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| 14 | pmbaty | 1 | //===- llvm/Support/BCD.h - Binary-Coded Decimal utility functions -*- C++ -*-// |
| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | // |
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| 9 | // This file declares some utility functions for encoding/decoding BCD values. |
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| 10 | // |
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| 11 | //===----------------------------------------------------------------------===// |
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| 12 | |||
| 13 | #ifndef LLVM_SUPPORT_BCD_H |
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| 14 | #define LLVM_SUPPORT_BCD_H |
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| 15 | |||
| 16 | #include <assert.h> |
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| 17 | #include <cstddef> |
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| 18 | #include <cstdint> |
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| 19 | |||
| 20 | namespace llvm { |
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| 21 | |||
| 22 | // Decode a packed BCD value. |
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| 23 | // Maximum value of int64_t is 9,223,372,036,854,775,807. These are 18 usable |
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| 24 | // decimal digits. Thus BCD numbers of up to 9 bytes can be converted. |
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| 25 | // Please note that s390 supports BCD numbers up to a length of 16 bytes. |
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| 26 | inline int64_t decodePackedBCD(const uint8_t *Ptr, size_t ByteLen, |
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| 27 | bool IsSigned = true) { |
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| 28 | assert(ByteLen >= 1 && ByteLen <= 9 && "Invalid BCD number"); |
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| 29 | int64_t Value = 0; |
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| 30 | size_t RunLen = ByteLen - static_cast<unsigned>(IsSigned); |
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| 31 | for (size_t I = 0; I < RunLen; ++I) { |
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| 32 | uint8_t DecodedByteValue = ((Ptr[I] >> 4) & 0x0f) * 10 + (Ptr[I] & 0x0f); |
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| 33 | Value = (Value * 100) + DecodedByteValue; |
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| 34 | } |
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| 35 | if (IsSigned) { |
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| 36 | uint8_t DecodedByteValue = (Ptr[ByteLen - 1] >> 4) & 0x0f; |
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| 37 | uint8_t Sign = Ptr[ByteLen - 1] & 0x0f; |
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| 38 | Value = (Value * 10) + DecodedByteValue; |
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| 39 | if (Sign == 0x0d || Sign == 0x0b) |
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| 40 | Value *= -1; |
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| 41 | } |
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| 42 | return Value; |
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| 43 | } |
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| 44 | |||
| 45 | template <typename ResultT, typename ValT> |
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| 46 | inline ResultT decodePackedBCD(const ValT Val, bool IsSigned = true) { |
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| 47 | return static_cast<ResultT>(decodePackedBCD( |
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| 48 | reinterpret_cast<const uint8_t *>(&Val), sizeof(ValT), IsSigned)); |
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| 49 | } |
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| 50 | |||
| 51 | } // namespace llvm |
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| 52 | |||
| 53 | #endif // LLVM_SUPPORT_BCD_H |