alternative to nested #define statements

[mzimmers]

Hi -

Though this doesn't work, it's what I'd like to do. The LOAD32 macro accepts two 16-bit values and loads them into a 32-bit integer. The LOAD96 is attempting to do these three at a time (for coding convenience).

I know that the following code doesn't do what I want; I'm showing to demonstrate what I'd like to do:

#define LOAD32(x,y) (((int16_t) x << 16) | y)
#define LOAD96(x,y,z,t,u,v) (LOAD32(x,y),LOAD32(z,t),LOAD32(u,v)) 

Any ideas for alternatives on this?

[firedraco]

Use an inline function? Compilers are pretty good at figuring out when to inline them, so you generally don't really need to use macros for stuff like this.

[mzimmers]

I thought of that, but I'm initializing the array in its declaration. I don't know how I'd make LOAD96 a function for this purpose. Or, are you suggesting that I make LOAD32 the function?

This is what I tried with LOAD96, and it didn't work:

#define LOAD32(x,y) ((x << 16) | y)

uint32_t LOAD96(uint16_t x, 
				uint16_t y, 
				uint16_t z,
				uint16_t t,
				uint16_t u,
				uint16_t v);

uint32_t LOAD96(uint16_t x, 
				uint16_t y, 
				uint16_t z,
				uint16_t t,
				uint16_t u,
				uint16_t v)
{
	LOAD32(x,y);
	LOAD32(z,t);
	LOAD32(u,v);
	return 0;
}

[Duthomhas]

Are you trying to do something like this:

#define LOAD32(x,y) (((int16_t)(x)<< 16) | (y))
#define LOAD96(x,y,z,t,u,v) {LOAD32(x,y),LOAD32(z,t),LOAD32(u,v)} 

int16_t myfoo[ 3 ] = LOAD96(1,2, 3,4, a,b-15);

?

BTW, please take note of the changes I made.

Edit: Also, I think it is cleaner if you just use a little extra typing:

int16_t myfoo[ 3 ] = { LOAD32(1,2), LOAD32(3,4), LOAD32(a,b-15) };

[mzimmers]

That's sort of what I'm hoping for. I'll have an array definition that looks something like this:

	uint32_t	regs[3] = 
	{
		LOAD32(-21,3),
		LOAD32(-2,14),
		LOAD32(10,5)
	};

Except instead of 3 elements, it will have a few hundred, hence my desire for brevity. (One LOAD96 would replace 3 LOAD32s.)

But your point is well-taken; I could just put the LOAD32s three at a time on one line. You suppose that's probably a cleaner way to do it?

And, I will duplicate the changes you made to encapsulate the parameters.

Thanks.

[Duthomhas]

I know it is obnoxious, but clarity should trump brevity.

You could easily write a script to take a table of numbers and generate your array declaration for you.

[mzimmers]

Agreed. I think I'll just tough it out and manually populate the array, using the LOAD32 macro (at least that helps somewhat).

Thanks, Duoas...I'll consider this (re)solved.