FreeDOS/kernel/serial.asm

183 lines
4.5 KiB
NASM

;
; File:
; serial.asm
; Description:
; Serial device driver
;
; Copyright (c) 1998
; Pasquale J. Villani
; All Rights Reserved
;
; This file is part of DOS-C.
;
; DOS-C 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
; 2, or (at your option) any later version.
;
; DOS-C 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 DOS-C; see the file COPYING. If not,
; write to the Free Software Foundation, 675 Mass Ave,
; Cambridge, MA 02139, USA.
;
; $Header$
;
%include "io.inc"
segment _IO_FIXED_DATA
global ComTable
ComTable db 0Ah
dw _IOExit
dw _IOExit
dw _IOExit
dw _IOCommandError
dw ComRead
dw ComNdRead
dw ComInStat
dw ComInpFlush
dw ComWrite
dw ComWrite
dw ComOutStat
segment _IO_TEXT
extern CommonNdRdExit:wrt LGROUP
ComRead:
jcxz ComRd3
call GetComStat
xor ax,ax
xchg [bx],al
or al,al
jnz ComRd2
ComRd1:
call BiosRdCom
or ah,ah ; timeout?
js ComRd1 ; yes, try again
ComRd2:
stosb
loop ComRd1
ComRd3:
jmp _IOExit
BiosRdCom:
mov ah,2
call ComIOCall
test ah,0Eh
jz BiosRdRetn
add sp,byte 2
xor al,al
or al,0B0h
jmp _IOErrCnt
BiosRdRetn:
retn
ComInStat: ; similar to ComNdRead but returns no char, only flags
call GetComStat
mov al,[bx]
or al,al
jnz ComInAvail
call ComRdStatus
test ah,1 ; char waiting
jz ComNdRtn
; test al,20h ; DSR (why do we test this?)
; jz ComNdRtn
ComInAvail: jmp _IOExit ; return "ready"
ComNdRead:
call GetComStat
mov al,[bx]
or al,al
jnz ComNdRd1
call ComRdStatus
test ah,1 ; char waiting
jz ComNdRtn
; test al,20h ; DSR (why do we test this?)
; jz ComNdRtn
call BiosRdCom
call GetComStat
mov [bx],al
ComNdRd1:
jmp CommonNdRdExit ; return that char
ComNdRtn:
jmp _IODone ; return "busy"
ComOutStat:
call ComRdStatus
test al,20h
jz ComNdRtn
test ah,20h
jz ComNdRtn
jmp _IOExit ; return "ready"
ComRdStatus:
mov ah,3
call ComIOCall
retn
ComIOCall:
call GetUnitNum
int 14h ; RS-232 get char al, ah=return status
retn
ComInpFlush:
call GetComStat
mov byte [bx],0
jmp _IOExit
ComWrite:
jcxz ComRd3
ComWr1:
mov al,[es:di]
inc di
mov ah,1
call ComIOCall
test ah,80h
jz ComWr2
mov al,0Ah
jmp _IOErrCnt
ComWr2:
loop ComWr1
jmp _IOExit
GetComStat:
call GetUnitNum
mov bx,dx
add bx,ComStatArray
retn
segment _DATA
ComStatArray db 0, 0, 0, 0
; Revision 1.2 1999/08/10 17:57:13 jprice
; ror4 2011-02 patch
;
; Revision 1.1.1.1 1999/03/29 15:41:31 jprice
; New version without IPL.SYS
;
; Revision 1.1 1999/02/08 05:55:57 jprice
; Added Pat's 1937 kernel patches
;
; EndLog
;