Revision 0:a7b003d6eac1, committed 2017-10-12

Comitter:

sral4054

Date:

Thu Oct 12 03:22:25 2017 +0000

Commit message:

Module 1 ECEN 5803 Project 1; ; Submitted by; 1. Rahul Yamasani; 2. Srivishnuj Alvakonda;

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Oct 12 03:22:25 2017 +0000
@@ -0,0 +1,153 @@
+#include "mbed.h"
+Serial pc(USBTX, USBRX);  //serial channel over HDK USB interface
+Timer timer;
+/************************************************************************//**
+* \file main.c
+* \brief LAB EXERCISE 5.2 - SQUARE ROOT APPROXIMATION
+*
+* Write an assembly code subroutine to approximate the square root of an 
+* argument using the bisection method. All math is done with integers, so the 
+* resulting square root will also be an integer
+******************************************************************************
+* GOOD LUCK!
+ ****************************************************************************/
+
+ #include "stdint.h"
+ 
+ 
+ /** @cond DO_NOT_INCLUDE_WITH_DOXYGEN */
+ #include "string.h"
+ /** @endcond */
+ 
+ /**
+ * @brief 5863 Write a brief description of the function here
+ *
+ * Detailed description of the function after one line gap
+ *
+ * @note You can also add a note this way
+ *
+ * @param[in] 
+ *  You can also start writing on a new line. 
+ *  And continue on the next line. This is how you describe an input parameter
+ *
+ * @return
+ *  This is how you describe the return value
+ * 
+ */
+ 
+__asm int my_sqrt(int x){
+    
+    
+    PUSH {R4-R7} ;
+    LDR R1, =0      ;done = 0
+    LDR R7, =0 ;a=0
+    LDR R2, =0xFFFF ;b=2^31 -1
+    LDR R3, =0xFFFFFFFF ;c=-1
+DO_WHILE
+    MOV  R4, R3    ;c_old = c HERE R4 is being considered as c_old
+    ADDS R5, R2, R7 ;R5 = a+b
+    ASRS R5, R5, #1 ;R5 >> 1 which is nothing but (a+b/2) 
+    MOV  R3, R5 ;c = (a+b)/2
+    MOV  R6,R3
+    MULS R6, R3, R6       ;R6 = c*c
+    CMP  R6,R0 ;compare c*c and x (input integer)
+    BEQ  DONE
+    BLT LESS_THAN
+    MOV  R2, R3 ;setting b=c
+    B FINAL
+
+LESS_THAN
+    MOV R7,R3 ;setting a=c
+    B FINAL
+
+
+DONE
+    LDR R1, =1 ;setting done = 1
+    B FINAL ;return C
+
+
+FINAL
+    CMP R1, #1 ;compare done = 1
+    BEQ END
+    BNE COMPARE
+
+
+COMPARE
+    CMP R4, R3 ;compare c_old and c
+    BNE DO_WHILE
+    BEQ END
+
+
+END
+    MOV R0, R3
+    POP {R4-R7}
+    BX LR
+}
+
+void printCpuCycles(double readValue, int number, int sqrt)
+{
+    double cpuCycles = 0;
+     
+    cpuCycles = (readValue * 48000000);   // read value * frequqncy of clock
+    pc.printf("Sqrt of %d using bisection menthod is %d \n\r", number, sqrt);
+    pc.printf("Total time of execution for sqrt of(%d)is %f \n\r", number, readValue);
+    pc.printf("Number of CPU cycles for sqrt(%d): %d\n\r\n\r", number, (int)cpuCycles);    
+}
+/*----------------------------------------------------------------------------
+ MAIN function
+ *----------------------------------------------------------------------------*/
+ /**
+ * @brief Main function
+ *
+ * Detailed description of the main
+ */
+int main(void){
+    
+    volatile int r, j=0;
+    
+    double timer_read = 0.0;
+    double sum = 0;   
+    
+    pc.printf("/*----------------------------------------------------------------------------*/\r\n\r\n");
+    pc.printf("Frequency of KL25Z (ARM Cortex M0+): 48 MHZ\n\r\n\r");
+    
+    timer.start();
+    
+    timer.reset();
+    r = my_sqrt(2);     // should be 1
+    timer_read = timer.read();
+    printCpuCycles(timer_read, 2, r);  
+    sum = sum + timer_read;
+    timer.reset();
+    
+    
+      
+    r = my_sqrt(4);    // should be 2
+    timer_read = timer.read();
+    printCpuCycles(timer_read, 4, r); 
+    sum = sum + timer_read; 
+    timer.reset(); 
+    
+
+         
+    r = my_sqrt(22);    // should be 4
+    timer_read = timer.read();
+    printCpuCycles(timer_read, 22, r);  
+    sum = sum + timer_read;
+    timer.reset();  
+    
+    r = my_sqrt(121);   // should be 11
+    timer_read = timer.read();
+    printCpuCycles(timer_read, 121, r);  
+    sum = sum + timer_read;
+    
+    pc.printf("Total time of operation: %f\n\r\n\r", sum);
+    sum = sum * 48000000;
+    pc.printf("CPU cycles: %d\n\r\n\r", (int)(sum));
+    
+    pc.printf("/*----------------------------------------------------------------------------*/\r\n\r\n"); 
+
+}
+
+// *******************************ARM University Program Copyright © ARM Ltd 2014*************************************/
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Thu Oct 12 03:22:25 2017 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/235179ab3f27
\ No newline at end of file