2* 2! 2+
2* ( a -- a*2 )  
ansi .6.1.0320 <CORE>
multiplies the value with two - but it does actually use a shift1 to be faster 
 simulate:
  : 2* 2 * ; ( canonic) : 2* 1 LSHIFT ; ( usual)

reference: p4_two_star in ../src/core.c:0408, export CO 2*