arch/i386-pc/kernel/kernel_debug.c

   1 /*
   2     Copyright © 1995-2014, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include <bootconsole.h>
   7 #include <string.h>
   8
   9 #include "kernel_base.h"
  10 #include "kernel_debug.h"
  11 #include "kernel_intern.h"
  12
  13 #define __save_flags(x)         __asm__ __volatile__("pushf ; pop %0":"=g" (x): /* no input */)
  14 #define __restore_flags(x)      __asm__ __volatile__("push %0 ; popf": /* no output */ :"g" (x):"memory", "cc")
  15 #define __cli()                 __asm__ __volatile__("cli": : :"memory")
  16 #define __sti()                 __asm__ __volatile__("sti": : :"memory")
  17
  18 __attribute__((section(".data"))) static unsigned int debug_y_resolution = 0;
  19 __attribute__((section(".data"))) static void *debug_framebuffer = NULL;
  20
  21 int krnPutC(int c, struct KernelBase *KernelBase)
  22 {
  23     unsigned long flags;
  24
  25     __save_flags(flags);
  26
  27     /*
  28      * stegerg: Don't use Disable/Enable, because we want  interrupt enabled flag
  29      * to stay the same as it was before the Disable() call
  30      */
  31     __cli();
  32
  33     /*
  34      * If we got 0x03, this means graphics driver wants to take over the screen.
  35      * If VESA hack is activated, it will use only upper half of the screen
  36      * because y resolution was adjusted.
  37      * In our turn, we need to switch over to lower half.
  38      * VESA hack is supported only on graphical console of course. And do not
  39      * expect it to work with native mode video driver. :)
  40      */
  41     if ((c == 0x03) && (scr_Type == SCR_GFX) && debug_framebuffer)
  42     {
  43         /* Reinitialize boot console with decreased height */
  44         scr_FrameBuffer = debug_framebuffer;
  45         fb_Resize(debug_y_resolution);
  46     }
  47     else
  48         con_Putc(c);
  49
  50     /*
  51      * Interrupt flag is stored in flags - if it was enabled before,
  52      * it will be renabled when the flags are restored
  53      */
  54     __restore_flags(flags);
  55
  56     return 1;
  57 }
  58
  59 void vesahack_Init(char *cmdline, struct vbe_mode *vmode)
  60 {
  61     if (cmdline && vmode && vmode->phys_base && strstr(cmdline, "vesahack"))
  62     {
  63         bug("[Kernel] VESA debugging hack activated\n");
  64
  65         /*
  66          * VESA hack.
  67          * It divides screen height by 2 and increments framebuffer pointer.
  68          * This allows VESA driver to use only upper half of the screen, while
  69          * lower half will still be used for debug output.
  70          */
  71         vmode->y_resolution >>= 1;
  72
  73         debug_y_resolution = vmode->y_resolution;
  74         debug_framebuffer  = (void *)(unsigned long)vmode->phys_base + vmode->y_resolution * vmode->bytes_per_scanline;
  75     }
  76 }