Dec 15, 2021 · Instructions not so marked are not critical. On the x86 processor, instructions are variable-sized, so disassembling backward is an exercise in pattern matching. To disassemble backward from an address, you should start disassembling at a point further back than you really want to go, then look forward until the instructions start making sense.

Appendix A: Intel x86 Instruction Reference. This appendix provides a complete list of the machine instructions which NASM will assemble, and a short description of the function of each one. It is not intended to be exhaustive documentation on the fine details of the instructions’ function, such as which exceptions they can trigger: for such documentation, you should go to …

Two one-word operands in memory or two double-word operands in memory, depending on operand-size attribute (used only by the BOUND instruction). b: Byte, regardless of operand-size attribute. c: Byte or word, depending on operand-size attribute. d: Doubleword, regardless of operand-size attribute : dq: Double-quadword, regardless of operand-size attribute. p