Function: _>>=_
Section: symbolic_operators
C-Name: gshiftre
Prototype: &L
Help: x>>=y: shortcut for x=x>>y.
Description:
 (*small, small):small:parens             $1 >>= $(2)
 (*int, small):int:parens                 $1 = shifti($1, -$(2))
 (*mp, small):mp:parens                   $1 = mpshift($1, -$(2))
 (*gen, small):mp:parens                  $1 = gshift($1, -$(2))
