Changeset c214a65 in mainline for kernel/genarch/src/drivers/ega/ega.c

Timestamp:

2009-02-27T13:30:20Z (16 years ago)

Author:

Martin Decky <martin@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

dbaaf0a

Parents:

c1f7f6ea

Message:

keep original contents of the EGA framebuffer,
make sure the cursor is on

File:

• kernel/genarch/src/drivers/ega/ega.c (modified) (3 diffs)

kernel/genarch/src/drivers/ega/ega.c

@@ -80 +80 @@
 }
 
+static void ega_show_cursor(void)
+{
+        pio_write_8(ega_base + EGA_INDEX_REG, 0x0a);
+        uint8_t stat = pio_read_8(ega_base + EGA_DATA_REG);
+        pio_write_8(ega_base + EGA_INDEX_REG, 0x0a);
+        pio_write_8(ega_base + EGA_DATA_REG, stat & (~(1 << 5)));
+}
+
 static void ega_move_cursor(void)
 {
-        pio_write_8(ega_base + EGA_INDEX_REG, 0xe);
+        pio_write_8(ega_base + EGA_INDEX_REG, 0x0e);
         pio_write_8(ega_base + EGA_DATA_REG, (uint8_t) ((ega_cursor >> 8) & 0xff));
-        pio_write_8(ega_base + EGA_INDEX_REG, 0xf);
+        pio_write_8(ega_base + EGA_INDEX_REG, 0x0f);
         pio_write_8(ega_base + EGA_DATA_REG, (uint8_t) (ega_cursor & 0xff));
+}
+
+static void ega_sync_cursor(void)
+{
+        pio_write_8(ega_base + EGA_INDEX_REG, 0x0e);
+        uint8_t hi = pio_read_8(ega_base + EGA_DATA_REG);
+        pio_write_8(ega_base + EGA_INDEX_REG, 0x0f);
+        uint8_t lo = pio_read_8(ega_base + EGA_DATA_REG);
+        
+        ega_cursor = (hi << 8) | lo;
+        if ((ega_cursor % EGA_COLS) != 0)
+                ega_cursor = (ega_cursor + EGA_COLS) - ega_cursor % EGA_COLS;
+        
+        ega_check_cursor();
+        ega_move_cursor();
+        ega_show_cursor();
 }
 
@@ -143 +167 @@
         videoram = (uint8_t *) hw_map(videoram_phys, EGA_VRAM_SIZE);
         
-        /* Clear the screen and set the cursor position. */
-        memsetw(videoram, EGA_SCREEN, 0x0720);
-        memsetw(backbuf, EGA_SCREEN, 0x0720);
-        ega_move_cursor();
+        /* Synchronize the back buffer and cursor position. */
+        memcpy(backbuf, videoram, EGA_VRAM_SIZE);
+        ega_sync_cursor();
         
         chardev_initialize("ega_out", &ega_console, &ega_ops);
@@ -163 +186 @@
         memcpy(videoram, backbuf, EGA_VRAM_SIZE);
         ega_move_cursor();
+        ega_show_cursor();
 }