Giacomo Travaglini has submitted this change and it was merged. (
https://gem5-review.googlesource.com/c/public/gem5/+/17188 )
Change subject: base: Fix CircularQueue when diffing iterators
......................................................................
base: Fix CircularQueue when diffing iterators
This patch is fixing CircularQueue iterators' subtraction, in particular
the behaviour when head and tail round multiple times.
Change-Id: Ie79ac8accd30a10cf039cf4def87675b01375d6b
Signed-off-by: Giacomo Travaglini <[email protected]>
Reviewed-by: Gabor Dozsa <[email protected]>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17188
Reviewed-by: Daniel Carvalho <[email protected]>
Reviewed-by: Jason Lowe-Power <[email protected]>
Maintainer: Andreas Sandberg <[email protected]>
---
M src/base/circular_queue.hh
M src/base/circular_queue.test.cc
2 files changed, 38 insertions(+), 4 deletions(-)
Approvals:
Jason Lowe-Power: Looks good to me, but someone else must approve
Daniel Carvalho: Looks good to me, approved
Andreas Sandberg: Looks good to me, approved
diff --git a/src/base/circular_queue.hh b/src/base/circular_queue.hh
index 5023661..f368ed0 100644
--- a/src/base/circular_queue.hh
+++ b/src/base/circular_queue.hh
@@ -106,10 +106,19 @@
static uint32_t
moduloSub(uint32_t op1, uint32_t op2, uint32_t size)
{
- int ret = (uint32_t)(op1 - op2) % size;
+ int32_t ret = sub(op1, op2, size);
return ret >= 0 ? ret : ret + size;
}
+ static int32_t
+ sub(uint32_t op1, uint32_t op2, uint32_t size)
+ {
+ if (op1 > op2)
+ return (op1 - op2) % size;
+ else
+ return -((op2 - op1) % size);
+ }
+
void increase(uint32_t& v, size_t delta = 1)
{
v = moduloAdd(v, delta, _capacity);
@@ -355,10 +364,10 @@
difference_type operator-(const iterator& that)
{
/* If a is already at the end, we can safely return 0. */
- auto ret = _cq->moduloSub(this->_idx, that._idx);
+ auto ret = _cq->sub(this->_idx, that._idx, _cq->capacity());
- if (ret == 0 && this->_round != that._round) {
- ret += this->_round * _cq->capacity();
+ if (this->_round != that._round) {
+ ret += ((this->_round - that._round) * _cq->capacity());
}
return ret;
}
diff --git a/src/base/circular_queue.test.cc
b/src/base/circular_queue.test.cc
index db59c30..cce6cb0 100644
--- a/src/base/circular_queue.test.cc
+++ b/src/base/circular_queue.test.cc
@@ -212,6 +212,7 @@
ASSERT_EQ(it_1 + 1, it_2);
ASSERT_EQ(it_1, it_2 - 1);
ASSERT_EQ(it_2 - it_1, 1);
+ ASSERT_EQ(it_1 - it_2, -1);
auto temp_it = it_1;
ASSERT_EQ(++temp_it, it_2);
@@ -241,3 +242,27 @@
ASSERT_EQ(starting_it._idx, ending_it._idx);
ASSERT_TRUE(starting_it != ending_it);
}
+
+/**
+ * Testing correct behaviour when rounding multiple times:
+ * - Round indexes in sync
+ * - Difference between begin() and end() iterator is still
+ * equal to the CircularQueue size.
+ */
+TEST(CircularQueueTest, MultipleRound)
+{
+ const auto cq_size = 8;
+ CircularQueue<uint32_t> cq(cq_size);
+
+ // Filling the queue making it round multiple times
+ auto items_added = cq_size * 3;
+ for (auto idx = 0; idx < items_added; idx++) {
+ cq.push_back(0);
+ }
+
+ auto starting_it = cq.begin();
+ auto ending_it = cq.end();
+
+ ASSERT_EQ(starting_it._round + 1, ending_it._round);
+ ASSERT_EQ(ending_it - starting_it, cq_size);
+}
--
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Gerrit-Project: public/gem5
Gerrit-Branch: master
Gerrit-Change-Id: Ie79ac8accd30a10cf039cf4def87675b01375d6b
Gerrit-Change-Number: 17188
Gerrit-PatchSet: 3
Gerrit-Owner: Giacomo Travaglini <[email protected]>
Gerrit-Reviewer: Andreas Sandberg <[email protected]>
Gerrit-Reviewer: Daniel Carvalho <[email protected]>
Gerrit-Reviewer: Gabor Dozsa <[email protected]>
Gerrit-Reviewer: Giacomo Travaglini <[email protected]>
Gerrit-Reviewer: Jason Lowe-Power <[email protected]>
Gerrit-MessageType: merged
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