Use the posted C++ program: Do not modify or change the C++ program. Write in as

Question

Use the posted C++ program:

Do not modify or change the C++ program.

Write in assembly language, created in a in a separate file named labxx.asm, where xx is the lab number (01, 02, 03…) the external assembler function AverageFunc.

The first parameter is the number of elements in the array and the address of the array is the second parameter.

For this assignment:
The stack must managed directly by the assembler code
No masm directives can be used to manage the stack
The masm function is called by the C++ program using the decl C style stack model
The masm function must do all its responsibilities for a decl C style stack mdel
The stack parameters must be accessed from the stack using [BP + stack offset] addressing style.

The function will determine the average of the values in the array and return the average rounded to the nearest whole number.

   So, if the fractional part of the result is >= 0.5, the result is rounded to the next integer number.
   If not, then the integer part of the number is used as the result.
  

.586              ;Target processor, use Pentium class machines
.MODEL FLAT, C    ;Use the flat memory model. Use C calling and return conventions

.STACK            ;Define a stack segment of 1KB (Not required for this example)
.DATA             ;Create a near data segment. Local variables are declared here (Not required for this example)

.CODE             ;Indicates the start of a code segment.

AverageFunc PROC
   ; Stack parameter offests
   NoOfElemenstsDW    EQU 08
   ArrayAddrStartPtr EQU 12
  
   ElementSizeBytes   EQU 04
           
   push ebp                                       ;save curent stack frame pointer
   mov ebp, esp                                  ;set current stack frame pointer

   push esi                                       ;perserve registers for calling program
   push ecx

   ;get parameters from stack using stack frame
   ;for NoOfElemenstsDW into ecx and ArrayAddrStartPtr into esi
  
    
   ;process the array sum
  
                                                  ;clear eax summer
   arrayLoop:
                                                  ; sum up into eax summer register
                                                  ; update esi to ext element
   loop arrayLoop

   push edx                                       ;perserve registers for calling program
   push ebx
  
   ;take average and calcuate rounding
                                                  ;clear upper dividend edx
                                                  ;set divisor into ebx
                                                  ;divide edx:eax / ebx

                        ;multiply remainder edx by 2
                          ;if 2 x edx remainder is greater than divisor ebx
   jbe NoRound          
                        ; round quotient eax up to next integer
   NoRound:                                       ;endif
  
   pop ebx                                       ; restore used registers
   pop edx

   pop ecx
   pop esi

   pop ebp                                       ;restore calling bp frame  

   ret

AverageFunc ENDP

END

Explanation / Answer

INCLUDE Irvine32.inc

.DATA
number1 DQ 1.365 ;loading numbers
number2 DQ 1.258
hundred DD 100 ;upto two decimal points

.CODE
_main PROC

fld number1
fimul hundred
frndint
fidiv hundred
call ShowFPUStack ;after rounding off, storing into stack

fld number2
fimul hundred
frndint
fidiv hundred
call ShowFPUStack ;after rounding off, storing into stack

invoke ExitProcess, 0

_main ENDP

END _main

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