com32/lib/sys/vesa/screencpy.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 2008 H. Peter Anvin - All Rights Reserved
   4  *
   5  *   Permission is hereby granted, free of charge, to any person
   6  *   obtaining a copy of this software and associated documentation
   7  *   files (the "Software"), to deal in the Software without
   8  *   restriction, including without limitation the rights to use,
   9  *   copy, modify, merge, publish, distribute, sublicense, and/or
  10  *   sell copies of the Software, and to permit persons to whom
  11  *   the Software is furnished to do so, subject to the following
  12  *   conditions:
  13  *
  14  *   The above copyright notice and this permission notice shall
  15  *   be included in all copies or substantial portions of the Software.
  16  *
  17  *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  18  *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
  19  *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  20  *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  21  *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  22  *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  23  *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  24  *   OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  * ----------------------------------------------------------------------- */
  27
  28 #include <inttypes.h>
  29 #include <minmax.h>
  30 #include <klibc/compiler.h>
  31 #include <string.h>
  32 #include <com32.h>
  33 #include <ilog2.h>
  34 #include "vesa.h"
  35 #include "video.h"
  36
  37 static struct win_info {
  38     char *win_base;
  39     size_t win_pos;
  40     size_t win_size;
  41     int win_gshift;
  42     int win_num;
  43 } wi;
  44
  45 void __vesacon_init_copy_to_screen(void)
  46 {
  47     struct vesa_mode_info *const mi = &__vesa_info.mi;
  48     int winn;
  49
  50     if (mi->mode_attr & 0x0080) {
  51         /* Linear frame buffer */
  52
  53         wi.win_base = (char *)mi->lfb_ptr;
  54         wi.win_size = 1 << 31;  /* 2 GB, i.e. one huge window */
  55         wi.win_pos = 0;         /* Already positioned (only one position...) */
  56         wi.win_num = -1;        /* Not a window */
  57     } else {
  58         /* Paged frame buffer */
  59
  60         /* We have already tested that *one* of these is usable */
  61         if ((mi->win_attr[0] & 0x05) == 0x05 && mi->win_seg[0])
  62             winn = 0;
  63         else
  64             winn = 1;
  65
  66         wi.win_num = winn;
  67         wi.win_base = (char *)(mi->win_seg[winn] << 4);
  68         wi.win_size = mi->win_size << 10;
  69         wi.win_gshift = ilog2(mi->win_grain) + 10;
  70         wi.win_pos = -1;        /* Undefined position */
  71     }
  72 }
  73
  74 static void set_window_pos(size_t win_pos)
  75 {
  76     static com32sys_t ireg;
  77
  78     wi.win_pos = win_pos;
  79
  80     if (wi.win_num < 0)
  81         return;                 /* This should never happen... */
  82
  83     ireg.eax.w[0] = 0x4F05;
  84     ireg.ebx.b[0] = wi.win_num;
  85     ireg.edx.w[0] = win_pos >> wi.win_gshift;
  86
  87     __intcall(0x10, &ireg, NULL);
  88 }
  89
  90 void __vesacon_copy_to_screen(size_t dst, const uint32_t * src, size_t npixels)
  91 {
  92     size_t win_pos, win_off;
  93     size_t win_size = wi.win_size;
  94     size_t omask = win_size - 1;
  95     char *win_base = wi.win_base;
  96     size_t l;
  97     size_t bytes = npixels * __vesacon_bytes_per_pixel;
  98     char rowbuf[bytes + 4] __aligned(4);
  99     const char *s;
 100
 101     s = (const char *)__vesacon_format_pixels(rowbuf, src, npixels);
 102
 103     while (bytes) {
 104         win_off = dst & omask;
 105         win_pos = dst & ~omask;
 106
 107         if (__unlikely(win_pos != wi.win_pos))
 108             set_window_pos(win_pos);
 109
 110         l = min(bytes, win_size - win_off);
 111         memcpy(win_base + win_off, s, l);
 112
 113         bytes -= l;
 114         s += l;
 115         dst += l;
 116     }
 117 }