#Hopper disassembler code#

For example, IDA allows the human user to make up mnemonic symbols for values or regions of code in an interactive session: human insight applied to the disassembly process often parallels human creativity in the code writing process. On CISC platforms with variable-width instructions, more than one disassembly may be valid. Disassemblers do not handle code that varies during execution. Writing a disassembler which produces code which, when assembled, produces exactly the original binary is possible however, there are often differences.

This poses demands on the expressivity of the assembler. For example, an x86 assembler takes an arbitrary choice between two binary codes for something as simple as MOV AX, BX. If the original code uses the other choice, the original code simply cannot be reproduced at any given point in time. However, even when a fully correct disassembly is produced, problems remain if the program requires modification. #Guide to using hopper disassembler codeįor example, the same machine language jump instruction can be generated by assembly code to jump to a specified location (for example, to execute specific code), or to jump a specified number of bytes (for example, to skip over an unwanted branch).

A disassembler cannot know what is intended, and may use either syntax to generate a disassembly which reproduces the original binary. However, if a programmer wants to add instructions between the jump instruction and its destination, it is necessary to understand the program's operation to determine whether the jump should be absolute or relative, i.e., whether its destination should remain at a fixed location, or be moved so as to skip both the original and added instructions.Ī disassembler may be stand-alone or interactive.

#Guide to using hopper disassembler code.

Hopper disassembler