mu - Soul of a tiny new machine. More thorough tests → More comprehensible and rewrite-friendly software → More resilient society.

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//:: Check that the different operands of an instruction aren't too large for their bitfields. :(scenario check_bitfield_sizes) % Hide_errors = true; == 0x1 01/add 4/mod 3/rm32 1/r32 # add ECX to EBX +error: '4/mod' too large to fit in bitfield mod :(before "End Globals") map<string, uint32_t> Operand_bound; :(before "End One-time Setup") put(Operand_bound, "subop", 1<<3); put(Operand_bound, "mod", 1<<2); put(Operand_bound, "rm32", 1<<3); put(Operand_bound, "base", 1<<3); put(Operand_bound, "index", 1<<3); put(Operand_bound, "scale", 1<<2); put(Operand_bound, "r32", 1<<3); put(Operand_bound, "disp8", 1<<8); put(Operand_bound, "disp16", 1<<16); // no bound needed for disp32 put(Operand_bound, "imm8", 1<<8); // no bound needed for imm32 :(before "Pack Operands(segment code)") check_operand_bounds(code); if (trace_contains_errors()) return; :(code) void check_operand_bounds(const segment& code) { trace(99, "transform") << "-- check operand bounds" << end(); for (int i = 0; i < SIZE(code.lines); ++i) { const line& inst = code.lines.at(i); for (int j = first_operand(inst); j < SIZE(inst.words); ++j) check_operand_bounds(inst.words.at(j)); if (trace_contains_errors()) return; // stop at the first mal-formed instruction } } void check_operand_bounds(const word& w) { for (map<string, uint32_t>::iterator p = Operand_bound.begin(); p != Operand_bound.end(); ++p) { if (!has_operand_metadata(w, p->first)) continue; if (!looks_like_hex_int(w.data)) continue; // later transforms are on their own to do their own bounds checking int32_t x = parse_int(w.data); if (x >= 0) { if (static_cast<uint32_t>(x) >= p->second) raise << "'" << w.original << "' too large to fit in bitfield " << p->first << '\n' << end(); } else { // hacky? assuming bound is a power of 2 if (x < -1*static_cast<int32_t>(p->second/2)) raise << "'" << w.original << "' too large to fit in bitfield " << p->first << '\n' << end(); } } }


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