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// LLM converted. Here be dragons.
#include "disas.h"
#include <string>
#include <vector>
#include <sstream>
#include <iomanip>
static const std::string ZERO = "#0";
static const std::string DEST_NONE = "_";
static const std::string JUMP_NONE = "";
static const std::vector<std::string> JUMPS_IF_NZERO = {"jgt", "jlt", "jne", "jmp"};
static const std::vector<std::string> JUMPS_IF_ZERO = {"jge", "jle", "jeq", "jmp"};
struct Decoded {
std::string mnemonic;
std::string dest;
std::string op1;
std::string op2;
std::string jumpdest;
};
static bool in_list(const std::string &s, const std::vector<std::string> &v) {
for (const auto &x : v) {
if (x == s) return true;
}
return false;
}
static std::string decode_jump(uint16_t ins) {
if ((ins & 0x7) == 0) {
return JUMP_NONE;
}
if ((ins & 0x7) == 0x7) {
return "jmp";
}
bool jl = (ins & (1 << 2)) != 0;
bool je = (ins & (1 << 1)) != 0;
bool jg = (ins & (1 << 0)) != 0;
if (jl && je) {
return "jle";
}
if (jl && jg) {
return "jne";
}
if (je && jg) {
return "jge";
}
if (jl) return "jlt";
if (je) return "jeq";
if (jg) return "jgt";
return "<unknown>";
}
static std::pair<std::string, bool> decode_ins(uint16_t ins) {
int opcode = (ins >> 8) & 0x03;
bool ar_n_log = (ins & (1 << 10)) != 0;
opcode |= (ar_n_log ? 1 : 0) << 2;
switch (opcode) {
case 0b000: return {"and", true};
case 0b001: return {"or", true};
case 0b010: return {"xor", true};
case 0b011: return {"not", false};
case 0b100: return {"add", true};
case 0b101: return {"inc", false};
case 0b110: return {"sub", true};
case 0b111: return {"dec", false};
default: return {"<?>", false};
}
}
static std::string decode_arg1(uint16_t ins) {
bool use_mem = (ins & (1 << 12)) != 0;
bool zx = (ins & (1 << 7)) != 0;
bool sw = (ins & (1 << 6)) != 0;
if (zx) return ZERO;
if (!sw) return "D";
return use_mem ? "M" : "A";
}
static std::string decode_arg2(uint16_t ins) {
bool use_mem = (ins & (1 << 12)) != 0;
bool sw = (ins & (1 << 6)) != 0;
if (sw) return "D";
return use_mem ? "M" : "A";
}
static std::string decode_dest(uint16_t ins) {
bool dA = (ins & (1 << 5)) != 0;
bool dD = (ins & (1 << 4)) != 0;
bool dM = (ins & (1 << 3)) != 0;
std::string dest;
if (dA) dest += "A";
if (dD) dest += "D";
if (dM) dest += "M";
return dest.empty() ? DEST_NONE : dest;
}
static Decoded decode_instruction(uint16_t ins) {
if ((ins & 0x8000) == 0) {
return {"mov", "A", "#" + std::to_string(ins), "", ""};
} else {
auto [mnemonic, two_op] = decode_ins(ins);
std::string dest = decode_dest(ins);
std::string op1 = decode_arg1(ins);
std::string op2 = two_op ? decode_arg2(ins) : "";
std::string jumpdst = decode_jump(ins);
return {mnemonic, dest, op1, op2, jumpdst};
}
}
static Decoded fixup_ins(uint16_t ins) {
Decoded d = decode_instruction(ins);
std::string &mnemonic = d.mnemonic;
std::string &dest = d.dest;
std::string &op1 = d.op1;
std::string &op2 = d.op2;
std::string &jumpdest = d.jumpdest;
if (op1 == ZERO) {
if (mnemonic == "sub") {
return {"neg", dest, op2, "", jumpdest};
}
if (mnemonic == "and") {
if (dest == DEST_NONE) {
if (in_list(jumpdest, JUMPS_IF_ZERO)) {
return {"jmp", "", "", "", ""};
} else {
return {"nop", "", "", "", ""};
}
} else {
std::string newjmp = in_list(jumpdest, JUMPS_IF_ZERO) ? "jmp" : "";
return {"mov", dest, ZERO, "", newjmp};
}
}
if (mnemonic == "add" || mnemonic == "or" || mnemonic == "xor") {
if (dest == DEST_NONE && jumpdest == JUMP_NONE) {
return {"nop", "", "", "", ""};
} else {
return {"mov", dest, op2, "", jumpdest};
}
}
if (mnemonic == "not") {
if (dest == DEST_NONE) {
if (jumpdest == "jeq" || jumpdest == "jgt" ||
jumpdest == "jge" || jumpdest == JUMP_NONE) {
return {"nop", "", "", "", ""};
} else {
return {"jmp", "", "", "", ""};
}
}
}
}
return d;
}
std::string print_decoded(uint16_t ins, bool simplify) {
Decoded d = simplify ? fixup_ins(ins) : decode_instruction(ins);
std::string jumpdest_str = d.jumpdest.empty() ? "" : "." + d.jumpdest;
std::string opcode_str = d.mnemonic + jumpdest_str;
std::string dest_str = d.dest.empty() ? std::string(7, ' ')
: d.dest + ", ";
std::string op2_str = d.op2.empty() ? "" : ", ";
std::string op1_str = d.op1 + op2_str;
std::ostringstream oss;
oss << std::left << std::setw(9) << opcode_str
<< std::setw(6) << dest_str
<< std::setw(4) << op1_str
<< d.op2;
return oss.str();
}
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