Fixed floor division on mp ints and small ints. Added a floordivide test case.

5 files changed, 49 insertions, 7 deletions

diff --git a/py/compile.c b/py/compile.c
index 4eab094230..0a10b81768 100644
--- a/py/compile.c
+++ b/py/compile.c
@@ -3,6 +3,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <assert.h>
+#include <math.h>
 
 #include "misc.h"
 #include "mpconfig.h"
@@ -141,12 +142,13 @@ mp_parse_node_t fold_constants(mp_parse_node_t pn) {
                     } else if (MP_PARSE_NODE_IS_TOKEN_KIND(pns->nodes[1], MP_TOKEN_OP_SLASH)) {
                         ; // pass
                     } else if (MP_PARSE_NODE_IS_TOKEN_KIND(pns->nodes[1], MP_TOKEN_OP_PERCENT)) {
-                        // XXX implement this properly as Python's % operator acts differently to C's
-                        //pn = mp_parse_node_new_leaf(MP_PARSE_NODE_SMALL_INT, arg0 % arg1);
                         pn = mp_parse_node_new_leaf(MP_PARSE_NODE_SMALL_INT, python_modulo(arg0, arg1));
                     } else if (MP_PARSE_NODE_IS_TOKEN_KIND(pns->nodes[1], MP_TOKEN_OP_DBL_SLASH)) {
-                        // XXX implement this properly as Python's // operator acts differently to C's
-                        pn = mp_parse_node_new_leaf(MP_PARSE_NODE_SMALL_INT, arg0 / arg1);
+                        //pn = mp_parse_node_new_leaf(MP_PARSE_NODE_SMALL_INT, 
+                          //                          floor((mp_float_t)arg0 / arg1));
+                        pn = mp_parse_node_new_leaf(MP_PARSE_NODE_SMALL_INT, 
+                                                    python_floor_divide(arg0, arg1));
+			
                     } else {
                         // shouldn't happen
                         assert(0);
diff --git a/py/intdivmod.c b/py/intdivmod.c
new file mode 100644
index 0000000000..4cb363b511
--- /dev/null
+++ b/py/intdivmod.c
@@ -0,0 +1,24 @@
+#include "mpconfig.h"
+
+machine_int_t python_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 python_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;
+    }
+}
diff --git a/py/intdivmod.h b/py/intdivmod.h
new file mode 100644
index 0000000000..7716bd21e9
--- /dev/null
+++ b/py/intdivmod.h
@@ -0,0 +1,4 @@
+// Functions for integer modulo and floor division
+
+machine_int_t python_modulo(machine_int_t dividend, machine_int_t divisor);
+machine_int_t python_floor_divide(machine_int_t num, machine_int_t denom);
diff --git a/py/objint_mpz.c b/py/objint_mpz.c
index 9c7727ba42..39ea7ca115 100644
--- a/py/objint_mpz.c
+++ b/py/objint_mpz.c
@@ -1,5 +1,6 @@
 #include <stdint.h>
 #include <string.h>
+#include <stdio.h>
 
 #include "nlr.h"
 #include "misc.h"
@@ -97,6 +98,12 @@ mp_obj_t int_binary_op(int op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
             case RT_BINARY_OP_INPLACE_FLOOR_DIVIDE: {
                 mpz_t rem; mpz_init_zero(&rem);
                 mpz_divmod_inpl(&res->mpz, &rem, zlhs, zrhs);
+		        if (zlhs->neg != zrhs->neg) {
+                    if (!mpz_is_zero(&rem)) {
+                        mpz_t mpzone; mpz_init_from_int(&mpzone, -1);
+                        mpz_add_inpl(&res->mpz, &res->mpz, &mpzone);
+                    }
+                }
                 mpz_deinit(&rem);
                 break;
             }
@@ -105,8 +112,8 @@ mp_obj_t int_binary_op(int op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
                 mpz_t quo; mpz_init_zero(&quo);
                 mpz_divmod_inpl(&quo, &res->mpz, zlhs, zrhs);
                 mpz_deinit(&quo);
-		// Check signs and do Python style modulo
-		if (zlhs->neg != zrhs->neg) {
+		        // Check signs and do Python style modulo
+		        if (zlhs->neg != zrhs->neg) {
                     mpz_add_inpl(&res->mpz, &res->mpz, zrhs);
                 }
                 break;
diff --git a/py/runtime.c b/py/runtime.c
index 95c3a44159..94f3190566 100644
--- a/py/runtime.c
+++ b/py/runtime.c
@@ -5,6 +5,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <assert.h>
+#include <math.h>
 
 #include "nlr.h"
 #include "misc.h"
@@ -661,7 +662,11 @@ mp_obj_t rt_binary_op(int op, mp_obj_t lhs, mp_obj_t rhs) {
                     break;
                 }
                 case RT_BINARY_OP_FLOOR_DIVIDE:
-                case RT_BINARY_OP_INPLACE_FLOOR_DIVIDE: lhs_val /= rhs_val; break;
+                case RT_BINARY_OP_INPLACE_FLOOR_DIVIDE:
+                {
+                    lhs_val = python_floor_divide(lhs_val, rhs_val);
+                    break;
+                }
                 #if MICROPY_ENABLE_FLOAT
                 case RT_BINARY_OP_TRUE_DIVIDE:
                 case RT_BINARY_OP_INPLACE_TRUE_DIVIDE: return mp_obj_new_float((mp_float_t)lhs_val / (mp_float_t)rhs_val);