diff options
Diffstat (limited to 'subx/032pack_operands.cc')
| -rw-r--r-- | subx/032pack_operands.cc | 205 |
1 files changed, 0 insertions, 205 deletions
diff --git a/subx/032pack_operands.cc b/subx/032pack_operands.cc deleted file mode 100644 index 771e063a..00000000 --- a/subx/032pack_operands.cc +++ /dev/null @@ -1,205 +0,0 @@ -//: Operands can refer to bitfields smaller than a byte. This layer packs -//: operands into their containing bytes in the right order. - -:(scenario pack_immediate_constants) -== 0x1 -# instruction effective address operand displacement immediate -# op subop mod rm32 base index scale r32 -# 1-3 bytes 3 bits 2 bits 3 bits 3 bits 3 bits 2 bits 2 bits 0/1/2/4 bytes 0/1/2/4 bytes - bb 0x2a/imm32 # copy 42 to EBX -+transform: packing instruction 'bb 0x2a/imm32' -+transform: instruction after packing: 'bb 2a 00 00 00' -+run: copy imm32 0x0000002a to EBX - -:(scenario pack_disp8) -== 0x1 -74 2/disp8 # jump 2 bytes away if ZF is set -+transform: packing instruction '74 2/disp8' -+transform: instruction after packing: '74 02' - -:(scenarios transform) -:(scenario pack_disp8_negative) -== 0x1 -# running this will cause an infinite loop -74 -1/disp8 # jump 1 byte before if ZF is set -+transform: packing instruction '74 -1/disp8' -+transform: instruction after packing: '74 ff' -:(scenarios run) - -:(scenario pack_modrm_imm32) -== 0x1 -# instruction effective address operand displacement immediate -# op subop mod rm32 base index scale r32 -# 1-3 bytes 3 bits 2 bits 3 bits 3 bits 3 bits 2 bits 2 bits 0/1/2/4 bytes 0/1/2/4 bytes - 81 0/add/subop 3/mod/direct 3/ebx/rm32 1/imm32 # add 1 to EBX -+transform: packing instruction '81 0/add/subop 3/mod/direct 3/ebx/rm32 1/imm32' -+transform: instruction after packing: '81 c3 01 00 00 00' - -:(scenario pack_imm32_large) -== 0x1 -b9 0x080490a7/imm32 # copy to ECX -+transform: packing instruction 'b9 0x080490a7/imm32' -+transform: instruction after packing: 'b9 a7 90 04 08' - -:(before "End Level-2 Transforms") -Transform.push_back(pack_operands); - -:(code) -void pack_operands(program& p) { - trace(99, "transform") << "-- pack operands" << end(); - if (p.segments.empty()) return; - segment& code = p.segments.at(0); - for (int i = 0; i < SIZE(code.lines); ++i) { - line& inst = code.lines.at(i); - if (all_hex_bytes(inst)) continue; - trace(99, "transform") << "packing instruction '" << to_string(/*with metadata*/inst) << "'" << end(); - pack_operands(inst); - trace(99, "transform") << "instruction after packing: '" << to_string(/*without metadata*/inst.words) << "'" << end(); - } -} - -void pack_operands(line& inst) { - line new_inst; - add_opcodes(inst, new_inst); - add_modrm_byte(inst, new_inst); - add_sib_byte(inst, new_inst); - add_disp_bytes(inst, new_inst); - add_imm_bytes(inst, new_inst); - inst.words.swap(new_inst.words); -} - -void add_opcodes(const line& in, line& out) { - out.words.push_back(in.words.at(0)); - if (in.words.at(0).data == "0f" || in.words.at(0).data == "f3") - out.words.push_back(in.words.at(1)); - if (in.words.at(0).data == "f3" && in.words.at(1).data == "0f") - out.words.push_back(in.words.at(2)); -} - -void add_modrm_byte(const line& in, line& out) { - uint8_t mod=0, reg_subop=0, rm32=0; - bool emit = false; - for (int i = 0; i < SIZE(in.words); ++i) { - const word& curr = in.words.at(i); - if (has_metadata(curr, "mod")) { - mod = hex_byte(curr.data); - emit = true; - } - else if (has_metadata(curr, "rm32")) { - rm32 = hex_byte(curr.data); - emit = true; - } - else if (has_metadata(curr, "r32")) { - reg_subop = hex_byte(curr.data); - emit = true; - } - else if (has_metadata(curr, "subop")) { - reg_subop = hex_byte(curr.data); - emit = true; - } - } - if (emit) - out.words.push_back(hex_byte_text((mod << 6) | (reg_subop << 3) | rm32)); -} - -void add_sib_byte(const line& in, line& out) { - uint8_t scale=0, index=0, base=0; - bool emit = false; - for (int i = 0; i < SIZE(in.words); ++i) { - const word& curr = in.words.at(i); - if (has_metadata(curr, "scale")) { - scale = hex_byte(curr.data); - emit = true; - } - else if (has_metadata(curr, "index")) { - index = hex_byte(curr.data); - emit = true; - } - else if (has_metadata(curr, "base")) { - base = hex_byte(curr.data); - emit = true; - } - } - if (emit) - out.words.push_back(hex_byte_text((scale << 6) | (index << 3) | base)); -} - -void add_disp_bytes(const line& in, line& out) { - for (int i = 0; i < SIZE(in.words); ++i) { - const word& curr = in.words.at(i); - if (has_metadata(curr, "disp8")) - emit_hex_bytes(out, curr, 1); - if (has_metadata(curr, "disp16")) - emit_hex_bytes(out, curr, 2); - else if (has_metadata(curr, "disp32")) - emit_hex_bytes(out, curr, 4); - } -} - -void add_imm_bytes(const line& in, line& out) { - for (int i = 0; i < SIZE(in.words); ++i) { - const word& curr = in.words.at(i); - if (has_metadata(curr, "imm8")) - emit_hex_bytes(out, curr, 1); - else if (has_metadata(curr, "imm32")) - emit_hex_bytes(out, curr, 4); - } -} - -void emit_hex_bytes(line& out, const word& w, int num) { - assert(num <= 4); - if (!is_hex_int(w.data)) { - out.words.push_back(w); - return; - } - emit_hex_bytes(out, static_cast<uint32_t>(parse_int(w.data)), num); -} - -void emit_hex_bytes(line& out, uint32_t val, int num) { - assert(num <= 4); - for (int i = 0; i < num; ++i) { - out.words.push_back(hex_byte_text(val & 0xff)); - val = val >> 8; - } -} - -word hex_byte_text(uint8_t val) { - ostringstream out; - out << HEXBYTE << NUM(val); - word result; - result.data = out.str(); - result.original = out.str()+"/auto"; - return result; -} - -string to_string(const vector<word>& in) { - ostringstream out; - for (int i = 0; i < SIZE(in); ++i) { - if (i > 0) out << ' '; - out << in.at(i).data; - } - return out.str(); -} - -:(scenario pack_immediate_constants_hex) -== 0x1 -# instruction effective address operand displacement immediate -# op subop mod rm32 base index scale r32 -# 1-3 bytes 3 bits 2 bits 3 bits 3 bits 3 bits 2 bits 2 bits 0/1/2/4 bytes 0/1/2/4 bytes - bb 0x2a/imm32 # copy 42 to EBX -+transform: packing instruction 'bb 0x2a/imm32' -+transform: instruction after packing: 'bb 2a 00 00 00' -+run: copy imm32 0x0000002a to EBX - -:(scenarios transform) -:(scenario pack_silently_ignores_non_hex) -== 0x1 -# instruction effective address operand displacement immediate -# op subop mod rm32 base index scale r32 -# 1-3 bytes 3 bits 2 bits 3 bits 3 bits 3 bits 2 bits 2 bits 0/1/2/4 bytes 0/1/2/4 bytes - bb foo/imm32 # copy foo to EBX -+transform: packing instruction 'bb foo/imm32' -# no change (we're just not printing metadata to the trace) -+transform: instruction after packing: 'bb foo' -$error: 0 -:(scenarios run) |