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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# Copyright (C) 2018 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Architecture-specific information."""
import collections
import json
class Arch(
collections.namedtuple('Arch', [
'arch_nr', 'arch_name', 'bits', 'syscalls', 'constants',
'syscall_groups'
])):
"""Holds architecture-specific information."""
def truncate_word(self, value):
"""Return the value truncated to fit in a word."""
return value & self.max_unsigned
@property
def min_signed(self):
"""The smallest signed value that can be represented in a word."""
return -(1 << (self.bits - 1))
@property
def max_unsigned(self):
"""The largest unsigned value that can be represented in a word."""
return (1 << self.bits) - 1
@staticmethod
def load_from_json(json_path):
"""Return an Arch from a .json file."""
with open(json_path, 'r') as json_file:
constants = json.load(json_file)
return Arch(
arch_nr=constants['arch_nr'],
arch_name=constants['arch_name'],
bits=constants['bits'],
syscalls=constants['syscalls'],
constants=constants['constants'],
syscall_groups=constants.get('syscall_groups', {}),
)