GN_Wbe, Write byte at extended address

Register parameters

RST 20H, DEFW $4009
IN:
     BDE = pointer to extended address (B = 0 -> DE is local)
     A = character to write
OUT:
     Fc = 0

Registers changed after return:
     A.BCDEHL/IXIY same
     .F....../.... different

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