\xfe!0\xff\xfe" \x01\xe3\xcd\x03\x800\xf2v
Note that non-ascii characters in the above source code will be escaped (such as \x9f).
Disassemble:
ORG 00000H CP 021H ;0000 FE 21 . ! JR NC,$+1 ;0002 30 FF 0 . CP 022H ;0004 FE 22 . " JR NZ,$+3 ;0006 20 01 . EX (SP),HL ;0008 E3 . CALL 08003H ;0009 CD 03 80 . . . JR NC,$-12 ;000C 30 F2 0 . HALT ;000E 76 V