LLVM  16.0.0git
BCD.h
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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
llvm
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
I
#define I(x, y, z)
Definition: MD5.cpp:58
assert
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
Ptr
@ Ptr
Definition: TargetLibraryInfo.cpp:60
llvm::TargetStackID::Value
Value
Definition: TargetFrameLowering.h:27
llvm::decodePackedBCD
int64_t decodePackedBCD(const uint8_t *Ptr, size_t ByteLen, bool IsSigned=true)
Definition: BCD.h:26
ValT
llvm::Value
LLVM Value Representation.
Definition: Value.h:74