System information

exitm
endif
;; otherwise, high order 1 not found yet
blkshf set blkshf+1
blkmsk set (blkmsk shl 1) or 1
blkval set blkval/2
endm
;; generate the extent mask byte
blkval set bls/1024 ;;number of kilobytes/block
extmsk set 0 ;;fill from right with 1's
rept 16
if blkval=1
exitm
endif
;; otherwise more to shift
extmsk set (extmsk shl 1) or 1
blkval set blkval/2
endm
;; may be double byte allocation
if (dks) > 256
extmsk set (extmsk shr 1)
endif
;; may be optional [0] in last position
if not nul k16
extmsk set k16
endif
;; now generate directory reservation bit vector
dirrem set dir ;;# remaining to process
dirbks set bls/32 ;;number of entries per block
dirblk set 0 ;;fill with 1's on each loop
rept 16
if dirrem=0
exitm
endif
;; not complete, iterate once again
;; shift right and add 1 high order bit
dirblk set (dirblk shr 1) or 8000h
if dirrem > dirbks
dirrem set dirrem-dirbks
else
dirrem set 0
endif
endm
dpbhdr dn ;;generate equ $
ddw %sectors,<;sec per track>
Appendix F : CP/M Disk Definition Library CP/M Operating System Manual
F-4