Machine code is binary (1’s and 0’s) code that can be executed directly by the CPU. If you open a machine code file in a text editor you would see garbage, including unprintable characters (no, not those unprintable characters 😉 ). Object code is a portion of machine code not yet linked into a complete program. It’s the machine … Read more
its pretty much just shifting all the bits left by 1 The example they showed was a shift by 1 bit. The sll instruction isn’t limited to just shifting by 1 bit; you can specify a shift amount in the range 0..31 (a shift by 0 might seem useless, but SLL $zero, $zero, 0 is used to encode a NOP on … Read more
means: move a literal decimal-10 long (4-bytes) into a 4-byte memory location that begins at the address pointed to by (the esp register plus decimal 24)–basically it is a local variable.
cmp arg2, arg1 performs the same operation as sub arg2, arg1 except that none of the operands are modified. The difference is not stored anywhere. However, the flags register is updated and can be used in a conditional jump, like jump-if-equal (JE), most often as the next instruction after the cmp. The advantage over other … Read more
With a debugger you can step through the program assembly interactively.With a disassembler, you can view the program assembly in more detail.With a decompiler, you can turn a program back into partial source code, assuming you know what it was written in (which you can find out with free tools such as PEiD – if … Read more
I am trying to learn assembly for windows and see that there are 2 assemblers: masm : https://www.microsoft.com/downloads/en/details.aspx?FamilyID=7a1c9da0-0510-44a2-b042-7ef370530c64 masm32 : http://masm32.com/index.htm are these equivalent? which one should i choose to learn assembly for windows?
As others have pointed out, LEA (load effective address) is often used as a “trick” to do certain computations, but that’s not its primary purpose. The x86 instruction set was designed to support high-level languages like Pascal and C, where arrays—especially arrays of ints or small structs—are common. Consider, for example, a struct representing (x, … Read more