Information Security System design basics 5th Week study notes

Chapter III Machine-level representation of the program

First, processor history-Moore's Law

Moore's law was proposed by Gordon Moore, one of Intel's founders, Gordon Moore.

The contents are as follows: When the price is constant, the number of components that can be accommodated on the integrated circuit will increase by one times every 18-24 months, and the performance will be increased by one times. In other words, the computer performance that every dollar can buy will be at every 18-24

More than twice a month. This law reveals the speed with which information technology advances.

Second, the program code

Linux default compiler--GCC C compiler

Process:

Suffix name Explanation:

GCC Common options:

Third, the data format

char-bytes-B

short-Word-W

int-Double word-l

Long int-double word-l

Long Long int-/-/

char*-Double word-l

float-Single precision-s

double-Double Precision-L

Long double-extended precision-t

Four, the way of addressing

Immediate addressing, register addressing, direct addressing, inter-register indirect addressing, register relative addressing (or direct address addressing), base address addressing, relative base address addressing

, proportional addressing mode, base address proportional address mode, and relative base address proportional addressing mode

V. directives

mov--transmitting data

add--Plus

sub--minus

imul--Multiply (signed)

xor--XOR

or--or

and--and

leal--delivery address

inc--Plus One

dec--minus One

neg--take negative?

not--to take the supplement?

Sal (SHL)--shift left

sar--Arithmetic Right Shift

shr--Logical Right Shift

loop--Cycle

Jump instruction: Slightly

Six, the flag bit

Common Conditional flag bits:

CF: Carry Flag

ZF: 0 Logo

SF: Symbol Sign

Of: Overflow flag

The corresponding position of the flag bit:

Vii. Use of

call--Call

ret--return (equivalent to the return of the C language)

Eight, the experiment

Experiment Code:

Assembly Original Code:

Remove the assembly code with the. Line of code:

Problems encountered:

1. There is some discrepancy between the assembly instruction and last semester's study ...

For example: The book neg is to take the negative instruction, not is the take-up instruction, but the compilation book on Neg is to take the supplementary instruction, not is to take the counter-instruction.

2. When using GDB's Bt/frame/up/down instruction, I do not know why the "no stack" is always displayed.

Information Security System design basics 5th Week study notes