chapter 7 low-level programming languages. 2 features in pep/7 figure 7.1 pep/7’s architecture
TRANSCRIPT
Chapter 7
Low-Level Programming Languages
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Features in Pep/7
Figure 7.1 Pep/7’s architecture
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Instruction Format
Figure 7.2 The Pep/7 instruction format
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Instruction Format
Figure 7.3 Difference between immediate-mode and direct-mode addressing
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Some Sample Instructions
Figure 7.3 Subset of Pep/7 instructions
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Sample Instructions
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Sample Instructions
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Sample Instructions
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Sample Instructions
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Algorithms
Write "H"Write 48 (hex)
Write "e"Write 65 (hex)
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.Write "o"
Write 6F (hex)
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A Program Example
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Hand Simulation
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Hand Simulation
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Hand Simulation
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Pep/7 Simulator
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Pep/7 Simulator
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Pep/7 Assembly Language
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Pep/7 Assembly Language
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Assembly Process
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A New Program
Reading and adding three numbersSet sum to 0Read num1Add num1 to sumRead num2Add num2 to sumRead num3Add num3 to sumWrite sum
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Our Completed Program
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Decision Making
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Decision Making
…Add num3 to sumIf sum is negative
Write "Error"Else
Write sum
Write "Error" if sum is negative.
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Decision Making
Add num3 to sumIf status bit N is 1
Go to NegMsgWrite sumQuit: STOPNegMsg: Write the message and go to Quit
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Decision Making
Read limitSet sum to 0While (limit is not zero)
Read numberSet sum to sum + numberSet limit to limit - 1
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Decision Making
Set the accumulator to limitSubtract one from the accumulatorCompare accumulator to zeroIf status bit Z is 1
go to QuitElse
go to Read
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Decision Making
What do you think?
Suppose the government no longer required physical crash tests for new cars. What factors might you consider before buying a car that was crash tested only by computer simulation?
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