1 files changed, 53 insertions, 0 deletions
diff --git a/py/smallint.c b/py/smallint.c
new file mode 100644
index 0000000000..ac0cf2f5f9
--- /dev/null
+++ b/py/smallint.c
@@ -0,0 +1,53 @@
+#include "misc.h"
+#include "mpconfig.h"
+#include "qstr.h"
+#include "obj.h"
+
+bool mp_small_int_mul_overflow(machine_int_t x, machine_int_t y) {
+    // Check for multiply overflow; see CERT INT32-C
+    if (x > 0) { // x is positive
+        if (y > 0) { // x and y are positive
+            if (x > (MP_SMALL_INT_MAX / y)) {
+                return true;
+            }
+        } else { // x positive, y nonpositive
+            if (y < (MP_SMALL_INT_MIN / x)) {
+                return true;
+            }
+        } // x positive, y nonpositive
+    } else { // x is nonpositive
+        if (y > 0) { // x is nonpositive, y is positive
+            if (x < (MP_SMALL_INT_MIN / y)) {
+                return true;
+            }
+        } else { // x and y are nonpositive
+            if (x != 0 && y < (MP_SMALL_INT_MAX / x)) {
+                return true;
+            }
+        } // End if x and y are nonpositive
+    } // End if x is nonpositive
+    return false;
+}
+
+machine_int_t mp_small_int_modulo(machine_int_t dividend, machine_int_t divisor) {
+    machine_int_t lsign = (dividend >= 0) ? 1 :-1;
+    machine_int_t rsign = (divisor >= 0) ? 1 :-1;
+    dividend %= divisor;
+    if (lsign != rsign) {
+        dividend += divisor;
+    }
+  return dividend;
+}
+
+
+machine_int_t mp_small_int_floor_divide(machine_int_t num, machine_int_t denom) {
+    machine_int_t lsign = num > 0 ? 1 : -1;
+    machine_int_t rsign = denom > 0 ? 1 : -1;
+    if (lsign == -1) {num *= -1;}
+    if (rsign == -1) {denom *= -1;}
+    if (lsign != rsign){
+        return - ( num + denom - 1) / denom;
+    } else {
+        return num / denom;
+    }
+}