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BankedArray.cc
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1 /*
2  * Copyright (c) 2012 Advanced Micro Devices, Inc.
3  * All rights reserved.
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27  *
28  * Author: Brad Beckmann
29  *
30  */
31 
33 
34 #include "base/intmath.hh"
36 
37 BankedArray::BankedArray(unsigned int banks, Cycles accessLatency,
38  unsigned int startIndexBit, RubySystem *rs)
39  : m_ruby_system(rs)
40 {
41  this->banks = banks;
42  this->accessLatency = accessLatency;
43  this->startIndexBit = startIndexBit;
44 
45  if (banks != 0) {
46  bankBits = floorLog2(banks);
47  }
48 
49  busyBanks.resize(banks);
50 }
51 
52 bool
54 {
55  if (accessLatency == 0)
56  return true;
57 
58  unsigned int bank = mapIndexToBank(idx);
59  assert(bank < banks);
60 
61  if (busyBanks[bank].endAccess >= curTick()) {
62  return false;
63  }
64 
65  return true;
66 }
67 
68 void
70 {
71  if (accessLatency == 0)
72  return;
73 
74  unsigned int bank = mapIndexToBank(idx);
75  assert(bank < banks);
76 
77  if (busyBanks[bank].endAccess >= curTick()) {
78  if (busyBanks[bank].startAccess == curTick() &&
79  busyBanks[bank].idx == idx) {
80  // this is the same reservation (can happen when
81  // e.g., reserve the same resource for read and write)
82  return; // OK
83  } else {
84  panic("BankedArray reservation error");
85  }
86  }
87 
88  busyBanks[bank].idx = idx;
89  busyBanks[bank].startAccess = curTick();
90  busyBanks[bank].endAccess = curTick() +
92 }
93 
94 unsigned int
96 {
97  if (banks == 1) {
98  return 0;
99  }
100  return idx % banks;
101 }
unsigned int mapIndexToBank(int64_t idx)
Definition: BankedArray.cc:95
Cycles is a wrapper class for representing cycle counts, i.e.
Definition: types.hh:83
#define panic(...)
Definition: misc.hh:153
bool tryAccess(int64_t idx)
Definition: BankedArray.cc:53
Cycles accessLatency
Definition: BankedArray.hh:45
std::vector< AccessRecord > busyBanks
Definition: BankedArray.hh:61
unsigned int startIndexBit
Definition: BankedArray.hh:47
unsigned int banks
Definition: BankedArray.hh:44
Tick curTick()
The current simulated tick.
Definition: core.hh:47
unsigned int bankBits
Definition: BankedArray.hh:46
int floorLog2(unsigned x)
Definition: intmath.hh:100
Tick clockPeriod() const
BankedArray(unsigned int banks, Cycles accessLatency, unsigned int startIndexBit, RubySystem *rs)
Definition: BankedArray.cc:37
void reserve(int64_t idx)
Definition: BankedArray.cc:69
RubySystem * m_ruby_system
Definition: BankedArray.hh:48
Bitfield< 9, 8 > rs
Definition: miscregs.hh:1560

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