About components for embedded programs, models of programs, assembly linking and loading

1. UNIT 3
EMBEDDED
PROGRAMMING
mr.C.KARTHIKEYAN
AP/ECE/RMKCET

2. OBJECTIVE
2

3. OBJECTIVE
3

4. TARGET SYSTEM
4

5. 5
Hello!
PROGRAM DESIGN AND
ANALYSIS

6. 6
1. COMPONENTSOF EMBEDDED
PROGRAM
2. MODELS OF PROGRAM
3.ASSEMBLY , LINKING &
LOADING

7. COMPONENTS
OF
EMBEDDED
PROGRAM
7

8. 1. Finite State Machine
2. Circular Buffer
3. Queue
8

9. PURPOSE OF DS
9

10. COMPONENTS OF EMBEDDED PROGRAM
FSM
Fetaures
Seat belt controller
Concept
C implementation
QUEUE
Unpredictable
Eg: Car driver
P/C system
10
CIRCULAR BUFFER
APP
Concept with 6 Data
stream
C implementation

11. MODELS
OF
PROGRAM
11

12. MODELS OF PROGRAM
C-text
Inorder to compile
& Optimize the pro
we need DS.
Reason not considering the source
code?
DFG
original basic block
single assignment form
Implementation of DFG from single
assignment form
12

13. MODELS OF PROGRAM
x = a + b;
y = c - d;
z = x * y;
y = b + d;
original basic block
single assignment form
x = a + b;
y = c - d;
z = x * y;
y1 = b + d;
13

14. DFGs and partial orders
14

15. Control-data flow graph
> CDFG: represents the
data flow with control.
> Uses data flow graphs as
components.
> Two types of nodes:
- decision;
- data flow.
15
x = a + b;
y = c + d

16. Control-data flow graph example
16

17. 17
CDFG for a While loop

18. ASSEMBLY ,
LINKING
&
LOADING
18

19. 19
Block diagram

20. TOOLS
.
20

21. DIFFERENCE BETWEEN
GPS & ES

23. LINKER

24. > Programs may be
composed from
several files.
> Addresses become
more specific during
processing:
> absolute addresses
> relative addresses
24

25. ASSEMBLER
> Major tasks:
- generate binary instruction format;
- translate labels into addresses;
- handle pseudo-ops
> Assembly labels:
ORG 100
Label1 ADR r4,c
25

26. SYMBOL TABLE
26
ADD r0,r1,r2
xx ADD r3,r4,r5
CMP r0,r3
yy SUB r5,r6,r7
assembly code
xx 0x8
yy 0x16
symbol table

27. Generating symbol table
27

28. 28

29. 29

30. 30

31. PROCESS.
1st PASS
SCANNING
It scans from top to
bottom
Any inst with label
name its value will be
stored in symbol table
.
While scanning,
PLC plays a major role.
It stores the current
location in the memory
After examining,
Assembler updated the
PLC+?
If next inst. Starts with
label name once again a new
entry will be made in Symbol
table
2nd PASS
When the same label
name is encountered
,the ST acts as LUT.
On looking @ the ST
that particular value
will be substituted.
31

32. Two-pass assembly
> Pass 1:
- generate symbol
table
> Pass 2:
- generate binary
instructions
32

33. LINKER
> Major tasks:
> Combines several object modules into a single
executable module.
> Jobs:
- put modules in order;
- resolve labels across modules.
33

34. LINKER- 2 PHASES
> First, it determines the address of the start of
each object file
> the loader merges all symbol tables from the
object files into a single, large table
> then edits the object files to change relative
addresses into addresses
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35. 35
Entry point &
external reference

36. 36
Thanks!