py: Temporary fix for conversion of float to int when fits in small int.

Addresses issue #1044 (see also #1040).  Could do with a better fix.

py/objint_mpz.c

@@ -303,6 +303,9 @@ mp_obj_t mp_obj_new_int_from_float(mp_float_t val) {
         nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OverflowError, "can't convert inf to int"));
     } else if (cl == FP_NAN) {
         nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "can't convert NaN to int"));
+    } else if (MICROPY_FLOAT_C_FUN(fabs)(val) < 10000) {
+        // temporary(?) fix for optimising case where int will be small int
+        return MP_OBJ_NEW_SMALL_INT(MICROPY_FLOAT_C_FUN(trunc)(val));
     } else {
         mp_obj_int_t *o = mp_obj_int_new_mpz();
         mpz_set_from_float(&o->mpz, val);

tests/float/float2int.py

@@ -1,22 +1,21 @@
-# This case occurs with time.time() values
-print(int(1418774543.))
+# check cases converting float to int, relying only on single precision float
 
+print(int(14187745.))
 print(int(2.**100))
-
-print("%d" % 1418774543.)
-
+print("%d" % 14187745.)
 print("%d" % 2.**100)
 
 testpass = True
-for i in range(0,1024):
+for i in range(0,128):
     bitcnt = len(bin(int(2.**i))) - 3;
     if i != bitcnt:
         print('fail: 2**%u was %u bits long' % (i, bitcnt));
         testpass = False
 print("power of  2 test: %s" % (testpass and 'passed' or 'failed'))
 
+# TODO why does 10**12 fail this test for single precision float?
 testpass = True
-for i in range(0,23):
+for i in range(0,12):
     digcnt = len(str(int(10.**i))) - 1;
     if i != digcnt:
         print('fail: 10**%u was %u digits long' % (i, digcnt));
@@ -34,3 +33,7 @@ try:
     int(float('nan'))
 except ValueError:
     print("ValueError")
+
+# test numbers < 1 (this used to fail; see issue #1044)
+import struct
+struct.pack('I', int(1/2))

tests/float/float2int_doubleprec.py

@@ -0,0 +1,21 @@
+# check cases converting float to int, requiring double precision float
+
+# This case occurs with time.time() values
+print(int(1418774543.))
+print("%d" % 1418774543.)
+
+testpass = True
+for i in range(0,1024):
+    bitcnt = len(bin(int(2.**i))) - 3;
+    if i != bitcnt:
+        print('fail: 2**%u was %u bits long' % (i, bitcnt));
+        testpass = False
+print("power of  2 test: %s" % (testpass and 'passed' or 'failed'))
+
+testpass = True
+for i in range(0,23):
+    digcnt = len(str(int(10.**i))) - 1;
+    if i != digcnt:
+        print('fail: 10**%u was %u digits long' % (i, digcnt));
+        testpass = False
+print("power of 10 test: %s" % (testpass and 'passed' or 'failed'))

tests/run-tests

@@ -65,7 +65,7 @@ def run_tests(pyb, tests, args):
     # Some tests shouldn't be run on pyboard
     if pyb is not None:
         skip_tests.add('float/float_divmod.py') # tested by float/float_divmod_relaxed.py instead
-        skip_tests.add('float/float2int.py') # requires double precision floating point to work
+        skip_tests.add('float/float2int_doubleprec.py') # requires double precision floating point to work
 
     # Some tests are known to fail on 64-bit machines
     if pyb is None and platform.architecture()[0] == '64bit':