Docsity
Docsity
Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity

Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan

Guidelines and tips
Guidelines and tips
Sell on Docsity
Sell on Docsity
Docsity AI
Docsity AI
Log inSign up

Prepare for your exams

Study with the several resources on Docsity

Find documents

Prepare for your exams with the study notes shared by other students like you on Docsity

Search for your university

Find the specific documents for your university's exams

Docsity AINEW

Summarize your documents, ask them questions, convert them into quizzes and concept maps

Explore questions

Clear up your doubts by reading the answers to questions asked by your fellow students

Earn points to download

Earn points by helping other students or get them with a premium plan

Share documents
download point icon20 Points

For each uploaded document

Answer questions
download point icon5 Points

For each given answer (max 1 per day)

All the ways to get free points
Get points immediately

Choose a premium plan with all the points you need

Study Opportunities

Choose your next study program

Get in touch with the best universities in the world. Search through thousands of universities and official partners

Community

Ask the community

Ask the community for help and clear up your study doubts

Free resources

Our save-the-student-ebooks!

Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors

Steps in Compiling a Program - Lecture Slides | CMSC 212, Exams of Computer Science

University of MarylandComputer Science
Prof. Jandelyn Dawn Plane

Material Type: Exam; Professor: Plane; Class: INTRO TO LOW-LEVEL PROG; Subject: Computer Science; University: University of Maryland; Term: Spring 2005;

Typology: Exams

Pre 2010

Uploaded on 07/30/2009

koofers-user-5pd-1
koofers-user-5pd-1 🇺🇸

8 documents

1 / 12

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
1
CMSC 212 – S05 (lect 11)
Announcements
●Exam #1
– re-grade requests due by 1:45 on Thursday
●Program #1b
– will return hand-grading portion today
– re-grade requests due by 1:45 one week from today
●Program #2
– Due March 15th at 8:00 pm
●Reading
– Chapter 14 (Today)
– Chapter 12, 10.2 (Thursday)
pf3
pf4
pf5
pf8
pf9
pfa

Partial preview of the text

Download Steps in Compiling a Program - Lecture Slides | CMSC 212 and more Exams Computer Science in PDF only on Docsity!

Announcements

l^ Exam #1– re-grade requests due by 1:45 on Thursday l^ Program #1b– will return hand-grading portion today– re-grade requests due by 1:45 one week from today l^ Program #2– Due March 15

th^ at 8:00 pm

l^ Reading– Chapter 14 (Today)– Chapter 12, 10.2 (Thursday)

Steps in compiling a program l Converting .c to .o files– Pre-processor– Compiler (or Translator)• Scanner/Parser• Type Checker• Optimizer• Code Generator– Assembler• Converts assembly code to machine code l Converting .o's to an executable– Linker• resolves symbols– function use and definitions– global variable declarations and use

Pre-defined Symbols

l^ FILE– the name of the source file being compiled l^ LINE– line number of the current line in the file l^ DATE– Date the file was compiled l^ TIME– Time the file was compiled l^ STDC– 1 if the compiler conforms to ANSI C l^ Note: these start with two underscores andend with two underscores

#define

l^ #define name stuff l^ Symbolic constants– Primary Use– #define MAX_SIZE_TABLE 1024 l^ Macros– #define name(parameter-list) stuff– Example:• #define SUM(a,b) a + b l^ Note: all caps is a convention–^ not required by the preprocessor– makes it easier for us l^ Macros are a single line– Can define a "continuation" by ending line with \– #define macro1 a very long macro \–^ that runs onto another line

Macro Substitution

l^ Items are textually replaced so you must be careful!! l^ Consider:– #define SQUARE(x)

x * x

  • foo = SQUARE(a + 1)– This is replaced to:• foo = a + 1 * a + 1– #define DOUBLE(x)

x + x

  • foo = 10 * DOUBLE(3)– This is replaced to:• foo = 10 * 3 + 3

#define substitution

1.^ Check macro invocation arguments for macros•^ If present, replace with macro values2.^ Replace macros invocations by defined macro3.^ Scan for any defined macros used in program•^ If found, repeat steps 1 & 2String literals are not scanned for macro replacement

Other Issues with Macros l Side Effects of Macro Parameters– Replace each use of parameter– Consider:• #define DOUBLE(x)

((x) + (x))

• y = DOUBLE(++j);• y = ((++j) + (++j)) l Can be hard to tell macros from functions– Solution, use all upper case for macro names l #undef name– un-define the macro named “name” l Compiler Command Line Definition– gcc -DFOO=3– defines FOO just as though #define FOO 3 appeared in program

Conditional Compilation

l^ #if const-ex1– statements done iff “const-ex1” is true l^ #elif const-ex2– statements done iff “const-ex1” is false and “const-ex2” is true l^ #else– statements done iff “const-ex1” is false and “const-ex2” is false l^ #endif l^ defined(macro-name)– one example of a constant expression– 1 if macro-name is defined, 0 if not l^ #error– stops the compilation at this point l^ Useful if code must be different on different systems l^ Tends to make code hard to read