"CODE" 31201;
"PROCEDURE" LNG INT SUBTRACT(U,V,DIFFERENCE);
"INTEGER""ARRAY" U,V,DIFFERENCE;
"BEGIN""INTEGER" LU,LV,DIFF,I,T,J,CARRY;
   LU:=U[0]; LV:=V[0];
   "IF" LU<LV "OR" LU=LV "AND" U[1]<V[1] "THEN" DIFFERENCE[0]:=0 "ELSE"
   "BEGIN" DIFF:=LU - LV + 1; CARRY:=0;
      "FOR" I:=LU "STEP" -1 "UNTIL" DIFF "DO"
      "BEGIN" T:=U[I] - V[I-DIFF+1] + CARRY;
         CARRY:="IF" T<0 "THEN" -1 "ELSE" 0;
         DIFFERENCE[I]:=T - CARRY * 10 000 000
      "END";
      "FOR" I:=DIFF - 1 "STEP" -1 "UNTIL" 1 "DO"
      "BEGIN" T:=U[I] + CARRY; CARRY:="IF" T<0 "THEN" -1 "ELSE" 0;
         DIFFERENCE[I]:=T - CARRY * 10 000 000
      "END";
      "IF" CARRY=-1 "THEN"
      "BEGIN" DIFFERENCE[0]:=0; "GOTO" READY "END";
      I:=0; J:=LU;
      "FOR" I:=I+1 "WHILE" DIFFERENCE[I]=0 "AND" J>1 "DO" J:=J-1;
      DIFFERENCE[0]:=J;
      "IF" J<LU "THEN"
      "FOR" I:=1 "STEP" 1 "UNTIL" J "DO"
      DIFFERENCE[I]:=DIFFERENCE[LU+I-J]
   "END";
   READY:
"END" LNG INT SUBTRACT;
        "EOP"