GN_Wbe, write byte at extended address

RST 20H, DEFW $4009

IN:

     BDE = pointer to extended address (B = 0 -> DE is local)
     A = character to write

     Fc = 0

     A.BCDEHL/IXIY same
     .F....../.... different

Bugs:

Related calls:

GN_Cme, compare null-terminated strings, one local, one extended
GN_Rbe, read byte at extended address
OS_Bde, copy bytes to extended address
OS_Bhl, copy bytes from extended address