x86 machine code, 39 bytes
00000000: 6a01 5e6a 055f 5251 31c0 39d1 0f44 c601 j.^j._RQ1.9..D..
00000010: d139 cf0f 44c6 595a 29d1 83f9 050f 44c6 .9..D.YZ).....D.
00000020: 83f9 fb0f 44c6 c3 ....D..
Assembly
section .text
global func
func: ;inputs int32_t ecx and edx
push 0x1
pop esi
push 0x5
pop edi
push edx
push ecx
xor eax, eax
;ecx==edx?
cmp ecx, edx
cmove eax, esi
;ecx+edx==5?
add ecx, edx
cmp edi, ecx
cmove eax, esi
;ecx-edx==5?
pop ecx
pop edx
sub ecx, edx
cmp ecx, 5
;ecx-edx==-5?
cmove eax, esi
cmp ecx, -5
cmove eax, esi
ret
Edit: fixed bash stderr errors on TIO