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Differentiation between the 8086 and 8088 microprocessors

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Tulipmania

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difference between 8088 and 8086 microprocessor

I needed to write a piece of code which checks the microprocessor platform it works on. The code is to tell if it is simulatd on an 8088 processor or 8086 one.
I've got an idea but I'm confused with the implementation . The key to this problem is using the instruction queue as the length varies in 8088 from 8086.
16-bit chips differ from their 8-bit bus versions in their Bus Interface Unit design. The instruction queue on 16-bit chips is 6 bytes long, while on 8-bit versions it is 4-bytes long. To test the length of instruction queue, we shall write a routine that modifies the instruction 5 bytes away from the current one (the one that actually modifies another one). The modified instruction can be NOP and it can be changed to INC register. If the instruction was executed as NOP, we have 6-byte queue (16-bit chip). If it was executed as INC, we have 4-bye queue (8-bit chip).Can anyone help me to implement this ?
another question ...after the jmp instruction the queue becomes embty.When exactly would the bytes of code accumulate in the instruction queue???
 

saudrehman

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why 8088 data bus is 8 bit and 8086 is 16 bit

The important distinction between the 8086 and the 8088 is that the 8086 processor had a 16-bit external data bus and a 16-bit internal data bus whereas the 8088 processor had an 8-bit external data bus and a 16-bit internal data bus.
otherwise they have essentially the same architecture
 

hoangkhoi

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difference between 8088 and 8086 microprocessors

The only difference between an 8088 microprocessor and an 8086 microprocessor is the BIU. In the 8088, the BIU data bus path is 8 bits wide versus the 8086's 16-bit data bus. Another difference is that the 8088 instruction queue is four bytes long instead of six.

The important point to note, however, is that because the EU is the same for each processor, the programming instructions are exactly the same for each. Programs written for the 8086 can be run on the 8088 without any changes.
 

Tulipmania

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difference between microprocessor 8086 and 8088

Yeah , But may i know what is the mechanism by which the BIU accumulate instructions in the instruction queue ?
 

Davood Amerion

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difference 8088 8086

I think, you can use external memory access difference feautre for finding processor part number.
For this you must start one (hardware) timer and, for example, push n digit to memory (with even address) and measure time diffrence.
In this test, time needed for 8088 is about twice of 8086.
 

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