tailieunhanh - Cracker Handbook 1.0 part 54

Tham khảo tài liệu 'cracker handbook part 54', công nghệ thông tin, kỹ thuật lập trình phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Use the TASM program to build the object program. C tasm Turbo Assembler Version Copyright 1988 1990 Borland International Assembling file Error messages None Warning messages None Passes 1 Remaining memory 471k fourth step Use the TLINK program to build the executable program C tlink Turbo Link Version Copyright 1987 1990 Borland International C fifth step Execute the executable program C ejem11 enter C This assembler program shows the asterisk character on the computer screen Types of instructions. Data movement Logic and arithmetic operations Jumps loops and procedures Data movement In any program it is necessary to move the data in the memory and in the CPU registers there are several ways to do this it can copy data in the memory to some register from register to register from a register to a stack from a stack to a register to transmit data to external devices as well as vice versa. This movement of data is subject to rules and restrictions. The following are some of them It is not possible to move data from a memory locality to another directly it is necessary to first move the data of the origin locality to a register and then from the register to the destiny locality. It is not possible to move a constant directly to a segment register it first must be moved to a register in the CPU. It is possible to move data blocks by means of the movs instructions which copies a chain of bytes or words movsb which copies n bytes from a locality to another and movsw copies n words from a locality to another. The last two instructions take the values from the defined addresses by DS SI as a group of data to move and ES DI as the new localization of the data. To move data there are also structures called batteries where the data is introduced with the push instruction and are extracted with the pop instruction. In a stack the first data to be introduced is the last one we can take this is if in our program