avrcpm/cpm/ipl.asm

   1 ;    CP/M IPL 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 org $2000
  18         ; IPL for the CP/M-emu in an AVR. Loads CPM from the 'disk' from
  19         ; track 0 sector 2 to track 1 sector 26.
  20
  21 READ_FUNC:  equ 7
  22 WRITE_FUNC: equ 6
  23 BOOT_FUNC:  equ 5
  24 HOME_FUNC:  equ 4
  25
  26         ld sp,$1000
  27
  28         call printipl
  29
  30
  31         ld b,49
  32         ld de,$0001
  33         ld hl,$3400+$A800
  34 loadloop:
  35         ld a,d ;track
  36         out (16),a
  37         ld a,e ; sector (base-0)
  38         out (18),a
  39         ld a,l ;dma L
  40         out (20),a
  41         ld a,h ;dma H
  42         out (21),a
  43         ld a,1<<READ_FUNC
  44         out (22),a
  45
  46         push bc
  47         ld bc,$80
  48         add hl,bc
  49         pop bc
  50
  51         inc e
  52         ld a,e
  53         cp 26
  54         jp nz,noNextTrack
  55
  56         inc d
  57         ld e,0
  58
  59 noNextTrack:
  60
  61         dec b
  62         jp nz,loadloop
  63
  64         jp $4A00+$A800
  65
  66 printipl:
  67         ld a,'i'
  68         out (2),a
  69         ld a,'p'
  70         out (2),a
  71         ld a,'l'
  72         out (2),a
  73         ld a,13
  74         out (2),a
  75         ld a,10
  76         out (2),a
  77         ret
  78
  79 end