I made a LUA script to show if a given instruction can be reached starting at $0081.
target = 0xae
lengths={2,2,2,2,2,2,2,2,1,2,1,2,3,3,3,3,
2,2,0,2,2,2,2,2,1,3,1,3,3,3,3,3}
while true do
addr=0x81
j=0
y=0
b=0
while y<16 do
op=memory.readbyte(addr)
l=lengths[AND(op,31)+1]
color='#ffffff'
if op==0x20 or op==0x4c then color='#ff0000' l=3 b=b+1 end
if l==0 or AND(op,0x8f)==2 or op==0x40 or op==0x60 then color='#ff0000' l=1 b=b+1 end
if AND(op,31)==0x10 then color='#c0c000' end
if addr==target then color='#00ff00' end
for i=0,l-1 do
x=memory.readbyte(addr)
if b>1 then color='#502020' end
gui.text(j*20,y*8,string.format('%02X',x),color)
color='#bf9090'
addr=addr+1
j=j+1
if j==12 then j=0 y=y+1 end
if b==1 then b=2 end
end
if addr>target or addr<0x80 then break end
end
FCEU.frameadvance()
end
This requires a recent version of FCEUX (2.0.3 doesn't support colored text).