Import question of microprocessor
1. Procedure, Re-entrant and Recursive Procedure:
Writing and using procedures
• Avoid writing the same sequence of instruction again and again.
• Write it in a separate subprogram and call that subprogram whenever necessary.
• For that CALL instruction is used.
•Reentrant procedures: The procedure which can be interrupted, used and “reentered” without losing or writing over anything.
•Recursive procedure: It is the procedure which call itself.
2. CALL and RET instructions, ISA, Data Types.
Ans:
CALL and RET instruction:
ISA
● Stands for Instruction Set Architecture.
● Provides functional specifications for software programmers to use/program hardware to perform certain tasks.
● Provides the functional requirements for hardware designers so that their hardware design (called micro-architectures) can execute software programs.
Data types
● The basic capability of using different classes of values.
● Typical data types.
● Numbers .
● Integers of different lengths (8, 16, 32, 64 bits).
▪ Possibly signed or unsigned.
▪ Commonly available.
● Floating point numbers, e.g. 32 bits (single precision) or 64 bits (double precision)
▪ Available in some processors such as PowerPC.
● BCD (binary coded decimal) numbers
▪ Available in some processors, such as 68K.
● Non-numeric
● Boolean
● Characters
3. Status register, PUSH and POP registers, Macros, and Procedures
Status register:
● Contains a number of bits with each bit associated with CPU operations
● Typical status bits:
● V: Overflow
● C: Carry
● Z: Zero
● N: Negative
● Used for controlling program execution flow.
PUSH and POP register:
• The PUSH register/memory instruction decrements the stack pointer by 2 and copies the contents of the specified 16-bit register or memory location to memory at the new top-of-stack location.
• The POP register/memory instruction copies the word on the top-of-stack to the specified 16-bit register or memory location and increments the stack pointer by 2.
4. Big- & Little-Endian
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