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RandomWOW/src/superscalar.cpp
tevador fd7186f873 Changed IADD_RS to use mod.mem
2019-04-27 23:52:26 +02:00

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/*
Copyright (c) 2019 tevador
This file is part of RandomX.
RandomX is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
RandomX is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with RandomX. If not, see<http://www.gnu.org/licenses/>.
*/
#include "configuration.h"
#include "program.hpp"
#include "blake2/endian.h"
#include <iostream>
#include <vector>
#include <algorithm>
#include <stdexcept>
#include <iomanip>
#include "superscalar.hpp"
#include "intrin_portable.h"
#include "reciprocal.h"
namespace randomx {
static bool isMultiplication(int type) {
return type == SuperscalarInstructionType::IMUL_R || type == SuperscalarInstructionType::IMULH_R || type == SuperscalarInstructionType::ISMULH_R || type == SuperscalarInstructionType::IMUL_RCP;
}
//uOPs (micro-ops) are represented only by the execution port they can go to
namespace ExecutionPort {
using type = int;
constexpr type Null = 0;
constexpr type P0 = 1;
constexpr type P1 = 2;
constexpr type P5 = 4;
constexpr type P01 = P0 | P1;
constexpr type P05 = P0 | P5;
constexpr type P015 = P0 | P1 | P5;
}
//Macro-operation as output of the x86 decoder
//Usually one macro-op = one x86 instruction, but 2 instructions are sometimes fused into 1 macro-op
//Macro-op can consist of 1 or 2 uOPs.
class MacroOp {
public:
MacroOp(const char* name, int size)
: name_(name), size_(size), latency_(0), uop1_(ExecutionPort::Null), uop2_(ExecutionPort::Null) {}
MacroOp(const char* name, int size, int latency, ExecutionPort::type uop)
: name_(name), size_(size), latency_(latency), uop1_(uop), uop2_(ExecutionPort::Null) {}
MacroOp(const char* name, int size, int latency, ExecutionPort::type uop1, ExecutionPort::type uop2)
: name_(name), size_(size), latency_(latency), uop1_(uop1), uop2_(uop2) {}
MacroOp(const MacroOp& parent, bool dependent)
: name_(parent.name_), size_(parent.size_), latency_(parent.latency_), uop1_(parent.uop1_), uop2_(parent.uop2_), dependent_(dependent) {}
const char* getName() const {
return name_;
}
int getSize() const {
return size_;
}
int getLatency() const {
return latency_;
}
ExecutionPort::type getUop1() const {
return uop1_;
}
ExecutionPort::type getUop2() const {
return uop2_;
}
bool isSimple() const {
return uop2_ == ExecutionPort::Null;
}
bool isEliminated() const {
return uop1_ == ExecutionPort::Null;
}
bool isDependent() const {
return dependent_;
}
static const MacroOp Add_rr;
static const MacroOp Add_ri;
static const MacroOp Lea_sib;
static const MacroOp Sub_rr;
static const MacroOp Imul_rr;
static const MacroOp Imul_r;
static const MacroOp Mul_r;
static const MacroOp Mov_rr;
static const MacroOp Mov_ri64;
static const MacroOp Xor_rr;
static const MacroOp Xor_ri;
static const MacroOp Ror_rcl;
static const MacroOp Ror_ri;
static const MacroOp TestJz_fused;
static const MacroOp Xor_self;
static const MacroOp Cmp_ri;
static const MacroOp Setcc_r;
private:
const char* name_;
int size_;
int latency_;
ExecutionPort::type uop1_;
ExecutionPort::type uop2_;
bool dependent_ = false;
};
//Size: 3 bytes
const MacroOp MacroOp::Add_rr = MacroOp("add r,r", 3, 1, ExecutionPort::P015);
const MacroOp MacroOp::Sub_rr = MacroOp("sub r,r", 3, 1, ExecutionPort::P015);
const MacroOp MacroOp::Xor_rr = MacroOp("xor r,r", 3, 1, ExecutionPort::P015);
const MacroOp MacroOp::Imul_r = MacroOp("imul r", 3, 4, ExecutionPort::P1, ExecutionPort::P5);
const MacroOp MacroOp::Mul_r = MacroOp("mul r", 3, 3, ExecutionPort::P1, ExecutionPort::P5);
const MacroOp MacroOp::Mov_rr = MacroOp("mov r,r", 3);
//Size: 4 bytes
const MacroOp MacroOp::Lea_sib = MacroOp("lea r,r+r*s", 4, 1, ExecutionPort::P01);
const MacroOp MacroOp::Imul_rr = MacroOp("imul r,r", 4, 3, ExecutionPort::P1);
const MacroOp MacroOp::Ror_ri = MacroOp("ror r,i", 4, 1, ExecutionPort::P05);
//Size: 7 bytes (can be optionally padded with nop to 8 or 9 bytes)
const MacroOp MacroOp::Add_ri = MacroOp("add r,i", 7, 1, ExecutionPort::P015);
const MacroOp MacroOp::Xor_ri = MacroOp("xor r,i", 7, 1, ExecutionPort::P015);
//Size: 10 bytes
const MacroOp MacroOp::Mov_ri64 = MacroOp("mov rax,i64", 10, 1, ExecutionPort::P015);
//Unused:
const MacroOp MacroOp::Ror_rcl = MacroOp("ror r,cl", 3, 1, ExecutionPort::P0, ExecutionPort::P5);
const MacroOp MacroOp::Xor_self = MacroOp("xor rcx,rcx", 3);
const MacroOp MacroOp::Cmp_ri = MacroOp("cmp r,i", 7, 1, ExecutionPort::P015);
const MacroOp MacroOp::Setcc_r = MacroOp("setcc cl", 3, 1, ExecutionPort::P05);
const MacroOp MacroOp::TestJz_fused = MacroOp("testjz r,i", 13, 0, ExecutionPort::P5);
const MacroOp IMULH_R_ops_array[] = { MacroOp::Mov_rr, MacroOp::Mul_r, MacroOp::Mov_rr };
const MacroOp ISMULH_R_ops_array[] = { MacroOp::Mov_rr, MacroOp::Imul_r, MacroOp::Mov_rr };
const MacroOp IMUL_RCP_ops_array[] = { MacroOp::Mov_ri64, MacroOp(MacroOp::Imul_rr, true) };
class SuperscalarInstructionInfo {
public:
const char* getName() const {
return name_;
}
int getSize() const {
return ops_.size();
}
bool isSimple() const {
return getSize() == 1;
}
int getLatency() const {
return latency_;
}
const MacroOp& getOp(int index) const {
return ops_[index];
}
int getType() const {
return type_;
}
int getResultOp() const {
return resultOp_;
}
int getDstOp() const {
return dstOp_;
}
int getSrcOp() const {
return srcOp_;
}
static const SuperscalarInstructionInfo ISUB_R;
static const SuperscalarInstructionInfo IXOR_R;
static const SuperscalarInstructionInfo IADD_RS;
static const SuperscalarInstructionInfo IMUL_R;
static const SuperscalarInstructionInfo IROR_C;
static const SuperscalarInstructionInfo IADD_C7;
static const SuperscalarInstructionInfo IXOR_C7;
static const SuperscalarInstructionInfo IADD_C8;
static const SuperscalarInstructionInfo IXOR_C8;
static const SuperscalarInstructionInfo IADD_C9;
static const SuperscalarInstructionInfo IXOR_C9;
static const SuperscalarInstructionInfo IMULH_R;
static const SuperscalarInstructionInfo ISMULH_R;
static const SuperscalarInstructionInfo IMUL_RCP;
static const SuperscalarInstructionInfo NOP;
private:
const char* name_;
int type_;
std::vector<MacroOp> ops_;
int latency_;
int resultOp_ = 0;
int dstOp_ = 0;
int srcOp_;
SuperscalarInstructionInfo(const char* name)
: name_(name), type_(-1), latency_(0) {}
SuperscalarInstructionInfo(const char* name, int type, const MacroOp& op, int srcOp)
: name_(name), type_(type), latency_(op.getLatency()), srcOp_(srcOp) {
ops_.push_back(MacroOp(op));
}
template <size_t N>
SuperscalarInstructionInfo(const char* name, int type, const MacroOp(&arr)[N], int resultOp, int dstOp, int srcOp)
: name_(name), type_(type), latency_(0), resultOp_(resultOp), dstOp_(dstOp), srcOp_(srcOp) {
for (unsigned i = 0; i < N; ++i) {
ops_.push_back(MacroOp(arr[i]));
latency_ += ops_.back().getLatency();
}
static_assert(N > 1, "Invalid array size");
}
};
const SuperscalarInstructionInfo SuperscalarInstructionInfo::ISUB_R = SuperscalarInstructionInfo("ISUB_R", SuperscalarInstructionType::ISUB_R, MacroOp::Sub_rr, 0);
const SuperscalarInstructionInfo SuperscalarInstructionInfo::IXOR_R = SuperscalarInstructionInfo("IXOR_R", SuperscalarInstructionType::IXOR_R, MacroOp::Xor_rr, 0);
const SuperscalarInstructionInfo SuperscalarInstructionInfo::IADD_RS = SuperscalarInstructionInfo("IADD_RS", SuperscalarInstructionType::IADD_RS, MacroOp::Lea_sib, 0);
const SuperscalarInstructionInfo SuperscalarInstructionInfo::IMUL_R = SuperscalarInstructionInfo("IMUL_R", SuperscalarInstructionType::IMUL_R, MacroOp::Imul_rr, 0);
const SuperscalarInstructionInfo SuperscalarInstructionInfo::IROR_C = SuperscalarInstructionInfo("IROR_C", SuperscalarInstructionType::IROR_C, MacroOp::Ror_ri, -1);
const SuperscalarInstructionInfo SuperscalarInstructionInfo::IADD_C7 = SuperscalarInstructionInfo("IADD_C7", SuperscalarInstructionType::IADD_C7, MacroOp::Add_ri, -1);
const SuperscalarInstructionInfo SuperscalarInstructionInfo::IXOR_C7 = SuperscalarInstructionInfo("IXOR_C7", SuperscalarInstructionType::IXOR_C7, MacroOp::Xor_ri, -1);
const SuperscalarInstructionInfo SuperscalarInstructionInfo::IADD_C8 = SuperscalarInstructionInfo("IADD_C8", SuperscalarInstructionType::IADD_C8, MacroOp::Add_ri, -1);
const SuperscalarInstructionInfo SuperscalarInstructionInfo::IXOR_C8 = SuperscalarInstructionInfo("IXOR_C8", SuperscalarInstructionType::IXOR_C8, MacroOp::Xor_ri, -1);
const SuperscalarInstructionInfo SuperscalarInstructionInfo::IADD_C9 = SuperscalarInstructionInfo("IADD_C9", SuperscalarInstructionType::IADD_C9, MacroOp::Add_ri, -1);
const SuperscalarInstructionInfo SuperscalarInstructionInfo::IXOR_C9 = SuperscalarInstructionInfo("IXOR_C9", SuperscalarInstructionType::IXOR_C9, MacroOp::Xor_ri, -1);
const SuperscalarInstructionInfo SuperscalarInstructionInfo::IMULH_R = SuperscalarInstructionInfo("IMULH_R", SuperscalarInstructionType::IMULH_R, IMULH_R_ops_array, 1, 0, 1);
const SuperscalarInstructionInfo SuperscalarInstructionInfo::ISMULH_R = SuperscalarInstructionInfo("ISMULH_R", SuperscalarInstructionType::ISMULH_R, ISMULH_R_ops_array, 1, 0, 1);
const SuperscalarInstructionInfo SuperscalarInstructionInfo::IMUL_RCP = SuperscalarInstructionInfo("IMUL_RCP", SuperscalarInstructionType::IMUL_RCP, IMUL_RCP_ops_array, 1, 1, -1);
const SuperscalarInstructionInfo SuperscalarInstructionInfo::NOP = SuperscalarInstructionInfo("NOP");
//these are some of the options how to split a 16-byte window into 3 or 4 x86 instructions.
//RandomX uses instructions with a native size of 3 (sub, xor, mul, mov), 4 (lea, mul), 7 (xor, add immediate) or 10 bytes (mov 64-bit immediate).
//Slots with sizes of 8 or 9 bytes need to be padded with a nop instruction.
const int buffer0[] = { 4, 8, 4 };
const int buffer1[] = { 7, 3, 3, 3 };
const int buffer2[] = { 3, 7, 3, 3 };
const int buffer3[] = { 4, 9, 3 };
const int buffer4[] = { 4, 4, 4, 4 };
const int buffer5[] = { 3, 3, 10 };
class DecoderBuffer {
public:
static const DecoderBuffer Default;
template <size_t N>
DecoderBuffer(const char* name, int index, const int(&arr)[N])
: name_(name), index_(index), counts_(arr), opsCount_(N) {}
const int* getCounts() const {
return counts_;
}
int getSize() const {
return opsCount_;
}
int getIndex() const {
return index_;
}
const char* getName() const {
return name_;
}
const DecoderBuffer* fetchNext(int instrType, int cycle, int mulCount, Blake2Generator& gen) const {
//If the current RandomX instruction is "IMULH", the next fetch configuration must be 3-3-10
//because the full 128-bit multiplication instruction is 3 bytes long and decodes to 2 uOPs on Intel CPUs.
//Intel CPUs can decode at most 4 uOPs per cycle, so this requires a 2-1-1 configuration for a total of 3 macro ops.
if (instrType == SuperscalarInstructionType::IMULH_R || instrType == SuperscalarInstructionType::ISMULH_R)
return &decodeBuffer3310;
//To make sure that the multiplication port is saturated, a 4-4-4-4 configuration is generated if the number of multiplications
//is lower than the number of cycles.
if (mulCount < cycle + 1)
return &decodeBuffer4444;
//If the current RandomX instruction is "IMUL_RCP", the next buffer must begin with a 4-byte slot for multiplication.
if(instrType == SuperscalarInstructionType::IMUL_RCP)
return (gen.getByte() & 1) ? &decodeBuffer484 : &decodeBuffer493;
//Default: select a random fetch configuration.
return fetchNextDefault(gen);
}
private:
const char* name_;
int index_;
const int* counts_;
int opsCount_;
DecoderBuffer() : index_(-1) {}
static const DecoderBuffer decodeBuffer484;
static const DecoderBuffer decodeBuffer7333;
static const DecoderBuffer decodeBuffer3733;
static const DecoderBuffer decodeBuffer493;
static const DecoderBuffer decodeBuffer4444;
static const DecoderBuffer decodeBuffer3310;
static const DecoderBuffer* decodeBuffers[4];
const DecoderBuffer* fetchNextDefault(Blake2Generator& gen) const {
return decodeBuffers[gen.getByte() & 3];
}
};
const DecoderBuffer DecoderBuffer::decodeBuffer484 = DecoderBuffer("4,8,4", 0, buffer0);
const DecoderBuffer DecoderBuffer::decodeBuffer7333 = DecoderBuffer("7,3,3,3", 1, buffer1);
const DecoderBuffer DecoderBuffer::decodeBuffer3733 = DecoderBuffer("3,7,3,3", 2, buffer2);
const DecoderBuffer DecoderBuffer::decodeBuffer493 = DecoderBuffer("4,9,3", 3, buffer3);
const DecoderBuffer DecoderBuffer::decodeBuffer4444 = DecoderBuffer("4,4,4,4", 4, buffer4);
const DecoderBuffer DecoderBuffer::decodeBuffer3310 = DecoderBuffer("3,3,10", 5, buffer5);
const DecoderBuffer* DecoderBuffer::decodeBuffers[4] = {
&DecoderBuffer::decodeBuffer484,
&DecoderBuffer::decodeBuffer7333,
&DecoderBuffer::decodeBuffer3733,
&DecoderBuffer::decodeBuffer493,
};
const DecoderBuffer DecoderBuffer::Default = DecoderBuffer();
const SuperscalarInstructionInfo* slot_3[] = { &SuperscalarInstructionInfo::ISUB_R, &SuperscalarInstructionInfo::IXOR_R };
const SuperscalarInstructionInfo* slot_3L[] = { &SuperscalarInstructionInfo::ISUB_R, &SuperscalarInstructionInfo::IXOR_R, &SuperscalarInstructionInfo::IMULH_R, &SuperscalarInstructionInfo::ISMULH_R };
const SuperscalarInstructionInfo* slot_4[] = { &SuperscalarInstructionInfo::IROR_C, &SuperscalarInstructionInfo::IADD_RS };
const SuperscalarInstructionInfo* slot_7[] = { &SuperscalarInstructionInfo::IXOR_C7, &SuperscalarInstructionInfo::IADD_C7 };
const SuperscalarInstructionInfo* slot_8[] = { &SuperscalarInstructionInfo::IXOR_C8, &SuperscalarInstructionInfo::IADD_C8 };
const SuperscalarInstructionInfo* slot_9[] = { &SuperscalarInstructionInfo::IXOR_C9, &SuperscalarInstructionInfo::IADD_C9 };
const SuperscalarInstructionInfo* slot_10 = &SuperscalarInstructionInfo::IMUL_RCP;
static bool selectRegister(std::vector<int>& availableRegisters, Blake2Generator& gen, int& reg) {
int index;
if (availableRegisters.size() == 0)
return false;
if (availableRegisters.size() > 1) {
index = gen.getInt32() % availableRegisters.size();
}
else {
index = 0;
}
reg = availableRegisters[index];
return true;
}
class RegisterInfo {
public:
RegisterInfo() : latency(0), lastOpGroup(-1), lastOpPar(-1), value(0) {}
int latency;
int lastOpGroup;
int lastOpPar;
int value;
};
//"SuperscalarInstruction" consists of one or more macro-ops
class SuperscalarInstruction {
public:
void toInstr(Instruction& instr) { //translate to a RandomX instruction format
instr.opcode = getType();
instr.dst = dst_;
instr.src = src_ >= 0 ? src_ : dst_;
instr.setMod(mod_);
instr.setImm32(imm32_);
}
void createForSlot(Blake2Generator& gen, int slotSize, int fetchType, bool isLast, bool isFirst) {
switch (slotSize)
{
case 3:
//if this is the last slot, we can also select "IMULH" instructions
if (isLast) {
create(slot_3L[gen.getByte() & 3], gen);
}
else {
create(slot_3[gen.getByte() & 1], gen);
}
break;
case 4:
//if this is the 4-4-4-4 buffer, issue multiplications as the first 3 instructions
if (fetchType == 4 && !isLast) {
create(&SuperscalarInstructionInfo::IMUL_R, gen);
}
else {
create(slot_4[gen.getByte() & 1], gen);
}
break;
case 7:
create(slot_7[gen.getByte() & 1], gen);
break;
case 8:
create(slot_8[gen.getByte() & 1], gen);
break;
case 9:
create(slot_9[gen.getByte() & 1], gen);
break;
case 10:
create(slot_10, gen);
break;
default:
UNREACHABLE;
}
}
void create(const SuperscalarInstructionInfo* info, Blake2Generator& gen) {
info_ = info;
reset();
switch (info->getType())
{
case SuperscalarInstructionType::ISUB_R: {
mod_ = 0;
imm32_ = 0;
opGroup_ = SuperscalarInstructionType::IADD_RS;
groupParIsSource_ = true;
} break;
case SuperscalarInstructionType::IXOR_R: {
mod_ = 0;
imm32_ = 0;
opGroup_ = SuperscalarInstructionType::IXOR_R;
groupParIsSource_ = true;
} break;
case SuperscalarInstructionType::IADD_RS: {
mod_ = gen.getByte();
imm32_ = 0;
opGroup_ = SuperscalarInstructionType::IADD_RS;
groupParIsSource_ = true;
} break;
case SuperscalarInstructionType::IMUL_R: {
mod_ = 0;
imm32_ = 0;
opGroup_ = SuperscalarInstructionType::IMUL_R;
groupParIsSource_ = true;
} break;
case SuperscalarInstructionType::IROR_C: {
mod_ = 0;
do {
imm32_ = gen.getByte() & 63;
} while (imm32_ == 0);
opGroup_ = SuperscalarInstructionType::IROR_C;
opGroupPar_ = -1;
} break;
case SuperscalarInstructionType::IADD_C7:
case SuperscalarInstructionType::IADD_C8:
case SuperscalarInstructionType::IADD_C9: {
mod_ = 0;
imm32_ = gen.getInt32();
opGroup_ = SuperscalarInstructionType::IADD_C7;
opGroupPar_ = -1;
} break;
case SuperscalarInstructionType::IXOR_C7:
case SuperscalarInstructionType::IXOR_C8:
case SuperscalarInstructionType::IXOR_C9: {
mod_ = 0;
imm32_ = gen.getInt32();
opGroup_ = SuperscalarInstructionType::IXOR_C7;
opGroupPar_ = -1;
} break;
case SuperscalarInstructionType::IMULH_R: {
canReuse_ = true;
mod_ = 0;
imm32_ = 0;
opGroup_ = SuperscalarInstructionType::IMULH_R;
opGroupPar_ = gen.getInt32();
} break;
case SuperscalarInstructionType::ISMULH_R: {
canReuse_ = true;
mod_ = 0;
imm32_ = 0;
opGroup_ = SuperscalarInstructionType::ISMULH_R;
opGroupPar_ = gen.getInt32();
} break;
case SuperscalarInstructionType::IMUL_RCP: {
mod_ = 0;
do {
imm32_ = gen.getInt32();
} while ((imm32_ & (imm32_ - 1)) == 0);
opGroup_ = SuperscalarInstructionType::IMUL_RCP;
opGroupPar_ = -1;
} break;
default:
break;
}
}
bool selectDestination(int cycle, bool allowChainedMul, RegisterInfo (&registers)[8], Blake2Generator& gen) {
/*if (allowChainedMultiplication && opGroup_ == SuperscalarInstructionType::IMUL_R)
std::cout << "Selecting destination with chained MUL enabled" << std::endl;*/
std::vector<int> availableRegisters;
//Conditions for the destination register:
// * value must be ready at the required cycle
// * cannot be the same as the source register unless the instruction allows it
// - this avoids optimizable instructions such as "xor r, r" or "sub r, r"
// * register cannot be multiplied twice in a row unless allowChainedMul is true
// - this avoids accumulation of trailing zeroes in registers due to excessive multiplication
// - allowChainedMul is set to true if an attempt to find source/destination registers failed (this is quite rare, but prevents a catastrophic failure of the generator)
// * either the last instruction applied to the register or its source must be different than this instruction
// - this avoids optimizable instruction sequences such as "xor r1, r2; xor r1, r2" or "ror r, C1; ror r, C2" or "add r, C1; add r, C2"
// * register r5 cannot be the destination of the IADD_RS instruction (limitation of the x86 lea instruction)
for (unsigned i = 0; i < 8; ++i) {
if (registers[i].latency <= cycle && (canReuse_ || i != src_) && (allowChainedMul || opGroup_ != SuperscalarInstructionType::IMUL_R || registers[i].lastOpGroup != SuperscalarInstructionType::IMUL_R) && (registers[i].lastOpGroup != opGroup_ || registers[i].lastOpPar != opGroupPar_) && (info_->getType() != SuperscalarInstructionType::IADD_RS || i != RegisterNeedsDisplacement))
availableRegisters.push_back(i);
}
return selectRegister(availableRegisters, gen, dst_);
}
bool selectSource(int cycle, RegisterInfo(&registers)[8], Blake2Generator& gen) {
std::vector<int> availableRegisters;
//all registers that are ready at the cycle
for (unsigned i = 0; i < 8; ++i) {
if (registers[i].latency <= cycle)
availableRegisters.push_back(i);
}
//if there are only 2 available registers for IADD_RS and one of them is r5, select it as the source because it cannot be the destination
if (availableRegisters.size() == 2 && info_->getType() == SuperscalarInstructionType::IADD_RS) {
if (availableRegisters[0] == RegisterNeedsDisplacement || availableRegisters[1] == RegisterNeedsDisplacement) {
opGroupPar_ = src_ = RegisterNeedsDisplacement;
return true;
}
}
if (selectRegister(availableRegisters, gen, src_)) {
if (groupParIsSource_)
opGroupPar_ = src_;
return true;
}
return false;
}
int getType() {
return info_->getType();
}
int getSource() {
return src_;
}
int getDestination() {
return dst_;
}
int getGroup() {
return opGroup_;
}
int getGroupPar() {
return opGroupPar_;
}
const SuperscalarInstructionInfo& getInfo() const {
return *info_;
}
static const SuperscalarInstruction Null;
private:
const SuperscalarInstructionInfo* info_;
int src_ = -1;
int dst_ = -1;
int mod_;
uint32_t imm32_;
int opGroup_;
int opGroupPar_;
bool canReuse_ = false;
bool groupParIsSource_ = false;
void reset() {
src_ = dst_ = -1;
canReuse_ = groupParIsSource_ = false;
}
SuperscalarInstruction(const SuperscalarInstructionInfo* info) : info_(info) {
}
};
const SuperscalarInstruction SuperscalarInstruction::Null = SuperscalarInstruction(&SuperscalarInstructionInfo::NOP);
constexpr int CYCLE_MAP_SIZE = RANDOMX_SUPERSCALAR_LATENCY + 4;
constexpr int LOOK_FORWARD_CYCLES = 4;
constexpr int MAX_THROWAWAY_COUNT = 256;
template<bool commit>
static int scheduleUop(ExecutionPort::type uop, ExecutionPort::type(&portBusy)[CYCLE_MAP_SIZE][3], int cycle) {
//The scheduling here is done optimistically by checking port availability in order P5 -> P0 -> P1 to not overload
//port P1 (multiplication) by instructions that can go to any port.
for (; cycle < CYCLE_MAP_SIZE; ++cycle) {
if ((uop & ExecutionPort::P5) != 0 && !portBusy[cycle][2]) {
if (commit) {
if (trace) std::cout << "; P5 at cycle " << cycle << std::endl;
portBusy[cycle][2] = uop;
}
return cycle;
}
if ((uop & ExecutionPort::P0) != 0 && !portBusy[cycle][0]) {
if (commit) {
if (trace) std::cout << "; P0 at cycle " << cycle << std::endl;
portBusy[cycle][0] = uop;
}
return cycle;
}
if ((uop & ExecutionPort::P1) != 0 && !portBusy[cycle][1]) {
if (commit) {
if (trace) std::cout << "; P1 at cycle " << cycle << std::endl;
portBusy[cycle][1] = uop;
}
return cycle;
}
}
return -1;
}
template<bool commit>
static int scheduleMop(const MacroOp& mop, ExecutionPort::type(&portBusy)[CYCLE_MAP_SIZE][3], int cycle, int depCycle) {
//if this macro-op depends on the previous one, increase the starting cycle if needed
//this handles an explicit dependency chain in IMUL_RCP
if (mop.isDependent()) {
cycle = std::max(cycle, depCycle);
}
//move instructions are eliminated and don't need an execution unit
if (mop.isEliminated()) {
if (commit)
if (trace) std::cout << "; (eliminated)" << std::endl;
return cycle;
}
else if (mop.isSimple()) {
//this macro-op has only one uOP
return scheduleUop<commit>(mop.getUop1(), portBusy, cycle);
}
else {
//macro-ops with 2 uOPs are scheduled conservatively by requiring both uOPs to execute in the same cycle
for (; cycle < CYCLE_MAP_SIZE; ++cycle) {
int cycle1 = scheduleUop<false>(mop.getUop1(), portBusy, cycle);
int cycle2 = scheduleUop<false>(mop.getUop2(), portBusy, cycle);
if (cycle1 == cycle2) {
if (commit) {
scheduleUop<true>(mop.getUop1(), portBusy, cycle1);
scheduleUop<true>(mop.getUop2(), portBusy, cycle2);
}
return cycle1;
}
}
}
return -1;
}
void generateSuperscalar(SuperscalarProgram& prog, Blake2Generator& gen) {
ExecutionPort::type portBusy[CYCLE_MAP_SIZE][3];
memset(portBusy, 0, sizeof(portBusy));
RegisterInfo registers[8];
const DecoderBuffer* decodeBuffer = &DecoderBuffer::Default;
SuperscalarInstruction currentInstruction = SuperscalarInstruction::Null;
int macroOpIndex = 0;
int codeSize = 0;
int macroOpCount = 0;
int cycle = 0;
int depCycle = 0;
int retireCycle = 0;
bool portsSaturated = false;
int programSize = 0;
int mulCount = 0;
int decodeCycle;
int throwAwayCount = 0;
//decode instructions for RANDOMX_SUPERSCALAR_LATENCY cycles or until an execution port is saturated.
//Each decode cycle decodes 16 bytes of x86 code.
//Since a decode cycle produces on average 3.45 macro-ops and there are only 3 ALU ports, execution ports are always
//saturated first. The cycle limit is present only to guarantee loop termination.
//Program size is limited to RANDOMX_SUPERSCALAR_MAX_SIZE instructions.
for (decodeCycle = 0; decodeCycle < RANDOMX_SUPERSCALAR_LATENCY && !portsSaturated && programSize < RANDOMX_SUPERSCALAR_MAX_SIZE; ++decodeCycle) {
//select a decode configuration
decodeBuffer = decodeBuffer->fetchNext(currentInstruction.getType(), decodeCycle, mulCount, gen);
if (trace) std::cout << "; ------------- fetch cycle " << cycle << " (" << decodeBuffer->getName() << ")" << std::endl;
int bufferIndex = 0;
//fill all instruction slots in the current decode buffer
while (bufferIndex < decodeBuffer->getSize()) {
int topCycle = cycle;
//if we have issued all macro-ops for the current RandomX instruction, create a new instruction
if (macroOpIndex >= currentInstruction.getInfo().getSize()) {
if (portsSaturated)
break;
//select an instruction so that the first macro-op fits into the current slot
currentInstruction.createForSlot(gen, decodeBuffer->getCounts()[bufferIndex], decodeBuffer->getIndex(), decodeBuffer->getSize() == bufferIndex + 1, bufferIndex == 0);
macroOpIndex = 0;
if (trace) std::cout << "; " << currentInstruction.getInfo().getName() << std::endl;
}
const MacroOp& mop = currentInstruction.getInfo().getOp(macroOpIndex);
if (trace) std::cout << mop.getName() << " ";
//calculate the earliest cycle when this macro-op (all of its uOPs) can be scheduled for execution
int scheduleCycle = scheduleMop<false>(mop, portBusy, cycle, depCycle);
if (scheduleCycle < 0) {
if (trace) std::cout << "Unable to map operation '" << mop.getName() << "' to execution port (cycle " << cycle << ")" << std::endl;
//__debugbreak();
portsSaturated = true;
break;
}
//find a source register (if applicable) that will be ready when this instruction executes
if (macroOpIndex == currentInstruction.getInfo().getSrcOp()) {
int forward;
//if no suitable operand is ready, look up to LOOK_FORWARD_CYCLES forward
for (forward = 0; forward < LOOK_FORWARD_CYCLES && !currentInstruction.selectSource(scheduleCycle, registers, gen); ++forward) {
if (trace) std::cout << "; src STALL at cycle " << cycle << std::endl;
++scheduleCycle;
++cycle;
}
//if no register was found, throw the instruction away and try another one
if (forward == LOOK_FORWARD_CYCLES) {
if (throwAwayCount < MAX_THROWAWAY_COUNT) {
throwAwayCount++;
macroOpIndex = currentInstruction.getInfo().getSize();
if (trace) std::cout << "; THROW away " << currentInstruction.getInfo().getName() << std::endl;
//cycle = topCycle;
continue;
}
//abort this decode buffer
if (trace) std::cout << "Aborting at cycle " << cycle << " with decode buffer " << decodeBuffer->getName() << " - source registers not available for operation " << currentInstruction.getInfo().getName() << std::endl;
currentInstruction = SuperscalarInstruction::Null;
break;
}
if (trace) std::cout << "; src = r" << currentInstruction.getSource() << std::endl;
}
//find a destination register that will be ready when this instruction executes
if (macroOpIndex == currentInstruction.getInfo().getDstOp()) {
int forward;
for (forward = 0; forward < LOOK_FORWARD_CYCLES && !currentInstruction.selectDestination(scheduleCycle, throwAwayCount > 0, registers, gen); ++forward) {
if (trace) std::cout << "; dst STALL at cycle " << cycle << std::endl;
++scheduleCycle;
++cycle;
}
if (forward == LOOK_FORWARD_CYCLES) { //throw instruction away
if (throwAwayCount < MAX_THROWAWAY_COUNT) {
throwAwayCount++;
macroOpIndex = currentInstruction.getInfo().getSize();
if (trace) std::cout << "; THROW away " << currentInstruction.getInfo().getName() << std::endl;
//cycle = topCycle;
continue;
}
//abort this decode buffer
if (trace) std::cout << "Aborting at cycle " << cycle << " with decode buffer " << decodeBuffer->getName() << " - destination registers not available" << std::endl;
currentInstruction = SuperscalarInstruction::Null;
break;
}
if (trace) std::cout << "; dst = r" << currentInstruction.getDestination() << std::endl;
}
throwAwayCount = 0;
//recalculate when the instruction can be scheduled for execution based on operand availability
scheduleCycle = scheduleMop<true>(mop, portBusy, scheduleCycle, scheduleCycle);
//calculate when the result will be ready
depCycle = scheduleCycle + mop.getLatency();
//if this instruction writes the result, modify register information
// RegisterInfo.latency - which cycle the register will be ready
// RegisterInfo.lastOpGroup - the last operation that was applied to the register
// RegisterInfo.lastOpPar - the last operation source value (-1 = constant, 0-7 = register)
if (macroOpIndex == currentInstruction.getInfo().getResultOp()) {
int dst = currentInstruction.getDestination();
RegisterInfo& ri = registers[dst];
retireCycle = depCycle;
ri.latency = retireCycle;
ri.lastOpGroup = currentInstruction.getGroup();
ri.lastOpPar = currentInstruction.getGroupPar();
if (trace) std::cout << "; RETIRED at cycle " << retireCycle << std::endl;
}
codeSize += mop.getSize();
bufferIndex++;
macroOpIndex++;
macroOpCount++;
//terminating condition
if (scheduleCycle >= RANDOMX_SUPERSCALAR_LATENCY) {
portsSaturated = true;
}
cycle = topCycle;
//when all macro-ops of the current instruction have been issued, add the instruction into the program
if (macroOpIndex >= currentInstruction.getInfo().getSize()) {
currentInstruction.toInstr(prog(programSize++));
mulCount += isMultiplication(currentInstruction.getType());
}
}
++cycle;
}
double ipc = (macroOpCount / (double)retireCycle);
memset(prog.asicLatencies, 0, sizeof(prog.asicLatencies));
//Calculate ASIC latency:
//Assumes 1 cycle latency for all operations and unlimited parallelization.
for (int i = 0; i < programSize; ++i) {
Instruction& instr = prog(i);
int latDst = prog.asicLatencies[instr.dst] + 1;
int latSrc = instr.dst != instr.src ? prog.asicLatencies[instr.src] + 1 : 0;
prog.asicLatencies[instr.dst] = std::max(latDst, latSrc);
}
//address register is the register with the highest ASIC latency
int asicLatencyMax = 0;
int addressReg = 0;
for (int i = 0; i < 8; ++i) {
if (prog.asicLatencies[i] > asicLatencyMax) {
asicLatencyMax = prog.asicLatencies[i];
addressReg = i;
}
prog.cpuLatencies[i] = registers[i].latency;
}
prog.setSize(programSize);
prog.setAddressRegister(addressReg);
prog.cpuLatency = retireCycle;
prog.asicLatency = asicLatencyMax;
prog.codeSize = codeSize;
prog.macroOps = macroOpCount;
prog.decodeCycles = decodeCycle;
prog.ipc = ipc;
prog.mulCount = mulCount;
/*if(INFO) std::cout << "; ALU port utilization:" << std::endl;
if (INFO) std::cout << "; (* = in use, _ = idle)" << std::endl;
int portCycles = 0;
for (int i = 0; i < CYCLE_MAP_SIZE; ++i) {
std::cout << "; " << std::setw(3) << i << " ";
for (int j = 0; j < 3; ++j) {
std::cout << (portBusy[i][j] ? '*' : '_');
portCycles += !!portBusy[i][j];
}
std::cout << std::endl;
}*/
}
void executeSuperscalar(int_reg_t(&r)[8], SuperscalarProgram& prog, std::vector<uint64_t> *reciprocals) {
for (unsigned j = 0; j < prog.getSize(); ++j) {
Instruction& instr = prog(j);
switch (instr.opcode)
{
case randomx::SuperscalarInstructionType::ISUB_R:
r[instr.dst] -= r[instr.src];
break;
case randomx::SuperscalarInstructionType::IXOR_R:
r[instr.dst] ^= r[instr.src];
break;
case randomx::SuperscalarInstructionType::IADD_RS:
r[instr.dst] += r[instr.src] << instr.getModMem();
break;
case randomx::SuperscalarInstructionType::IMUL_R:
r[instr.dst] *= r[instr.src];
break;
case randomx::SuperscalarInstructionType::IROR_C:
r[instr.dst] = rotr(r[instr.dst], instr.getImm32());
break;
case randomx::SuperscalarInstructionType::IADD_C7:
case randomx::SuperscalarInstructionType::IADD_C8:
case randomx::SuperscalarInstructionType::IADD_C9:
r[instr.dst] += signExtend2sCompl(instr.getImm32());
break;
case randomx::SuperscalarInstructionType::IXOR_C7:
case randomx::SuperscalarInstructionType::IXOR_C8:
case randomx::SuperscalarInstructionType::IXOR_C9:
r[instr.dst] ^= signExtend2sCompl(instr.getImm32());
break;
case randomx::SuperscalarInstructionType::IMULH_R:
r[instr.dst] = mulh(r[instr.dst], r[instr.src]);
break;
case randomx::SuperscalarInstructionType::ISMULH_R:
r[instr.dst] = smulh(r[instr.dst], r[instr.src]);
break;
case randomx::SuperscalarInstructionType::IMUL_RCP:
if (reciprocals != nullptr)
r[instr.dst] *= (*reciprocals)[instr.getImm32()];
else
r[instr.dst] *= randomx_reciprocal(instr.getImm32());
break;
default:
UNREACHABLE;
}
}
}
}
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