System information

; disk parameter header for disk 01
dw trans, 0000h
dw 0000h, 0000h
dw dirbf, dpblk
dw chk01, all01
; disk parameter header for disk 02
dw trans, 0000h
dw 0000h, 0000h
dw dirbf, dpblk
dw chk02, all02
; disk parameter header for disk 03
dw trans, 0000h
dw 0000h, 0000h
dw dirbf, dpblk
dw chk03, all03
;
; sector translate vector
trans: db 1, 7, 13, 19 ;sectors 1, 2, 3, 4
db 25, 5, 11, 17 ;sectors 5, 6, 7, 6
db 23, 3, 9, 15 ;sectors 9, 10, 11, 12
db 21, 2, 8, 14 ;sectors 13, 14, 15, 16
db 20, 26, 6, 12 ;sectors 17, 18, 19, 20
db 18, 24, 4, 10 ;sectors 21, 22, 23, 24
db 16, 22 ;sectors 25, 26
;
dpblk: ;disk parameter block, common to all disks
dw 26 ;sectors per track
db 3 ;block shift factor
db 7 ;block mask
db 0 ;null mask
dw 242 ;disk size-1
dw 63 ;directory max
db 192 ;alloc 0
db 0 ;alloc 1
dw 16 ;check size
dw 2 ;track offset
;
; end of fixed tables
;
; individual subroutines to perform each function
boot: ;simplest case is to just perform parameter initialization
xra a ;zero in the accum
sta iobyte ;clear the iobyte
sta cdisk ;select disk zero
jmp gocpm ;initialize and go to cp/m
Appendix B : A Sekletal CBIOS CP/M Operating System Manual
B-2