From a3e113239b76956218bc89ff530b93d615aeeacc Mon Sep 17 00:00:00 2001 From: Gabe Black Date: Tue, 18 Aug 2020 00:25:39 -0700 Subject: [PATCH] cpu,arch: Delegate fetching ROM microops to the decoder. In most cases, the microcode ROM doesn't actually do anything. The structural existence of a microcode ROM doesn't make sense in the general case, and in architectures that know they have one and need to interact with it, they can cast their decoder into an arch specific type and access the ROM that way. Change-Id: I25b67bfe65df1fdb84eb5bc894cfcb83da1ce64b Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/32898 Reviewed-by: Andreas Sandberg Maintainer: Andreas Sandberg Tested-by: kokoro --- src/arch/generic/SConscript | 1 + src/arch/generic/decoder.cc | 36 ++++++++++++++++++++++++++++++++++++ src/arch/generic/decoder.hh | 6 ++++++ src/arch/x86/decoder.cc | 8 ++++++++ src/arch/x86/decoder.hh | 6 ++++++ src/cpu/checker/cpu_impl.hh | 4 ++-- src/cpu/o3/fetch_impl.hh | 2 +- src/cpu/simple/base.cc | 4 ++-- 8 files changed, 62 insertions(+), 5 deletions(-) create mode 100644 src/arch/generic/decoder.cc diff --git a/src/arch/generic/SConscript b/src/arch/generic/SConscript index e3c2567ae..0cba60a5b 100644 --- a/src/arch/generic/SConscript +++ b/src/arch/generic/SConscript @@ -42,6 +42,7 @@ if env['TARGET_ISA'] == 'null': Return() Source('decode_cache.cc') +Source('decoder.cc') SimObject('BaseInterrupts.py') SimObject('BaseISA.py') diff --git a/src/arch/generic/decoder.cc b/src/arch/generic/decoder.cc new file mode 100644 index 000000000..c28fa00d1 --- /dev/null +++ b/src/arch/generic/decoder.cc @@ -0,0 +1,36 @@ +/* + * Copyright 2020 Google, Inc. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer; + * redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution; + * neither the name of the copyright holders nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "arch/generic/decoder.hh" + +#include "base/logging.hh" + +StaticInstPtr +InstDecoder::fetchRomMicroop(MicroPC micropc, StaticInstPtr curMacroop) +{ + panic("ROM based microcode isn't implemented."); +} diff --git a/src/arch/generic/decoder.hh b/src/arch/generic/decoder.hh index 00aecf2cc..3df4dccfd 100644 --- a/src/arch/generic/decoder.hh +++ b/src/arch/generic/decoder.hh @@ -28,8 +28,14 @@ #ifndef __ARCH_GENERIC_DECODER_HH__ #define __ARCH_GENERIC_DECODER_HH__ +#include "base/types.hh" +#include "cpu/static_inst_fwd.hh" + class InstDecoder { + public: + virtual StaticInstPtr fetchRomMicroop( + MicroPC micropc, StaticInstPtr curMacroop); }; #endif // __ARCH_DECODER_GENERIC_HH__ diff --git a/src/arch/x86/decoder.cc b/src/arch/x86/decoder.cc index 28034cba4..415c7b4c8 100644 --- a/src/arch/x86/decoder.cc +++ b/src/arch/x86/decoder.cc @@ -37,6 +37,8 @@ namespace X86ISA { +X86ISAInst::MicrocodeRom Decoder::microcodeRom; + Decoder::State Decoder::doResetState() { @@ -725,4 +727,10 @@ Decoder::decode(PCState &nextPC) return si; } +StaticInstPtr +Decoder::fetchRomMicroop(MicroPC micropc, StaticInstPtr curMacroop) +{ + return microcodeRom.fetchMicroop(micropc, curMacroop); +} + } diff --git a/src/arch/x86/decoder.hh b/src/arch/x86/decoder.hh index 6b05324b8..94ebd0cf2 100644 --- a/src/arch/x86/decoder.hh +++ b/src/arch/x86/decoder.hh @@ -34,6 +34,7 @@ #include #include "arch/generic/decoder.hh" +#include "arch/x86/microcode_rom.hh" #include "arch/x86/regs/misc.hh" #include "arch/x86/types.hh" #include "base/bitfield.hh" @@ -67,6 +68,8 @@ class Decoder : public InstDecoder static ByteTable ImmediateTypeThreeByte0F3A; static ByteTable ImmediateTypeVex[10]; + static X86ISAInst::MicrocodeRom microcodeRom; + protected: struct InstBytes { @@ -332,6 +335,9 @@ class Decoder : public InstDecoder /// @retval A pointer to the corresponding StaticInst object. StaticInstPtr decode(ExtMachInst mach_inst, Addr addr); StaticInstPtr decode(X86ISA::PCState &nextPC); + + StaticInstPtr fetchRomMicroop( + MicroPC micropc, StaticInstPtr curMacroop) override; }; } // namespace X86ISA diff --git a/src/cpu/checker/cpu_impl.hh b/src/cpu/checker/cpu_impl.hh index b48f6daef..0656035c8 100644 --- a/src/cpu/checker/cpu_impl.hh +++ b/src/cpu/checker/cpu_impl.hh @@ -287,8 +287,8 @@ Checker::verify(const DynInstPtr &completed_inst) if (isRomMicroPC(pcState.microPC())) { fetchDone = true; - curStaticInst = - microcodeRom.fetchMicroop(pcState.microPC(), NULL); + curStaticInst = thread->decoder.fetchRomMicroop( + pcState.microPC(), nullptr); } else if (!curMacroStaticInst) { //We're not in the middle of a macro instruction StaticInstPtr instPtr = nullptr; diff --git a/src/cpu/o3/fetch_impl.hh b/src/cpu/o3/fetch_impl.hh index 6a0184a4b..7ecab5461 100644 --- a/src/cpu/o3/fetch_impl.hh +++ b/src/cpu/o3/fetch_impl.hh @@ -1316,7 +1316,7 @@ DefaultFetch::fetch(bool &status_change) bool newMacro = false; if (curMacroop || inRom) { if (inRom) { - staticInst = cpu->microcodeRom.fetchMicroop( + staticInst = decoder[tid]->fetchRomMicroop( thisPC.microPC(), curMacroop); } else { staticInst = curMacroop->fetchMicroop(thisPC.microPC()); diff --git a/src/cpu/simple/base.cc b/src/cpu/simple/base.cc index e63ad4eda..a597f0616 100644 --- a/src/cpu/simple/base.cc +++ b/src/cpu/simple/base.cc @@ -500,8 +500,8 @@ BaseSimpleCPU::preExecute() if (isRomMicroPC(pcState.microPC())) { t_info.stayAtPC = false; - curStaticInst = microcodeRom.fetchMicroop(pcState.microPC(), - curMacroStaticInst); + curStaticInst = thread->decoder.fetchRomMicroop( + pcState.microPC(), curMacroStaticInst); } else if (!curMacroStaticInst) { //We're not in the middle of a macro instruction StaticInstPtr instPtr = NULL; -- 2.30.2