What's wrong with this code?

[Sean Eskapp]

I had some code that was segfaulting, so I rewrote the basic idea as a
fibonacci function, and lo and behold, it still segfaults. Why, and how to fix?
begin 644 main.d
M8VQA<W, at 1FEB#0I[#0H)<')I=F%T92!C;VYS="!&:6(J(&QE9G0L(')I9VAT
M.PT*"0T*"71H:7,H*0T*"7L-"@D);&5F="`](')I9VAT(#T@;G5L;#L-"@E]
M#0H)#0H)=&AI<RAI;B!&:6(@;&5F="P@:6X at 1FEB(')I9VAT*0T*"7L-"@D)
M=&AI<RYL969T(#T@)FQE9G0[#0H)"71H:7,N<FEG:'0@/2`F<FEG:'0[#0H)
M?0T*"0T*"6-O;G-T(&EN="!%=F%L=6%T92 at I#0H)>PT*"0EI9BAL969T(#T]
M(&YU;&PI#0H)"0ER971U<FX@,3L-"@D)#0H)"7)E='5R;B!L969T+D5V86QU
M871E*"D@*R!R:6=H="Y%=F%L=6%T92 at I.PT*"7T-"GT-"@T*1FEB($)A<BAI
M;G0@;BD-"GL-"@EI9BAN(#T](#`@?'P@;B`]/2`Q*0T*"0ER971U<FX@;F5W
M($9I8CL-"@D-"@ER971U<FX@;F5W($9I8BA"87(H;B`M(#$I+"!"87(H;B`M
M(#(I*3L-"GT-"@T*=F]I9"!M86EN*"D-"GL-"@EA=71O('@@/2!"87(H-2D[
5#0H)>"Y%=F%L=6%T92 at I.PT*?0T*
`
end