avrcpm/z80/bios.asm

   1 ;    CP/M BIOS for avrcpm
   2 ;    Copyright (C) 2010 Sprite_tm
   3 ;
   4 ;    This program is free software: you can redistribute it and/or modify
   5 ;    it under the terms of the GNU General Public License as published by
   6 ;    the Free Software Foundation, either version 3 of the License, or
   7 ;    (at your option) any later version.
   8 ;
   9 ;    This program is distributed in the hope that it will be useful,
  10 ;    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 ;    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 ;    GNU General Public License for more details.
  13 ;
  14 ;    You should have received a copy of the GNU General Public License
  15 ;    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17
  18 org $4A00+$A800
  19         jp boot
  20         jp wboot
  21         jp const
  22         jp conin
  23         jp conout
  24         jp list
  25         jp punch
  26         jp reader
  27         jp home
  28         jp seldsk
  29         jp settrk
  30         jp setsec
  31         jp setdma
  32         jp read
  33         jp write
  34         jp listst
  35         jp sectran
  36
  37 boot:
  38         xor a
  39         ld (3),a
  40         ld (4),a
  41
  42 wboot:
  43         ld a,'B'
  44         out (2),a
  45         ld a,'I'
  46         out (2),a
  47         ld a,'O'
  48         out (2),a
  49         ld a,'S'
  50         out (2),a
  51         ld a,13
  52         out (2),a
  53         ld a,10
  54         out (2),a
  55
  56         ;ToDo: re-load CP/M
  57
  58         ld hl,firstBytes
  59         ld de,0
  60         ld c,100 ;7
  61 fbloop:
  62         ld a,(hl)
  63         ld (de),a
  64         inc hl
  65         inc de
  66         dec c
  67         jp nz,fbloop
  68
  69         ld c,0
  70         jp $3400+$A800
  71
  72 const:
  73         in a,(0)
  74         ret
  75
  76 conin:
  77         in a,(0)
  78         cp $ff
  79         jp nz,conin
  80
  81         in a,(1)
  82         ret
  83
  84 conout:
  85         push af
  86         ld a,c
  87         out (2),a
  88         pop af
  89         ret
  90
  91 list:
  92         ret
  93
  94 punch:
  95         ret
  96
  97 reader:
  98         ld a,$1F
  99         ret
 100
 101 home:
 102         push af
 103         ld a,0
 104         out (16),a
 105         pop af
 106         ret
 107
 108 seldsk:
 109         push af
 110         ld a,c
 111         cp 0
 112         jp nz,seldsk_na
 113         ld hl,dph
 114         pop af
 115         ret
 116 seldsk_na:
 117         ld hl,0
 118         pop af
 119         ret
 120
 121 settrk:
 122         push af
 123         ld a,c
 124         out (16),a
 125         pop af
 126         ret
 127
 128 setsec:
 129         push af
 130         ld a,c
 131         out (18),a
 132         pop af
 133         ret
 134
 135 setdma:
 136         push af
 137         ld a,c
 138         out (20),a
 139         ld a,b
 140         out (21),a
 141         pop af
 142         ret
 143
 144 read:
 145         ld a,1
 146         out (22),a
 147         ld a,0
 148         ret
 149
 150 write:
 151         ld a,2
 152         out (22),a
 153         ld a,0
 154         ret
 155
 156 listst:
 157         ld a,0
 158         ret
 159
 160 sectran:
 161         ;translate sector bc using table at de, res into hl
 162         ;not implemented :)
 163         ld h,b
 164         ld l,c
 165         ret
 166
 167
 168 firstBytes:
 169         jp $4A03+$A800  ;JMP WBOOT
 170         db 0                    ;IOBYTE
 171         db 0                    ;user:drive
 172         jp $3C06+$A800  ;JMP BDOS
 173
 174 ;Disk Parameter Header
 175 dph:
 176         dw trans ;XLT: Address of translation table
 177         dw 0 ;000: Scratchpad
 178         dw 0 ;000: Scratchpad
 179         dw 0 ;000: Scratchpad
 180         dw dirbuf ;DIRBUF: Address of a dirbuff scratchpad
 181         dw dpb ;DPB: Address of a disk parameter block
 182         dw chk ;CSV: Address of scratchpad area for changed disks
 183         dw all ;ALV: Address of an allocation info sratchpad
 184
 185 dpb:
 186         dw 26 ;SPT: sectors per track
 187         db 3 ;BSH: data allocation block shift factor
 188         db 7 ;BLM: Data Allocation Mask
 189         db 0 ;Extent mask
 190         dw 242 ;DSM: Disk storage capacity
 191         dw 63 ;DRM, no of directory entries
 192         db 192 ;AL0
 193         db 0 ;AL1
 194         dw 16 ;CKS, size of dir check vector
 195         dw 2 ;OFF, no of reserved tracks
 196
 197 trans:
 198         db 0,1,2,3,4,5,6,7,8,9
 199         db 10,11,12,13,14,15,16,17,18,19
 200         db 19,20,21,22,23,24,25,26
 201
 202 dirbuf:
 203         ds 128
 204
 205 chk:
 206         ds 16
 207
 208 all:
 209         ds 31
 210
 211 end