Support the linear frame buffer if available

If the linear frame buffer is in use, the entire frame buffer is
visible all at once, and no calls to the window function are needed.

diff --git a/sys/msdos/vidvesa.c b/sys/msdos/vidvesa.c
index 07a76219e12af5e1b1caf98817c03046a699f037..9061d7ee7ae914f4a5ce2b7b062cc38b4e10c0ce 100644 (file)
--- a/sys/msdos/vidvesa.c
+++ b/sys/msdos/vidvesa.c
@@ -123,6 +123,7 @@ static int vesa_write_win; /* Select the write window */
 static unsigned long vesa_win_func;
 static unsigned long vesa_win_pos[2]; /* Window position */
 static unsigned long vesa_win_addr[2]; /* Window physical address */
+static unsigned long vesa_segment;  /* Selector of linear frame buffer */
 static unsigned long vesa_win_size; /* Window size */
 static unsigned long vesa_win_gran; /* Window granularity */
 static unsigned char vesa_pixel_size;
@@ -222,6 +223,20 @@ error:
     return FALSE;
 }
 
+static unsigned
+vesa_map_frame_buffer(unsigned phys_addr, unsigned size)
+{
+    __dpmi_meminfo info;
+    int rc;
+
+    info.handle = 0;
+    info.address = phys_addr;
+    info.size = size;
+    rc = __dpmi_physical_address_mapping(&info);
+
+    return rc == 0 ? info.address : 0;
+}
+
 /* Set the memory window and return the offset */
 static unsigned long
 vesa_SetWindow(window, offset)
@@ -276,31 +291,66 @@ unsigned x, y;
     unsigned long addr, color;
     unsigned i;
 
-    switch (vesa_pixel_size) {
-    case 8:
-        addr = vesa_SetWindow(vesa_read_win, offset);
-        color = _farpeekb(_dos_ds, addr);
-        break;
+    if (vesa_segment != 0) {
+        /* Linear frame buffer in use */
+        switch (vesa_pixel_size) {
+        case 8:
+            color = _farpeekb(vesa_segment, offset);
+            break;
 
-    case 15:
-    case 16:
-        addr = vesa_SetWindow(vesa_read_win, offset);
-        color = _farpeekw(_dos_ds, addr);
-        break;
+        case 15:
+        case 16:
+            color = _farpeekw(vesa_segment, offset);
+            break;
+
+        case 24:
+            /* Don't cross a 4 byte boundary if it can be avoided */
+            if (offset & 1) {
+                color = _farpeekl(vesa_segment, offset - 1) >> 8;
+            } else {
+                color = _farpeekl(vesa_segment, offset) & 0xFFFFFFFF;
+            }
+            break;
 
-    case 24:
-        /* Pixel may cross a window boundary */
-        color = 0;
-        for (i = 0; i < 3; ++i) {
-            addr = vesa_SetWindow(vesa_read_win, offset + i);
-            color |= (unsigned long) _farpeekb(_dos_ds, addr) << (i * 8);
+        case 32:
+            color = _farpeekl(vesa_segment, offset);
+            break;
+
+        default: /* Shouldn't happen */
+            color = 0;
+            break;
         }
-        break;
+    } else {
+        switch (vesa_pixel_size) {
+        case 8:
+            addr = vesa_SetWindow(vesa_read_win, offset);
+            color = _farpeekb(_dos_ds, addr);
+            break;
 
-    case 32:
-        addr = vesa_SetWindow(vesa_read_win, offset);
-        color = _farpeekl(_dos_ds, addr);
-        break;
+        case 15:
+        case 16:
+            addr = vesa_SetWindow(vesa_read_win, offset);
+            color = _farpeekw(_dos_ds, addr);
+            break;
+
+        case 24:
+            /* Pixel may cross a window boundary */
+            color = 0;
+            for (i = 0; i < 3; ++i) {
+                addr = vesa_SetWindow(vesa_read_win, offset + i);
+                color |= (unsigned long) _farpeekb(_dos_ds, addr) << (i * 8);
+            }
+            break;
+
+        case 32:
+            addr = vesa_SetWindow(vesa_read_win, offset);
+            color = _farpeekl(_dos_ds, addr);
+            break;
+
+        default: /* Shouldn't happen */
+            color = 0;
+            break;
+        }
     }
     return color;
 }
@@ -314,30 +364,62 @@ unsigned long color;
     unsigned long addr;
     unsigned i;
 
-    switch (vesa_pixel_size) {
-    case 8:
-        addr = vesa_SetWindow(vesa_write_win, offset);
-        _farpokeb(_dos_ds, addr, color);
-        break;
+    if (vesa_segment != 0) {
+        /* Linear frame buffer in use */
+        switch (vesa_pixel_size) {
+        case 8:
+            _farpokeb(vesa_segment, offset, color);
+            break;
 
-    case 15:
-    case 16:
-        addr = vesa_SetWindow(vesa_write_win, offset);
-        _farpokew(_dos_ds, addr, color);
-        break;
+        case 15:
+        case 16:
+            _farpokew(vesa_segment, offset, color);
+            break;
 
-    case 24:
-        /* Pixel may cross a window boundary */
-        for (i = 0; i < 3; ++i) {
-            addr = vesa_SetWindow(vesa_read_win, offset + i);
-            _farpokeb(_dos_ds, addr, (unsigned char) (color >> (i * 8)));
+        case 24:
+            if (offset & 1) {
+                _farpokeb(vesa_segment, offset + 0, color & 0xFF);
+                _farpokew(vesa_segment, offset + 1, color >> 8);
+            } else {
+                _farpokew(vesa_segment, offset + 0, color & 0xFFFF);
+                _farpokeb(vesa_segment, offset + 2, color >> 16);
+            }
+            break;
+
+        case 32:
+            _farpokel(vesa_segment, offset, color);
+            break;
+
+        default: /* Shouldn't happen */
+            color = 0;
+            break;
         }
-        break;
+    } else {
+        switch (vesa_pixel_size) {
+        case 8:
+            addr = vesa_SetWindow(vesa_write_win, offset);
+            _farpokeb(_dos_ds, addr, color);
+            break;
 
-    case 32:
-        addr = vesa_SetWindow(vesa_write_win, offset);
-        _farpokel(_dos_ds, addr, color);
-        break;
+        case 15:
+        case 16:
+            addr = vesa_SetWindow(vesa_write_win, offset);
+            _farpokew(_dos_ds, addr, color);
+            break;
+
+        case 24:
+            /* Pixel may cross a window boundary */
+            for (i = 0; i < 3; ++i) {
+                addr = vesa_SetWindow(vesa_write_win, offset + i);
+                _farpokeb(_dos_ds, addr, (unsigned char) (color >> (i * 8)));
+            }
+            break;
+
+        case 32:
+            addr = vesa_SetWindow(vesa_write_win, offset);
+            _farpokel(_dos_ds, addr, color);
+            break;
+        }
     }
 }
 
@@ -1034,6 +1116,25 @@ vesa_detect()
         goto error; /* Shouldn't happen */
     }
 
+    /* Configure a linear frame buffer if we have it */
+    if ((mode_info.ModeAttributes & 0x80) != 0) {
+        unsigned sel = vesa_segment;
+        unsigned win_size = mode_info.BytesPerScanLine * mode_info.YResolution;
+        unsigned addr = vesa_map_frame_buffer(mode_info.PhysBasePtr, win_size);
+        if (sel == 0) {
+            sel = __dpmi_allocate_ldt_descriptors(1);
+        }
+        if (addr != 0) {
+            vesa_mode |= 0x4000;
+            vesa_segment = sel;
+            __dpmi_set_segment_base_address(sel, addr);
+            __dpmi_set_segment_limit(sel, (win_size - 1) | 0xFFF);
+        } else {
+            __dpmi_free_ldt_descriptor(sel);
+            vesa_segment = 0;
+        }
+    }
+
     __dpmi_free_dos_memory(vbe_info_sel);
     return TRUE;