Instruction Set

1
Instruction Set

• Introduction to Microcontroller Programming

2
Instruction Set

• See the Instruction Set summary in the
  Programming Reference Guide (pp.13-21)
• For a detailed description of each instruction
  see Appendix A of the Reference Manual
  (pp.487-604)

3
(No Transcript)
4
(No Transcript)
5
Arithmetic Instructions (2)
6
Arithmetic Instructions (3)
7
Example 16-bit addition
8
Logic Instructions
9
Data Testing and Bit Manipulations
10
Example
11
Shift and Rotate Instructions
12
Example
13
(No Transcript)
14
CCR Instructions
15
Program Flow Control

• High level programming structures
• if-then-else
• while loop
• for loop

16
if-then-else
Example in C if v2 gt v1 is_greater() else
is_less_or_equal()
Example in Assembly
ldaa v2 cmpa v1 bgt GTLABEL
jsr ISLESSOREQUAL bra
CONTINUE GTLABEL bra ISGREATER CONTINUE ISL
ESSOREQUAL ISGREATER
bra CONTINUE
17
while-loop
Example in C while (v2 gt v1) task_a()
Example in Assembly
WLOOP ldaa v2 cmpa v1 bgt
TASKA bra CONTINUE TASKA
bra WLOOP CONTINUE
18
for-loop
Example in C for (i 4 i lt67i)
task_a()
iinitialvalue
Example in Assembly
for (true)
ldd 4 FLOOP cpd 67 bhs
CONTINUE addd 1 bra TASKA TASKA
bra FLOOP CONTINUE

(false)
true?
ii1
19
(No Transcript)
20
Jump and Subroutine Instructions
21
Jump Instructions

• Jump instructions specify the exact absolute
  16-bit location for the next instruction (and are
  not conditional)
• Example
• START CBA compare A to B
• BEQ SKIP branch if equal
• JMP NEQ jump
• SKIP INCA increment A
• NEQ BRA loop here forever

22
Interrupt Handling Instructions
23
Miscellaneous Instructions
24
Relocatable Programs

• A relocatable program is one that can start
  anywhere in memory without changing the machine
  code.
• Branch instructions are relocatable because their
  address is relative to the instruction itself.
• Jump instructions are not relocatable because
  their address is absolute