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vm.cc
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vm.cc
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#include "vm.h"
#include "opcodes.h"
#include "sections.h"
#include <cassert>
namespace ceos {
extern "C" void execute(
const uint8_t *bytecode,
char **stringTable,
VM *vm);
extern "C" uint64_t getScope(VM *vm, char *name);
uint64_t getScope(VM *vm, char *name) {
auto value = vm->m_scope->get(name);
if (value.isUndefined()) {
std::cerr << "Symbol not found: " << name << "\n";
throw;
}
return value.encode();
}
extern "C" void pushScope();
void pushScope() { }
extern "C" uint64_t prepareClosure(unsigned argc, Value *args, Value fnAddress, VM *vm);
uint64_t prepareClosure(unsigned argc, Value *args, Value fnAddress, VM *vm) {
auto closure = fnAddress.asClosure();
vm->m_scope = vm->m_scope->create(closure->scope);
for (unsigned i = 0; i < argc; i++) {
vm->m_scope->set(closure->fn->arg(i), args[i]);
}
return closure->fn->offset;
}
void VM::execute() {
auto header = read<uint64_t>();
// section marker
assert(header == Section::Header);
while (true) {
auto section = read<uint64_t>();
if (pc > length) {
return;
}
switch (section) {
case Section::Strings:
loadStrings();
break;
case Section::Functions:
loadFunctions();
break;
case Section::Text:
::ceos::execute(m_bytecode + pc, m_stringTable.data(), this);
return;
default:
std::cerr << "Unknown section: `0x0" << std::hex << section << "`\n";
throw;
}
}
}
void VM::loadStrings() {
while (true) {
auto header = read<uint64_t>();
if (header == Section::Header) {
break;
}
pc -= sizeof(header);
char *str = readStr();
m_stringTable.push_back(str);
}
}
void VM::loadFunctions() {
auto initialHeader = read<uint64_t>();
assert(initialHeader == Section::FunctionHeader);
while (true) {
auto fnid = read<unsigned>();
auto nargs = read<unsigned>();
std::vector<char *> args;
for (unsigned i = 0; i < nargs; i++) {
auto argID = read<uint64_t>();
args.push_back(m_stringTable[argID]);
}
m_userFunctions.push_back(Function(fnid, nargs, pc, std::move(args)));
while (true) {
auto opcode = read<uint64_t>();
if (opcode == Section::Header) {
return;
} else if (opcode == Section::FunctionHeader) {
break;
}
}
}
}
void VM::trackAllocation(void *ptr, size_t size) {
heapSize += size;
if (heapSize > heapLimit) {
collect();
heapLimit = std::max(heapLimit, 2 * heapSize);
}
blocks.push_back(std::make_pair(size, ptr));
}
void VM::collect() {
GC::start();
for (auto value : stack) {
GC::markValue(value, blocks);
}
GC::markScope(m_scope, blocks);
GC::sweep(blocks, &heapSize);
}
}