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inorder: find register dependencies "lazily"

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Architectures like SPARC need to read the window pointer
in order to figure out it's register dependence. However,
this may not get updated until after an instruction gets
executed, so now we lazily detect the register dependence
in the EXE stage (execution unit or use_def). This
makes sure we get the mapping after the most current change.
This commit is contained in:
Korey Sewell 2011-06-19 21:43:34 -04:00
parent bd67ee9852
commit 3c417ea23a
3 changed files with 17 additions and 3 deletions
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1
src/cpu/inorder/resources/decode_unit.cc
View file

@ -68,7 +68,6 @@ DecodeUnit::execute(int slot_num)
DPRINTF(InOrderDecode,
"[tid:%i]: %s Setting Destination Register(s) for [sn:%i].\n",
tid, inst->instName(), inst->seqNum);
regDepMap[tid]->insert(inst);
//inst->printSked();

13
src/cpu/inorder/resources/execution_unit.cc
View file

@ -100,6 +100,17 @@ ExecutionUnit::execute(int slot_num)
}
//@todo: may want to make a separate schedule entry for setting
// destination register dependencies
//@note: typically want to set the output dependencies right
// before we do any reading or writing of registers
// (in RegFile Manager(use_def.cc)) but there are some
// instructions that dont have src regs, so just in case
// take care of reg. dep. map stuff here
if (!inst->isRegDepEntry()) {
regDepMap[tid]->insert(inst);
}
switch (exec_req->cmd)
{
case ExecuteInst:
@ -139,11 +150,9 @@ ExecutionUnit::execute(int slot_num)
lastControlTick = curTick();
// Evaluate Branch
DPRINTF(IEW, "Pre-Execute %s PC:%s nextPC:%s predPC:%s\n", inst->instName(), inst->pcState(), inst->readPredTarg());
fault = inst->execute();
executions++;
inst->setExecuted();
DPRINTF(IEW, "Post-Execute %s PC:%s nextPC:%s predPC:%s\n", inst->instName(), inst->pcState(), inst->readPredTarg());
if (fault == NoFault) {
// If branch is mispredicted, then signal squash

6
src/cpu/inorder/resources/use_def.cc
View file

@ -159,6 +159,12 @@ UseDefUnit::execute(int slot_idx)
*nonSpecSeqNum[tid] = seq_num;
}
//@todo: may want to make a separate schedule entry for setting
// destination register dependencies
if (!inst->isRegDepEntry()) {
regDepMap[tid]->insert(inst);
}
switch (ud_req->cmd)
{
case ReadSrcReg: