1 /*
2  * This file is part of the MicroPython project, http://micropython.org/
3  *
4  * The MIT License (MIT)
5  *
6  * Copyright (c) 2013, 2014 Damien P. George
7  *
8  * Permission is hereby granted, free of charge, to any person obtaining a copy
9  * of this software and associated documentation files (the "Software"), to deal
10  * in the Software without restriction, including without limitation the rights
11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
12  * copies of the Software, and to permit persons to whom the Software is
13  * furnished to do so, subject to the following conditions:
14  *
15  * The above copyright notice and this permission notice shall be included in
16  * all copies or substantial portions of the Software.
17  *
18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
21  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
24  * THE SOFTWARE.
25  */
26 #ifndef MICROPY_INCLUDED_PY_SMALLINT_H
27 #define MICROPY_INCLUDED_PY_SMALLINT_H
28 
29 #include "py/mpconfig.h"
30 #include "py/misc.h"
31 
32 // Functions for small integer arithmetic
33 
34 #ifndef MP_SMALL_INT_MIN
35 
36 // In SMALL_INT, next-to-highest bits is used as sign, so both must match for value in range
37 #if MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_A || MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_C
38 
39 #define MP_SMALL_INT_MIN ((mp_int_t)(((mp_int_t)MP_OBJ_WORD_MSBIT_HIGH) >> 1))
40 #define MP_SMALL_INT_FITS(n) ((((n) ^ ((mp_uint_t)(n) << 1)) & MP_OBJ_WORD_MSBIT_HIGH) == 0)
41 // Mask to truncate mp_int_t to positive value
42 #define MP_SMALL_INT_POSITIVE_MASK ~(MP_OBJ_WORD_MSBIT_HIGH | (MP_OBJ_WORD_MSBIT_HIGH >> 1))
43 
44 #elif MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_B
45 
46 #define MP_SMALL_INT_MIN ((mp_int_t)(((mp_int_t)MP_OBJ_WORD_MSBIT_HIGH) >> 2))
47 #define MP_SMALL_INT_FITS(n) ((((n) & MP_SMALL_INT_MIN) == 0) || (((n) & MP_SMALL_INT_MIN) == MP_SMALL_INT_MIN))
48 // Mask to truncate mp_int_t to positive value
49 #define MP_SMALL_INT_POSITIVE_MASK ~(MP_OBJ_WORD_MSBIT_HIGH | (MP_OBJ_WORD_MSBIT_HIGH >> 1) | (MP_OBJ_WORD_MSBIT_HIGH >> 2))
50 
51 #elif MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_D
52 
53 #define MP_SMALL_INT_MIN ((mp_int_t)(((mp_int_t)0xffff800000000000) >> 1))
54 #define MP_SMALL_INT_FITS(n) ((((n) ^ ((n) << 1)) & 0xffff800000000000) == 0)
55 // Mask to truncate mp_int_t to positive value
56 #define MP_SMALL_INT_POSITIVE_MASK ~(0xffff800000000000 | (0xffff800000000000 >> 1))
57 
58 #endif
59 
60 #endif
61 
62 #define MP_SMALL_INT_MAX ((mp_int_t)(~(MP_SMALL_INT_MIN)))
63 
64 bool mp_small_int_mul_overflow(mp_int_t x, mp_int_t y);
65 mp_int_t mp_small_int_modulo(mp_int_t dividend, mp_int_t divisor);
66 mp_int_t mp_small_int_floor_divide(mp_int_t num, mp_int_t denom);
67 
68 #endif // MICROPY_INCLUDED_PY_SMALLINT_H
69