0xcfe3: 0001    ; R2   ***R6***
0xcfe4: 0002    ; R1
0xcfe5: 0000    ; placeholder local variable    ***R5***
0xcfe6: cfec    ; frame pointer of sum_rec(2)
0xcfe7: 3032    ; return address
0xcfe8: 0000    ; return value
0xcfe9: 0001    ; parameter  = 1
----------------------------
0xcfea: 0002    ; R2
0xcfeb: 0003    ; R1
0xcfec: 0000    ; placeholder local variable
0xcfed: cff3    ; frame pointer of sum_rec(3)
0xcfee: 3032    ; return address
0xcfef: 0000    ; return value
0xcff0: 0002    ; parameter  = 2
----------------------------
0xcff1: 0003    ; R2
0xcff2: 0004    ; R1
0xcff3: 0000    ; placeholder local variable
0xcff4: cffa    ; frame pointer of sum_rec(4)
0xcff5: 3032    ; return address
0xcff6: 0000    ; return value
0xcff7: 0003    ; parameter  = 3
----------------------------
0xcff8: 0000    ; R2
0xcff9: 0004    ; R1
0xcffa: 0000    ; placeholder local variable
0xcffb: cfff    ; frame pointer of main
0xcffc: 3008    ; return address
0xcffd: 0000    ; return value
0xcffe: 0004    ; parameter  = 4
----------------------------
0xcfff: 0000    ; local variable "return"
0xd000: 0000    ; frame pointer of "caller to main"