By Derrick Morris
Read Online or Download An Introduction to System Programming — Based on the PDP11 PDF
Similar introduction books
Financial risk taking: an introduction to the psychology of trading and behavioural finance
In monetary danger Taking, dealer and psychologist Mike Elvin explores the advanced dating among human behaviour styles and the markets, providing the reader a context within which to evaluate their very own strengths and weaknesses as traders. The ebook deals an apposite and basic process of abilities improvement within the type of competences and skills that may be utilized wherever alongside the continuum from informal investor to full-time day dealer.
- Théorie des fonctions holomorphes de plusieurs variables
- The Nasdaq Investor
- Introduction to Statistics and Data Analysis for Physicists
- Chaos in Discrete Dynamical Systems: A Visual Introduction in 2 Dimensions
- Hedge funds demystified : a self-teaching guide
- Motley Fool Money Guide
Additional resources for An Introduction to System Programming — Based on the PDP11
Sample text
It Is called Jump to SUbroutine and has the ' mnemonic JSR. Two actions result from the execution of this Instruction . First. after the operand address has been evaluated . the value of the program counter (PC) Is stacked. It wil l at this time be the address of the next Instruction and the stacked copy Is called a 'link' . Next the program counter Is reset to the address of the operand . Thus If the Instruction 004737 002000 was In store lines 1000 and 1002, Its execution would ba aqulvalenl 10 the two Instructions 012746 001004 012707 002000 -[SP)<=1004 PC<=2000 It should now be obvious that the Instruction required at the end of the subroutine must perform the action PC<=[SP)+ .
Some discussion is necessary for the other two groups The Structure 01 the PDP11 37 which perform multiple tests. The group BGE . BlT. BGT and BlE are used for quite straightforward comparisons but the means by which they achieve the required effects are possibly obscure . Consider BGE which branches If the last result was greater than or equal to zero . This might be used after comparing two numbers . X and Y say . by means of the compare Instruction CMP X Y. which will subtract Y from X. As we would expect .
It Is called Jump to SUbroutine and has the ' mnemonic JSR. Two actions result from the execution of this Instruction . First. after the operand address has been evaluated . the value of the program counter (PC) Is stacked. It wil l at this time be the address of the next Instruction and the stacked copy Is called a 'link' . Next the program counter Is reset to the address of the operand . Thus If the Instruction 004737 002000 was In store lines 1000 and 1002, Its execution would ba aqulvalenl 10 the two Instructions 012746 001004 012707 002000 -[SP)<=1004 PC<=2000 It should now be obvious that the Instruction required at the end of the subroutine must perform the action PC<=[SP)+ .
