Conversion of immediate operands In sequence push seg push num IDA will try to convert 'num' to offset. In sequence mov reg, num mov segreg, immseg where reg - any general register num - a number segreg - any segment register immseg - any form of operand representing a segment paragraph 'num' will be converted to an offset. In sequence mov x1, num mov x2, seg where x1,x2 - any references to memory 'num' will be converted to an offset. Padding instructions Sequence jmp short label db 90h will be converted to jmp short label nop This option allows ida to disassemble the following instructions: 00 00 add [bx+si], al ; 16 bit 00 00 add [eax], al ; 32 bit Usually this option is disabled. Advanced instructions This option makes the disassembly more readable by hiding the superfluous instruction prefixes which are not used in the instruction. This option turns on interpretation of int 3?h instructions as FPU emulation instructions. If this option is turned on, then RIP addressing is always represented with the RIP register: mov rax, [rip+1234] Otherwise RIP addressing is replaced by the corresponding memory reference (when possible). This option is valid only for the 64-bit mode. High-level language This option allows IDA to test and create RTTI structures. The analysis is triggered by renaming a location. If the new name can be demangled as Borland's RTTI descriptor name then the analysis is performed. This option allows IDA to test locations named as "unknown_libname" for RTTI structures. This option is meaningful only if the advanced analysis of RTTI is allowed. This option allows IDA to check for catch/finally exception blocks. Misc This option turns on interpretation of int 20h as a VxDcall/jump (for 32-bit files). This option allows IDA to display a reference to a symbol even if the reference value is not equal to the symbol value. For example, to refer to symbol "x" at 0000:0100 with expression 0010:0000. This option is useful for disassembling BIOS images.