1. 8086 Flag Register With Examples
2. Write A Program In 8086 Assembly Language For Displaying The Contents Of Cl Register.

The 8086/8088 uses a stack pointer that points to the lastpushed data on the stack, or to the last address + 1 of an unusedstack.When you push something on the stack, the stack pointer isdecremented by 2 and the data is written at that address.When you pop something off the stack, the data is read from theaddress and then the stack pointer is incremented by 2.Note that the sequence is important. On push we decrement andstore - On pop we read and THEN increment.Pushing is akin to stacking papers on your desk on top of eachother. You are working on the one on top.

CODE ProgramStart:; assembler instructions. Mov ax,SEG DATA; set up data segment. The MOV instruction is the most important command in the 8086 because it moves. PUSH and POP can be used to save and restore the values of registers. The flags are a set of variables in the CPU which indicate the status of. The following C program will read the FLAGS register when compiled with GCC and any x86 or x8664 machine following a calling convention in which integers are returned to%eax. You may need to pass the -zexecstack argument to the compiler.

You want to do somethingelse, so you put another on top and work on that. When you aredone, you take the top off, put it away, and continue working onthe first. This can be nested, arbitrarily deep, so long as youhave sufficient memory. Just remember that the stack is backwardsin memory, growing from top down.You can explicitly push/pop with the push/pop instructions, oryou can implicitly push/pop with the call/ret and int/iretinstructions.

8086 Flag Register With Examples

Write A Program In 8086 Assembly Language For Displaying The Contents Of Cl Register.

Pushf; Use the stack to transfer the FLAGS pop ax.into the AX register push ax; and copy them back onto the stack for storage xor ax, 400h; Toggle (complement) DF only; other bits are unchanged push ax; Use the stack again to move the modified value popf.into the FLAGS register; Insert here the code that required the DF flag to be complemented popf; Restore the original value of the FLAGSBy manipulating the FLAGS register, a program can determine the model of the installed processor. For example, the alignment flag can only be changed on the and above. If the program tries to modify this flag and senses that the modification did not persist, the processor is earlier than the 486.Starting with the, the instruction reports the processor model. However, the above method remains useful to distinguish between earlier models.See also.References.