Merge branch 'nrf52' into nrf5_no_sdk

25 files changed, 166 insertions, 67 deletions

diff --git a/py/bc.h b/py/bc.h
index 4707da179..c7dffbac5 100644
--- a/py/bc.h
+++ b/py/bc.h
@@ -94,9 +94,9 @@ mp_code_state_t *mp_obj_fun_bc_prepare_codestate(mp_obj_t func, size_t n_args, s
 struct _mp_obj_fun_bc_t;
 void mp_setup_code_state(mp_code_state_t *code_state, struct _mp_obj_fun_bc_t *self, size_t n_args, size_t n_kw, const mp_obj_t *args);
 void mp_bytecode_print(const void *descr, const byte *code, mp_uint_t len, const mp_uint_t *const_table);
-void mp_bytecode_print2(const byte *code, mp_uint_t len);
+void mp_bytecode_print2(const byte *code, size_t len, const mp_uint_t *const_table);
 const byte *mp_bytecode_print_str(const byte *ip);
-#define mp_bytecode_print_inst(code) mp_bytecode_print2(code, 1)
+#define mp_bytecode_print_inst(code, const_table) mp_bytecode_print2(code, 1, const_table)
 
 // Helper macros to access pointer with least significant bits holding flags
 #define MP_TAGPTR_PTR(x) ((void*)((uintptr_t)(x) & ~((uintptr_t)3)))
diff --git a/py/lexer.c b/py/lexer.c
index 458fba090..33af21e9c 100644
--- a/py/lexer.c
+++ b/py/lexer.c
@@ -753,7 +753,7 @@ mp_lexer_t *mp_lexer_new_from_str_len(qstr src_name, const char *str, mp_uint_t
     return mp_lexer_new(src_name, reader);
 }
 
-#if MICROPY_READER_POSIX || MICROPY_READER_FATFS
+#if MICROPY_READER_POSIX || MICROPY_READER_VFS
 
 mp_lexer_t *mp_lexer_new_from_file(const char *filename) {
     mp_reader_t reader;
diff --git a/py/modbuiltins.c b/py/modbuiltins.c
index f62afd807..a0c68930d 100644
--- a/py/modbuiltins.c
+++ b/py/modbuiltins.c
@@ -378,7 +378,14 @@ MP_DEFINE_CONST_FUN_OBJ_1(mp_builtin_ord_obj, mp_builtin_ord);
 STATIC mp_obj_t mp_builtin_pow(size_t n_args, const mp_obj_t *args) {
     switch (n_args) {
         case 2: return mp_binary_op(MP_BINARY_OP_POWER, args[0], args[1]);
-        default: return mp_binary_op(MP_BINARY_OP_MODULO, mp_binary_op(MP_BINARY_OP_POWER, args[0], args[1]), args[2]); // TODO optimise...
+        default:
+#if !MICROPY_PY_BUILTINS_POW3
+            mp_raise_msg(&mp_type_NotImplementedError, "3-arg pow() not supported");
+#elif MICROPY_LONGINT_IMPL != MICROPY_LONGINT_IMPL_MPZ
+            return mp_binary_op(MP_BINARY_OP_MODULO, mp_binary_op(MP_BINARY_OP_POWER, args[0], args[1]), args[2]);
+#else
+            return mp_obj_int_pow3(args[0], args[1], args[2]);
+#endif
     }
 }
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_builtin_pow_obj, 2, 3, mp_builtin_pow);
diff --git a/py/mpconfig.h b/py/mpconfig.h
index 3bccada11..afd9a0be5 100644
--- a/py/mpconfig.h
+++ b/py/mpconfig.h
@@ -398,9 +398,9 @@
 #define MICROPY_READER_POSIX (0)
 #endif
 
-// Whether to use the FatFS reader for importing files
-#ifndef MICROPY_READER_FATFS
-#define MICROPY_READER_FATFS (0)
+// Whether to use the VFS reader for importing files
+#ifndef MICROPY_READER_VFS
+#define MICROPY_READER_VFS (0)
 #endif
 
 // Hook for the VM at the start of the opcode loop (can contain variable
@@ -616,9 +616,9 @@ typedef double mp_float_t;
 #define MICROPY_USE_INTERNAL_PRINTF (1)
 #endif
 
-// Support for user-space VFS mount (selected ports)
-#ifndef MICROPY_FSUSERMOUNT
-#define MICROPY_FSUSERMOUNT (0)
+// Support for generic VFS sub-system
+#ifndef MICROPY_VFS
+#define MICROPY_VFS (0)
 #endif
 
 /*****************************************************************************/
@@ -759,6 +759,11 @@ typedef double mp_float_t;
 #define MICROPY_PY_BUILTINS_MIN_MAX (1)
 #endif
 
+// Support for calls to pow() with 3 integer arguments
+#ifndef MICROPY_PY_BUILTINS_POW3
+#define MICROPY_PY_BUILTINS_POW3 (0)
+#endif
+
 // Whether to provide the help function
 #ifndef MICROPY_PY_BUILTINS_HELP
 #define MICROPY_PY_BUILTINS_HELP (0)
diff --git a/py/mpstate.h b/py/mpstate.h
index 91fb68b3a..54392a994 100644
--- a/py/mpstate.h
+++ b/py/mpstate.h
@@ -160,9 +160,9 @@ typedef struct _mp_state_vm_t {
     mp_obj_t lwip_slip_stream;
     #endif
 
-    #if MICROPY_FSUSERMOUNT
-    // for user-mountable block device (max fixed at compile time)
-    struct _fs_user_mount_t *fs_user_mount[MICROPY_FATFS_VOLUMES];
+    #if MICROPY_VFS
+    struct _mp_vfs_mount_t *vfs_cur;
+    struct _mp_vfs_mount_t *vfs_mount_table;
     #endif
 
     //
diff --git a/py/mpz.c b/py/mpz.c
index 6477c3f8d..230eb921c 100644
--- a/py/mpz.c
+++ b/py/mpz.c
@@ -1395,9 +1395,6 @@ void mpz_pow_inpl(mpz_t *dest, const mpz_t *lhs, const mpz_t *rhs) {
     mpz_free(n);
 }
 
-#if 0
-these functions are unused
-
 /* computes dest = (lhs ** rhs) % mod
    can have dest, lhs, rhs the same; mod can't be the same as dest
 */
@@ -1436,6 +1433,9 @@ void mpz_pow3_inpl(mpz_t *dest, const mpz_t *lhs, const mpz_t *rhs, const mpz_t
     mpz_free(n);
 }
 
+#if 0
+these functions are unused
+
 /* computes gcd(z1, z2)
    based on Knuth's modified gcd algorithm (I think?)
    gcd(z1, z2) >= 0
diff --git a/py/mpz.h b/py/mpz.h
index a26cbea5c..8facb1a0f 100644
--- a/py/mpz.h
+++ b/py/mpz.h
@@ -123,6 +123,7 @@ void mpz_add_inpl(mpz_t *dest, const mpz_t *lhs, const mpz_t *rhs);
 void mpz_sub_inpl(mpz_t *dest, const mpz_t *lhs, const mpz_t *rhs);
 void mpz_mul_inpl(mpz_t *dest, const mpz_t *lhs, const mpz_t *rhs);
 void mpz_pow_inpl(mpz_t *dest, const mpz_t *lhs, const mpz_t *rhs);
+void mpz_pow3_inpl(mpz_t *dest, const mpz_t *lhs, const mpz_t *rhs, const mpz_t *mod);
 void mpz_and_inpl(mpz_t *dest, const mpz_t *lhs, const mpz_t *rhs);
 void mpz_or_inpl(mpz_t *dest, const mpz_t *lhs, const mpz_t *rhs);
 void mpz_xor_inpl(mpz_t *dest, const mpz_t *lhs, const mpz_t *rhs);
diff --git a/py/nlrx64.S b/py/nlrx64.S
index caea35de2..fc8b8e344 100644
--- a/py/nlrx64.S
+++ b/py/nlrx64.S
@@ -257,3 +257,6 @@ nlr_jump:
 #endif // !defined(NLR_OS_WINDOWS)
 
 #endif // defined(__x86_64__) && !MICROPY_NLR_SETJMP
+#if defined(linux)
+    .section    .note.GNU-stack,"",@progbits
+#endif
diff --git a/py/nlrx86.S b/py/nlrx86.S
index 8c538ba17..f1de61e11 100644
--- a/py/nlrx86.S
+++ b/py/nlrx86.S
@@ -190,3 +190,6 @@ nlr_jump:
 #endif
 
 #endif // defined(__i386__) && !MICROPY_NLR_SETJMP
+#if defined(linux)
+    .section    .note.GNU-stack,"",@progbits
+#endif
diff --git a/py/nlrxtensa.S b/py/nlrxtensa.S
index 289996cce..73af4832f 100644
--- a/py/nlrxtensa.S
+++ b/py/nlrxtensa.S
@@ -114,3 +114,6 @@ nlr_jump:
     .size   nlr_jump, .-nlr_jump
 
 #endif // defined(__xtensa__)
+#if defined(linux)
+    .section    .note.GNU-stack,"",@progbits
+#endif
diff --git a/py/objcomplex.c b/py/objcomplex.c
index 96be25255..426e76e5f 100644
--- a/py/objcomplex.c
+++ b/py/objcomplex.c
@@ -222,8 +222,8 @@ mp_obj_t mp_obj_complex_binary_op(mp_uint_t op, mp_float_t lhs_real, mp_float_t
             //        = exp(x3)*(cos(y3) + i*sin(y3))
             mp_float_t abs1 = MICROPY_FLOAT_C_FUN(sqrt)(lhs_real*lhs_real + lhs_imag*lhs_imag);
             if (abs1 == 0) {
-                if (rhs_imag == 0) {
-                    lhs_real = 1;
+                if (rhs_imag == 0 && rhs_real >= 0) {
+                    lhs_real = (rhs_real == 0);
                     rhs_real = 0;
                 } else {
                     mp_raise_msg(&mp_type_ZeroDivisionError, "0.0 to a complex power");
diff --git a/py/objfloat.c b/py/objfloat.c
index 73d07feac..9292490a9 100644
--- a/py/objfloat.c
+++ b/py/objfloat.c
@@ -228,7 +228,12 @@ mp_obj_t mp_obj_float_binary_op(mp_uint_t op, mp_float_t lhs_val, mp_obj_t rhs_i
             }
             break;
         case MP_BINARY_OP_POWER:
-        case MP_BINARY_OP_INPLACE_POWER: lhs_val = MICROPY_FLOAT_C_FUN(pow)(lhs_val, rhs_val); break;
+        case MP_BINARY_OP_INPLACE_POWER:
+            if (lhs_val == 0 && rhs_val < 0) {
+                goto zero_division_error;
+            }
+            lhs_val = MICROPY_FLOAT_C_FUN(pow)(lhs_val, rhs_val);
+            break;
         case MP_BINARY_OP_DIVMOD: {
             if (rhs_val == 0) {
                 goto zero_division_error;
diff --git a/py/objint.c b/py/objint.c
index a61ed8e27..222aa1de7 100644
--- a/py/objint.c
+++ b/py/objint.c
@@ -383,7 +383,7 @@ STATIC mp_obj_t int_from_bytes(size_t n_args, const mp_obj_t *args) {
 
     #if MICROPY_LONGINT_IMPL != MICROPY_LONGINT_IMPL_NONE
     // If result guaranteedly fits in small int, use that
-    if (!MP_SMALL_INT_FITS(1 << (bufinfo.len * 8 - 1))) {
+    if (bufinfo.len >= sizeof(mp_uint_t) || !MP_SMALL_INT_FITS(1 << (bufinfo.len * 8 - 1))) {
         return mp_obj_int_from_bytes_impl(args[2] != MP_OBJ_NEW_QSTR(MP_QSTR_little), bufinfo.len, bufinfo.buf);
     } else
     #endif
diff --git a/py/objint.h b/py/objint.h
index a84a33fa5..7205761ad 100644
--- a/py/objint.h
+++ b/py/objint.h
@@ -66,5 +66,6 @@ mp_obj_t mp_obj_int_abs(mp_obj_t self_in);
 mp_obj_t mp_obj_int_unary_op(mp_uint_t op, mp_obj_t o_in);
 mp_obj_t mp_obj_int_binary_op(mp_uint_t op, mp_obj_t lhs_in, mp_obj_t rhs_in);
 mp_obj_t mp_obj_int_binary_op_extra_cases(mp_uint_t op, mp_obj_t lhs_in, mp_obj_t rhs_in);
+mp_obj_t mp_obj_int_pow3(mp_obj_t base, mp_obj_t exponent,  mp_obj_t modulus);
 
 #endif // __MICROPY_INCLUDED_PY_OBJINT_H__
diff --git a/py/objint_mpz.c b/py/objint_mpz.c
index d465ef965..2b27df4f6 100644
--- a/py/objint_mpz.c
+++ b/py/objint_mpz.c
@@ -326,6 +326,39 @@ mp_obj_t mp_obj_int_binary_op(mp_uint_t op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
     }
 }
 
+#if MICROPY_PY_BUILTINS_POW3
+STATIC mpz_t *mp_mpz_for_int(mp_obj_t arg, mpz_t *temp) {
+    if (MP_OBJ_IS_SMALL_INT(arg)) {
+        mpz_init_from_int(temp, MP_OBJ_SMALL_INT_VALUE(arg));
+        return temp;
+    } else {
+        mp_obj_int_t *arp_p = MP_OBJ_TO_PTR(arg);
+        return &(arp_p->mpz);
+    }
+}
+
+mp_obj_t mp_obj_int_pow3(mp_obj_t base, mp_obj_t exponent,  mp_obj_t modulus) {
+    if (!MP_OBJ_IS_INT(base) || !MP_OBJ_IS_INT(exponent) || !MP_OBJ_IS_INT(modulus)) {
+        mp_raise_TypeError("pow() with 3 arguments requires integers");
+    } else {
+        mp_obj_t result = mp_obj_new_int_from_ull(0); // Use the _from_ull version as this forces an mpz int
+        mp_obj_int_t *res_p = (mp_obj_int_t *) MP_OBJ_TO_PTR(result);
+
+        mpz_t l_temp, r_temp, m_temp;
+        mpz_t *lhs = mp_mpz_for_int(base,     &l_temp);
+        mpz_t *rhs = mp_mpz_for_int(exponent, &r_temp);
+        mpz_t *mod = mp_mpz_for_int(modulus,  &m_temp);
+
+        mpz_pow3_inpl(&(res_p->mpz), lhs, rhs, mod);
+
+        if (lhs == &l_temp) { mpz_deinit(lhs); }
+        if (rhs == &r_temp) { mpz_deinit(rhs); }
+        if (mod == &m_temp) { mpz_deinit(mod); }
+        return result;
+    }
+}
+#endif
+
 mp_obj_t mp_obj_new_int(mp_int_t value) {
     if (MP_SMALL_INT_FITS(value)) {
         return MP_OBJ_NEW_SMALL_INT(value);
diff --git a/py/objmodule.c b/py/objmodule.c
index a0a179de4..43bb36b98 100644
--- a/py/objmodule.c
+++ b/py/objmodule.c
@@ -237,14 +237,6 @@ STATIC const mp_rom_map_elem_t mp_builtin_module_weak_links_table[] = {
 MP_DEFINE_CONST_MAP(mp_builtin_module_weak_links_map, mp_builtin_module_weak_links_table);
 #endif
 
-void mp_module_init(void) {
-    mp_obj_dict_init(&MP_STATE_VM(mp_loaded_modules_dict), 3);
-}
-
-void mp_module_deinit(void) {
-    //mp_map_deinit(&MP_STATE_VM(mp_loaded_modules_map));
-}
-
 // returns MP_OBJ_NULL if not found
 mp_obj_t mp_module_get(qstr module_name) {
     mp_map_t *mp_loaded_modules_map = &MP_STATE_VM(mp_loaded_modules_dict).map;
diff --git a/py/objmodule.h b/py/objmodule.h
index 937ff8416..4e6612adc 100644
--- a/py/objmodule.h
+++ b/py/objmodule.h
@@ -31,8 +31,6 @@
 extern const mp_map_t mp_builtin_module_map;
 extern const mp_map_t mp_builtin_module_weak_links_map;
 
-void mp_module_init(void);
-void mp_module_deinit(void);
 mp_obj_t mp_module_get(qstr module_name);
 void mp_module_register(qstr qstr, mp_obj_t module);
 
diff --git a/py/objset.c b/py/objset.c
index fc124fcd8..778bbe15b 100644
--- a/py/objset.c
+++ b/py/objset.c
@@ -479,6 +479,11 @@ STATIC mp_obj_t set_unary_op(mp_uint_t op, mp_obj_t self_in) {
 
 STATIC mp_obj_t set_binary_op(mp_uint_t op, mp_obj_t lhs, mp_obj_t rhs) {
     mp_obj_t args[] = {lhs, rhs};
+    #if MICROPY_PY_BUILTINS_FROZENSET
+    bool update = MP_OBJ_IS_TYPE(lhs, &mp_type_set);
+    #else
+    bool update = true;
+    #endif
     switch (op) {
         case MP_BINARY_OP_OR:
             return set_union(lhs, rhs);
@@ -489,13 +494,28 @@ STATIC mp_obj_t set_binary_op(mp_uint_t op, mp_obj_t lhs, mp_obj_t rhs) {
         case MP_BINARY_OP_SUBTRACT:
             return set_diff(2, args);
         case MP_BINARY_OP_INPLACE_OR:
-            return set_union(lhs, rhs);
+            if (update) {
+                set_update(2, args);
+                return lhs;
+            } else {
+                return set_union(lhs, rhs);
+            }
         case MP_BINARY_OP_INPLACE_XOR:
-            return set_symmetric_difference(lhs, rhs);
+            if (update) {
+                set_symmetric_difference_update(lhs, rhs);
+                return lhs;
+            } else {
+                return set_symmetric_difference(lhs, rhs);
+            }
         case MP_BINARY_OP_INPLACE_AND:
-            return set_intersect(lhs, rhs);
+            rhs = set_intersect_int(lhs, rhs, update);
+            if (update) {
+                return lhs;
+            } else {
+                return rhs;
+            }
         case MP_BINARY_OP_INPLACE_SUBTRACT:
-            return set_diff(2, args);
+            return set_diff_int(2, args, update);
         case MP_BINARY_OP_LESS:
             return set_issubset_proper(lhs, rhs);
         case MP_BINARY_OP_MORE:
diff --git a/py/objstr.c b/py/objstr.c
index f082e9559..b437d9795 100644
--- a/py/objstr.c
+++ b/py/objstr.c
@@ -36,7 +36,7 @@
 #include "py/runtime.h"
 #include "py/stackctrl.h"
 
-STATIC mp_obj_t str_modulo_format(mp_obj_t pattern, mp_uint_t n_args, const mp_obj_t *args, mp_obj_t dict);
+STATIC mp_obj_t str_modulo_format(mp_obj_t pattern, size_t n_args, const mp_obj_t *args, mp_obj_t dict);
 
 STATIC mp_obj_t mp_obj_new_bytes_iterator(mp_obj_t str);
 STATIC NORETURN void bad_implicit_conversion(mp_obj_t self_in);
@@ -282,19 +282,14 @@ const byte *find_subbytes(const byte *haystack, mp_uint_t hlen, const byte *need
 mp_obj_t mp_obj_str_binary_op(mp_uint_t op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
     // check for modulo
     if (op == MP_BINARY_OP_MODULO) {
-        mp_obj_t *args;
-        mp_uint_t n_args;
+        mp_obj_t *args = &rhs_in;
+        mp_uint_t n_args = 1;
         mp_obj_t dict = MP_OBJ_NULL;
         if (MP_OBJ_IS_TYPE(rhs_in, &mp_type_tuple)) {
             // TODO: Support tuple subclasses?
             mp_obj_tuple_get(rhs_in, &n_args, &args);
         } else if (MP_OBJ_IS_TYPE(rhs_in, &mp_type_dict)) {
-            args = NULL;
-            n_args = 0;
             dict = rhs_in;
-        } else {
-            args = &rhs_in;
-            n_args = 1;
         }
         return str_modulo_format(lhs_in, n_args, args, dict);
     }
@@ -358,6 +353,13 @@ mp_obj_t mp_obj_str_binary_op(mp_uint_t op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
     switch (op) {
         case MP_BINARY_OP_ADD:
         case MP_BINARY_OP_INPLACE_ADD: {
+            if (lhs_len == 0) {
+                return rhs_in;
+            }
+            if (rhs_len == 0) {
+                return lhs_in;
+            }
+
             vstr_t vstr;
             vstr_init_len(&vstr, lhs_len + rhs_len);
             memcpy(vstr.buf, lhs_data, lhs_len);
@@ -652,7 +654,7 @@ STATIC mp_obj_t str_rsplit(size_t n_args, const mp_obj_t *args) {
     return MP_OBJ_FROM_PTR(res);
 }
 
-STATIC mp_obj_t str_finder(mp_uint_t n_args, const mp_obj_t *args, mp_int_t direction, bool is_index) {
+STATIC mp_obj_t str_finder(size_t n_args, const mp_obj_t *args, mp_int_t direction, bool is_index) {
     const mp_obj_type_t *self_type = mp_obj_get_type(args[0]);
     mp_check_self(MP_OBJ_IS_STR_OR_BYTES(args[0]));
 
@@ -738,7 +740,7 @@ STATIC mp_obj_t str_endswith(size_t n_args, const mp_obj_t *args) {
 
 enum { LSTRIP, RSTRIP, STRIP };
 
-STATIC mp_obj_t str_uni_strip(int type, mp_uint_t n_args, const mp_obj_t *args) {
+STATIC mp_obj_t str_uni_strip(int type, size_t n_args, const mp_obj_t *args) {
     mp_check_self(MP_OBJ_IS_STR_OR_BYTES(args[0]));
     const mp_obj_type_t *self_type = mp_obj_get_type(args[0]);
 
@@ -890,7 +892,7 @@ STATIC NORETURN void terse_str_format_value_error(void) {
 #define terse_str_format_value_error()
 #endif
 
-STATIC vstr_t mp_obj_str_format_helper(const char *str, const char *top, int *arg_i, mp_uint_t n_args, const mp_obj_t *args, mp_map_t *kwargs) {
+STATIC vstr_t mp_obj_str_format_helper(const char *str, const char *top, int *arg_i, size_t n_args, const mp_obj_t *args, mp_map_t *kwargs) {
     vstr_t vstr;
     mp_print_t print;
     vstr_init_print(&vstr, 16, &print);
@@ -1342,13 +1344,13 @@ mp_obj_t mp_obj_str_format(size_t n_args, const mp_obj_t *args, mp_map_t *kwargs
     return mp_obj_new_str_from_vstr(&mp_type_str, &vstr);
 }
 
-STATIC mp_obj_t str_modulo_format(mp_obj_t pattern, mp_uint_t n_args, const mp_obj_t *args, mp_obj_t dict) {
+STATIC mp_obj_t str_modulo_format(mp_obj_t pattern, size_t n_args, const mp_obj_t *args, mp_obj_t dict) {
     mp_check_self(MP_OBJ_IS_STR_OR_BYTES(pattern));
 
     GET_STR_DATA_LEN(pattern, str, len);
     const byte *start_str = str;
     bool is_bytes = MP_OBJ_IS_TYPE(pattern, &mp_type_bytes);
-    int arg_i = 0;
+    size_t arg_i = 0;
     vstr_t vstr;
     mp_print_t print;
     vstr_init_print(&vstr, 16, &print);
@@ -1369,6 +1371,10 @@ STATIC mp_obj_t str_modulo_format(mp_obj_t pattern, mp_uint_t n_args, const mp_o
 
         // Dictionary value lookup
         if (*str == '(') {
+            if (dict == MP_OBJ_NULL) {
+                mp_raise_TypeError("format requires a dict");
+            }
+            arg_i = 1; // we used up the single dict argument
             const byte *key = ++str;
             while (*str != ')') {
                 if (str >= top) {
@@ -1403,7 +1409,7 @@ STATIC mp_obj_t str_modulo_format(mp_obj_t pattern, mp_uint_t n_args, const mp_o
         int width = 0;
         if (str < top) {
             if (*str == '*') {
-                if ((uint)arg_i >= n_args) {
+                if (arg_i >= n_args) {
                     goto not_enough_args;
                 }
                 width = mp_obj_get_int(args[arg_i++]);
@@ -1416,7 +1422,7 @@ STATIC mp_obj_t str_modulo_format(mp_obj_t pattern, mp_uint_t n_args, const mp_o
         if (str < top && *str == '.') {
             if (++str < top) {
                 if (*str == '*') {
-                    if ((uint)arg_i >= n_args) {
+                    if (arg_i >= n_args) {
                         goto not_enough_args;
                     }
                     prec = mp_obj_get_int(args[arg_i++]);
@@ -1439,7 +1445,7 @@ incomplete_format:
 
         // Tuple value lookup
         if (arg == MP_OBJ_NULL) {
-            if ((uint)arg_i >= n_args) {
+            if (arg_i >= n_args) {
 not_enough_args:
                 mp_raise_TypeError("not enough arguments for format string");
             }
@@ -1527,7 +1533,7 @@ not_enough_args:
         }
     }
 
-    if ((uint)arg_i != n_args) {
+    if (arg_i != n_args) {
         mp_raise_TypeError("not all arguments converted during string formatting");
     }
 
diff --git a/py/objstringio.c b/py/objstringio.c
index a430fca3b..a77ffae24 100644
--- a/py/objstringio.c
+++ b/py/objstringio.c
@@ -147,21 +147,34 @@ STATIC mp_obj_t stringio___exit__(size_t n_args, const mp_obj_t *args) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(stringio___exit___obj, 4, 4, stringio___exit__);
 
-STATIC mp_obj_stringio_t *stringio_new(const mp_obj_type_t *type) {
+STATIC mp_obj_stringio_t *stringio_new(const mp_obj_type_t *type, mp_uint_t alloc) {
     mp_obj_stringio_t *o = m_new_obj(mp_obj_stringio_t);
     o->base.type = type;
-    o->vstr = vstr_new(16);
+    o->vstr = vstr_new(alloc);
     o->pos = 0;
     return o;
 }
 
 STATIC mp_obj_t stringio_make_new(const mp_obj_type_t *type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     (void)n_kw; // TODO check n_kw==0
-    mp_obj_stringio_t *o = stringio_new(type_in);
+
+    mp_uint_t sz = 16;
+    bool initdata = false;
+    mp_buffer_info_t bufinfo;
 
     if (n_args > 0) {
-        mp_buffer_info_t bufinfo;
-        mp_get_buffer_raise(args[0], &bufinfo, MP_BUFFER_READ);
+        if (MP_OBJ_IS_INT(args[0])) {
+            sz = mp_obj_get_int(args[0]);
+        } else {
+            mp_get_buffer_raise(args[0], &bufinfo, MP_BUFFER_READ);
+            sz = bufinfo.len;
+            initdata = true;
+        }
+    }
+
+    mp_obj_stringio_t *o = stringio_new(type_in, sz);
+
+    if (initdata) {
         stringio_write(MP_OBJ_FROM_PTR(o), bufinfo.buf, bufinfo.len, NULL);
         // Cur ptr is always at the beginning of buffer at the construction
         o->pos = 0;
diff --git a/py/py.mk b/py/py.mk
index b78cdba35..01a802674 100644
--- a/py/py.mk
+++ b/py/py.mk
@@ -19,6 +19,9 @@ CSUPEROPT = -O3
 INC += -I../lib
 INC += -I../lib/netutils
 
+# this sets the config file for FatFs
+CFLAGS_MOD += -DFFCONF_H=\"lib/oofatfs/ffconf.h\"
+
 ifeq ($(MICROPY_PY_USSL),1)
 CFLAGS_MOD += -DMICROPY_PY_USSL=1
 ifeq ($(MICROPY_SSL_AXTLS),1)
@@ -219,6 +222,7 @@ PY_O_BASENAME = \
 	../extmod/virtpin.o \
 	../extmod/machine_mem.o \
 	../extmod/machine_pinbase.o \
+	../extmod/machine_signal.o \
 	../extmod/machine_pulse.o \
 	../extmod/machine_i2c.o \
 	../extmod/machine_spi.o \
@@ -229,12 +233,11 @@ PY_O_BASENAME = \
 	../extmod/modwebsocket.o \
 	../extmod/modwebrepl.o \
 	../extmod/modframebuf.o \
-	../extmod/fsusermount.o \
+	../extmod/vfs.o \
+	../extmod/vfs_reader.o \
 	../extmod/vfs_fat.o \
-	../extmod/vfs_fat_ffconf.o \
 	../extmod/vfs_fat_diskio.o \
 	../extmod/vfs_fat_file.o \
-	../extmod/vfs_fat_reader.o \
 	../extmod/vfs_fat_misc.o \
 	../extmod/utime_mphal.o \
 	../extmod/uos_dupterm.o \
diff --git a/py/qstrdefs.h b/py/qstrdefs.h
index c98a253a6..4581e5e1b 100644
--- a/py/qstrdefs.h
+++ b/py/qstrdefs.h
@@ -36,6 +36,7 @@ QCFG(BYTES_IN_HASH, MICROPY_QSTR_BYTES_IN_HASH)
 Q()
 Q(*)
 Q(_)
+Q(/)
 Q(%#o)
 Q(%#x)
 Q({:#b})
diff --git a/py/runtime.c b/py/runtime.c
index 9d2c0ef46..e6aef21d7 100644
--- a/py/runtime.c
+++ b/py/runtime.c
@@ -85,8 +85,8 @@ void mp_init(void) {
     // optimization disabled by default
     MP_STATE_VM(mp_optimise_value) = 0;
 
-    // init global module stuff
-    mp_module_init();
+    // init global module dict
+    mp_obj_dict_init(&MP_STATE_VM(mp_loaded_modules_dict), 3);
 
     // initialise the __main__ module
     mp_obj_dict_init(&MP_STATE_VM(dict_main), 1);
@@ -105,6 +105,12 @@ void mp_init(void) {
     memset(MP_STATE_VM(fs_user_mount), 0, sizeof(MP_STATE_VM(fs_user_mount)));
     #endif
 
+    #if MICROPY_VFS
+    // initialise the VFS sub-system
+    MP_STATE_VM(vfs_cur) = NULL;
+    MP_STATE_VM(vfs_mount_table) = NULL;
+    #endif
+
     #if MICROPY_PY_THREAD_GIL
     mp_thread_mutex_init(&MP_STATE_VM(gil_mutex));
     #endif
@@ -114,7 +120,7 @@ void mp_init(void) {
 
 void mp_deinit(void) {
     //mp_obj_dict_free(&dict_main);
-    mp_module_deinit();
+    //mp_map_deinit(&MP_STATE_VM(mp_loaded_modules_map));
 
     // call port specific deinitialization if any 
 #ifdef MICROPY_PORT_INIT_FUNC
diff --git a/py/showbc.c b/py/showbc.c
index 684d9af0c..9d20decdc 100644
--- a/py/showbc.c
+++ b/py/showbc.c
@@ -82,7 +82,6 @@ const mp_uint_t *mp_showbc_const_table;
 
 void mp_bytecode_print(const void *descr, const byte *ip, mp_uint_t len, const mp_uint_t *const_table) {
     mp_showbc_code_start = ip;
-    mp_showbc_const_table = const_table;
 
     // get bytecode parameters
     mp_uint_t n_state = mp_decode_uint(&ip);
@@ -159,7 +158,7 @@ void mp_bytecode_print(const void *descr, const byte *ip, mp_uint_t len, const m
             printf("  bc=" INT_FMT " line=" UINT_FMT "\n", bc, source_line);
         }
     }
-    mp_bytecode_print2(ip, len - 0);
+    mp_bytecode_print2(ip, len - 0, const_table);
 }
 
 const byte *mp_bytecode_print_str(const byte *ip) {
@@ -547,8 +546,9 @@ const byte *mp_bytecode_print_str(const byte *ip) {
     return ip;
 }
 
-void mp_bytecode_print2(const byte *ip, mp_uint_t len) {
+void mp_bytecode_print2(const byte *ip, size_t len, const mp_uint_t *const_table) {
     mp_showbc_code_start = ip;
+    mp_showbc_const_table = const_table;
     while (ip < len + mp_showbc_code_start) {
         printf("%02u ", (uint)(ip - mp_showbc_code_start));
         ip = mp_bytecode_print_str(ip);
diff --git a/py/vm.c b/py/vm.c
index 363824e5f..f4cfa2cd6 100644
--- a/py/vm.c
+++ b/py/vm.c
@@ -38,8 +38,7 @@
 #include "py/bc.h"
 
 #if 0
-//#define TRACE(ip) printf("sp=" INT_FMT " ", sp - code_state->sp); mp_bytecode_print2(ip, 1);
-#define TRACE(ip) printf("sp=%d ", sp - code_state->sp); mp_bytecode_print2(ip, 1);
+#define TRACE(ip) printf("sp=%d ", (int)(sp - code_state->sp)); mp_bytecode_print2(ip, 1, code_state->const_table);
 #else
 #define TRACE(ip)
 #endif