I want to replace the last parameter of this multistruct with a macro.

const struct SaveSectionLocation gSaveSectionLocations[] =
{
	{((u8 *) &gSaveBlock2),							0x890},
	{((u8 *) &gSaveBlock1) + 0xF80 * 0,			0xF80},
	{((u8 *) &gSaveBlock1) + 0xF80 * 1,			0xF80},
	{((u8 *) &gSaveBlock1) + 0xF80 * 2,			0xF80},
	{((u8 *) &gSaveBlock1) + 0xF80 * 3,			0xC40},
	{((u8 *) &gPokemonStorage) + 0xF80 * 0,	0xF80},
	{((u8 *) &gPokemonStorage) + 0xF80 * 1,	0xF80},
	{((u8 *) &gPokemonStorage) + 0xF80 * 2,	0xF80},
	{((u8 *) &gPokemonStorage) + 0xF80 * 3,	0xF80},
	{((u8 *) &gPokemonStorage) + 0xF80 * 4,	0xF80},
	{((u8 *) &gPokemonStorage) + 0xF80 * 5,	0xF80},
	{((u8 *) &gPokemonStorage) + 0xF80 * 6,	0xF80},
	{((u8 *) &gPokemonStorage) + 0xF80 * 7,	0xF80},
	{((u8 *) &gPokemonStorage) + 0xF80 * 8,	0x7D0}
};

For the intended macro being GETCHUNKSIZE(chunk, n), The formula to figure out the constant is:

if (sizeof(chunk) - (0xF80 * (n - 1))) >= 0xF80
    return 0xF80
else
    sizeof(chunk) // can optimize

Can I define this using a macro? the check itself isn't in the compiled ROM, these are hardcoded attributes. However, I would like to calculate them on the fly using a macro/define. Any way to do this?