System information

; (ACCUMULATOR BITS ARE NUMBERED 7 6 5 4 3 2 1 0)
;
; IT MAY BE USEFUL TO FILTER OUT THE VARIOUS CONDITIONS,
; BUT WE WILL GET A PERMANENT ERROR MESSAGE IF IT IS NOT
; RECOVERABLE. IN ANY CASE, THE NOT READY CONDITION IS
; TREATED AS A SEPARATE CONDITION FOR LATER IMPROVEMENT
TRYCOUNT:
; REGISTER C CONTAINS RETRY COUNT, DECREMENT 'TIL ZERO
1838 0D DCR C
1839 C2F217 JNZ REWAIT ;FOR ANOTHER TRY
;
; CANNOT RECOVER FROM ERROR
183C 3E01 MVI A,1 ;ERROR CODE
183E C9 RET
;
; INTYPE, INBYTE, INSTAT READ DRIVE BANK 00 OR 10
183F 3A6618 INTYPE: LDA DBANK
1842 B7 ORA A
1843 C24918 JNZ INTYP1 ;SKIP TO BANK 10
1846 DB79 IN RTYPE
1848 C9 RET
1849 DB89 INTYP1: IN RTYPE+10H ;78 FOR 0,1 88 FOR 2,3
184B C9 RET
;
184C 3A6618 INBYTE: LDA DBANK
184F B7 ORA A
1850 C25618 JNZ INBYT1
1853 DB7B IN RBYTE
1855 C9 RET
1856 DB8B INBYT1: IN RBYTE+10H
1858 C9 RET
;
1859 3A6618 INSTAT: LDA DBANK
185C B7 ORA A
185D C26318 JNZ INSTA1
1860 DB78 IN DSTAT
1862 C9 RET
1863 DB88 INSTA1: IN DSTAT+10H
1865 C9 RET
;
;
;
; DATA AREAS (MUST BE IN RAM)
1866 00 DBANK: DB 0 ;DISK BANK 00 IF DRIVE 0,1
; 10 IF DRIVE 2,3
Appendix A : The MDS-800 BIOS CP/M Operating System Manual
A-13