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c9ff5b8ca40b6c68fad2ef203202956eeda67f34
BlitzNext/compiler/assem_x86/assem_x86.cpp
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Michael Fabian 'Xaymar' Dirks c9ff5b8ca4 compiler: Formatting
2019-01-18 17:04:57 +01:00

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/*
BlitzPC assembler.
This REALLY needs some work - very slow.
*/
#include "assem_x86.h"
#include "../ex.h"
#include "../std.h"
#include <iomanip>
typedef map<string, Inst*> InstMap;
typedef InstMap::value_type InstPair;
typedef InstMap::const_iterator InstIter;
static InstMap instMap;
//#define LOG
Assem_x86::Assem_x86(istream& in, Module* mod) : Assem(in, mod)
{
//build instruction map, if not built already.
if (!instMap.size()) {
for (int k = 0; !insts[k].name || insts[k].name[0]; ++k) {
if (insts[k].name)
instMap.insert(InstPair(insts[k].name, &insts[k]));
}
}
}
static int findCC(const string& s)
{
if (s == "o")
return 0;
if (s == "no")
return 1;
if (s == "b" || s == "c" || s == "nae")
return 2;
if (s == "ae" || s == "nb" || s == "nc")
return 3;
if (s == "e" || s == "z")
return 4;
if (s == "ne" || s == "nz")
return 5;
if (s == "be" || s == "na")
return 6;
if (s == "a" || s == "nbe")
return 7;
if (s == "s")
return 8;
if (s == "ns")
return 9;
if (s == "p" || s == "pe")
return 10;
if (s == "ne" || s == "po")
return 11;
if (s == "l" || s == "nge")
return 12;
if (s == "ge" || s == "nl")
return 13;
if (s == "le" || s == "ng")
return 14;
if (s == "g" || s == "nle")
return 15;
return -1;
}
void Assem_x86::align(int n)
{
int pc = mod->getPC();
int sz = (pc + (n - 1)) / n * n - pc;
while (sz--)
mod->emit(0x90);
}
void Assem_x86::emit(int n)
{
#ifdef LOG
clog << hex << (int(n) & 0xff) << dec << ' ';
#endif
mod->emit(n);
}
void Assem_x86::emitw(int n)
{
emit(n);
emit((n >> 8));
}
void Assem_x86::emitd(int n)
{
emitw(n);
emitw(n >> 16);
}
void Assem_x86::emitImm(const Operand& o, int size)
{
if (size < 4 && o.immLabel.size())
throw Ex("immediate value cannot by a label");
switch (size) {
case 1:
emit(o.imm);
return;
case 2:
emitw(o.imm);
return;
case 4:
a_reloc(o.immLabel);
emitd(o.imm);
return;
}
}
void Assem_x86::emitImm(const string& s, int size)
{
Operand op(s);
op.parse();
if (!(op.mode & IMM))
throw Ex("operand must be immediate");
emitImm(op, size);
}
void Assem_x86::r_reloc(const string& s)
{
if (!s.size())
return;
mod->addReloc(s.c_str(), mod->getPC(), true);
}
void Assem_x86::a_reloc(const string& s)
{
if (!s.size())
return;
mod->addReloc(s.c_str(), mod->getPC(), false);
}
void Assem_x86::assemInst(const string& name, const string& lhs, const string& rhs)
{
//parse operands
Operand lop(lhs), rop(rhs);
lop.parse();
rop.parse();
//find instruction
int cc = -1;
Inst* inst = 0;
//kludge for condition code instructions...
if (name[0] == 'j') {
if ((cc = findCC(name.substr(1))) >= 0) {
static Inst jCC = {"jCC", IMM, NONE, RW_RD | PLUSCC, "\x2\x0F\x80"};
inst = &jCC;
}
} else if (name[0] == 's' && name.substr(0, 3) == "set") {
if ((cc = findCC(name.substr(3))) >= 0) {
static Inst setCC = {"setne", R_M8, NONE, _2 | PLUSCC, "\x2\x0F\x90"};
inst = &setCC;
}
}
if (inst) {
if (!(lop.mode & inst->lmode) || !(rop.mode & inst->rmode))
throw Ex("illegal addressing mode");
} else {
InstIter it = instMap.find(name);
if (it == instMap.end())
throw Ex("unrecognized instruction");
inst = it->second;
for (;;) {
if ((lop.mode & inst->lmode) && (rop.mode & inst->rmode))
break;
if ((++inst)->name)
throw Ex("illegal addressing mode");
}
}
//16/32 bit modifier - NOP for now
if (inst->flags & (O16 | O32)) {
}
int k, n = inst->bytes[0];
for (k = 1; k < n; ++k)
emit(inst->bytes[k]);
if (inst->flags & PLUSREG)
emit(inst->bytes[k] + lop.reg);
else if (inst->flags & PLUSCC)
emit(inst->bytes[k] + cc);
else
emit(inst->bytes[k]);
if (inst->flags & (_0 | _1 | _2 | _3 | _4 | _5 | _6 | _7 | _R)) {
//find the memop;
const Operand& mop = (inst->rmode & (MEM | MEM8 | MEM16 | MEM32 | R_M | R_M8 | R_M16 | R_M32)) ? rop : lop;
//find the spare field value.
int rm = 0;
switch (inst->flags & (_0 | _1 | _2 | _3 | _4 | _5 | _6 | _7 | _R)) {
case _0:
rm = 0;
break;
case _1:
rm = 1;
break;
case _2:
rm = 2;
break;
case _3:
rm = 3;
break;
case _4:
rm = 4;
break;
case _5:
rm = 5;
break;
case _6:
rm = 6;
break;
case _7:
rm = 7;
break;
case _R:
rm = (inst->rmode & (REG8 | REG16 | REG32)) ? rop.reg : lop.reg;
break;
}
rm <<= 3;
if (mop.mode & REG) { //reg
emit(0xc0 | rm | mop.reg);
} else if (mop.baseReg >= 0) { //base, index?
int mod = mop.offset ? 0x40 : 0x00;
if (mop.baseLabel.size() || mop.offset < -128 || mop.offset > 127)
mod = 0x80;
if (mop.baseReg == 5 && !mod)
mod = 0x40;
if (mop.indexReg >= 0) { //base, index!
emit(mod | rm | 4);
emit((mop.shift << 6) | (mop.indexReg << 3) | mop.baseReg);
} else { //base, no index!
if (mop.baseReg != 4)
emit(mod | rm | mop.baseReg);
else {
emit(mod | rm | 4);
emit((4 << 3) | mop.baseReg);
}
}
if ((mod & 0xc0) == 0x40)
emit(mop.offset);
else if ((mod & 0xc0) == 0x80) {
//reloc
a_reloc(mop.baseLabel);
emitd(mop.offset);
}
} else if (mop.indexReg >= 0) { //index, no base!
emit(rm | 4);
emit((mop.shift << 6) | (mop.indexReg << 3) | 5);
//reloc
a_reloc(mop.baseLabel);
emitd(mop.offset);
} else { //[disp]
emit(rm | 5);
//reloc
a_reloc(mop.baseLabel);
emitd(mop.offset);
}
}
if (inst->flags & RW_RD) {
r_reloc(lop.immLabel);
emitd(lop.imm - 4);
}
if (inst->flags & IB) {
if (lop.mode & IMM)
emitImm(lop, 1);
else
emitImm(rop, 1);
} else if (inst->flags & IW) {
if (lop.mode & IMM)
emitImm(lop, 2);
else
emitImm(rop, 2);
} else if (inst->flags & ID) {
if (lop.mode & IMM)
emitImm(lop, 4);
else
emitImm(rop, 4);
}
}
void Assem_x86::assemDir(const string& name, const string& op)
{
if (!op.size())
throw Ex("operand error");
if (name == ".db") {
if (op[0] != '\"')
emitImm(op, 1);
else {
if (op.size() < 2 || op[op.size() - 1] != '\"')
throw Ex("operand error");
for (int k = 1; k < op.size() - 1; ++k)
emit(op[k]);
}
} else if (name == ".dw") {
emitImm(op, 2);
} else if (name == ".dd") {
emitImm(op, 4);
} else if (name == ".align") {
Operand o(op);
o.parse();
if (!(o.mode & IMM))
throw Ex("operand must be immediate");
align(o.imm);
} else {
throw Ex("unrecognized assembler directive");
}
}
void Assem_x86::assemLine(const string& line)
{
int i = 0;
string name;
vector<string> ops;
//label?
if (!isspace(line[i])) {
while (!isspace(line[i]))
++i;
string lab = line.substr(0, i);
if (!mod->addSymbol(lab.c_str(), mod->getPC()))
throw Ex("duplicate label");
}
//skip space
while (isspace(line[i]) && line[i] != '\n')
++i;
if (line[i] == '\n' || line[i] == ';')
return;
//fetch instruction name
int from = i;
for (++i; !isspace(line[i]); ++i) {
}
name = line.substr(from, i - from);
for (;;) {
//skip space
while (isspace(line[i]) && line[i] != '\n')
++i;
if (line[i] == '\n' || line[i] == ';')
break;
int from = i;
if (line[i] == '\"') {
for (++i; line[i] != '\"' && line[i] != '\n'; ++i) {
}
if (line[i++] != '\"')
throw Ex("missing close quote");
} else {
for (++i; line[i] != ',' && line[i] != ';' && line[i] != '\n'; ++i) {
}
}
//back-up over space
while (i && isspace(line[i - 1]))
--i;
ops.push_back(line.substr(from, i - from));
//skip space
while (isspace(line[i]) && line[i] != '\n')
++i;
if (line[i] == '\n' || line[i] == ';')
break;
if (line[i++] != ',')
throw Ex("expecting ','");
}
//pseudo op?
if (name[0] == '.') {
for (int k = 0; k < ops.size(); ++k)
assemDir(name, ops[k]);
return;
}
//normal instruction!
if (ops.size() > 2)
throw Ex("Too many operands");
ops.push_back("");
ops.push_back("");
assemInst(name, ops[0], ops[1]);
}
void Assem_x86::assemble()
{
string line;
while (!in.eof()) {
try {
getline(in, line);
line += '\n';
#ifdef LOG
clog << line;
#endif
assemLine(line);
#ifdef LOG
clog << endl;
#endif
} catch (Ex& x) {
throw Ex(line + x.ex);
}
}
}
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