Tiny VN computer_ - AC IN<Device&gt A...

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The Tiny Von Neumann Architecture CGS 3269 Spring 2007 The Instruction Cycle: FETCH : Fetch an instruction from the memory address pointed to by the PC (Program counter), place it in the instruction register (IR) and increment the PC by one. EXECUTE : The OP tells the computer what is the instruction that must be executed. NOTE: The PC always points to the instruction that will be fetched. When the program is loaded in memory, the PC points to the first instruction of the program. 000 MEMORY 001 100 002 ACCUMULATOR CPU INSTRUCTION REGISTER OP ADDRESS ADDRESS
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CGS 3269 Spring 2007 Instruction Set Architecture : LOAD <X> Loads the contents of memory location “X” into AC (AC stand for Accumulator). ADD <X> The data value stored at address “X” is added to the AC and the result is stored back in the AC. STORE <X> Store the contents of AC into memory location “X”. SUB <X> Subtracts the value located at address “X” from the AC and stored the result back in the
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Unformatted text preview: AC. IN &amp;lt;Device # &amp;gt;* A value from the input device is transferred into the AC. OUT &amp;lt;Device #&amp;gt; * Print out the contents of the AC in the output device. END The machine stops execution of the program. JMP &amp;lt;X&amp;gt; Causes an unconditional branch to address X. PC X SKIPZ If the contents of the Accumulator = 0 the next instruction is skipped. * Device # Device 5 Keyboard 7 Printer 9 Screen For instance you can write: 003 IN &amp;lt;5&amp;gt; 23 where 23 is the value you are typing in. CGS 3269 Spring 2007 Instruction Set Architecture Codes : 01 LOAD 02 ADD 03 STORE 04 SUB 05 IN 06 OUT 07 END 08 JMP 09 SKIPZ Instruction format assuming 6 digits, 2 are used for the op-code and 6 for the address, for example LOAD &amp;lt;0004&amp;gt; will be represented as: It can be written as 010004 using decimal numbers. LOAD 0004...
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This note was uploaded on 06/13/2011 for the course CGS 3269 taught by Professor Staff during the Spring '08 term at University of Central Florida.

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Tiny VN computer_ - AC IN&amp;lt;Device&amp;gt A...

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