User`s guide

;************************************
;* *
;* load SP, Set-up file for random access *
;* *
;************************************
0100 313703 lxi sp,stack
; version3.1?
0103 0E0c mvi c,version
0105 cD0500 call bdos
0108 FE20 cp 31h ;version 3.1 or better?
0i0a D21601 jnc versok
; bad version, message and go back
0l0D 118102 lxi d,badver
0110 cD3102 call Print
0113 c30000 jmp reboot
versok :
; correct versionfor random access
0116 QEof mvi c,openf;open default fcb
0118 3a5D00rdname: lda fcb+1
011b FE20 cPi ' '
011d c22c01 jnz opfile
0120 11E002 lxi d,entmsg
0123 cD3102 call Print
0126 cD2002 call Parse
0129 c31801 jmP rdname
012c iisc00 opfile: lxi d,fcb
012F cd0so0 call bdos
0132 3c inr a ;err 255 becomes zero
0133 c24501 jnz ready
; cannot open file, so create it
0136 0E16 mvi c,makef
0138 115c00 lxi d,fcb
013b cd0so0 call bdos
013E 3c inr a ;err 255 becomes zero
013F c24b01 jnz ready
; cannot create file, directory full
0142 iia00z lxi d,nospace
0145 cd3102 call print
0148 c30000 jmp reboot ;back to ccP
4-12
4.3 A Sample Random Access Program CP/M 3 Programmer's Guide