Gabe Black has uploaded this change for review. (
https://gem5-review.googlesource.com/6825
Change subject: riscv,x86: Stop using the arch Nop machine instruction
unnecessarily.
......................................................................
riscv,x86: Stop using the arch Nop machine instruction unnecessarily.
That particular ExtMachInst is a convenient placeholder, but a value
of 0 in RISCV or a static uninitialized ExtMachInst (which will
therefore be all zeroes) on x86 works just as well, and removes the
need for an ISA specific constant.
Also, the idea of a universal Nop doesn't always make sense since it
could be that what, exactly, doesn't do anything depends on context
which would be lost on a constant value of an ExtMachInst. For
instance, the value of an ExtMachInst that makes sense might depend on
what mode the CPU was in, etc.
Change-Id: I1f1a43a5c607a667e11b79bcf6e059e4f7141b3f
---
M src/arch/riscv/decoder.cc
M src/arch/x86/insts/badmicroop.cc
M src/arch/x86/isa/microops/base.isa
3 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/src/arch/riscv/decoder.cc b/src/arch/riscv/decoder.cc
index 020c5e3..41a5202 100644
--- a/src/arch/riscv/decoder.cc
+++ b/src/arch/riscv/decoder.cc
@@ -45,7 +45,7 @@
aligned = true;
mid = false;
more = true;
- emi = NoopMachInst;
+ emi = 0;
instDone = false;
}
diff --git a/src/arch/x86/insts/badmicroop.cc
b/src/arch/x86/insts/badmicroop.cc
index 21af128..0924873 100644
--- a/src/arch/x86/insts/badmicroop.cc
+++ b/src/arch/x86/insts/badmicroop.cc
@@ -42,14 +42,21 @@
#include "arch/x86/generated/decoder.hh"
#include "arch/x86/isa_traits.hh"
+namespace {
+
+static X86ISA::ExtMachInst dummyMachInst;
+
+}
+
namespace X86ISA
{
// This microop needs to be allocated on the heap even though it could
// theoretically be statically allocated. The reference counted pointer
would
// try to delete the static memory when it was destructed.
+
const StaticInstPtr badMicroop =
- new X86ISAInst::MicroPanic(NoopMachInst, "BAD",
+ new X86ISAInst::MicroPanic(dummyMachInst, "BAD",
StaticInst::IsMicroop | StaticInst::IsLastMicroop,
"Invalid microop!", 0);
diff --git a/src/arch/x86/isa/microops/base.isa
b/src/arch/x86/isa/microops/base.isa
index dc36d0e..42e7d2e 100644
--- a/src/arch/x86/isa/microops/base.isa
+++ b/src/arch/x86/isa/microops/base.isa
@@ -59,8 +59,7 @@
''' + generatorNameTemplate + '''(StaticInstPtr curMacroop)
{
static const char *macrocodeBlock = romMnemonic;
- static const ExtMachInst dummyExtMachInst = \
- X86ISA::NoopMachInst;
+ static ExtMachInst dummyExtMachInst;
static const EmulEnv dummyEmulEnv(0, 0, 1, 1, 1);
Macroop * macroop = dynamic_cast<Macroop
*>(curMacroop.get());
--
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Gerrit-Project: public/gem5
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: I1f1a43a5c607a667e11b79bcf6e059e4f7141b3f
Gerrit-Change-Number: 6825
Gerrit-PatchSet: 1
Gerrit-Owner: Gabe Black <[email protected]>
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