6.1.1670
HOLD
 
CORE
 
( char -- )

Add char to the beginning of the pictured numeric output string. An ambiguous condition exists if HOLD executes outside of a <# #> delimited number conversion.

Testing:
: GP1 <# 41 HOLD 42 HOLD 0 0 #> S" BA" S= ;
T{ GP1 -> <TRUE> }T