So, can only shoot/throw things in cardinal directions?
That... limits things somewhat...
You are silly. Again.
Diagonals
exist in XCEF (And FE in general) HOWEVER, the distance (hereby termed as 'range'--the distance between the starting point and endpoint) is calculated cardinally.
Let's mark that example out in code, so y'all can see it.
o o o o o
o o x o o
o x @ x o
o o x o o
o o o o o
See the adventurer above! In generally all roguelikes, they have a range of 1 tile! The same goes for FireEmblem, and its associated spinoffs, like XCEF! The range is denoted in the x's. The person is obviously the @.
Now let's give em a recurve bow (as seen in the many FEFs around) [range 2]
o o x o o
o x o x o
x o @ o x
o x o x o
o o x o o
See the range in how it can get diagonals--but requiring 2 moves, cardinally?
As a mirror, the Crossbow has a range of 1-2.
o o x o o
o x x x o
x x @ x x
o x x x o
o o x o o
So you can see minimal and maximal differences.
Let's extend that to a Customized Machine Gun with a range of 1-4!
o o o o x o o o o
o o o x x x o o o
o o x x x x x o o
o x x x x x x x o
x x x x @ x x x x
o x x x x x x x o
o o x x x x x o o
o o o x x x o o o
o o o o x o o o o
Damn good aim, soldier.
AS A RULE BY THUMB: Think of your range as a 'pyramid' or a quadralateral. Assign the number to stretch out cardinally, then draw diagonal lines from the MAXIMUM range tip in the cardinal direction to each other tip--and that's how far you can attack.