diff --git a/vm/bignum.cpp b/vm/bignum.cpp
index f7c78d6e5b..2610be3a3c 100644
--- a/vm/bignum.cpp
+++ b/vm/bignum.cpp
@@ -270,8 +270,6 @@ bignum* factor_vm::bignum_remainder(bignum* numerator, bignum* denominator) {
 #define FOO_TO_BIGNUM(name, type, stype, utype)                       \
   bignum* factor_vm::name##_to_bignum(type n) {                       \
     int negative_p;                                                   \
-    bignum_digit_type result_digits[BIGNUM_DIGITS_FOR(type)];         \
-    bignum_digit_type* end_digits = result_digits;                    \
     /* Special cases win when these small constants are cached. */    \
     if (n == 0)                                                       \
       return (BIGNUM_ZERO());                                         \
@@ -282,19 +280,22 @@ bignum* factor_vm::bignum_remainder(bignum* numerator, bignum* denominator) {
     {                                                                 \
       utype accumulator =                                             \
           ((negative_p = (n < (type) 0)) ? ((type)(-(stype) n)) : n); \
-      do {                                                            \
-        (*end_digits++) = (accumulator & BIGNUM_DIGIT_MASK);          \
+      if (accumulator < BIGNUM_RADIX)                                 \
+      {                                                               \
+        bignum* result = allot_bignum(1, negative_p);                 \
+        bignum_digit_type* scan = (BIGNUM_START_PTR(result));         \
+        *scan = (accumulator & BIGNUM_DIGIT_MASK);                    \
+        return (result);                                              \
+      } else {                                                        \
+        BIGNUM_ASSERT(BIGNUM_DIGITS_FOR(type) == 2);                  \
+        bignum* result = allot_bignum(2, negative_p);                 \
+        bignum_digit_type* scan = (BIGNUM_START_PTR(result));         \
+        (*scan++) = (accumulator & BIGNUM_DIGIT_MASK);                \
         accumulator >>= BIGNUM_DIGIT_LENGTH;                          \
-      } while (accumulator != 0);                                     \
-    }                                                                 \
-    {                                                                 \
-      bignum* result =                                                \
-          (allot_bignum((end_digits - result_digits), negative_p));   \
-      bignum_digit_type* scan_digits = result_digits;                 \
-      bignum_digit_type* scan_result = (BIGNUM_START_PTR(result));    \
-      while (scan_digits < end_digits)                                \
-        (*scan_result++) = (*scan_digits++);                          \
-      return (result);                                                \
+        *scan = (accumulator & BIGNUM_DIGIT_MASK);                    \
+        BIGNUM_ASSERT((accumulator >> BIGNUM_DIGIT_LENGTH) == 0);     \
+        return (result);                                              \
+      }                                                               \
     }                                                                 \
   }