Serial output console (disable by default)

When enabled with current settings,
it will work on com1 using a 115200 baud connection
8 bits words, no parity bit, 1 stop bit

git-svn-id: svn://kolibrios.org@1043 a494cfbc-eb01-0410-851d-a64ba20cac60

kernel/trunk/kernel.asm

@@ -17,6 +17,7 @@
 ;; Sergey Semyonov (Serge)
 ;; Johnny_B
 ;; SPraid (simba)
+;; Hidnplayr
 ;;
 ;; Data in this file was originally part of MenuetOS project which is
 ;; distributed under the terms of GNU GPL. It is modified and redistributed as
@@ -60,6 +61,9 @@ $Revision$
 
 USE_COM_IRQ	equ 1	   ; make irq 3 and irq 4 available for PCI devices
 
+; Enabling the next line will enable serial output console
+;debug_com_base  equ 0x3f8  ; 0x3f8 is com1, 0x2f8 is com2, 0x3e8 is com3, 0x2e8 is com4, no irq's are used
+
 include "proc32.inc"
 include "kglobals.inc"
 include "lang.inc"
@@ -870,6 +874,48 @@ first_app_found:
 	call  set_lights
      ;// mike.dld ]
 
+
+; Setup serial output console (if enabled)
+
+if defined debug_com_base
+
+	; enable Divisor latch
+
+	mov	dx, debug_com_base+3
+	mov	al, 1 shl 7
+	out	dx, al
+
+	; Set speed to 115200 baud (max speed)
+
+	mov	dx, debug_com_base
+	mov	al, 0x01
+	out	dx, al
+
+	mov	dx, debug_com_base+1
+	mov	al, 0x00
+	out	dx, al
+
+	; No parity, 8bits words, one stop bit, dlab bit back to 0
+
+	mov	dx, debug_com_base+3
+	mov	al, 3
+	out	dx, al
+
+	; disable interrupts
+
+	mov	dx, debug_com_base+1
+	mov	al, 0
+	out	dx, al
+
+	; clear +  enable fifo (64 bits)
+
+	mov	dx, debug_com_base+2
+	mov	al, 0x7 + 1 shl 5
+	out	dx, al
+
+
+end if
+
 ; START MULTITASKING
 
 if preboot_blogesc
@@ -4763,6 +4809,23 @@ sys_msg_board:
 	cmp	eax, 1
 	jne	.smbl1
 
+if defined debug_com_base
+
+	push	dx ax
+
+       @@:				; Wait for empty transmit register  (yes, this slows down system..)
+	mov	dx, debug_com_base+5
+	in	al, dx
+	test	al, 1 shl 5
+	jz	@r
+
+	mov	dx, debug_com_base	; Output the byte
+	mov	al, bl
+	out	dx, al
+
+	pop	ax dx
+
+end if
 
 	mov	[msg_board_data+ecx],bl
 	inc	ecx