; CP/M BIOS for avrcpm
; Copyright (C) 2010 Sprite_tm
;
; This program is free software: you can redistribute it and/or modify
; it under the terms of the GNU General Public License as published by
; the Free Software Foundation, either version 3 of the License, or
; (at your option) any later version.
;
; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
; GNU General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program. If not, see .
msize: equ 62 ;size of available RAM in k
bias: equ (msize-20) * 1024
ccp: equ $3400+bias ;base of cpm ccp
bdos: equ ccp+$806 ;base of bdos
bios: equ ccp+$1600 ;base of bios
cdisk: equ $0004 ;current disk number (0 ... 15)
iobyte: equ $0003 ;intel iobyte
buff: equ $0080 ;default buffer address
retry: equ 3 ;max retries on disk i/o before error
cr: equ 13
lf: equ 10
READ_FUNC: equ 7
WRITE_FUNC: equ 6
BOOT_FUNC: equ 5
HOME_FUNC: equ 4
org bios
nsects: equ ($-ccp)/128 ;warm start sector count
jp boot
wboote:
jp wboot
jp const
jp conin
jp conout
jp list
jp punch
jp reader
jp home
jp seldsk
jp settrk
jp setsec
jp setdma
jp read
jp write
jp listst
jp sectran
signon:
db cr,lf
db msize/10+'0'
db msize - (msize/10)*10 + '0' ;modulo doesn't work?
db "k cp/m vers 2.2"
db cr,lf,0
boot:
ld sp,buff
ld hl,signon
call prmsg
xor a
ld (iobyte),a
ld (cdisk),a
jp gocpm
wboot: ;re-load CP/M
ld sp,buff
ld a,1<= 26 then change tracks
jp c,load1
ld d,0
inc c
push bc
push de
push hl
ld b,0
call settrk
pop hl
pop de
pop bc
jp load1
gocpm:
ld a,0c3h
ld (0),a
ld hl,wboote
ld (1),hl
ld (5),a
ld hl,bdos
ld (6),hl
ld bc,buff
call setdma
ld a,(cdisk)
ld c,a
jp ccp
const:
in a,(0)
ret
conin:
in a,(0)
cp $ff
jp nz,conin
in a,(1)
ret
conout:
ld a,c
out (2),a
ret
list:
ret
listst:
ld a,0
ret
punch:
ret
reader:
ld a,$1F
ret
seldsk:
ld hl,0 ;error return code
ld a,c
out (15),a
in a,(15) ;querry, if disk exists
or a ;0 = disk is ok
ret nz
ld l,c
ld h,0
add hl,hl
add hl,hl
add hl,hl
add hl,hl ;*16
ld de,dpbase
add hl,de ;return disk parameter header address
ret
home:
ld a,1<