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/*
* vga.c: fns for outputting strings to VGA display
*
* Copyright (c) 2010, Intel Corporation
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
* * Neither the name of the Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <config.h>
#include <efibase.h>
#include <types.h>
#include <stdbool.h>
#include <string.h>
#include <misc.h>
#include <io.h>
#include <vga.h>
static uint16_t * const screen = (uint16_t * const)VGA_BASE;
static __data uint8_t cursor_x, cursor_y;
static __data unsigned int num_lines;
uint8_t g_vga_delay = 0; /* default to no delay */
static inline void reset_screen(void)
{
memset(screen, 0, SCREEN_BUFFER);
cursor_x = 0;
cursor_y = 0;
num_lines = 0;
outb(CTL_ADDR_REG, START_ADD_HIGH_REG);
outb(CTL_DATA_REG, 0x00);
outb(CTL_ADDR_REG, START_ADD_LOW_REG);
outb(CTL_DATA_REG, 0x00);
}
static void scroll_screen(void)
{
long long x,y;
for ( y = 1; y < MAX_LINES; y++ ) {
for ( x = 0; x < MAX_COLS; x++ )
writew(VGA_ADDR(x, y-1), readw(VGA_ADDR(x, y)));
}
/* clear last line */
for ( x = 0; x < MAX_COLS; x++ )
writew(VGA_ADDR(x, MAX_LINES-1), 0x720);
}
static void __putc(uint8_t x, uint8_t y, int c)
{
screen[(y * MAX_COLS) + x] = (COLOR << 8) | c;
}
static void vga_putc(int c)
{
bool new_row = false;
switch ( c ) {
case '\n':
cursor_y++;
cursor_x = 0;
new_row = true;
break;
case '\r':
cursor_x = 0;
break;
case '\t':
cursor_x += 4;
break;
default:
__putc(cursor_x, cursor_y, c);
cursor_x++;
break;
}
if ( cursor_x >= MAX_COLS ) {
cursor_x %= MAX_COLS;
cursor_y++;
new_row = true;
}
if ( new_row ) {
num_lines++;
if ( cursor_y >= MAX_LINES ) {
scroll_screen();
cursor_y--;
}
/* (optionally) pause after every screenful */
if ( (num_lines % (MAX_LINES - 1)) == 0 && g_vga_delay > 0 )
delay(g_vga_delay * 1000);
}
}
void vga_init(void)
{
reset_screen();
}
void vga_puts(const char *s, unsigned int cnt)
{
while ( *s && cnt-- ) {
vga_putc(*s);
s++;
}
}
/*
* Local variables:
* mode: C
* c-set-style: "BSD"
* c-basic-offset: 4
* tab-width: 4
* indent-tabs-mode: nil
* End:
*/
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