Fix some conversions

jerry-core/ecma/base/ecma-helpers-conversion.c

@@ -812,7 +812,48 @@ ecma_number_to_decimal (ecma_number_t num, /**< ecma-number */
   JERRY_ASSERT (!ecma_number_is_infinity (num));
   JERRY_ASSERT (!ecma_number_is_negative (num));
 
+#if JERRY_NUMBER_TYPE_FLOAT64
   return ecma_errol0_dtoa ((double) num, out_digits_p, out_decimal_exp_p);
+#else /* !JERRY_NUMBER_TYPE_FLOAT64 */
+  /* Float32: snprintf with ECMA_NUMBER_MAX_DIGITS significant digits guarantees round-trip.
+   * Using %e gives "D.DDDDDDDDe±EEE" which we parse into digits + decimal exponent. */
+  char buf[ECMA_NUMBER_MAX_DIGITS + 16];
+  snprintf (buf, sizeof (buf), "%.*e", ECMA_NUMBER_MAX_DIGITS - 1, (double) num);
+
+  char *p = buf;
+  lit_utf8_byte_t *out_p = out_digits_p;
+  int32_t k = 0;
+
+  *out_p++ = (lit_utf8_byte_t) *p++; /* first significant digit */
+  k++;
+  p++; /* skip '.' */
+
+  while (*p != 'e' && *p != 'E')
+  {
+    *out_p++ = (lit_utf8_byte_t) *p++;
+    k++;
+  }
+
+  /* strip trailing zeros */
+  while (k > 1 && out_digits_p[k - 1] == '0')
+  {
+    k--;
+  }
+
+  p++; /* skip 'e' */
+  int32_t exp_sign = (*p == '-') ? -1 : 1;
+  p++; /* skip sign */
+  int32_t exponent = 0;
+  while (*p)
+  {
+    exponent = exponent * 10 + (*p++ - '0');
+  }
+
+  /* decimal exponent convention: n=1 means first digit is units, n=0 means "0.d..." */
+  *out_decimal_exp_p = exp_sign * exponent + 1;
+
+  return (lit_utf8_size_t) k;
+#endif /* JERRY_NUMBER_TYPE_FLOAT64 */
 } /* ecma_number_to_decimal */
 
 /**