Bug or Feature?

[na_th_an]

Hmmm. I'm afraid not. This is a feature, the same way as in C, due to truncation. c1 is always uByte and you can't gues in compile time it's value, so there might be a chance that, effectively, c1 * 9 > 255. C does the same. What you get is (PEEK(x) * 9 bAND 0xFFh)

We already discussed this. It's not the same way as C. In fact, C does the calculation correctly. In both z88dk and gcc, this program:

Code:

#include <stdio.h>

int main (void) {
  unsigned char c = 255;        // This will have to do for PEEK 3 ;-)
  printf ("%d * 3 = %d\n", c, c * 9);
  return 0;
}

Outputs

Code:

255 * 3 = 2295

I still find zxb behaviour quite confusing regarding the lack of type promotion. I shouldn't have to typecast this:

Code:

Dim numAttrs as uInteger
Dim numLines as uByte
...
numAttrs = 32 * numLines

as I don't have to do it in either freeBasic or C... But in ZX Basic I have to explicitly typecast numLines to uInteger for it to work correctly, which I find quite awkward.