Comparing two numbers problem

[infoMASM]

Hey everyone I know this might not be a difficult problem but I have been having a hard time with assembly language and keep doing this wrong. All I have to do is Implement the following C++ code in assembly language. Substitute calls to WriteString for the printf() function calls.
I then will run the program several times with different ranges of values for x and y to test the programs logic. But first I need to get it to work right.

If anyone can help I would really appreciate it! Thank you!!

C code:
double X;
double Y;
if( X < Y )
      printf("X is lower\n");
else
      printf("X is not lower\n")

This is what I have in assembly:

Code Select Expand


;C code origional:
; double X
; double Y
; if(X < Y)
; printf("X is lower\n")
; else
; printf("X is not lower\n")
;

INCLUDE Irvine32.inc

.data
mssg1 BYTE "X is lower",0dh,0ah,0
mssg2 BYTE "X is not lower",0dh,0ah,0

X = 10
Y = 12

.code

main PROC

compare:

mov eax, X
cmp eax, Y
jl xlower
mov eax, Y
cmp eax, X
jmp xhigher

xlower:
mov edx, OFFSET mssg1
Call WriteString
jmp compare

xhigher:
mov edx, OFFSET mssg2
Call WriteString


exit
main ENDP

END main

[ragdog]

Code Select Expand


mov eax,10
mov ebx,12
.if( eax < ebx )

      invoke printf,chr$ ("X is lower",CR,LF)
.else
       invoke printf,chr$ ("X is not lower",CR,LF)
.endif


or

Code Select Expand


mov eax,10
mov ebx,12
CMP EAX,EBX
JNB @notlower
PUSH  chr$ ("X is lower",CR,LF)
CALL printf
JMP @out
@notlower: 
PUSH chr$ ("X is not lower",CR,LF)
CALL printf
@out:


[infoMASM]

Thank you for your reply ragdog!! but I need to use calls such as WriteString but your code does help and I am working on it!

[infoMASM]

Thank you so much! I got it working the way I think it should!

Code Select Expand

;C code origional:
; double X
; double Y
; if(X < Y)
; printf("X is lower\n")
; else
; printf("X is not lower\n")
;

INCLUDE Irvine32.inc

.data
mssg1 BYTE "X is lower",0dh,0ah,0
mssg2 BYTE "X is not lower",0dh,0ah,0

X = 9
Y = 12

.code

main PROC

compare:

mov eax, X
mov ebx, Y
cmp eax, ebx
jnb xhigher
mov edx, OFFSET mssg1
call WriteString
jmp finished

xlower:
mov edx, OFFSET mssg1
Call WriteString
jmp finished

xhigher:
mov edx, OFFSET mssg2
Call WriteString

finished:


exit
main ENDP

END main

[TWell]

more like from this.

Code Select Expand

//C code original:
#include <stdio.h>
#define X  9
#define Y 12
int main(void) {
if(X < Y)
printf("X is lower\n");
else
printf("X is not lower\n");
  return 0;
}
C's double is REAL8 is asm.

That xlower block is useless ?

[MichaelW]

The compiler is not going to compare floating-point values (doubles in this case) with integer instructions (even though there is a way to do it). At least for the Microsoft Visual C++ Toolkit 2003 compiler, it will use FPU instructions (primarily fcomp), or SSE2 instructions (primarily comisd) with /arch:SSE2.

[jj2007]

double X;
double Y;
if( X < Y )
      printf("X is lower\n");
else
      printf("X is not lower\n")

In your C code, you would have to initialise x and y. If you want to stay close to the C version, and work with doubles, here is one option in Assembler (it needs the MasmBasic library):

include \masm32\MasmBasic\MasmBasic.inc

double equ <REAL8>  ; make it look like C ;-)
.data
x double      12.34
y double      56.78

  Init
  Fcmp x, y  ; more
  .if Sign?
      inkey "x is less than y"
  .elseif Zero?
      inkey "x and y are equal"
  .else
      inkey "x is greater than y"
  .endif
  Exit
end start

Note the real fun starts (in both C and Assembler) when x and y are almost equal - see this thread in the old Forum.

[infoMASM]

Thank you everyone for you input! Thank you for showing me how to use the MasmBasic library and getting it to work in that sense. I need to stick with the Irvine32.inc unfortunately but I will remember this for future reference.