a) ALP

Part A
1. ALP to multiply two 16 bit binary numbers.
Theory:

Mnemonics used:
MUL, LDR,STR,BX: write explanation for these mnemonics


/*A main code calls the assembly code. A global variable by name "globvar" is declared at main in C code is loaded at asm code using the variable address.
*Basically extern keyword extends the visibility of the C variables and C functions.
*extern explicitly for C variables when we want to declare them without defining them
*to know more about extern visit:https://www.geeksforgeeks.org/understanding-extern-keyword-in-c/
*/

/*********************************c file*******************************************/
#include <LPC17xx.h>

extern  void MULTIPLY(void);      //MULTIPLY:Name of assembly routine
extern unsigned long int globvar;   //global variable to access at asm code

unsigned long int globvar,result;
#include "LCD.h"
int main(void)
{

SystemInit();
MULTIPLY(); //Function Call
result = globvar;
LCD_DISP(globvar);
while(1);

}
/*********************** ALP file or .s file ******************************************/
  AREA  MULTI , CODE , READONLY
  EXPORT MULTIPLY
  IMPORT globvar

MULTIPLY

  LDR R0,=0X706F   ; load 16 bit no. to R0 
  LDR R1,=0X7161  ; load 16 bit no. to R1
  MUL R2,R1,R0       ; multiply R1 with R0 and store result in destregister R2
LDR R3,=globvar ; load the addr of globvar into R3
  STR R2,[R3]         ;load the result present in R2 to memory location whose addr is in R3
  BX LR          ; Branch and exchange Link register content [jumps back to C code]

  END
*********************************************************************************

Download program:two 16 bit binary numbers Multiplication

2. ALP to find the sum of first 10 integer numbers.
Theory:

Mnemonics used:

/*A main code calls the assembly code. A global variable by name "globvar" is declared at main in C code is loaded at asm code using the variable address.
*Basically extern keyword extends the visibility of the C variables and C functions.
*extern explicitly for C variables when we want to declare them without defining them
*to know more about extern visit:https://www.geeksforgeeks.org/understanding-extern-keyword-in-c/
*/

/*********************************c file*******************************************/
#include <LPC17xx.h>


extern void sumten(void);          //sumten :Name of assembly routine
extern unsigned long int globvar;   //global variable to access at asm code

unsigned long int globvar,result;
#include "LCD.h"
int main(void)
{

SystemInit();
sumten();   //calling asm code
result = globvar;
LCD_DISP(globvar);
while(1);

}
/*********************** ALP file or .s file ******************************************/
THUMB
  AREA sum,CODE,READONLY
  EXPORT sumten
  IMPORT globvar
ENTRY

sumten
  MOV R1,#10 ; load 10 to register
  MOV R2,#0 ; empty R2 register to store result
loop
  ADD R2,R2,R1 ; add the content of R1 with result at R2
  SUBS R1,#0x01 ; Decreament R1 by 1
  BNE loop ; repeat till R1 goes 0

  LDR R0,=globvar         ; load the addr of var into R0
  STR R2,[R0]         ; store the result into addrs location

  BX LR ; jumps back to C code

  END

*********************************************************************************

Download program:sum of first 10 integer numbers