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248c554524
Add Float16 (IEEE 754 binary16) to the standard library, plus assorted runtime support operations. Swift Evolution thread: https://forums.swift.org/t/se-0277-float16/33546
54 lines
2.1 KiB
Python
54 lines
2.1 KiB
Python
# ===--- SwiftFloatingPointTypes.py ------------------*- coding: utf-8 -*-===//
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#
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# This source file is part of the Swift.org open source project
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#
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# Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
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# Licensed under Apache License v2.0 with Runtime Library Exception
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#
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# See https://swift.org/LICENSE.txt for license information
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# See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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# returns (lower, upper) exclusive bounds for the integer values
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# that can be stored into a float
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def getFtoIBounds(floatBits, intBits, signed):
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floatTy = floating_point_bits_to_type()[floatBits]
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sigBits = floatTy.explicit_significand_bits
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if not signed:
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return (-1, 1 << intBits)
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upper = 1 << (intBits - 1)
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if intBits <= sigBits:
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return (-upper - 1, upper)
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ulp = 1 << (intBits - sigBits)
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return (-upper - ulp, upper)
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class SwiftFloatType(object):
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def __init__(self, name, cFuncSuffix, significandBits, exponentBits,
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significandSize, totalBits):
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self.stdlib_name = name
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self.cFuncSuffix = cFuncSuffix
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self.significand_bits = significandBits
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self.significand_size = significandSize
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self.exponent_bits = exponentBits
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self.explicit_significand_bits = significandBits + 1
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self.bits = totalBits
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def floating_point_bits_to_type():
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return {
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16: SwiftFloatType(name="Float16", cFuncSuffix="f", significandBits=10,
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exponentBits=5, significandSize=16, totalBits=16),
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32: SwiftFloatType(name="Float", cFuncSuffix="f", significandBits=23,
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exponentBits=8, significandSize=32, totalBits=32),
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64: SwiftFloatType(name="Double", cFuncSuffix="", significandBits=52,
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exponentBits=11, significandSize=64, totalBits=64),
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80: SwiftFloatType(name="Float80", cFuncSuffix="l", significandBits=63,
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exponentBits=15, significandSize=64, totalBits=80),
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}
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def all_floating_point_types():
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return floating_point_bits_to_type().values()
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