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circuitpython/py/runtime0.h
Damien George b5ebfadbd6 py: Compress first part of bytecode prelude. 
The start of the bytecode prelude contains 6 numbers telling the amount of
stack needed for the Python values and exceptions, and the signature of the
function.  Prior to this patch these numbers were all encoded one after the
other (2x variable unsigned integers, then 4x bytes), but using so many
bytes is unnecessary.

An entropy analysis of around 150,000 bytecode functions from the CPython
standard library showed that the optimal Shannon coding would need about
7.1 bits on average to encode these 6 numbers, compared to the existing 48
bits.

This patch attempts to get close to this optimal value by packing the 6
numbers into a single, varible-length unsigned integer via bit-wise
interleaving.  The interleaving scheme is chosen to minimise the average
number of bytes needed, and at the same time keep the scheme simple enough
so it can be implemented without too much overhead in code size or speed.
The scheme requires about 10.5 bits on average to store the 6 numbers.

As a result most functions which originally took 6 bytes to encode these 6
numbers now need only 1 byte (in 80% of cases).
2019-10-01 12:26:22 +10:00

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef MICROPY_INCLUDED_PY_RUNTIME0_H
#define MICROPY_INCLUDED_PY_RUNTIME0_H
// The first four must fit in 8 bits, see emitbc.c
// The remaining must fit in 16 bits, see scope.h
#define MP_SCOPE_FLAG_GENERATOR (0x01)
#define MP_SCOPE_FLAG_VARKEYWORDS (0x02)
#define MP_SCOPE_FLAG_VARARGS (0x04)
#define MP_SCOPE_FLAG_DEFKWARGS (0x08)
#define MP_SCOPE_FLAG_REFGLOBALS (0x10) // used only if native emitter enabled
#define MP_SCOPE_FLAG_HASCONSTS (0x20) // used only if native emitter enabled
#define MP_SCOPE_FLAG_VIPERRET_POS (6) // 3 bits used for viper return type
// types for native (viper) function signature
#define MP_NATIVE_TYPE_OBJ (0x00)
#define MP_NATIVE_TYPE_BOOL (0x01)
#define MP_NATIVE_TYPE_INT (0x02)
#define MP_NATIVE_TYPE_UINT (0x03)
#define MP_NATIVE_TYPE_PTR (0x04)
#define MP_NATIVE_TYPE_PTR8 (0x05)
#define MP_NATIVE_TYPE_PTR16 (0x06)
#define MP_NATIVE_TYPE_PTR32 (0x07)
typedef enum {
// These ops may appear in the bytecode. Changing this group
// in any way requires changing the bytecode version.
MP_UNARY_OP_POSITIVE,
MP_UNARY_OP_NEGATIVE,
MP_UNARY_OP_INVERT,
MP_UNARY_OP_NOT,
// Following ops cannot appear in the bytecode
MP_UNARY_OP_NUM_BYTECODE,
MP_UNARY_OP_BOOL = MP_UNARY_OP_NUM_BYTECODE, // __bool__
MP_UNARY_OP_LEN, // __len__
MP_UNARY_OP_HASH, // __hash__; must return a small int
MP_UNARY_OP_ABS, // __abs__
MP_UNARY_OP_INT, // __int__
MP_UNARY_OP_SIZEOF, // for sys.getsizeof()
MP_UNARY_OP_NUM_RUNTIME,
} mp_unary_op_t;
// Note: the first 9+12+12 of these are used in bytecode and changing
// them requires changing the bytecode version.
typedef enum {
// 9 relational operations, should return a bool; order of first 6 matches corresponding mp_token_kind_t
MP_BINARY_OP_LESS,
MP_BINARY_OP_MORE,
MP_BINARY_OP_EQUAL,
MP_BINARY_OP_LESS_EQUAL,
MP_BINARY_OP_MORE_EQUAL,
MP_BINARY_OP_NOT_EQUAL,
MP_BINARY_OP_IN,
MP_BINARY_OP_IS,
MP_BINARY_OP_EXCEPTION_MATCH,
// 13 inplace arithmetic operations; order matches corresponding mp_token_kind_t
MP_BINARY_OP_INPLACE_OR,
MP_BINARY_OP_INPLACE_XOR,
MP_BINARY_OP_INPLACE_AND,
MP_BINARY_OP_INPLACE_LSHIFT,
MP_BINARY_OP_INPLACE_RSHIFT,
MP_BINARY_OP_INPLACE_ADD,
MP_BINARY_OP_INPLACE_SUBTRACT,
MP_BINARY_OP_INPLACE_MULTIPLY,
MP_BINARY_OP_INPLACE_MAT_MULTIPLY,
MP_BINARY_OP_INPLACE_FLOOR_DIVIDE,
MP_BINARY_OP_INPLACE_TRUE_DIVIDE,
MP_BINARY_OP_INPLACE_MODULO,
MP_BINARY_OP_INPLACE_POWER,
// 13 normal arithmetic operations; order matches corresponding mp_token_kind_t
MP_BINARY_OP_OR,
MP_BINARY_OP_XOR,
MP_BINARY_OP_AND,
MP_BINARY_OP_LSHIFT,
MP_BINARY_OP_RSHIFT,
MP_BINARY_OP_ADD,
MP_BINARY_OP_SUBTRACT,
MP_BINARY_OP_MULTIPLY,
MP_BINARY_OP_MAT_MULTIPLY,
MP_BINARY_OP_FLOOR_DIVIDE,
MP_BINARY_OP_TRUE_DIVIDE,
MP_BINARY_OP_MODULO,
MP_BINARY_OP_POWER,
// Operations below this line don't appear in bytecode, they
// just identify special methods.
MP_BINARY_OP_NUM_BYTECODE,
// MP_BINARY_OP_REVERSE_* must follow immediately after MP_BINARY_OP_*
#if MICROPY_PY_REVERSE_SPECIAL_METHODS
MP_BINARY_OP_REVERSE_OR = MP_BINARY_OP_NUM_BYTECODE,
MP_BINARY_OP_REVERSE_XOR,
MP_BINARY_OP_REVERSE_AND,
MP_BINARY_OP_REVERSE_LSHIFT,
MP_BINARY_OP_REVERSE_RSHIFT,
MP_BINARY_OP_REVERSE_ADD,
MP_BINARY_OP_REVERSE_SUBTRACT,
MP_BINARY_OP_REVERSE_MULTIPLY,
MP_BINARY_OP_REVERSE_MAT_MULTIPLY,
MP_BINARY_OP_REVERSE_FLOOR_DIVIDE,
MP_BINARY_OP_REVERSE_TRUE_DIVIDE,
MP_BINARY_OP_REVERSE_MODULO,
MP_BINARY_OP_REVERSE_POWER,
#endif
// This is not emitted by the compiler but is supported by the runtime
MP_BINARY_OP_DIVMOD
#if !MICROPY_PY_REVERSE_SPECIAL_METHODS
= MP_BINARY_OP_NUM_BYTECODE
#endif
,
// The runtime will convert MP_BINARY_OP_IN to this operator with swapped args.
// A type should implement this containment operator instead of MP_BINARY_OP_IN.
MP_BINARY_OP_CONTAINS,
MP_BINARY_OP_NUM_RUNTIME,
// These 2 are not supported by the runtime and must be synthesised by the emitter
MP_BINARY_OP_NOT_IN,
MP_BINARY_OP_IS_NOT,
} mp_binary_op_t;
typedef enum {
MP_F_CONST_NONE_OBJ = 0,
MP_F_CONST_FALSE_OBJ,
MP_F_CONST_TRUE_OBJ,
MP_F_CONVERT_OBJ_TO_NATIVE,
MP_F_CONVERT_NATIVE_TO_OBJ,
MP_F_NATIVE_SWAP_GLOBALS,
MP_F_LOAD_NAME,
MP_F_LOAD_GLOBAL,
MP_F_LOAD_BUILD_CLASS,
MP_F_LOAD_ATTR,
MP_F_LOAD_METHOD,
MP_F_LOAD_SUPER_METHOD,
MP_F_STORE_NAME,
MP_F_STORE_GLOBAL,
MP_F_STORE_ATTR,
MP_F_OBJ_SUBSCR,
MP_F_OBJ_IS_TRUE,
MP_F_UNARY_OP,
MP_F_BINARY_OP,
MP_F_BUILD_TUPLE,
MP_F_BUILD_LIST,
MP_F_BUILD_MAP,
MP_F_BUILD_SET,
MP_F_STORE_SET,
MP_F_LIST_APPEND,
MP_F_STORE_MAP,
MP_F_MAKE_FUNCTION_FROM_RAW_CODE,
MP_F_NATIVE_CALL_FUNCTION_N_KW,
MP_F_CALL_METHOD_N_KW,
MP_F_CALL_METHOD_N_KW_VAR,
MP_F_NATIVE_GETITER,
MP_F_NATIVE_ITERNEXT,
MP_F_NLR_PUSH,
MP_F_NLR_POP,
MP_F_NATIVE_RAISE,
MP_F_IMPORT_NAME,
MP_F_IMPORT_FROM,
MP_F_IMPORT_ALL,
MP_F_NEW_SLICE,
MP_F_UNPACK_SEQUENCE,
MP_F_UNPACK_EX,
MP_F_DELETE_NAME,
MP_F_DELETE_GLOBAL,
MP_F_NEW_CELL,
MP_F_MAKE_CLOSURE_FROM_RAW_CODE,
MP_F_ARG_CHECK_NUM_SIG,
MP_F_SETUP_CODE_STATE,
MP_F_SMALL_INT_FLOOR_DIVIDE,
MP_F_SMALL_INT_MODULO,
MP_F_NATIVE_YIELD_FROM,
MP_F_NUMBER_OF,
} mp_fun_kind_t;
extern const void *const mp_fun_table[MP_F_NUMBER_OF];
#endif // MICROPY_INCLUDED_PY_RUNTIME0_H
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