Wednesday, September 27, 2017
|
|
- Tamsin Patterson
- 6 years ago
- Views:
Transcription
1 Wednesday, September 27, 2017 Topics for today Chapter 6: Mapping High-level to assembly-level The Pep/9 run-time stack (6.1) Stack-relative addressing (,s) SP manipulation Stack as scratch space Global variables and local variables Parameter passing and return values The Pep/9 run-time stack (Section 6.1) The Pep/9 run-time stack is at the high end of the memory allocated to the user (see e.g., Fig. 4.41). This is to minimize the possibility that when the stack grows it runs into the user program. The stack pointer register (SP) holds the address of the top item of the stack. Stacks in general The stack data structure is sometimes referred to as a Last-in First-out queue (or First-In, Lastout) meaning that the last item put into the stack is the first one to be removed. Think of a stack of books or a stack of plates. The push operation adds an item to the stack (at the top) and the pop operation removes the top item Push 3 Push 7 Pop Push 4 Push 9 Pop Comp 162 Notes Page 1 of 10 September 27, 2017
2 Stack in Pep/9 The Pep/9 stack plays a large part in non-trivial assembly code programs - those with subroutine calls. The Pep/9 stack is used for: - storing local variables - remembering a return address when a subroutine is called - passing parameters into subroutines - returning values from subroutines - scratch space We do not (usually) need to know the actual memory address of any item in the stack because we can access them using stack-relative addressing. So far, we have seen two of Pep/9 s eight addressing modes: Direct addressing: E.g. ldwa 3,d ; load contents of address 3 (and 4) into register A Immediate addressing: E.g. ldwa 3,i ; load the number 3 into register A In section 6.1, Warford introduces the third addressing mode (stack-relative addressing) and shows how the stack is used in providing space for local variables (he uses the example of the locals in the main program function). Stack-relative addressing E.g. ldwa 3,s loads into register A the word that begins at memory[ SP + 3] that is, loads the word that starts three bytes down from the top of the stack If the bytes of the stack (in hex) are Comp 162 Notes Page 2 of 10 September 27, 2017
3 A7 SP E 4C then after the load instruction, register A contains 7E4C. Similarly, loads 1355 into Register X. ldwx 1,s The number before,s can be negative allowing us to access locations above the stack pointer. There are various reasons why we might want to do that see later. Note that the Pep/9 stack grows upwards towards address zero (000016) so items that are in the middle of the stack have larger addresses than the item at the top of the stack. You may have encountered the stack Abstract Data Type (ADT) in a data structures class. In the case of the stack ADT we are only permitted to access the top of the stack using POP and PUSH operations to remove or add items respectively. At the assembly language level we may need to be able to quickly access items stored within the stack; stack relative addressing lets us do that. Changing the size of the stack Some instructions (see later) change the size of the stack (the value in SP) as a side effect of their actions (think pop and push). In addition, there are two instructions that let us directly manipulate the SP register. We use these two instructions to allocate and deallocate space on the stack. ADDSP - add to SP, i.e. move SP away from zero so make the stack smaller SUBSP - subtract from SP, i.e. move the SP towards zero so make the stack bigger. [Note that Pep/9 does not really need two different instructions. For example, ] SUBSP 6,i ADDSP -6,i Comp 162 Notes Page 3 of 10 September 27, 2017
4 Stack trace question. What does the stack look like after the following sequence? subsp 5,i ldwa 0x9876,i ldwx 0x1234,i stwa 2,s stwx 3,s adda 1,i addsp 4,i stba -4,s Answer 77?? Preview of stack operations During the course of Chapter 6 we will look at the various ways in which the stack is used. Here is a preview of some of them don t worry yet about the details. (1) Stack used as scratch space We can use the stack as temporary space without changing SP. In the following code we input three numbers then output them in reverse order. deci -2,s deci -4,s deci -6,s deco -6,s deco -4,s deco -2,s Technically we are not using the stack but the area above it. This is usually a safe thing to do and avoids having to declare variables to hold temporary values. Comp 162 Notes Page 4 of 10 September 27, 2017
5 (2) Stack contains local variables In the following example C program there are global variables (a,b and c) that can be accessed anywhere variables local to test (p,q and r) that can accessed only from inside test variables local to main (x, y and z) that can be accessed only from inside main. #include <stdio.h> int a,b,c; test() int p,q,r; // these are globals // p, q and r are local to test main () int x,y,z; test(); // x, y and z are local to main // calling test When a function is called, we have to allocate bytes on the stack for its local variables (if any) and adopt some convention about which location corresponds to which variable. For example, here is how the stack might look as the program runs. On entry to a function (main or test) we allocate space for the local variables. When we exit from the call of a function we deallocate this space. In addition, we have the space for the return address (RA) that lets us return to the correct location in main when we have finished the call of test. z y x RA z y x r q p RA z y x Initially Main starts Main calls test Test running Test finishes Main resumes End RA z y x z y x Comp 162 Notes Page 5 of 10 September 27, 2017
6 Consider the following C program #include <stdio.h> int A,B; int main() int C,D,E; A = C+D; Ignoring for the moment the fact that main is really a function, this might be translated into Pep/9 assembly code as br main A:.block 2 B:.block 2 main: subsp 6,i ; allocate stack space for C, D and E ldwa 4,s ; C adda 2,s ; D stwa A,d addsp 6,i stop.end ; end of main so finished with C, D and E At the end of the "main" function it does not really matter if we deallocate the stack space allocated at the beginning of main because the program is about to terminate. However, in the case of all other functions it is normally critically important that we tidy up the stack before exiting - more later. The following run of a C program illustrates that in at least one environment, when we allocate space for local variables we get whatever values are in those locations last time they were used. If no other function calls intervene then we might find values left over from the previous call of one of our functions. #include <stdio.h> void test() int A,B,C; printf("%d %d %d\n",a,b,c); // print initial contents of locals A=1; B=2; C=3; printf("%d %d %d\n",a,b,c); int main() test(); test(); Comp 162 Notes Page 6 of 10 September 27, 2017
7 The program output shows that the first time test was called, the initial values of the local variables were garbage but the second time, the space still had the numbers left there by the first call. ~$./a.out Here is a summary of some differences between local variables and global variables as commonly implemented in Pep/9. Globals Locals Declaration using.block,.word,.byte allocated space on the stack dynamically Accessibility anywhere in the program. In theory, only while appropriate function is active (space goes away on exit from the function) Referenced by identifier stack-relative addressing Initialization by.word,.byte,.ascii at load time. by assignment of values at run-time (3) Return addresses, passed parameters and return values Suppose we have the Pep/9 equivalent of the following C function int functionname (int B, int C) int D, E; *** and it is being called as follows W = functionname(p,q) Comp 162 Notes Page 7 of 10 September 27, 2017
8 then during the execution of the function, at the point marked ***, the topmost locations on the stack can be depicted Space for local variable D Space for local variable E Address to return to when function terminates Value of parameter P Value of parameter Q Space for the value returned by functionname (P and Q could be the other way round; D and E could be the other way round). We will look later at many examples of translations of C functions into Pep/9 (including recursive ones!). The stack is a shared memory location that lets information (parameter values) be passed from main program to subprogram and information (returned value) be passed from subprogram to main program Reading. Section 6.1. We will begin looking at functions (C) and subroutines (Pep/9) next week but Section 6.3 is tricky so read slowly. Comp 162 Notes Page 8 of 10 September 27, 2017
9 Review Questions 1. If this diagram represents the top of the stack 32 4F E What number does the following instruction put in Register A? ldwa 1,s 2. If register A contains ABCD 16 which byte in the stack of Q1 changes and what is the new value when the following instruction is executed? stba 3,s 3. Consider the following two sequences of instructions subsp 4,i deci -4,s deci 0,s deci -2,s deci 2,s subsp 4,i Do they have the same net effect on memory and the SP register? 4. Consider the diagram from earlier Space for local variable D Space for local variable E Address to return to when function terminates Value of parameter P Value of parameter Q Space for the value returned by functionname Which of these 6 spaces is always the same size and how big is it? 5. If E and Q are char and D and P are int and the function returns a char, how much total space is needed for the 6 items in the diagram? Comp 162 Notes Page 9 of 10 September 27, 2017
10 Review Answers 1. 4F is changed to CD 3. Yes. 4. The return address is always 2 bytes bytes ( ) Comp 162 Notes Page 10 of 10 September 27, 2017
Monday, September 28, 2015
Monda, September 28, 2015 Topics for toda Chapter 6: Mapping High-level to assembl-level The Pep/8 run-time stack (6.1) Stack-relative addressing (,s) SP manipulation Stack as scratch space Global variables
More informationWednesday, February 19, 2014
Wednesda, Februar 19, 2014 Topics for toda Solutions to HW #2 Topics for Eam #1 Chapter 6: Mapping High-level to assembl-level The Pep/8 run-time stack Stack-relative addressing (,s) SP manipulation Stack
More informationWednesday, February 28, 2018
Wednesday, February 28, 2018 Topics for today C functions and Pep/9 subroutines Introduction Location of subprograms in a program Translating functions (a) Void functions (b) Void functions with parameters
More informationMonday, March 13, 2017
Monday, March 13, 2017 Topics for today Arrays and Indexed Addressing Global arrays Local arrays Buffer exploit attacks Arrays and indexed addressing (section 6.4) So far we have looked at scalars (int,
More informationMonday, March 6, We have seen how to translate void functions. What about functions that return a value such as
Monday, March 6, 2017 Topics for today C functions and Pep/9 subroutines Translating functions (c) Non-void functions (d) Recursive functions Reverse Engineering: Pep/9 to C C Functions and Pep/9 Subroutines
More informationWednesday, February 15, 2017
Wednesday, February 15, 2017 Topics for today Before and after assembly: Macros, Linkers Overview of Chapter 6 Branching Unconditional Status bits and branching If statements While statements The V and
More informationMonday, March 27, 2017
Monday, March 27, 2017 Topics for today Indexed branching Implementation of switch statement Reusable subroutines Indexed branching It turns out that arrays are useful in translating other language constructs,
More informationWednesday, March 14, 2018
Wednesday, March 14, 2018 Topics for today Arrays and Indexed Addressing Arrays as parameters of functions Multi-dimensional arrays Option A: Space-minimal solution Option B: Iliffe vectors Array bound
More informationWednesday, March 29, Implementation of sets in an efficient manner illustrates some bit-manipulation ideas.
Wednesday, March 29, 2017 Topics for today Sets: representation and manipulation using bits Dynamic memory allocation Addressing mode summary Sets Implementation of sets in an efficient manner illustrates
More informationMonday, October 17, 2016
Monday, October 17, 2016 Topics for today C functions and Pep/8 subroutines Passing parameters by reference Globals Locals Reverse Engineering II Representation of Booleans C Functions and Pep/8 Subroutines
More informationMonday, March 9, 2015
Monday, March 9, 2015 Topics for today C functions and Pep/8 subroutines Passing parameters by reference Globals Locals More reverse engineering: Pep/8 to C Representation of Booleans C Functions and Pep/8
More informationWednesday, September 20, 2017
Wednesday, September 20, 2017 Topics for today More high-level to Pep/9 translations Compilers and Assemblers How assemblers work Symbol tables ILC Pass 1 algorithm, Error checking Pass 2 Immediate mode
More informationWednesday, February 7, 2018
Wednesday, February 7, 2018 Topics for today The Pep/9 memory Four example programs The loader The assembly language level (Chapter 5) Symbolic Instructions Assembler directives Immediate mode and equate
More informationWednesday, November 15, 2017
Wednesday, November 15, 2017 Topics for today Code generation Synthesis Algorithm 5: tree to code Optimizations Code generation Algorithm 5: generating assembly code Visiting all the nodes in a linked
More informationWednesday, March 12, 2014
Wednesday, March 12, 2014 Topics for today Solutions to HW #3 Arrays and Indexed Addressing Global arrays Local arrays Buffer exploit attacks Solutions to Homework #3 1. deci N,d < (a) N not defined lda
More informationMonday, February 16, 2015
Monday, February 16, 2015 Topics for today How assemblers work Symbol tables ILC Pass 1 algorithm, Error checking Pass 2 Immediate mode and equate Assembler variants: Disassembler, Cross assembler Macros
More informationWednesday, September 21, 2016
Wednesday, September 21, 2016 Topics for today More high-level to translations Compilers and Assemblers How assemblers work Symbol tables ILC Pass 1 algorithm, Error checking Pass 2 Immediate mode and
More informationMonday, November 7, Structures and dynamic memory
Monday, November 7, 2016 Topics for today Structures Structures and dynamic memory Grammars and Languages (Chapter 7) String generation Parsing Regular languages Structures We have seen one composite data
More informationWednesday, April 19, 2017
Wednesday, April 19, 2017 Topics for today Process management (Chapter 8) Loader Traps Interrupts, Time-sharing Storage management (Chapter 9) Main memory (1) Uniprogramming (2) Fixed-partition multiprogramming
More informationMonday, October 24, 2016
Monday, October 24, 2016 Topics for today Arrays and Indexed Addressing Arrays as parameters of functions Multi-dimensional arrays Option A: Space-minimal solution Option B: Iliffe vectors Array bound
More informationWednesday, October 17, 2012
Wednesday, October 17, 2012 Topics for today Arrays and Indexed Addressing Arrays as parameters of functions Multi-dimensional arrays Indexed branching Implementation of switch statement Arrays as parameters
More informationCSC 221: Computer Organization, Spring 2009
1 of 7 4/17/2009 10:52 AM Overview Schedule Resources Assignments Home CSC 221: Computer Organization, Spring 2009 Practice Exam 2 Solutions The exam will be open-book, so that you don't have to memorize
More informationWednesday, April
Wednesday, April 9. 2014 Topics for today Addressing mode summary Structures Structures and dynamic memory Grammars and Languages (Chapter 7) String generation Parsing Regular languages Summary of addressing
More informationQ1: /20 Q2: /30 Q3: /24 Q4: /26. Total: /100
ECE 2035(B) Programming for Hardware/Software Systems Fall 2013 Exam Two October 22 nd 2013 Name: Q1: /20 Q2: /30 Q3: /24 Q4: /26 Total: /100 1/6 For functional call related questions, let s assume the
More informationWednesday, April 22, 2015
Wednesday, April 22, 2015 Topics for today Topics for Exam 3 Process management (Chapter 8) Loader Traps Interrupts, Time-sharing Storage management (Chapter 9) Main memory (1) Uniprogramming (2) Fixed-partition
More informationImplementing Procedure Calls
1 / 39 Implementing Procedure Calls February 18 22, 2013 2 / 39 Outline Intro to procedure calls Caller vs. callee Procedure call basics Calling conventions The stack Interacting with the stack Structure
More informationWednesday, September 13, Chapter 4
Wednesday, September 13, 2017 Topics for today Introduction to Computer Systems Static overview Operation Cycle Introduction to Pep/9 Features of the system Operational cycle Program trace Categories of
More informationCOMP 303 Computer Architecture Lecture 3. Comp 303 Computer Architecture
COMP 303 Computer Architecture Lecture 3 Comp 303 Computer Architecture 1 Supporting procedures in computer hardware The execution of a procedure Place parameters in a place where the procedure can access
More informationSubroutines. int main() { int i, j; i = 5; j = celtokel(i); i = j; return 0;}
Subroutines Also called procedures or functions Example C code: int main() { int i, j; i = 5; j = celtokel(i); i = j; return 0;} // subroutine converts Celsius to kelvin int celtokel(int i) { return (i
More informationCS61C : Machine Structures
inst.eecs.berkeley.edu/~cs61c/su06 CS61C : Machine Structures Lecture #6: Memory Management CS 61C L06 Memory Management (1) 2006-07-05 Andy Carle Memory Management (1/2) Variable declaration allocates
More informationWednesday, November 8, 2017
Wednesday, November 8, 207 Topics for today Grammars and Languages (hapter 7) Finite State Machines Semantic actions ode generation - Overview Finite State Machines (see 7.2) If a language is regular (Type
More informationNotes on the Exam. Question 1. Today. Comp 104:Operating Systems Concepts 11/05/2015. Revision Lectures (separate questions and answers)
Comp 104:Operating Systems Concepts Revision Lectures (separate questions and answers) Today Here are a sample of questions that could appear in the exam Please LET ME KNOW if there are particular subjects
More informationMonday, April 9, 2018
Monday, April 9, 208 Topics for today Grammars and Languages (Chapter 7) Finite State Machines Semantic actions Code generation Overview Finite State Machines (see 7.2) If a language is regular (Type 3)
More informationMonday, August 28, 2017
Monday, August 28, 2017 Topics for today Course in context. Course outline, requirements, grading. Administrivia: Tutoring: Department, PLTL, LRC Knowledge Survey The concept of a multi-level machine Motivations
More informationImplementing Subroutines. Outline [1]
Implementing Subroutines In Text: Chapter 9 Outline [1] General semantics of calls and returns Implementing simple subroutines Call Stack Implementing subroutines with stackdynamic local variables Nested
More informationComp 204: Computer Systems and Their Implementation. Lecture 25a: Revision Lectures (separate questions and answers)
Comp 204: Computer Systems and Their Implementation Lecture 25a: Revision Lectures (separate questions and answers) 1 Today Here are a sample of questions that could appear in the exam Please LET ME KNOW
More informationCPS311 Lecture: Procedures Last revised 9/9/13. Objectives:
CPS311 Lecture: Procedures Last revised 9/9/13 Objectives: 1. To introduce general issues that any architecture must address in terms of calling/returning from procedures, passing parameters (including
More informationFunctions in MIPS. Functions in MIPS 1
Functions in MIPS We ll talk about the 3 steps in handling function calls: 1. The program s flow of control must be changed. 2. Arguments and return values are passed back and forth. 3. Local variables
More informationInstruction Set Architectures (4)
Computer Architecture Week 06 Instruction Set Architectures (4) College of Information Science and Engineering Ritsumeikan University subroutines functions, procedures remember the next instruction s address
More informationStacks and Function Calls
Stacks and Function Calls Embedded Systems 3-1 Remember the Memory Map for Our MCU Embedded Systems 3-2 Classifying Data Variables Automatic declared within a function Only exist while the function executes
More informationSystems I. Machine-Level Programming V: Procedures
Systems I Machine-Level Programming V: Procedures Topics abstraction and implementation IA32 stack discipline Procedural Memory Usage void swap(int *xp, int *yp) int t0 = *xp; int t1 = *yp; *xp = t1; *yp
More informationWednesday, April 16, 2014
Wednesday, pril 16, 2014 Topics for today Homework #5 solutions Code generation nalysis lgorithm 4: infix to tree Synthesis lgorithm 5: tree to code Optimization HW #5 solutions 1. lda 0,i ; for sum of
More informationSubprograms, Subroutines, and Functions
Subprograms, Subroutines, and Functions Subprograms are also called subroutines, functions, procedures and methods. A function is just a subprogram that returns a value; say Y = SIN(X). In general, the
More informationAssembly labs start this week. Don t forget to submit your code at the end of your lab section. Download MARS4_5.jar to your lab PC or laptop.
CSC258 Week 10 Logistics Assembly labs start this week. Don t forget to submit your code at the end of your lab section. Download MARS4_5.jar to your lab PC or laptop. Quiz review A word-addressable RAM
More informationRun Time Environment
CS 403 Compiler Construction Lecture 12 Run Time Environment and Management [Based on Chapter 7 of Aho2] 1 Run Time Environment From Lecture 1 to 11, we have seen many jobs that are done by a compiler.
More informationLecture 5. Announcements: Today: Finish up functions in MIPS
Lecture 5 Announcements: Today: Finish up functions in MIPS 1 Control flow in C Invoking a function changes the control flow of a program twice. 1. Calling the function 2. Returning from the function In
More informationLectures 5. Announcements: Today: Oops in Strings/pointers (example from last time) Functions in MIPS
Lectures 5 Announcements: Today: Oops in Strings/pointers (example from last time) Functions in MIPS 1 OOPS - What does this C code do? int foo(char *s) { int L = 0; while (*s++) { ++L; } return L; } 2
More informationCS356: Discussion #6 Assembly Procedures and Arrays. Marco Paolieri
CS356: Discussion #6 Assembly Procedures and Arrays Marco Paolieri (paolieri@usc.edu) Procedures Functions are a key abstraction in software They break down a problem into subproblems. Reusable functionality:
More informationUnited States Naval Academy Electrical and Computer Engineering Department EC310-6 Week Midterm Spring AY2017
United States Naval Academy Electrical and Computer Engineering Department EC310-6 Week Midterm Spring AY2017 1. Do a page check: you should have 8 pages including this cover sheet. 2. You have 50 minutes
More informationMIPS Programming. A basic rule is: try to be mechanical (that is, don't be "tricky") when you translate high-level code into assembler code.
MIPS Programming This is your crash course in assembler programming; you will teach yourself how to program in assembler for the MIPS processor. You will learn how to use the instruction set summary to
More informationWhere does the insert method place the new entry in the array? Assume array indexing starts from 0(zero).
Suppose we have a circular array implementation of the queue,with ten items in the queue stored at data[2] through data[11]. The current capacity of an array is 12. Where does the insert method place the
More informationRun-time Environment
Run-time Environment Prof. James L. Frankel Harvard University Version of 3:08 PM 20-Apr-2018 Copyright 2018, 2016, 2015 James L. Frankel. All rights reserved. Storage Organization Automatic objects are
More informationComputer Systems Lecture 9
Computer Systems Lecture 9 CPU Registers in x86 CPU status flags EFLAG: The Flag register holds the CPU status flags The status flags are separate bits in EFLAG where information on important conditions
More informationECE331: Hardware Organization and Design
ECE331: Hardware Organization and Design Lecture 8: Procedures (cont d), Binary Numbers and Adders Adapted from Computer Organization and Design, Patterson & Hennessy, UCB Review: Procedure Calling Steps
More informationQuestion 1. Notes on the Exam. Today. Comp 104: Operating Systems Concepts 11/05/2015. Revision Lectures
Comp 104: Operating Systems Concepts Revision Lectures Today Here are a sample of questions that could appear in the exam Please LET ME KNOW if there are particular subjects you want to know about??? 1
More informationECE 2035 Programming HW/SW Systems Fall problems, 5 pages Exam Three 28 November 2012
Instructions: This is a closed book, closed note exam. Calculators are not permitted. If you have a question, raise your hand and I will come to you. Please work the exam in pencil and do not separate
More informationQUIZ. Name all the 4 parts of the fetch-execute cycle.
QUIZ Name all the 4 parts of the fetch-execute cycle. 1 Solution Name all the 4 parts of the fetch-execute cycle. 2 QUIZ Name two fundamental differences between magnetic drives and optical drives: 3 QUIZ
More informationShift and Rotate Instructions
Shift and Rotate Instructions Shift and rotate instructions facilitate manipulations of data (that is, modifying part of a 32-bit data word). Such operations might include: Re-arrangement of bytes in a
More informationreply db y prompt db Enter your favourite colour:, 0 colour db 80 dup(?) i db 20 k db? num dw 4000 large dd 50000
Declaring Variables in Assembly Language As in Java, variables must be declared before they can be used Unlike Java, we do not specify a variable type in the declaration in assembly language Instead we
More informationAssembly Language Programming. CPSC 252 Computer Organization Ellen Walker, Hiram College
Assembly Language Programming CPSC 252 Computer Organization Ellen Walker, Hiram College Instruction Set Design Complex and powerful enough to enable any computation Simplicity of equipment MIPS Microprocessor
More informationQUIZ. Name all the 4 parts of the fetch-execute cycle.
QUIZ Name all the 4 parts of the fetch-execute cycle. 1 Solution Name all the 4 parts of the fetch-execute cycle. 2 QUIZ Name two fundamental differences between magnetic drives and optical drives: 3 Solution
More informationECE251: Tuesday September 11
ECE251: Tuesday September 11 Finish Branch related instructions Stack Subroutines Note: Lab 3 is a 2 week lab, starting this week and covers the Stack and Subroutines. Labs: Lab #2 is due this week. Lab
More informationWednesday, February 4, Chapter 4
Wednesday, February 4, 2015 Topics for today Introduction to Computer Systems Static overview Operation Cycle Introduction to Pep/8 Features of the system Operational cycle Program trace Categories of
More informationMonday, April 15, We will lead up to the Analysis and Synthesis algorithms involved by first looking at three simpler ones.
Monday, pril 15, 2013 Topics for today Code generation nalysis lgorithm 1: evaluation of postfix lgorithm 2: infix to postfix lgorithm 3: evaluation of infix lgorithm 4: infix to tree Synthesis lgorithm
More information143A: Principles of Operating Systems. Lecture 4: Calling conventions. Anton Burtsev October, 2017
143A: Principles of Operating Systems Lecture 4: Calling conventions Anton Burtsev October, 2017 Recap from last time Stack and procedure calls What is stack? Stack It's just a region of memory Pointed
More informationUnderstand Execution of a Program
Understand Execution of a Program Prof. Zhang September 17, 2014 1 Program in Memory When you execute a program, the program (i.e., executable code) is loaded into the memory (i.e., main memory, RAM) in
More informationToday. Putting it all together
Today! One complete example To put together the snippets of assembly code we have seen! Functions in MIPS Slides adapted from Josep Torrellas, Craig Zilles, and Howard Huang Putting it all together! Count
More informationintroduction to Programming in C Department of Computer Science and Engineering Lecture No. #40 Recursion Linear Recursion
introduction to Programming in C Department of Computer Science and Engineering Lecture No. #40 Recursion Linear Recursion Today s video will talk about an important concept in computer science which is
More informationToday's Topics. CISC 458 Winter J.R. Cordy
Today's Topics Last Time Semantics - the meaning of program structures Stack model of expression evaluation, the Expression Stack (ES) Stack model of automatic storage, the Run Stack (RS) Today Managing
More informationECE251: Tuesday September 12
ECE251: Tuesday September 12 Finish Branch related instructions Stack Subroutines Note: Lab 3 is a 2 week lab, starting this week and covers the Stack and Subroutines. Labs: Lab #2 is due this week. Lab
More informationDEEPIKA KAMBOJ UNIT 2. What is Stack?
What is Stack? UNIT 2 Stack is an important data structure which stores its elements in an ordered manner. You must have seen a pile of plates where one plate is placed on top of another. Now, when you
More informationDo-While Example. In C++ In assembly language. do { z--; while (a == b); z = b; loop: addi $s2, $s2, -1 beq $s0, $s1, loop or $s2, $s1, $zero
Do-While Example In C++ do { z--; while (a == b); z = b; In assembly language loop: addi $s2, $s2, -1 beq $s0, $s1, loop or $s2, $s1, $zero 25 Comparisons Set on less than (slt) compares its source registers
More informationMonday, October 26, 2015
Monday, October 26, 2015 Topics for today Indexed branching Implementation of switch statement Reusable subroutines Indexed branching It turns out that arrays are useful in translating other language constructs,
More informationLecture 5: Procedure Calls
Lecture 5: Procedure Calls Today s topics: Procedure calls and register saving conventions 1 Example Convert to assembly: while (save[i] == k) i += 1; i and k are in $s3 and $s5 and base of array save[]
More informationPart 7. Stacks. Stack. Stack. Examples of Stacks. Stack Operation: Push. Piles of Data. The Stack
Part 7 Stacks The Stack Piles of Data Stack Stack A stack is an abstract data structure that stores objects Based on the concept of a stack of items like a stack of dishes Data can only be added to or
More informationjust a ((somewhat) safer) dialect.
Intro_to_C Page 1 Intro to C Tuesday, September 07, 2004 5:30 PM C was developed specifically for writing operating systems Low level of abstraction. "Just above machine language." Direct access to the
More informationCS 536 Introduction to Programming Languages and Compilers Charles N. Fischer Lecture 11
CS 536 Introduction to Programming Languages and Compilers Charles N. Fischer Lecture 11 CS 536 Spring 2015 1 Handling Overloaded Declarations Two approaches are popular: 1. Create a single symbol table
More informationWednesday, November 4, 2009
Wednesday, November 4, 2009 Topics for today Storage management Main memory (1) Uniprogramming (2) Fixed-partition multiprogramming (3) Variable-partition multiprogramming (4) Paging (5) Virtual memory
More information143A: Principles of Operating Systems. Lecture 5: Calling conventions. Anton Burtsev January, 2017
143A: Principles of Operating Systems Lecture 5: Calling conventions Anton Burtsev January, 2017 Stack and procedure calls Stack Main purpose: Store the return address for the current procedure Caller
More informationProvided by - Microsoft Placement Paper Technical 2012
Provided by www.yuvajobs.com - Microsoft Placement Paper Technical 2012 1. Analytical 25 questions ( 30 minutes) 2. Reasoning 25 questions (25 minutes) 3. Verbal 20 questions (20 minutes) Analytical (some
More information238P: Operating Systems. Lecture 3: Calling conventions. Anton Burtsev October, 2018
238P: Operating Systems Lecture 3: Calling conventions Anton Burtsev October, 2018 What does CPU do internally? (Remember Lecture 01 - Introduction?) CPU execution loop CPU repeatedly reads instructions
More informationLecture 10 Notes Linked Lists
Lecture 10 Notes Linked Lists 15-122: Principles of Imperative Computation (Spring 2016) Frank Pfenning, Rob Simmons, André Platzer 1 Introduction In this lecture we discuss the use of linked lists to
More informationWednesday, October 4, Optimizing compilers source modification Optimizing compilers code generation Your program - miscellaneous
Wednesday, October 4, 2017 Topics for today Code improvement Optimizing compilers source modification Optimizing compilers code generation Your program - miscellaneous Optimization Michael Jackson Donald
More informationMonday, February 11, 2013
Monday, February 11, 2013 Topics for today The Pep/8 memory Four example programs The loader The assembly language level (Chapter 5) Symbolic Instructions Assembler directives Immediate mode and equate
More informationCS 2113 Software Engineering
CS 2113 Software Engineering Do this now!!! From C to Java git clone https://github.com/cs2113f18/c-to-java.git cd c-to-java./install_java Professor Tim Wood - The George Washington University We finished
More informationExtra-credit QUIZ Pipelining -due next time-
QUIZ Pipelining A computer pipeline has 4 processors, as shown above. Each processor takes 15 ms to execute, and each instruction must go sequentially through all 4 processors. A program has 10 instructions.
More information12/4/18. Outline. Implementing Subprograms. Semantics of a subroutine call. Storage of Information. Semantics of a subroutine return
Outline Implementing Subprograms In Text: Chapter 10 General semantics of calls and returns Implementing simple subroutines Call Stack Implementing subroutines with stackdynamic local variables Nested
More informationSPIM Procedure Calls
SPIM Procedure Calls 22C:60 Jonathan Hall March 29, 2008 1 Motivation We would like to create procedures that are easy to use and easy to read. To this end we will discuss standard conventions as it relates
More informationUNIT-II. Part-2: CENTRAL PROCESSING UNIT
Page1 UNIT-II Part-2: CENTRAL PROCESSING UNIT Stack Organization Instruction Formats Addressing Modes Data Transfer And Manipulation Program Control Reduced Instruction Set Computer (RISC) Introduction:
More informationCh. 11: References & the Copy-Constructor. - continued -
Ch. 11: References & the Copy-Constructor - continued - const references When a reference is made const, it means that the object it refers cannot be changed through that reference - it may be changed
More informationThis section provides some reminders and some terminology with which you might not be familiar.
Chapter 3: Functions 3.1 Introduction The previous chapter assumed that all of your Bali code would be written inside a sole main function. But, as you have learned from previous programming courses, modularizing
More information[2:3] Linked Lists, Stacks, Queues
[2:3] Linked Lists, Stacks, Queues Helpful Knowledge CS308 Abstract data structures vs concrete data types CS250 Memory management (stack) Pointers CS230 Modular Arithmetic !!!!! There s a lot of slides,
More informationProgramming Language Concepts Scoping. Janyl Jumadinova January 31, 2017
Programming Language Concepts Scoping Janyl Jumadinova January 31, 2017 Scope Rules A scope is a program section of maximal size in which no bindings change, or at least in which no re-declarations are
More informationECE232: Hardware Organization and Design
ECE232: Hardware Organization and Design Lecture 6: Procedures Adapted from Computer Organization and Design, Patterson & Hennessy, UCB Overview Procedures have different names in different languages Java:
More informationCSE Lecture In Class Example Handout
CSE 30321 Lecture 07-09 In Class Example Handout Part A: A Simple, MIPS-based Procedure: Swap Procedure Example: Let s write the MIPS code for the following statement (and function call): if (A[i] > A
More informationWednesday, September 6, 2017
Wednesday, September 6, 2017 Topics for today Arithmetic operations and status bits Logical operators Introduction to bigger bases Encoding characters Coding in general Status bits We saw last time that
More informationDATA STRUCTURE : A MCQ QUESTION SET Code : RBMCQ0305
Q.1 If h is any hashing function and is used to hash n keys in to a table of size m, where n
More information2SKILL. Variables Lesson 6. Remembering numbers (and other stuff)...
Remembering numbers (and other stuff)... Let s talk about one of the most important things in any programming language. It s called a variable. Don t let the name scare you. What it does is really simple.
More informationCompilers and computer architecture: A realistic compiler to MIPS
1 / 1 Compilers and computer architecture: A realistic compiler to MIPS Martin Berger November 2017 Recall the function of compilers 2 / 1 3 / 1 Recall the structure of compilers Source program Lexical
More informationFunction Calls. Tom Kelliher, CS 220. Oct. 24, SPIM programs due Wednesday. Refer to homework handout for what to turn in, and how.
Function Calls Tom Kelliher, CS 220 Oct. 24, 2011 1 Administrivia Announcements Assignment SPIM programs due Wednesday. Refer to homework handout for what to turn in, and how. From Last Time Outline 1.
More information