X86/Disassembler/X86DisassemblerDecoder.c

49  *   the ModR/M byte is required to decode a particular instruction.
54  * @param opcode      - The last byte of the instruction's opcode, not counting
56  * @return            - TRUE if the ModR/M byte is required, FALSE otherwise.
104  * @param modRM       - The ModR/M byte if required, or any value if not.
180  *   byte from the instruction's memory and advance the cursor.
184  * @param byte  - A pointer to a pre-allocated memory buffer to be populated
188 static int consumeByte(struct InternalInstruction* insn, uint8_t* byte) {
189   int ret = insn->reader(insn->readerArg, byte, insn->readerCursor);
201  * @param byte  - See consumeByte().
204 static int lookAtByte(struct InternalInstruction* insn, uint8_t* byte) {
205   return insn->reader(insn->readerArg, byte, insn->readerCursor);
217       uint8_t byte;                                               \
219                              &byte,                               \
223       combined = combined | ((uint64_t)byte << (offset * 8));     \
323   uint8_t byte = 0;
335     if (consumeByte(insn, &byte))
339      * If the byte is a LOCK/REP/REPNE prefix and not a part of the opcode, then
342     if (insn->readerCursor - 1 == insn->startLocation && byte == 0xf0)
346         && (byte == 0xf2 || byte == 0xf3)
350        * If the byte is 0xf2 or 0xf3, and any of the following conditions are
356       if ((byte == 0xf2 || byte == 0xf3) &&
361        * Also if the byte is 0xf3, and the following condition is met:
366       if (byte == 0xf3 &&
381     switch (byte) {
388       setPrefixPresent(insn, byte, prefixLocation);
396       switch (byte) {
422       setPrefixPresent(insn, byte, prefixLocation);
429       setPrefixPresent(insn, byte, prefixLocation);
436       setPrefixPresent(insn, byte, prefixLocation);
438     default:    /* Not a prefix byte */
444       dbgprintf(insn, "Found prefix 0x%hhx", byte);
449   if (byte == 0xc4) {
453       dbgprintf(insn, "Couldn't read second byte of VEX");
467       insn->vexXopPrefix[0] = byte;
495   else if (byte == 0xc5) {
499       dbgprintf(insn, "Couldn't read second byte of VEX");
511       insn->vexXopPrefix[0] = byte;
531   else if (byte == 0x8f) {
535       dbgprintf(insn, "Couldn't read second byte of XOP");
549       insn->vexXopPrefix[0] = byte;
579       if ((byte & 0xf0) == 0x40) {
587         insn->rexPrefix = byte;
590         dbgprintf(insn, "Found REX prefix 0x%hhx", byte);
634  * readOpcode - Reads the opcode (excepting the ModR/M byte in the case of
697     dbgprintf(insn, "Found a two-byte escape prefix (0x%hhx)", current);
703       dbgprintf(insn, "Found a three-byte escape prefix (0x%hhx)", current);
710       dbgprintf(insn, "Found a three-byte escape prefix (0x%hhx)", current);
717       dbgprintf(insn, "Found a three-byte escape prefix (0x%hhx)", current);
724       dbgprintf(insn, "Found a three-byte escape prefix (0x%hhx)", current);
731       dbgprintf(insn, "Didn't find a three-byte escape prefix");
751  *   the ModR/M byte as appropriate for extended and escape opcodes,
820  * getID - Determines the ID of an instruction, consuming the ModR/M byte as
999  * readSIB - Consumes the SIB byte to determine addressing information for an
1002  * @param insn  - The instruction whose SIB byte is to be read.
1003  * @return      - 0 if the SIB byte was successfully read; nonzero otherwise.
1083       debug("Cannot have Mod = 0b11 and a SIB byte");
1099  * @return      - 0 if the displacement byte was successfully read; nonzero
1141  * readModRM - Consumes all addressing information (ModR/M byte, SIB byte, and
1705  *                    byte in the instruction.
1745     dbgprintf(insn, "Instruction exceeds 15-byte limit");