MPL Bytecode Compiler Code

16 lines (9 with data), 303 Bytes

HEAP=0

USEVEC(V,N) [HEAP=V;!V=N<<1;V!N=0]

MEMUSED(;P,R) [R=0;P=HEAP;!P@!P<0?[R-=!P;P-=!P],P+=!P;R]

GETVEC(N;V,R) [N=(N+2)<<1;V=HEAP;
  !V@[!V<0@V-=!V;R=V;!V>0@V+=!V;!R=V-R;N<=!R?[!(R+N)=!R-N;!R=-N;=R+2]]
]

FREEVEC(V) V?V!-1<0?V!-1=-V!-1

MALLOC(A) GETVEC((A-1)/2)
FREE(P) FREEVEC(P)