Assembly, expressions..which order?

browneyes · 10-07-2004, 01:05 PM

What is the order of precedence in assembly?

for like this expression:

i = a + 4 + b * 7 / c * 3

I tried to do it in C and I got answer of 24, when a=8, b=10, c=15.

But I keep getting 26 in assembly, I must have made a mistake in order.

m00t00 · 10-07-2004, 01:19 PM

that aint assembly, unless you're talking about HLA...

/me despises HLA...

fiomba · 10-07-2004, 01:35 PM

the 'mistake' has beeen made by C.

Perhaps you have declared a, b and c as integer

and so the b*7/c is an integer division which has 4 as answer (instead of 4.6666666...)

You must declare all your variables float or double
and write the equation like that:

a + 4. + b * 7. / c * 3. = 26.0

itsme86 · 10-07-2004, 02:18 PM

Quote:

Originally posted by fiomba
the 'mistake' has beeen made by C.

Perhaps you have declared a, b and c as integer

and so the b*7/c is an integer division which has 4 as answer (instead of 4.6666666...)

You must declare all your variables float or double
and write the equation like that:

a + 4. + b * 7. / c * 3. = 26.0

Actually, with the way that promotion in C works, you can still get the correct answer by only changing the 7 into 7. No need to change them all:

Code:

itsme@itsme:~/C$ cat stuff.c
#include <stdio.h>

int main(void)
{
  int a = 8, b = 10, c = 15;

  printf("%f\n", a + 4 + b * 7. / c * 3);
  return 0;
}
itsme@itsme:~/C$ ./stuff
26.000000