1 //===- llvm/Support/BCD.h - Binary-Coded Decimal utility functions -*- C++ -*-// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file declares some utility functions for encoding/decoding BCD values. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_SUPPORT_BCD_H 14 #define LLVM_SUPPORT_BCD_H 15 16 #include <assert.h> 17 #include <cstddef> 18 #include <cstdint> 19 20 namespace llvm { 21 22 // Decode a packed BCD value. 23 // Maximum value of int64_t is 9,223,372,036,854,775,807. These are 18 usable 24 // decimal digits. Thus BCD numbers of up to 9 bytes can be converted. 25 // Please note that s390 supports BCD numbers up to a length of 16 bytes. 26 inline int64_t decodePackedBCD(const uint8_t *Ptr, size_t ByteLen, 27 bool IsSigned = true) { 28 assert(ByteLen >= 1 && ByteLen <= 9 && "Invalid BCD number"); 29 int64_t Value = 0; 30 size_t RunLen = ByteLen - static_cast<unsigned>(IsSigned); 31 for (size_t I = 0; I < RunLen; ++I) { 32 uint8_t DecodedByteValue = ((Ptr[I] >> 4) & 0x0f) * 10 + (Ptr[I] & 0x0f); 33 Value = (Value * 100) + DecodedByteValue; 34 } 35 if (IsSigned) { 36 uint8_t DecodedByteValue = (Ptr[ByteLen - 1] >> 4) & 0x0f; 37 uint8_t Sign = Ptr[ByteLen - 1] & 0x0f; 38 Value = (Value * 10) + DecodedByteValue; 39 if (Sign == 0x0d || Sign == 0x0b) 40 Value *= -1; 41 } 42 return Value; 43 } 44 45 template <typename ResultT, typename ValT> 46 inline ResultT decodePackedBCD(const ValT Val, bool IsSigned = true) { 47 return static_cast<ResultT>(decodePackedBCD( 48 reinterpret_cast<const uint8_t *>(&Val), sizeof(ValT), IsSigned)); 49 } 50 51 } // namespace llvm 52 53 #endif // LLVM_SUPPORT_BCD_H 54