Chapter 3 JUMP, LOOP and CALL Instructions

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Suranaree UniversitySuranaree UniversityOf TechnologyOf Technologyมทสมทส

2002 Anant Oonsivilai2002 Anant Oonsivilai

Chapter 3Chapter 3JUMP, LOOP and CALL JUMP, LOOP and CALL

InstructionsInstructions

22 2002 Anant Oonsivilai2002 Anant Oonsivilai

OutlinesOutlines

Loop instructionsLoop instructionsConditional jump instructionsConditional jump instructionsConditions determining conditional jumpConditions determining conditional jumpUnconditional long & short jumpsUnconditional long & short jumpsCalculate target addresses for jumpsCalculate target addresses for jumpsSubroutinesSubroutinesUsing stack in subroutinesUsing stack in subroutinesCrystal frequency vs. machine cycleCrystal frequency vs. machine cycleCode programs to generate time delayCode programs to generate time delay


LoopingLooping- DJNZ


Loop inside a Loop (Nested Loop inside a Loop (Nested Loop)Loop)


8051 Conditional Jump Instructions8051 Conditional Jump Instructions


Conditional Jump ExampleConditional Jump Example

- JNZ , JNC


Conditional Jump ExampleConditional Jump Example


Unconditional Jump InstructionsUnconditional Jump Instructions

All conditional jumps are short jumpsAll conditional jumps are short jumps Target address within -128 to +127 of PCTarget address within -128 to +127 of PC

LJMPLJMP (long jump): 3-byte instruction (long jump): 3-byte instruction 2-byte target address: 0000 to FFFFH2-byte target address: 0000 to FFFFH Original 8051 has only 4KB on-chip ROMOriginal 8051 has only 4KB on-chip ROM

SJMPSJMP (short jump): 2-byte instruction (short jump): 2-byte instruction 1-byte relative address: -128 to +1271-byte relative address: -128 to +127


Calculating Short Jump AddressesCalculating Short Jump Addresses


Call InstructionsCall Instructions

LCALLLCALL (long call): 3-byte instruction (long call): 3-byte instruction 2-byte address2-byte address Target address within 64K-byte rangeTarget address within 64K-byte range

ACALLACALL (absolute call): 2-byte instruction (absolute call): 2-byte instruction 11-bit address11-bit address Target address within 2K-byte rangeTarget address within 2K-byte range


LCALLLCALL


CALL Instruction & Role of StackCALL Instruction & Role of Stack


Using PUSH & POP in SubroutinesUsing PUSH & POP in Subroutines


Calling SubroutinesCalling Subroutines


ACALL (absolute call)ACALL (absolute call)


Programming EfficientlyProgramming Efficiently


Time Delay Generation & CalculationTime Delay Generation & Calculation

1 instruction = 1 instruction = nn machine cycle machine cycle

1 machine cycle = 12 clock cycles1 machine cycle = 12 clock cycles


Delay CalculationDelay Calculation


Delay Calculation ExampleDelay Calculation Example


Increasing Delay Using NOPIncreasing Delay Using NOP


Large Delay Using Nested LoopLarge Delay Using Nested Loop

Chapter 3 JUMP, LOOP and CALL Instructions

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