At 08:00 AM 3/6/97 PST, you wrote:
>Hi,
>
>I think I'm missing something very basic.  I'm using ByteCraft's MPC and
>the target controller is the PIC16C74A.  This macro is supposed to take
>2 unsigned 8-bit chars (h: high, l: low), concatenate them, and return
>the unsigned 16 bit result.  Instead, it's masking (zeroing) the high
>byte.
>
>#define WORD(h,l)   (((unsigned long)(h) << 8) | (unsigned char)(l))
>
>Thanks, Matt
>
I don't use the MPC compiler, but have you tried:
- extra brackets around the first cast & the "(h)", like this:
#define WORD(h,l)   ((((unsigned long)(h)) << 8) | (unsigned char)(l))

- using a different cast like (uint16) or (word), to see if the compiler is
only allowing 8 bits for the "long".

- casting the whole macro to ensure a 16 bit output:
#define WORD(h,l)   (unsigned long)(((unsigned long)(h) << 8) | \
                                     (unsigned char)(l))

IMHO, it seems there should be a much more efficient way to create a word
out of two bytes than this.  I'm curious as heck what the compiler gives
you for that macro.  Maybe it actually sets up a loop and shifts eight
times (gross!).  Trouble is, I can't think of any alternatives right now.
Anyone got ideas?

-Ed V.