xref: /freebsd/lib/libvgl/simple.c (revision a93ca07acd64b432e6f6a5e350b12522c87e29f7) 
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1991-1997 Søren Schmidt
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer
12  *    in this position and unchanged.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. The name of the author may not be used to endorse or promote products
17  *    derived from this software without specific prior written permission
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include <signal.h>
35 #include <sys/fbio.h>
36 #include <sys/kbio.h>
37 #include <sys/endian.h>
38 #include "vgl.h"
39 
40 static int VGLBlank;
41 static byte VGLBorderColor;
42 static byte VGLSavePaletteRed[256];
43 static byte VGLSavePaletteGreen[256];
44 static byte VGLSavePaletteBlue[256];
45 
46 #define ABS(a)		(((a)<0) ? -(a) : (a))
47 #define SGN(a)		(((a)<0) ? -1 : 1)
48 #define min(x, y)	(((x) < (y)) ? (x) : (y))
49 #define max(x, y)	(((x) > (y)) ? (x) : (y))
50 
51 void
52 VGLSetXY(VGLBitmap *object, int x, int y, u_long color)
53 {
54   int offset;
55 
56   VGLCheckSwitch();
57   if (x>=0 && x<object->VXsize && y>=0 && y<object->VYsize) {
58     if (object == VGLDisplay)
59       VGLSetXY(&VGLVDisplay, x, y, color);
60     if (object->Type == MEMBUF ||
61         !VGLMouseFreeze(x, y, 1, 1, 0x80000000 | color)) {
62       offset = (y * object->VXsize + x) * object->PixelBytes;
63       switch (object->Type) {
64       case VIDBUF8S:
65       case VIDBUF16S:
66       case VIDBUF24S:
67       case VIDBUF32S:
68         offset = VGLSetSegment(offset);
69         /* FALLTHROUGH */
70       case MEMBUF:
71       case VIDBUF8:
72       case VIDBUF16:
73       case VIDBUF24:
74       case VIDBUF32:
75         color = htole32(color);
76         switch (object->PixelBytes) {
77         case 1:
78           memcpy(&object->Bitmap[offset], &color, 1);
79           break;
80         case 2:
81           memcpy(&object->Bitmap[offset], &color, 2);
82           break;
83         case 3:
84           memcpy(&object->Bitmap[offset], &color, 3);
85           break;
86         case 4:
87           memcpy(&object->Bitmap[offset], &color, 4);
88           break;
89         }
90         break;
91       case VIDBUF8X:
92         outb(0x3c4, 0x02);
93         outb(0x3c5, 0x01 << (x&0x3));
94 	object->Bitmap[(unsigned)(VGLAdpInfo.va_line_width*y)+(x/4)] = ((byte)color);
95 	break;
96       case VIDBUF4S:
97 	offset = VGLSetSegment(y*VGLAdpInfo.va_line_width + x/8);
98 	goto set_planar;
99       case VIDBUF4:
100 	offset = y*VGLAdpInfo.va_line_width + x/8;
101 set_planar:
102         outb(0x3c4, 0x02); outb(0x3c5, 0x0f);
103         outb(0x3ce, 0x00); outb(0x3cf, (byte)color & 0x0f);	/* set/reset */
104         outb(0x3ce, 0x01); outb(0x3cf, 0x0f);		/* set/reset enable */
105         outb(0x3ce, 0x08); outb(0x3cf, 0x80 >> (x%8));	/* bit mask */
106 	object->Bitmap[offset] |= (byte)color;
107       }
108     }
109     if (object->Type != MEMBUF)
110       VGLMouseUnFreeze();
111   }
112 }
113 
114 static u_long
115 __VGLGetXY(VGLBitmap *object, int x, int y)
116 {
117   int offset;
118   u_long color;
119 
120   offset = (y * object->VXsize + x) * object->PixelBytes;
121   switch (object->PixelBytes) {
122   case 1:
123     memcpy(&color, &object->Bitmap[offset], 1);
124     return le32toh(color) & 0xff;
125   case 2:
126     memcpy(&color, &object->Bitmap[offset], 2);
127     return le32toh(color) & 0xffff;
128   case 3:
129     memcpy(&color, &object->Bitmap[offset], 3);
130     return le32toh(color) & 0xffffff;
131   case 4:
132     memcpy(&color, &object->Bitmap[offset], 4);
133     return le32toh(color);
134   }
135   return 0;		/* invalid */
136 }
137 
138 u_long
139 VGLGetXY(VGLBitmap *object, int x, int y)
140 {
141   VGLCheckSwitch();
142   if (x<0 || x>=object->VXsize || y<0 || y>=object->VYsize)
143     return 0;
144   if (object == VGLDisplay)
145     object = &VGLVDisplay;
146   if (object->Type != MEMBUF)
147     return 0;		/* invalid */
148   return __VGLGetXY(object, x, y);
149 }
150 
151  /*
152   * Symmetric Double Step Line Algorithm by Brian Wyvill from
153   * "Graphics Gems", Academic Press, 1990.
154   */
155 
156 #define SL_SWAP(a,b)           {a^=b; b^=a; a^=b;}
157 #define SL_ABSOLUTE(i,j,k)     ( (i-j)*(k = ( (i-j)<0 ? -1 : 1)))
158 
159 void
160 plot(VGLBitmap * object, int x, int y, int flag, u_long color)
161 {
162   /* non-zero flag indicates the pixels need swapping back. */
163   if (flag)
164     VGLSetXY(object, y, x, color);
165   else
166     VGLSetXY(object, x, y, color);
167 }
168 
169 
170 void
171 VGLLine(VGLBitmap *object, int x1, int y1, int x2, int y2, u_long color)
172 {
173   int dx, dy, incr1, incr2, D, x, y, xend, c, pixels_left;
174   int sign_x, sign_y, step, reverse, i;
175 
176   dx = SL_ABSOLUTE(x2, x1, sign_x);
177   dy = SL_ABSOLUTE(y2, y1, sign_y);
178   /* decide increment sign by the slope sign */
179   if (sign_x == sign_y)
180     step = 1;
181   else
182     step = -1;
183 
184   if (dy > dx) {	/* chooses axis of greatest movement (make dx) */
185     SL_SWAP(x1, y1);
186     SL_SWAP(x2, y2);
187     SL_SWAP(dx, dy);
188     reverse = 1;
189   } else
190     reverse = 0;
191   /* note error check for dx==0 should be included here */
192   if (x1 > x2) {      /* start from the smaller coordinate */
193     x = x2;
194     y = y2;
195 /*  x1 = x1;
196     y1 = y1; */
197   } else {
198     x = x1;
199     y = y1;
200     x1 = x2;
201     y1 = y2;
202   }
203 
204 
205   /* Note dx=n implies 0 - n or (dx+1) pixels to be set */
206   /* Go round loop dx/4 times then plot last 0,1,2 or 3 pixels */
207   /* In fact (dx-1)/4 as 2 pixels are already plotted */
208   xend = (dx - 1) / 4;
209   pixels_left = (dx - 1) % 4;  /* number of pixels left over at the
210            * end */
211   plot(object, x, y, reverse, color);
212   if (pixels_left < 0)
213     return;      /* plot only one pixel for zero length
214            * vectors */
215   plot(object, x1, y1, reverse, color);  /* plot first two points */
216   incr2 = 4 * dy - 2 * dx;
217   if (incr2 < 0) {    /* slope less than 1/2 */
218     c = 2 * dy;
219     incr1 = 2 * c;
220     D = incr1 - dx;
221 
222     for (i = 0; i < xend; i++) {  /* plotting loop */
223       ++x;
224       --x1;
225       if (D < 0) {
226         /* pattern 1 forwards */
227         plot(object, x, y, reverse, color);
228         plot(object, ++x, y, reverse, color);
229         /* pattern 1 backwards */
230         plot(object, x1, y1, reverse, color);
231         plot(object, --x1, y1, reverse, color);
232         D += incr1;
233       } else {
234         if (D < c) {
235           /* pattern 2 forwards */
236           plot(object, x, y, reverse, color);
237           plot(object, ++x, y += step, reverse,
238               color);
239           /* pattern 2 backwards */
240           plot(object, x1, y1, reverse, color);
241           plot(object, --x1, y1 -= step, reverse,
242               color);
243         } else {
244           /* pattern 3 forwards */
245           plot(object, x, y += step, reverse, color);
246           plot(object, ++x, y, reverse, color);
247           /* pattern 3 backwards */
248           plot(object, x1, y1 -= step, reverse,
249               color);
250           plot(object, --x1, y1, reverse, color);
251         }
252         D += incr2;
253       }
254     }      /* end for */
255 
256     /* plot last pattern */
257     if (pixels_left) {
258       if (D < 0) {
259         plot(object, ++x, y, reverse, color);  /* pattern 1 */
260         if (pixels_left > 1)
261           plot(object, ++x, y, reverse, color);
262         if (pixels_left > 2)
263           plot(object, --x1, y1, reverse, color);
264       } else {
265         if (D < c) {
266           plot(object, ++x, y, reverse, color);  /* pattern 2  */
267           if (pixels_left > 1)
268             plot(object, ++x, y += step, reverse, color);
269           if (pixels_left > 2)
270             plot(object, --x1, y1, reverse, color);
271         } else {
272           /* pattern 3 */
273           plot(object, ++x, y += step, reverse, color);
274           if (pixels_left > 1)
275             plot(object, ++x, y, reverse, color);
276           if (pixels_left > 2)
277             plot(object, --x1, y1 -= step, reverse, color);
278         }
279       }
280     }      /* end if pixels_left */
281   }
282   /* end slope < 1/2 */
283   else {        /* slope greater than 1/2 */
284     c = 2 * (dy - dx);
285     incr1 = 2 * c;
286     D = incr1 + dx;
287     for (i = 0; i < xend; i++) {
288       ++x;
289       --x1;
290       if (D > 0) {
291         /* pattern 4 forwards */
292         plot(object, x, y += step, reverse, color);
293         plot(object, ++x, y += step, reverse, color);
294         /* pattern 4 backwards */
295         plot(object, x1, y1 -= step, reverse, color);
296         plot(object, --x1, y1 -= step, reverse, color);
297         D += incr1;
298       } else {
299         if (D < c) {
300           /* pattern 2 forwards */
301           plot(object, x, y, reverse, color);
302           plot(object, ++x, y += step, reverse,
303               color);
304 
305           /* pattern 2 backwards */
306           plot(object, x1, y1, reverse, color);
307           plot(object, --x1, y1 -= step, reverse,
308               color);
309         } else {
310           /* pattern 3 forwards */
311           plot(object, x, y += step, reverse, color);
312           plot(object, ++x, y, reverse, color);
313           /* pattern 3 backwards */
314           plot(object, x1, y1 -= step, reverse, color);
315           plot(object, --x1, y1, reverse, color);
316         }
317         D += incr2;
318       }
319     }      /* end for */
320     /* plot last pattern */
321     if (pixels_left) {
322       if (D > 0) {
323         plot(object, ++x, y += step, reverse, color);  /* pattern 4 */
324         if (pixels_left > 1)
325           plot(object, ++x, y += step, reverse,
326               color);
327         if (pixels_left > 2)
328           plot(object, --x1, y1 -= step, reverse,
329               color);
330       } else {
331         if (D < c) {
332           plot(object, ++x, y, reverse, color);  /* pattern 2  */
333           if (pixels_left > 1)
334             plot(object, ++x, y += step, reverse, color);
335           if (pixels_left > 2)
336             plot(object, --x1, y1, reverse, color);
337         } else {
338           /* pattern 3 */
339           plot(object, ++x, y += step, reverse, color);
340           if (pixels_left > 1)
341             plot(object, ++x, y, reverse, color);
342           if (pixels_left > 2) {
343             if (D > c)  /* step 3 */
344               plot(object, --x1, y1 -= step, reverse, color);
345             else  /* step 2 */
346               plot(object, --x1, y1, reverse, color);
347           }
348         }
349       }
350     }
351   }
352 }
353 
354 void
355 VGLBox(VGLBitmap *object, int x1, int y1, int x2, int y2, u_long color)
356 {
357   VGLLine(object, x1, y1, x2, y1, color);
358   VGLLine(object, x2, y1, x2, y2, color);
359   VGLLine(object, x2, y2, x1, y2, color);
360   VGLLine(object, x1, y2, x1, y1, color);
361 }
362 
363 void
364 VGLFilledBox(VGLBitmap *object, int x1, int y1, int x2, int y2, u_long color)
365 {
366   int y;
367 
368   for (y=y1; y<=y2; y++) VGLLine(object, x1, y, x2, y, color);
369 }
370 
371 static inline void
372 set4pixels(VGLBitmap *object, int x, int y, int xc, int yc, u_long color)
373 {
374   if (x!=0) {
375     VGLSetXY(object, xc+x, yc+y, color);
376     VGLSetXY(object, xc-x, yc+y, color);
377     if (y!=0) {
378       VGLSetXY(object, xc+x, yc-y, color);
379       VGLSetXY(object, xc-x, yc-y, color);
380     }
381   }
382   else {
383     VGLSetXY(object, xc, yc+y, color);
384     if (y!=0)
385       VGLSetXY(object, xc, yc-y, color);
386   }
387 }
388 
389 void
390 VGLEllipse(VGLBitmap *object, int xc, int yc, int a, int b, u_long color)
391 {
392   int x = 0, y = b, asq = a*a, asq2 = a*a*2, bsq = b*b;
393   int bsq2 = b*b*2, d = bsq-asq*b+asq/4, dx = 0, dy = asq2*b;
394 
395   while (dx<dy) {
396     set4pixels(object, x, y, xc, yc, color);
397     if (d>0) {
398       y--; dy-=asq2; d-=dy;
399     }
400     x++; dx+=bsq2; d+=bsq+dx;
401   }
402   d+=(3*(asq-bsq)/2-(dx+dy))/2;
403   while (y>=0) {
404     set4pixels(object, x, y, xc, yc, color);
405     if (d<0) {
406       x++; dx+=bsq2; d+=dx;
407     }
408     y--; dy-=asq2; d+=asq-dy;
409   }
410 }
411 
412 static inline void
413 set2lines(VGLBitmap *object, int x, int y, int xc, int yc, u_long color)
414 {
415   if (x!=0) {
416     VGLLine(object, xc+x, yc+y, xc-x, yc+y, color);
417     if (y!=0)
418       VGLLine(object, xc+x, yc-y, xc-x, yc-y, color);
419   }
420   else {
421     VGLLine(object, xc, yc+y, xc, yc-y, color);
422   }
423 }
424 
425 void
426 VGLFilledEllipse(VGLBitmap *object, int xc, int yc, int a, int b, u_long color)
427 {
428   int x = 0, y = b, asq = a*a, asq2 = a*a*2, bsq = b*b;
429   int bsq2 = b*b*2, d = bsq-asq*b+asq/4, dx = 0, dy = asq2*b;
430 
431   while (dx<dy) {
432     set2lines(object, x, y, xc, yc, color);
433     if (d>0) {
434       y--; dy-=asq2; d-=dy;
435     }
436     x++; dx+=bsq2; d+=bsq+dx;
437   }
438   d+=(3*(asq-bsq)/2-(dx+dy))/2;
439   while (y>=0) {
440     set2lines(object, x, y, xc, yc, color);
441     if (d<0) {
442       x++; dx+=bsq2; d+=dx;
443     }
444     y--; dy-=asq2; d+=asq-dy;
445   }
446 }
447 
448 void
449 VGLClear(VGLBitmap *object, u_long color)
450 {
451   VGLBitmap src;
452   int offset;
453   int len;
454   int i;
455 
456   VGLCheckSwitch();
457   if (object == VGLDisplay) {
458     VGLMouseFreeze(0, 0, object->Xsize, object->Ysize, color);
459     VGLClear(&VGLVDisplay, color);
460   } else if (object->Type != MEMBUF)
461     return;		/* invalid */
462   switch (object->Type) {
463   case MEMBUF:
464   case VIDBUF8:
465   case VIDBUF8S:
466   case VIDBUF16:
467   case VIDBUF16S:
468   case VIDBUF24:
469   case VIDBUF24S:
470   case VIDBUF32:
471   case VIDBUF32S:
472     src.Type = MEMBUF;
473     src.Xsize = object->Xsize;
474     src.VXsize = object->VXsize;
475     src.Ysize = 1;
476     src.VYsize = 1;
477     src.Xorigin = 0;
478     src.Yorigin = 0;
479     src.Bitmap = alloca(object->VXsize * object->PixelBytes);
480     src.PixelBytes = object->PixelBytes;
481     color = htole32(color);
482     for (i = 0; i < object->VXsize; i++)
483       bcopy(&color, src.Bitmap + i * object->PixelBytes, object->PixelBytes);
484     for (i = 0; i < object->VYsize; i++)
485       __VGLBitmapCopy(&src, 0, 0, object, 0, i, object->VXsize, 1);
486     break;
487 
488   case VIDBUF8X:
489     /* XXX works only for Xsize % 4 = 0 */
490     outb(0x3c6, 0xff);
491     outb(0x3c4, 0x02); outb(0x3c5, 0x0f);
492     memset(object->Bitmap, (byte)color, VGLAdpInfo.va_line_width*object->VYsize);
493     break;
494 
495   case VIDBUF4:
496   case VIDBUF4S:
497     /* XXX works only for Xsize % 8 = 0 */
498     outb(0x3c4, 0x02); outb(0x3c5, 0x0f);
499     outb(0x3ce, 0x05); outb(0x3cf, 0x02);		/* mode 2 */
500     outb(0x3ce, 0x01); outb(0x3cf, 0x00);		/* set/reset enable */
501     outb(0x3ce, 0x08); outb(0x3cf, 0xff);		/* bit mask */
502     for (offset = 0; offset < VGLAdpInfo.va_line_width*object->VYsize; ) {
503       VGLSetSegment(offset);
504       len = min(object->VXsize*object->VYsize - offset,
505 		VGLAdpInfo.va_window_size);
506       memset(object->Bitmap, (byte)color, len);
507       offset += len;
508     }
509     outb(0x3ce, 0x05); outb(0x3cf, 0x00);
510     break;
511   }
512   if (object == VGLDisplay)
513     VGLMouseUnFreeze();
514 }
515 
516 static inline u_long
517 VGLrgbToNative(uint16_t r, uint16_t g, uint16_t b)
518 {
519   int nr, ng, nb;
520 
521   nr = VGLModeInfo.vi_pixel_fsizes[2];
522   ng = VGLModeInfo.vi_pixel_fsizes[1];
523   nb = VGLModeInfo.vi_pixel_fsizes[0];
524   return (r >> (16 - nr) << (ng + nb)) | (g >> (16 - ng) << nb) |
525 	 (b >> (16 - nb) << 0);
526 }
527 
528 u_long
529 VGLrgb332ToNative(byte c)
530 {
531   uint16_t r, g, b;
532 
533   /* 3:3:2 to 16:16:16 */
534   r = ((c & 0xe0) >> 5) * 0xffff / 7;
535   g = ((c & 0x1c) >> 2) * 0xffff / 7;
536   b = ((c & 0x03) >> 0) * 0xffff / 3;
537 
538   return VGLrgbToNative(r, g, b);
539 }
540 
541 void
542 VGLRestorePalette()
543 {
544   int i;
545 
546   if (VGLModeInfo.vi_mem_model == V_INFO_MM_DIRECT)
547     return;
548   outb(0x3C6, 0xFF);
549   inb(0x3DA);
550   outb(0x3C8, 0x00);
551   for (i=0; i<256; i++) {
552     outb(0x3C9, VGLSavePaletteRed[i]);
553     inb(0x84);
554     outb(0x3C9, VGLSavePaletteGreen[i]);
555     inb(0x84);
556     outb(0x3C9, VGLSavePaletteBlue[i]);
557     inb(0x84);
558   }
559   inb(0x3DA);
560   outb(0x3C0, 0x20);
561 }
562 
563 void
564 VGLSavePalette()
565 {
566   int i;
567 
568   if (VGLModeInfo.vi_mem_model == V_INFO_MM_DIRECT)
569     return;
570   outb(0x3C6, 0xFF);
571   inb(0x3DA);
572   outb(0x3C7, 0x00);
573   for (i=0; i<256; i++) {
574     VGLSavePaletteRed[i] = inb(0x3C9);
575     inb(0x84);
576     VGLSavePaletteGreen[i] = inb(0x3C9);
577     inb(0x84);
578     VGLSavePaletteBlue[i] = inb(0x3C9);
579     inb(0x84);
580   }
581   inb(0x3DA);
582   outb(0x3C0, 0x20);
583 }
584 
585 void
586 VGLSetPalette(byte *red, byte *green, byte *blue)
587 {
588   int i;
589 
590   if (VGLModeInfo.vi_mem_model == V_INFO_MM_DIRECT)
591     return;
592   for (i=0; i<256; i++) {
593     VGLSavePaletteRed[i] = red[i];
594     VGLSavePaletteGreen[i] = green[i];
595     VGLSavePaletteBlue[i] = blue[i];
596   }
597   VGLCheckSwitch();
598   outb(0x3C6, 0xFF);
599   inb(0x3DA);
600   outb(0x3C8, 0x00);
601   for (i=0; i<256; i++) {
602     outb(0x3C9, VGLSavePaletteRed[i]);
603     inb(0x84);
604     outb(0x3C9, VGLSavePaletteGreen[i]);
605     inb(0x84);
606     outb(0x3C9, VGLSavePaletteBlue[i]);
607     inb(0x84);
608   }
609   inb(0x3DA);
610   outb(0x3C0, 0x20);
611 }
612 
613 void
614 VGLSetPaletteIndex(byte color, byte red, byte green, byte blue)
615 {
616   if (VGLModeInfo.vi_mem_model == V_INFO_MM_DIRECT)
617     return;
618   VGLSavePaletteRed[color] = red;
619   VGLSavePaletteGreen[color] = green;
620   VGLSavePaletteBlue[color] = blue;
621   VGLCheckSwitch();
622   outb(0x3C6, 0xFF);
623   inb(0x3DA);
624   outb(0x3C8, color);
625   outb(0x3C9, red); outb(0x3C9, green); outb(0x3C9, blue);
626   inb(0x3DA);
627   outb(0x3C0, 0x20);
628 }
629 
630 void
631 VGLRestoreBorder(void)
632 {
633   VGLSetBorder(VGLBorderColor);
634 }
635 
636 void
637 VGLSetBorder(byte color)
638 {
639   if (VGLModeInfo.vi_mem_model == V_INFO_MM_DIRECT && ioctl(0, KDENABIO, 0))
640     return;
641   VGLCheckSwitch();
642   inb(0x3DA);
643   outb(0x3C0,0x11); outb(0x3C0, color);
644   inb(0x3DA);
645   outb(0x3C0, 0x20);
646   VGLBorderColor = color;
647   if (VGLModeInfo.vi_mem_model == V_INFO_MM_DIRECT)
648     ioctl(0, KDDISABIO, 0);
649 }
650 
651 void
652 VGLRestoreBlank(void)
653 {
654   VGLBlankDisplay(VGLBlank);
655 }
656 
657 void
658 VGLBlankDisplay(int blank)
659 {
660   byte val;
661 
662   if (VGLModeInfo.vi_mem_model == V_INFO_MM_DIRECT && ioctl(0, KDENABIO, 0))
663     return;
664   VGLCheckSwitch();
665   outb(0x3C4, 0x01); val = inb(0x3C5); outb(0x3C4, 0x01);
666   outb(0x3C5, ((blank) ? (val |= 0x20) : (val &= 0xDF)));
667   VGLBlank = blank;
668   if (VGLModeInfo.vi_mem_model == V_INFO_MM_DIRECT)
669     ioctl(0, KDDISABIO, 0);
670 }
671