x86: Rework how "split" loads/stores are handled.
Explicitly separate the way the data is represented in the underlying
representation from how it's represented in the instruction.
In order to make the ISA parser happy, the Mem operand needs to have
a single, particular type. To handle that with scalar types, we just
used uint64_ts and then worked with values that were smaller than the
maximum we could hold. To work with these new array values, we also
use an underlying uint64_t for each element.
To make accessing the underlying memory system more natural, when we
go to actually read or write values, we translate the access into an
array of the actual, correct underlying type. That way we don't have
non-exact asserts which confuse gcc, or weird endianness conversion
which assumes that the data should be flipped 8 bytes at a time.
Because the functions involved are generally inline, the syntactic
niceness should all boil off, and the final implementation in the
binary should be simple and efficient for the given data types.
Change-Id: I14ce7a2fe0dc2cbaf6ad4a0d19f743c45ee78e26
Reviewed-on: https://gem5-review.googlesource.com/6582
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
diff --git a/src/arch/x86/isa/microops/ldstop.isa b/src/arch/x86/isa/microops/ldstop.isa
index 5ff4f0c..a3d9c5a 100644
--- a/src/arch/x86/isa/microops/ldstop.isa
+++ b/src/arch/x86/isa/microops/ldstop.isa
@@ -99,8 +99,7 @@
%(ea_code)s;
DPRINTF(X86, "%s : %s: The address is %#x\n", instMnem, mnemonic, EA);
- fault = readMemAtomic(xc, traceData, EA, Mem,
- %(memDataSize)s, memFlags);
+ fault = readMemAtomic(xc, traceData, EA, Mem, dataSize, memFlags);
if (fault == NoFault) {
%(code)s;
@@ -145,7 +144,7 @@
%(op_decl)s;
%(op_rd)s;
- getMem(pkt, Mem, %(memDataSize)s, traceData);
+ getMem(pkt, Mem, dataSize, traceData);
%(code)s;
@@ -174,12 +173,10 @@
%(code)s;
- if(fault == NoFault)
- {
- fault = writeMemAtomic(xc, traceData, Mem, %(memDataSize)s, EA,
- memFlags, NULL);
- if(fault == NoFault)
- {
+ if (fault == NoFault) {
+ fault = writeMemAtomic(xc, traceData, Mem, dataSize, EA,
+ memFlags, NULL);
+ if (fault == NoFault) {
%(op_wb)s;
}
}
@@ -202,10 +199,9 @@
%(code)s;
- if(fault == NoFault)
- {
- fault = writeMemTiming(xc, traceData, Mem, %(memDataSize)s, EA,
- memFlags, NULL);
+ if (fault == NoFault) {
+ fault = writeMemTiming(xc, traceData, Mem, dataSize, EA,
+ memFlags, NULL);
}
return fault;
}
@@ -561,18 +557,9 @@
microopClasses[name] = LoadOp
code = '''
- switch (dataSize) {
- case 4:
- DataLow = bits(Mem_u2qw[0], 31, 0);
- DataHi = bits(Mem_u2qw[0], 63, 32);
- break;
- case 8:
- DataLow = Mem_u2qw[0];
- DataHi = Mem_u2qw[1];
- break;
- default:
- panic("Unhandled data size %d in LdSplit.\\n", dataSize);
- }'''
+ DataLow = Mem_u2qw[0];
+ DataHi = Mem_u2qw[1];
+ '''
defineMicroLoadSplitOp('LdSplit', code,
'(StoreCheck << FlagShift)')
@@ -683,17 +670,9 @@
microopClasses[name] = StoreOp
code = '''
- switch (dataSize) {
- case 4:
- Mem_u2qw[0] = (DataHi << 32) | DataLow;
- break;
- case 8:
- Mem_u2qw[0] = DataLow;
- Mem_u2qw[1] = DataHi;
- break;
- default:
- panic("Unhandled data size %d in StSplit.\\n", dataSize);
- }'''
+ Mem_u2qw[0] = DataLow;
+ Mem_u2qw[1] = DataHi;
+ '''
defineMicroStoreSplitOp('StSplit', code);
diff --git a/src/arch/x86/memhelpers.hh b/src/arch/x86/memhelpers.hh
index 00a6e9a..aa3617b 100644
--- a/src/arch/x86/memhelpers.hh
+++ b/src/arch/x86/memhelpers.hh
@@ -74,24 +74,30 @@
traceData->setData(mem);
}
+template <typename T, size_t N>
+static void
+getPackedMem(PacketPtr pkt, std::array<uint64_t, N> &mem, unsigned dataSize)
+{
+ std::array<T, N> real_mem = pkt->get<std::array<T, N> >();
+ for (int i = 0; i < N; i++)
+ mem[i] = real_mem[i];
+}
template <size_t N>
-void
+static void
getMem(PacketPtr pkt, std::array<uint64_t, N> &mem, unsigned dataSize,
Trace::InstRecord *traceData)
{
- assert(dataSize >= 8);
- assert((dataSize % 8) == 0);
-
- int num_words = dataSize / 8;
- assert(num_words <= N);
-
- auto pkt_data = pkt->getConstPtr<const uint64_t>();
- for (int i = 0; i < num_words; ++i)
- mem[i] = gtoh(pkt_data[i]);
-
- // traceData record only has space for 64 bits, so we just record
- // the first qword
+ switch (dataSize) {
+ case 4:
+ getPackedMem<uint32_t, N>(pkt, mem, dataSize);
+ break;
+ case 8:
+ getPackedMem<uint64_t, N>(pkt, mem, dataSize);
+ break;
+ default:
+ panic("Unhandled element size in getMem.\n");
+ }
if (traceData)
traceData->setData(mem[0]);
}
@@ -114,62 +120,86 @@
return fault;
}
+template <typename T, size_t N>
+static Fault
+readPackedMemAtomic(ExecContext *xc, Addr addr, std::array<uint64_t, N> &mem,
+ unsigned flags)
+{
+ std::array<T, N> real_mem;
+ Fault fault = xc->readMem(addr, (uint8_t *)&real_mem,
+ sizeof(T) * N, flags);
+ if (fault == NoFault) {
+ real_mem = gtoh(real_mem);
+ for (int i = 0; i < N; i++)
+ mem[i] = real_mem[i];
+ }
+ return fault;
+}
+
template <size_t N>
-Fault
+static Fault
readMemAtomic(ExecContext *xc, Trace::InstRecord *traceData, Addr addr,
std::array<uint64_t, N> &mem, unsigned dataSize,
unsigned flags)
{
- assert(dataSize >= 8);
- assert((dataSize % 8) == 0);
+ Fault fault = NoFault;
- Fault fault = xc->readMem(addr, (uint8_t *)&mem, dataSize, flags);
-
- if (fault == NoFault) {
- int num_words = dataSize / 8;
- assert(num_words <= N);
-
- for (int i = 0; i < num_words; ++i)
- mem[i] = gtoh(mem[i]);
-
- if (traceData)
- traceData->setData(mem[0]);
+ switch (dataSize) {
+ case 4:
+ fault = readPackedMemAtomic<uint32_t, N>(xc, addr, mem, flags);
+ break;
+ case 8:
+ fault = readPackedMemAtomic<uint64_t, N>(xc, addr, mem, flags);
+ break;
+ default:
+ panic("Unhandled element size in readMemAtomic\n");
}
+ if (fault == NoFault && traceData)
+ traceData->setData(mem[0]);
return fault;
}
+template <typename T, size_t N>
+static Fault
+writePackedMem(ExecContext *xc, std::array<uint64_t, N> &mem, Addr addr,
+ unsigned flags, uint64_t *res)
+{
+ std::array<T, N> real_mem;
+ for (int i = 0; i < N; i++)
+ real_mem[i] = mem[i];
+ real_mem = htog(real_mem);
+ return xc->writeMem((uint8_t *)&real_mem, sizeof(T) * N,
+ addr, flags, res);
+}
+
static Fault
writeMemTiming(ExecContext *xc, Trace::InstRecord *traceData, uint64_t mem,
unsigned dataSize, Addr addr, Request::Flags flags,
uint64_t *res)
{
- if (traceData) {
+ if (traceData)
traceData->setData(mem);
- }
mem = TheISA::htog(mem);
return xc->writeMem((uint8_t *)&mem, dataSize, addr, flags, res);
}
template <size_t N>
-Fault
+static Fault
writeMemTiming(ExecContext *xc, Trace::InstRecord *traceData,
std::array<uint64_t, N> &mem, unsigned dataSize,
Addr addr, unsigned flags, uint64_t *res)
{
- assert(dataSize >= 8);
- assert((dataSize % 8) == 0);
-
- if (traceData) {
+ if (traceData)
traceData->setData(mem[0]);
+
+ switch (dataSize) {
+ case 4:
+ return writePackedMem<uint32_t, N>(xc, mem, addr, flags, res);
+ case 8:
+ return writePackedMem<uint64_t, N>(xc, mem, addr, flags, res);
+ default:
+ panic("Unhandled element size in writeMemTiming.\n");
}
-
- int num_words = dataSize / 8;
- assert(num_words <= N);
-
- for (int i = 0; i < num_words; ++i)
- mem[i] = htog(mem[i]);
-
- return xc->writeMem((uint8_t *)&mem, dataSize, addr, flags, res);
}
static Fault
@@ -177,39 +207,39 @@
unsigned dataSize, Addr addr, Request::Flags flags,
uint64_t *res)
{
- if (traceData) {
+ if (traceData)
traceData->setData(mem);
- }
uint64_t host_mem = TheISA::htog(mem);
Fault fault =
xc->writeMem((uint8_t *)&host_mem, dataSize, addr, flags, res);
- if (fault == NoFault && res != NULL) {
+ if (fault == NoFault && res)
*res = gtoh(*res);
- }
return fault;
}
template <size_t N>
-Fault
+static Fault
writeMemAtomic(ExecContext *xc, Trace::InstRecord *traceData,
std::array<uint64_t, N> &mem, unsigned dataSize,
Addr addr, unsigned flags, uint64_t *res)
{
- if (traceData) {
+ if (traceData)
traceData->setData(mem[0]);
+
+ Fault fault;
+ switch (dataSize) {
+ case 4:
+ fault = writePackedMem<uint32_t, N>(xc, mem, addr, flags, res);
+ break;
+ case 8:
+ fault = writePackedMem<uint64_t, N>(xc, mem, addr, flags, res);
+ break;
+ default:
+ panic("Unhandled element size in writeMemAtomic.\n");
}
- int num_words = dataSize / 8;
- assert(num_words <= N);
-
- for (int i = 0; i < num_words; ++i)
- mem[i] = htog(mem[i]);
-
- Fault fault = xc->writeMem((uint8_t *)&mem, dataSize, addr, flags, res);
-
- if (fault == NoFault && res != NULL) {
+ if (fault == NoFault && res)
*res = gtoh(*res);
- }
return fault;
}
