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