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 cr:     equ     13
  21 lf:     equ     10
  22
  23 READ_FUNC:  equ 7
  24 WRITE_FUNC: equ 6
  25 BOOT_FUNC:  equ 5
  26 HOME_FUNC:  equ 4
  27
  28         org $2000
  29         ; IPL for the CP/M-emu in an AVR. Loads CPM from the 'disk' from
  30         ; track 0 sector 2 to track 1 sector 26.
  31
  32         ld sp,$1000
  33         ld hl,msgipl
  34         call prmsg
  35
  36         ld b,51
  37         ld de,$0001
  38         ld hl,$3400+$A800
  39 loadloop:
  40         ld a,d ;track
  41         out (16),a
  42         ld a,e ; sector (base-0)
  43         out (18),a
  44         ld a,l ;dma L
  45         out (20),a
  46         ld a,h ;dma H
  47         out (21),a
  48         ld a,1<<READ_FUNC
  49         out (22),a
  50
  51         push bc
  52         ld bc,$80
  53         add hl,bc
  54         pop bc
  55
  56         inc e
  57         ld a,e
  58         cp 26
  59         jp nz,noNextTrack
  60
  61         inc d
  62         ld e,0
  63
  64 noNextTrack:
  65
  66         dec b
  67         jp nz,loadloop
  68
  69         jp $4A00+$A800
  70
  71 prmsg:
  72         ld      a,(hl)
  73         or      a
  74         ret     z
  75         out     (2),a
  76         inc     hl
  77         jp      prmsg
  78
  79 msgipl: db      cr,lf
  80         db      "ipl"
  81         db      0
  82
  83 end