simple assembly programming
Author
I was wondering how I can test if a value is within 100 of another value. How would I go about doing this using assembly? Thanks
Most compilers have an option to output an assembly file. Check the docs on your compiler in question. (I think it''s a -S switch w/ Borland, but I''m not sure).
Then open the assembly file in your favorite text editor.
Actually, writing it in C and then doing the conversion yourself might be better. Some compilers are more efficient than others.
JSwing
quote:Original post by randomDecay
I was wondering how I can test if a value is within 100 of another value. How would I go about doing this using assembly? Thanks
I can almost guarantee that writing this routine in assembly will not be faster than writing the same routine in C/C++, so if that is why you are writing the routine please reconsider, from one programmer to another.
quote:
how do I do that?
In VC Project->Settings->C/C++
change CATAGORY to LISTING FILES
chage LISTING FILE TYPE to ASSEMBLY WITH SOURCE CODE
its pretty easy, here is part of what you have to do:
cmp ax,value + 100
jbe label1
label1:
cmp ax,value - 100
jge label2
label2:
here you know that it is within the range, if you don''t come here then its not withing the range
cmp ax,value + 100
jbe label1
label1:
cmp ax,value - 100
jge label2
label2:
here you know that it is within the range, if you don''t come here then its not withing the range
C version...
in ASM you'd do something like this...
Hope this helps....
Edited by - Gladiator on November 14, 2001 2:41:32 AM
BOOL Range_Within_100(int value, int another_value) { return (abs(another_value-value) <= 100); } in ASM you'd do something like this...
BOOL Range_Within_100(int value, int another_value) { _asm { // do subtraction: another_value - value mov ecx, another_value sub ecx, value // absolute value mov edx, ecx sar edx, 15 xor ecx, edx sub ecx, edx // assume it's not within range sub eax, eax // we were correct cmp ecx, 100 jg done // no we weren't change it to 1 (withing range) inc eax done: // return value in EAX } } Hope this helps....
Edited by - Gladiator on November 14, 2001 2:41:32 AM
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