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### call a simple function, that sums its 2 arguments
## store sth at h1000 to later check if calee restored it properly
# 1 16-bit instruction
const h23
# 2 16-bit instructions
store h1000
# function arguments - each loaded with 1 16-bit instruction
const h32
const h14
# also 1 16-bit instruction
call 18
## this executes after return - store the computed difference at h400
# this takes 2 16-bit instructions
store h400
# and this takes 1 16-bit instruction
halt
# address 18 here
## function frame will look like this:
## *****higher addresses*****
## argument1
## argument2
## ...
## return address
## local1
## local2
## ...
## previous frame address
## *****lower addresses*****
## push the arguments out of r0 and r1 to memory (+ claim space for
## backed stack frame address and backed return address);
## if we had n local variables, we'd repeat that n more times
const 0
const 0
const 0
## with this we get the address to reference our locals from into r1
get_frame
tee
## we get our previous frame and back it up as first local
load h1000
store+ h0
## we now store our new function frame
store h1000
## here the actual function body starts
## fetch the first argument
load h1000
load+ hC
## fetch the second one
load h1000
load+ h8
sub
## function exit - store the result at the the top of current frame
load h1000
swap
store+ hC
## put the return address just below result
load h1000
tee
tee
load+ h4
store+ h8
## restore old frame
load+ 0
store h1000
## discard current frame
drop
drop
drop
drop
## return
ret
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