command("<<", "i1V", [](auto &, auto args, auto &res) {
         cs_mathop<CsInt>(
             args, res, 0, [](CsInt val1, CsInt val2) {
-                return (val2 < CsInt(sizeof(CsInt) * CHAR_BIT))
+                return (val2 < CsInt(ostd::SizeInBits<CsInt>))
                     ? (val1 << ostd::max(val2, CsInt(0)))
                     : 0;
             }, CsMathNoop<CsInt>()
@@ -319,7 +317,7 @@ void cs_init_lib_math(CsState &cs) {
         cs_mathop<CsInt>(
             args, res, 0, [](CsInt val1, CsInt val2) {
                 return val1 >> ostd::clamp(
-                    val2, CsInt(0), CsInt(sizeof(CsInt) * CHAR_BIT)
+                    val2, CsInt(0), CsInt(ostd::SizeInBits<CsInt>)
                 );
             }, CsMathNoop<CsInt>()
         );