
366 EMBEDDED SYSTEMS
Example 10.6
Write a program to fi nd the sum of 3X + 4Y + 9Z, where X = 2, Y = 3 and Z = 4.
Solution
AREA SUMM, CODE, READONLY
X RN 1 ;register R1 is named X
Y RN 2 ;register R2 is named Y
Z RN 3 ;register R3 is named Z
ENTRY
MOV X,#2 ;load X = 2 into register R1
MOV Y,#3 ;load Y = 3 into register R2
MOV Z,#4 ;load Z = 4 into register R3
ADD R1,R1,R1,LSL#1 ;R1 = 3X
MOV R2,R2,LSL#2 ;R2 = 4Y
ADD R3,R3,R3,LSL#3 ;R3 = 9Z
ADD R1,R1,R2 ;R1 = R1+R2 i.e. 3X+4Y
ADD R1,R1,R3 ;R1 = R1+R3 i.e. 3X+4Y+9Z
STOP B STOP ;continue branching at STOP
END ;end of the assembly fi le
Since this is ...