Unit 2 Macro Processors and compilers

Question 1

What is a macro?

Answer 1

Unit of specification for program generation through expansion.

It defines new operation or a new method of declaring data.

Question 2

Macro expansion:

Answer 2

Macro name with parameters is replaced by some code generated from its body.

Question 3

Macro Processor tasks:

Answer 3

1. Recognise macro definitions
2. Save it.
3. Recognise macro calls
4. expand macro calls

Question 4

Compare MAcro with

Answer 4

functions

Question 5

Types of Macro Expansion:

Answer 5

1. Lexical 2. Semantic

Question 6

Lexical Expansion

Answer 6

• Replace formal args by actual args.
• Replace a char string by another char string.

Generate assembly statement from model statement.

Question 7

Semantic Satiation:

Answer 7

Generation of instructions tailored to requirements of a specific usage.
It makes it more adaptive.
Conditional stuff.

Question 8

Macro Definition:

Answer 8

it consists of name of macro, params (optional), body.

Definition enclosed btw macro and mend.

macro
name
\:
body instructions
\:
mend

Question 9

formal paramter specification:

Answer 9

&[] refer ppt

Question 10

types of param :

Answer 10

• Positional (Default)
• Keyword
• default specification of param
• Macro with mixed param lists.

Question 11

Macro call:

Answer 11

[[,..]]
refer ppt
macro name, appears in the mnemonic opcode field of the assembly statement.

Question 12

check chapter 3 in tht book

Answer 12

for similarities in actual param specification and operand specification.

Question 13

+

Answer 13

it’s apparently used to differentiate btw original statements and macro statements.

pata naheee

Question 14

Expansion time control flow:

Answer 14

• If no preprocessor statements then its sequentially.

- Macro Exansion Counter (MEC) helps in implementation of flow control.

Question 15

strings that Model statement has:

Answer 15

1. Ordinary string that stand for itself.
2. name formal params preceded by &.
3. name of preprocessor variable preceeded by &.

Question 16

Positional Param :

Answer 16

written as &

formal param take value of actual param at same position.

Question 17

Keyword param:

Answer 17

for this, when calling macro, actual pram spec is written as =
refer ppt < . >

look at macro definition for them as well
&name=

Question 18

Default specifications with paramenters:

Answer 18

assign a default value in the macro definition, usually at last.
so if when calling, no value assigned to this arg then default val is automatically assigned

Question 19

more about args.. order?

Answer 19

Positional before keyword