#!/usr/bin/env python # This Source Code Form is subject to the terms of the Mozilla Public # License, v. 2.0. If a copy of the MPL was not distributed with this # file, You can obtain one at http://mozilla.org/MPL/2.0/. """Generate tables of immediately-encodable VFP doubles. DOES NOT get automatically run during the build process. If you need to modify this file (which is unlikely), you must re-run this script: python gen-double-encode-table.py > $(topsrcdir)/path/to/DoubleEntryTable.tbl """ import operator def rep(bit, count): return reduce(operator.ior, [bit << c for c in range(count)]) def encodeDouble(value): """Generate an ARM ARM 'VFP modified immediate constant' with format: aBbbbbbb bbcdefgh 000... We will return the top 32 bits of the double; the rest are 0.""" assert (0 <= value) and (value <= 255) a = value >> 7 b = (value >> 6) & 1 B = int(b == 0) cdefgh = value & 0x3F return (a << 31) | (B << 30) | (rep(b, 8) << 22) | cdefgh << 16 print("/* THIS FILE IS AUTOMATICALLY GENERATED BY gen-double-encode-table.py. */") for i in range(256): print(" { 0x%08x, { %d, %d, 0 } }," % (encodeDouble(i), i & 0xF, i >> 4))