System information

; skeletal cbios for first level of CP/M 2.0 alteration
;
msize equ 20 ;cp/m version memory size in kilobytes
;
; "bias" is address offset from 3400h for memory systems
; than 16k (referred to as"b" throughout the text)
;
bias equ (msize-20)*1024
ccp equ 3400h+bias ;base of ccp
bdos equ ccp+806h ;base of bdos
bios equ ccp+1600h ;base of bios
cdisk equ 0004h ;current disk number 0=a,... l5=p
iobyte equ 0003h ;intel i/o byte
;
org bios ;origin of this program
nsects equ ($-ccp)/128 ;warm start sector count
;
; jump vector for individual subroutines
;
jmp boot ;cold start
wboote: jmp wboot ;warm start
jmp const ;console status
jmp conin ;console character in
jmp conout ;console character out
jmp list ;list character out
jmp punch ;punch character out
jmp reader ;reader character out
jmp home ;move head to home position
jmp seldsk ;select disk
jmp settrk ;set track number
jmp setsec ;set sector number
jmp setdma ;set dma address
jmp read ;read disk
mp write ;write disk
jmp listst ;return list status
jmp sectran ;sector translate
;
; fixed data tables for four-drive standard
; ibm-compatible 8" disks
;
; disk Parameter header for disk 00
dpbase: dw trans, 0000h
dw 0000h, 0000h
dw dirbf, dpblk
dw chk00, all00
Appendix A : The MDS-800 BIOS CP/M Operating System Manual
B-1