1#!/usr/bin/env python3 2# -*- coding: utf-8 -*- 3# 4# Copyright (C) 2018 The Android Open Source Project 5# 6# Licensed under the Apache License, Version 2.0 (the "License"); 7# you may not use this file except in compliance with the License. 8# You may obtain a copy of the License at 9# 10# http://www.apache.org/licenses/LICENSE-2.0 11# 12# Unless required by applicable law or agreed to in writing, software 13# distributed under the License is distributed on an "AS IS" BASIS, 14# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15# See the License for the specific language governing permissions and 16# limitations under the License. 17"""Architecture-specific information.""" 18 19import collections 20import json 21 22 23class Arch( 24 collections.namedtuple('Arch', [ 25 'arch_nr', 'arch_name', 'bits', 'syscalls', 'constants', 26 'syscall_groups' 27 ])): 28 """Holds architecture-specific information.""" 29 30 def truncate_word(self, value): 31 """Return the value truncated to fit in a word.""" 32 return value & self.max_unsigned 33 34 @property 35 def min_signed(self): 36 """The smallest signed value that can be represented in a word.""" 37 return -(1 << (self.bits - 1)) 38 39 @property 40 def max_unsigned(self): 41 """The largest unsigned value that can be represented in a word.""" 42 return (1 << self.bits) - 1 43 44 @staticmethod 45 def load_from_json(json_path): 46 """Return an Arch from a .json file.""" 47 with open(json_path, 'r') as json_file: 48 return Arch.load_from_json_bytes(json_file.read()) 49 50 @staticmethod 51 def load_from_json_bytes(json_bytes): 52 """Return an Arch from a json string.""" 53 constants = json.loads(json_bytes) 54 return Arch( 55 arch_nr=constants["arch_nr"], 56 arch_name=constants["arch_name"], 57 bits=constants["bits"], 58 syscalls=constants["syscalls"], 59 constants=constants["constants"], 60 syscall_groups=constants.get("syscall_groups", {}), 61 ) 62