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-rw-r--r--src/arch/x86/predecoder.hh65
-rw-r--r--src/arch/x86/predecoder_tables.cc79
-rw-r--r--src/arch/x86/types.hh6
3 files changed, 122 insertions, 28 deletions
diff --git a/src/arch/x86/predecoder.hh b/src/arch/x86/predecoder.hh
index 371ce9db9..062025a61 100644
--- a/src/arch/x86/predecoder.hh
+++ b/src/arch/x86/predecoder.hh
@@ -70,8 +70,11 @@ namespace X86ISA
class Predecoder
{
private:
+ //These are defined and documented in predecoder_tables.cc
static const uint8_t Prefixes[256];
static const uint8_t UsesModRM[2][256];
+ static const uint8_t ImmediateType[2][256];
+ static const uint8_t ImmediateTypeToSize[3][10];
protected:
ThreadContext * tc;
@@ -193,10 +196,11 @@ namespace X86ISA
break;
case Rex:
warn("Found Rex prefix %#x!\n", nextByte);
+ emi.rexPrefix = nextByte;
offset++;
break;
case 0:
- emi.twoByteOpcode = false;
+ emi.numOpcodes = 0;
state = Opcode;
break;
default:
@@ -204,20 +208,30 @@ namespace X86ISA
}
break;
case Opcode:
+ emi.numOpcodes++;
+ assert(emi.numOpcodes < 2);
if(nextByte == 0xf0)
{
warn("Found two byte opcode!\n");
- emi.twoByteOpcode = true;
}
else
{
+ immediateCollected = 0;
+ displacementCollected = 0;
+ emi.immediate = 0;
+ emi.displacement = 0;
+ int immType = ImmediateType[
+ emi.numOpcodes - 1][nextByte];
+ if(0) //16 bit mode
+ immediateSize = ImmediateTypeToSize[0][immType];
+ else if(!(emi.rexPrefix & 0x4)) //32 bit mode
+ immediateSize = ImmediateTypeToSize[1][immType];
+ else //64 bit mode
+ immediateSize = ImmediateTypeToSize[2][immType];
warn("Found opcode %#x!\n", nextByte);
- if (UsesModRM[emi.twoByteOpcode ? 1 : 0][nextByte]) {
+ if (UsesModRM[emi.numOpcodes - 1][nextByte]) {
state = ModRM;
- } else if(0 /* uses immediate */) {
- //Figure out how big the immediate should be
- immediateCollected = 0;
- emi.immediate = 0;
+ } else if(immediateSize) {
state = Immediate;
} else {
emiIsReady = true;
@@ -231,21 +245,21 @@ namespace X86ISA
if (0) {//in 16 bit mode
//figure out 16 bit displacement size
if(nextByte & 0xC7 == 0x06 ||
- nextByte & 0xC0 == 0x40)
- displacementSize = 1;
- else if(nextByte & 0xC7 == 0x80)
+ nextByte & 0xC0 == 0x80)
displacementSize = 2;
+ else if(nextByte & 0xC0 == 0x40)
+ displacementSize = 1;
else
displacementSize = 0;
} else {
//figure out 32/64 bit displacement size
- if(nextByte & 0xC7 == 0x06 ||
- nextByte & 0xC0 == 0x40)
+ if(nextByte & 0xC7 == 0x05 ||
+ nextByte & 0xC0 == 0x80)
displacementSize = 4;
- else if(nextByte & 0xC7 == 0x80)
+ else if(nextByte & 0xC0 == 0x40)
displacementSize = 2;
else
- displacementSize = 4;
+ displacementSize = 0;
}
//If there's an SIB, get that next.
//There is no SIB in 16 bit mode.
@@ -254,12 +268,8 @@ namespace X86ISA
// && in 32/64 bit mode)
state = SIB;
} else if(displacementSize) {
- displacementCollected = 0;
- emi.displacement = 0;
state = Displacement;
} else if(immediateSize) {
- immediateCollected = 0;
- emi.immediate = 0;
state = Immediate;
} else {
emiIsReady = true;
@@ -272,12 +282,8 @@ namespace X86ISA
warn("Found SIB byte %#x!\n", nextByte);
offset++;
if(displacementSize) {
- displacementCollected = 0;
- emi.displacement = 0;
state = Displacement;
} else if(immediateSize) {
- immediateCollected = 0;
- emi.immediate = 0;
state = Immediate;
} else {
emiIsReady = true;
@@ -306,6 +312,9 @@ namespace X86ISA
emi.displacement |= partialDisp;
//Update how many bytes we've collected.
displacementCollected += toGet;
+ offset += toGet;
+ warn("Collecting %d byte displacement, got %d bytes!\n",
+ displacementSize, toGet);
if(displacementSize == displacementCollected) {
//Sign extend the displacement
@@ -324,8 +333,6 @@ namespace X86ISA
panic("Undefined displacement size!\n");
}
if(immediateSize) {
- immediateCollected = 0;
- emi.immediate = 0;
state = Immediate;
} else {
emiIsReady = true;
@@ -350,11 +357,15 @@ namespace X86ISA
//Mask off what we don't want
partialDisp &= mask(toGet * 8);
//Shift it over to overlay with our immediate.
- partialDisp <<= displacementCollected;
+ partialDisp <<= immediateCollected;
//Put it into our immediate
- emi.displacement |= partialDisp;
+ emi.immediate |= partialDisp;
//Update how many bytes we've collected.
- displacementCollected += toGet;
+ immediateCollected += toGet;
+ offset += toGet;
+ warn("Collecting %d byte immediate, got %d bytes!\n",
+ immediateSize, toGet);
+
if(immediateSize == immediateCollected)
{
emiIsReady = true;
diff --git a/src/arch/x86/predecoder_tables.cc b/src/arch/x86/predecoder_tables.cc
index 9304eee47..0cebef61a 100644
--- a/src/arch/x86/predecoder_tables.cc
+++ b/src/arch/x86/predecoder_tables.cc
@@ -140,4 +140,83 @@ namespace X86ISA
/* F */ 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 0
}
};
+
+ enum ImmediateTypes {
+ NoImm,
+ NI = NoImm,
+ ByteImm,
+ BY = ByteImm,
+ WordImm,
+ WO = WordImm,
+ DWordImm,
+ DW = DWordImm,
+ QWordImm,
+ QW = QWordImm,
+ OWordImm,
+ OW = OWordImm,
+ VWordImm,
+ VW = VWordImm,
+ ZWordImm,
+ ZW = ZWordImm,
+ Pointer,
+ PO = Pointer,
+ //The enter instruction takes -2- immediates for a total of 3 bytes
+ Enter,
+ EN = Enter
+ };
+
+ const uint8_t Predecoder::ImmediateTypeToSize[3][10] =
+ {
+// noimm byte word dword qword oword vword zword enter
+ {0, 1, 2, 4, 8, 16, 2, 2, 3, 4}, //16 bit
+ {0, 1, 2, 4, 8, 16, 4, 4, 3, 6}, //32 bit
+ {0, 1, 2, 4, 8, 16, 4, 8, 3, 0} //64 bit
+ };
+
+ //This table determines the immediate type. The first index is the
+ //number of bytes in the instruction, and the second is the meaningful
+ //byte of the opcode. I didn't use the NI constant here for the sake
+ //of clarity.
+ const uint8_t Predecoder::ImmediateType[2][256] =
+ {//For one byte instructions
+ { //LSB
+// MSB 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F
+/* 0 */ 0 , 0 , 0 , 0 , BY, ZW, 0 , 0 , 0 , 0 , 0 , 0 , BY, ZW, 0 , 0 ,
+/* 1 */ 0 , 0 , 0 , 0 , BY, ZW, 0 , 0 , 0 , 0 , 0 , 0 , BY, ZW, 0 , 0 ,
+/* 2 */ 0 , 0 , 0 , 0 , BY, ZW, 0 , 0 , 0 , 0 , 0 , 0 , BY, ZW, 0 , 0 ,
+/* 3 */ 0 , 0 , 0 , 0 , BY, ZW, 0 , 0 , 0 , 0 , 0 , 0 , BY, ZW, 0 , 0 ,
+/* 4 */ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,
+/* 5 */ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,
+/* 6 */ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , ZW, ZW, BY, BY, 0 , 0 , 0 , 0 ,
+/* 7 */ BY, BY, BY, BY, BY, BY, BY, BY, BY, BY, BY, BY, BY, BY, BY, BY,
+/* 8 */ BY, ZW, BY, BY, 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,
+/* 9 */ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,
+/* A */ BY, VW, BY, VW, 0 , 0 , 0 , 0 , BY, ZW, 0 , 0 , 0 , 0 , 0 , 0 ,
+/* B */ BY, BY, BY, BY, BY, BY, BY, BY, VW, VW, VW, VW, VW, VW, VW, VW,
+/* C */ BY, BY, WO, 0 , 0 , 0 , BY, ZW, EN, 0 , WO, 0 , 0 , BY, 0 , 0 ,
+/* D */ 0 , 0 , 0 , 0 , BY, BY, 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,
+/* E */ BY, BY, BY, BY, BY, BY, BY, BY, ZW, ZW, PO, BY, 0 , 0 , 0 , 0 ,
+/* F */ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0
+ },
+ //For two byte instructions
+ { //LSB
+// MSB 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F
+/* 0 */ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,
+/* 0 */ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,
+/* 2 */ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,
+/* 3 */ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,
+/* 4 */ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,
+/* 5 */ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,
+/* 6 */ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,
+/* 7 */ BY, 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,
+/* 8 */ ZW, ZW, ZW, ZW, ZW, ZW, ZW, ZW, ZW, ZW, ZW, ZW, ZW, ZW, ZW, ZW,
+/* 9 */ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,
+/* A */ 0 , 0 , 0 , 0 , BY, 0 , 0 , 0 , 0 , 0 , 0 , 0 , BY, 0 , 0 , 0 ,
+/* B */ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , ZW, 0 , BY, 0 , 0 , 0 , 0 , 0 ,
+/* C */ 0 , 0 , BY, 0 , BY, BY, BY, 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,
+/* D */ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,
+/* E */ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ,
+/* F */ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0
+ }
+ };
}
diff --git a/src/arch/x86/types.hh b/src/arch/x86/types.hh
index 68d95de94..583f03d55 100644
--- a/src/arch/x86/types.hh
+++ b/src/arch/x86/types.hh
@@ -94,7 +94,11 @@ namespace X86ISA
uint8_t legacyPrefixes;
uint8_t rexPrefix;
- bool twoByteOpcode;
+ //Right now, we ignore that this can be 3 in
+ //some cases
+ uint8_t numOpcodes;
+ //This will need to be decoded specially later
+ bool is3dnow;
uint8_t opcode;
uint64_t immediate;
uint64_t displacement;
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-11 05:44:25 +0000