Gabe Black has uploaded this change for review. (
https://gem5-review.googlesource.com/c/public/gem5/+/32894 )
Change subject: x86: Style fix in the decoder class.
......................................................................
x86: Style fix in the decoder class.
Change-Id: If06a8771b5db0fb68e88b16dedfe60fc2ce306d9
---
M src/arch/x86/decoder.cc
M src/arch/x86/decoder.hh
2 files changed, 96 insertions(+), 106 deletions(-)
diff --git a/src/arch/x86/decoder.cc b/src/arch/x86/decoder.cc
index 320cbdc..28034cb 100644
--- a/src/arch/x86/decoder.cc
+++ b/src/arch/x86/decoder.cc
@@ -71,11 +71,11 @@
void
Decoder::process()
{
- //This function drives the decoder state machine.
+ // This function drives the decoder state machine.
- //Some sanity checks. You shouldn't try to process more bytes if
- //there aren't any, and you shouldn't overwrite an already
- //decoder ExtMachInst.
+ // Some sanity checks. You shouldn't try to process more bytes if
+ // there aren't any, and you shouldn't overwrite an already decoded
+ // ExtMachInst.
assert(!outOfBytes);
assert(!instDone);
@@ -87,7 +87,7 @@
instBytes->chunks.push_back(fetchChunk);
}
- //While there's still something to do...
+ // While there's still something to do...
while (!instDone && !outOfBytes) {
uint8_t nextByte = getNextByte();
switch (state) {
@@ -170,8 +170,8 @@
}
}
-//Either get a prefix and record it in the ExtMachInst, or send the
-//state machine on to get the opcode(s).
+// Either get a prefix and record it in the ExtMachInst, or send the
+// state machine on to get the opcode(s).
Decoder::State
Decoder::doPrefixState(uint8_t nextByte)
{
@@ -182,9 +182,8 @@
prefix = 0;
if (prefix)
consumeByte();
- switch(prefix)
- {
- //Operand size override prefixes
+ switch(prefix) {
+ // Operand size override prefixes
case OperandSizeOverride:
DPRINTF(Decoder, "Found operand size override prefix.\n");
emi.legacy.op = true;
@@ -193,7 +192,7 @@
DPRINTF(Decoder, "Found address size override prefix.\n");
emi.legacy.addr = true;
break;
- //Segment override prefixes
+ // Segment override prefixes
case CSOverride:
case DSOverride:
case ESOverride:
@@ -451,8 +450,8 @@
State nextState = ErrorState;
const uint8_t opcode = emi.opcode.op;
- //Figure out the effective operand size. This can be overriden to
- //a fixed value at the decoder level.
+ // Figure out the effective operand size. This can be overriden to
+ // a fixed value at the decoder level.
int logOpSize;
if (emi.rex.w)
logOpSize = 3; // 64 bit operand size
@@ -461,33 +460,33 @@
else
logOpSize = defOp;
- //Set the actual op size
+ // Set the actual op size.
emi.opSize = 1 << logOpSize;
- //Figure out the effective address size. This can be overriden to
- //a fixed value at the decoder level.
+ // Figure out the effective address size. This can be overriden to
+ // a fixed value at the decoder level.
int logAddrSize;
if (emi.legacy.addr)
logAddrSize = altAddr;
else
logAddrSize = defAddr;
- //Set the actual address size
+ // Set the actual address size.
emi.addrSize = 1 << logAddrSize;
- //Figure out the effective stack width. This can be overriden to
- //a fixed value at the decoder level.
+ // Figure out the effective stack width. This can be overriden to
+ // a fixed value at the decoder level.
emi.stackSize = 1 << stack;
- //Figure out how big of an immediate we'll retreive based
- //on the opcode.
+ // Figure out how big of an immediate we'll retreive based
+ // on the opcode.
int immType = immTable[opcode];
if (addrSizedImm)
immediateSize = SizeTypeToSize[logAddrSize - 1][immType];
else
immediateSize = SizeTypeToSize[logOpSize - 1][immType];
- //Determine what to expect next
+ // Determine what to expect next.
if (modrmTable[opcode]) {
nextState = ModRMState;
} else {
@@ -501,9 +500,9 @@
return nextState;
}
-//Get the ModRM byte and determine what displacement, if any, there is.
-//Also determine whether or not to get the SIB byte, displacement, or
-//immediate next.
+// Get the ModRM byte and determine what displacement, if any, there is.
+// Also determine whether or not to get the SIB byte, displacement, or
+// immediate next.
Decoder::State
Decoder::doModRMState(uint8_t nextByte)
{
@@ -511,7 +510,7 @@
ModRM modRM = nextByte;
DPRINTF(Decoder, "Found modrm byte %#x.\n", nextByte);
if (defOp == 1) {
- //figure out 16 bit displacement size
+ // Figure out 16 bit displacement size.
if ((modRM.mod == 0 && modRM.rm == 6) || modRM.mod == 2)
displacementSize = 2;
else if (modRM.mod == 1)
@@ -519,7 +518,7 @@
else
displacementSize = 0;
} else {
- //figure out 32/64 bit displacement size
+ // Figure out 32/64 bit displacement size.
if ((modRM.mod == 0 && modRM.rm == 5) || modRM.mod == 2)
displacementSize = 4;
else if (modRM.mod == 1)
@@ -537,8 +536,8 @@
immediateSize = (emi.opSize == 8) ? 4 : emi.opSize;
}
- //If there's an SIB, get that next.
- //There is no SIB in 16 bit mode.
+ // If there's an SIB, get that next.
+ // There is no SIB in 16 bit mode.
if (modRM.rm == 4 && modRM.mod != 3) {
// && in 32/64 bit mode)
nextState = SIBState;
@@ -550,15 +549,15 @@
instDone = true;
nextState = ResetState;
}
- //The ModRM byte is consumed no matter what
+ // The ModRM byte is consumed no matter what.
consumeByte();
emi.modRM = modRM;
return nextState;
}
-//Get the SIB byte. We don't do anything with it at this point, other
-//than storing it in the ExtMachInst. Determine if we need to get a
-//displacement or immediate next.
+// Get the SIB byte. We don't do anything with it at this point, other
+// than storing it in the ExtMachInst. Determine if we need to get a
+// displacement or immediate next.
Decoder::State
Decoder::doSIBState(uint8_t nextByte)
{
@@ -579,8 +578,7 @@
return nextState;
}
-//Gather up the displacement, or at least as much of it
-//as we can get.
+// Gather up the displacement, or at least as much of it as we can get.
Decoder::State
Decoder::doDisplacementState()
{
@@ -594,9 +592,9 @@
displacementSize, immediateCollected);
if (displacementSize == immediateCollected) {
- //Reset this for other immediates.
+ // Reset this for other immediates.
immediateCollected = 0;
- //Sign extend the displacement
+ // Sign extend the displacement.
switch(displacementSize)
{
case 1:
@@ -627,35 +625,30 @@
return nextState;
}
-//Gather up the immediate, or at least as much of it
-//as we can get
+// Gather up the immediate, or at least as much of it as we can get.
Decoder::State
Decoder::doImmediateState()
{
State nextState = ErrorState;
- getImmediate(immediateCollected,
- emi.immediate,
- immediateSize);
+ getImmediate(immediateCollected, emi.immediate, immediateSize);
DPRINTF(Decoder, "Collecting %d byte immediate, got %d bytes.\n",
immediateSize, immediateCollected);
- if (immediateSize == immediateCollected)
- {
- //Reset this for other immediates.
+ if (immediateSize == immediateCollected) {
+ // Reset this for other immediates.
immediateCollected = 0;
//XXX Warning! The following is an observed pattern and might
- //not always be true!
+ // not always be true!
- //Instructions which use 64 bit operands but 32 bit immediates
- //need to have the immediate sign extended to 64 bits.
- //Instructions which use true 64 bit immediates won't be
- //affected, and instructions that use true 32 bit immediates
- //won't notice.
- switch(immediateSize)
- {
+ // Instructions which use 64 bit operands but 32 bit immediates
+ // need to have the immediate sign extended to 64 bits.
+ // Instructions which use true 64 bit immediates won't be
+ // affected, and instructions that use true 32 bit immediates
+ // won't notice.
+ switch(immediateSize) {
case 4:
emi.immediate = sext<32>(emi.immediate);
break;
@@ -667,9 +660,9 @@
emi.immediate);
instDone = true;
nextState = ResetState;
- }
- else
+ } else {
nextState = ImmediateState;
+ }
return nextState;
}
diff --git a/src/arch/x86/decoder.hh b/src/arch/x86/decoder.hh
index be9b13f..b864e67 100644
--- a/src/arch/x86/decoder.hh
+++ b/src/arch/x86/decoder.hh
@@ -50,7 +50,7 @@
class Decoder
{
private:
- //These are defined and documented in decoder_tables.cc
+ // These are defined and documented in decoder_tables.cc
static const uint8_t SizeTypeToSize[3][10];
typedef const uint8_t ByteTable[256];
static ByteTable Prefixes;
@@ -80,19 +80,19 @@
static InstBytes dummy;
- //The bytes to be predecoded
+ // The bytes to be predecoded.
MachInst fetchChunk;
InstBytes *instBytes;
int chunkIdx;
- //The pc of the start of fetchChunk
+ // The pc of the start of fetchChunk.
Addr basePC;
- //The pc the current instruction started at
+ // The pc the current instruction started at.
Addr origPC;
- //The offset into fetchChunk of current processing
+ // The offset into fetchChunk of current processing.
int offset;
- //The extended machine instruction being generated
+ // The extended machine instruction being generated.
ExtMachInst emi;
- //Predecoding state
+ // Predecoding state.
X86Mode mode;
X86SubMode submode;
uint8_t altOp;
@@ -101,35 +101,38 @@
uint8_t defAddr;
uint8_t stack;
- uint8_t getNextByte()
+ uint8_t
+ getNextByte()
{
return ((uint8_t *)&fetchChunk)[offset];
}
- void getImmediate(int &collected, uint64_t ¤t, int size)
+ void
+ getImmediate(int &collected, uint64_t ¤t, int size)
{
- //Figure out how many bytes we still need to get for the
- //immediate.
+ // Figure out how many bytes we still need to get for the
+ // immediate.
int toGet = size - collected;
- //Figure out how many bytes are left in our "buffer"
+ // Figure out how many bytes are left in our "buffer".
int remaining = sizeof(MachInst) - offset;
- //Get as much as we need, up to the amount available.
+ // Get as much as we need, up to the amount available.
toGet = toGet > remaining ? remaining : toGet;
- //Shift the bytes we want to be all the way to the right
+ // Shift the bytes we want to be all the way to the right
uint64_t partialImm = fetchChunk >> (offset * 8);
- //Mask off what we don't want
+ // Mask off what we don't want.
partialImm &= mask(toGet * 8);
- //Shift it over to overlay with our displacement.
+ // Shift it over to overlay with our displacement.
partialImm <<= (immediateCollected * 8);
- //Put it into our displacement
+ // Put it into our displacement.
current |= partialImm;
- //Update how many bytes we've collected.
+ // Update how many bytes we've collected.
collected += toGet;
consumeBytes(toGet);
}
- void updateOffsetState()
+ void
+ updateOffsetState()
{
assert(offset <= sizeof(MachInst));
if (offset == sizeof(MachInst)) {
@@ -146,30 +149,32 @@
}
}
- void consumeByte()
+ void
+ consumeByte()
{
offset++;
updateOffsetState();
}
- void consumeBytes(int numBytes)
+ void
+ consumeBytes(int numBytes)
{
offset += numBytes;
updateOffsetState();
}
- //State machine state
+ // State machine state.
protected:
- //Whether or not we're out of bytes
+ // Whether or not we're out of bytes.
bool outOfBytes;
- //Whether we've completed generating an ExtMachInst
+ // Whether we've completed generating an ExtMachInst.
bool instDone;
- //The size of the displacement value
+ // The size of the displacement value.
int displacementSize;
- //The size of the immediate value
+ // The size of the immediate value.
int immediateSize;
- //This is how much of any immediate value we've gotten. This is used
- //for both the actual immediate and the displacement.
+ // This is how much of any immediate value we've gotten. This is used
+ // for both the actual immediate and the displacement.
int immediateCollected;
enum State {
@@ -188,13 +193,13 @@
SIBState,
DisplacementState,
ImmediateState,
- //We should never get to this state. Getting here is an error.
+ // We should never get to this state. Getting here is an error.
ErrorState
};
State state;
- //Functions to handle each of the states
+ // Functions to handle each of the states
State doResetState();
State doFromCacheState();
State doPrefixState(uint8_t);
@@ -211,7 +216,7 @@
State doDisplacementState();
State doImmediateState();
- //Process the actual opcode found earlier, using the supplied tables.
+ // Process the actual opcode found earlier, using the supplied tables.
State processOpcode(ByteTable &immTable, ByteTable &modrmTable,
bool addrSizedImm = false);
// Process the opcode found with VEX / XOP prefix.
@@ -234,8 +239,7 @@
public:
Decoder(ISA* isa = nullptr) : basePC(0), origPC(0), offset(0),
- outOfBytes(true), instDone(false),
- state(ResetState)
+ outOfBytes(true), instDone(false), state(ResetState)
{
emi.reset();
mode = LongMode;
@@ -252,7 +256,8 @@
instMap = NULL;
}
- void setM5Reg(HandyM5Reg m5Reg)
+ void
+ setM5Reg(HandyM5Reg m5Reg)
{
mode = (X86Mode)(uint64_t)m5Reg.mode;
submode = (X86SubMode)(uint64_t)m5Reg.submode;
@@ -281,7 +286,8 @@
}
}
- void takeOverFrom(Decoder *old)
+ void
+ takeOverFrom(Decoder *old)
{
mode = old->mode;
submode = old->submode;
@@ -294,16 +300,14 @@
stack = old->stack;
}
- void reset()
- {
- state = ResetState;
- }
+ void reset() { state = ResetState; }
void process();
- //Use this to give data to the decoder. This should be used
- //when there is control flow.
- void moreBytes(const PCState &pc, Addr fetchPC, MachInst data)
+ // Use this to give data to the decoder. This should be used
+ // when there is control flow.
+ void
+ moreBytes(const PCState &pc, Addr fetchPC, MachInst data)
{
DPRINTF(Decoder, "Getting more bytes.\n");
basePC = fetchPC;
@@ -313,15 +317,8 @@
process();
}
- bool needMoreBytes()
- {
- return outOfBytes;
- }
-
- bool instReady()
- {
- return instDone;
- }
+ bool needMoreBytes() { return outOfBytes; }
+ bool instReady() { return instDone; }
void
updateNPC(X86ISA::PCState &nextPC)
--
To view, visit https://gem5-review.googlesource.com/c/public/gem5/+/32894
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Gerrit-Project: public/gem5
Gerrit-Branch: develop
Gerrit-Change-Id: If06a8771b5db0fb68e88b16dedfe60fc2ce306d9
Gerrit-Change-Number: 32894
Gerrit-PatchSet: 1
Gerrit-Owner: Gabe Black <[email protected]>
Gerrit-MessageType: newchange
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