[Qemu-devel] [PATCH] vga: Implement blinking of text cursor

[Jan Kiszka <jan.kiszka@siemens.com>]

Let the text cursor blink at 5 Hz. No timer is used, instead we rely on
the fact that the display is updated periodically.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 hw/vga.c     |   14 +++++++++++++-
 hw/vga_int.h |    2 ++
 2 files changed, 15 insertions(+), 1 deletions(-)

diff --git a/hw/vga.c b/hw/vga.c
index acb3f7d..f22c4d9 100644
--- a/hw/vga.c
+++ b/hw/vga.c
@@ -38,6 +38,8 @@
 
 //#define DEBUG_BOCHS_VBE
 
+#define VGA_TEXT_CURSOR_PERIOD  200
+
 /*
  * Video Graphics Array (VGA)
  *
@@ -1300,6 +1302,7 @@ static void vga_draw_text(VGACommonState *s, int full_update)
     uint32_t *ch_attr_ptr;
     vga_draw_glyph8_func *vga_draw_glyph8;
     vga_draw_glyph9_func *vga_draw_glyph9;
+    int64_t now = qemu_get_clock_ms(vm_clock);
 
     /* compute font data address (in plane 2) */
     v = s->sr[VGA_SEQ_CHARACTER_MAP];
@@ -1370,6 +1373,11 @@ static void vga_draw_text(VGACommonState *s, int full_update)
         s->cursor_end = s->cr[VGA_CRTC_CURSOR_END];
     }
     cursor_ptr = s->vram_ptr + (s->start_addr + cursor_offset) * 4;
+    if (now >= s->cursor_blink_time) {
+        s->cursor_blink_time = now + VGA_TEXT_CURSOR_PERIOD;
+        s->cursor_blink_state ^= 1;
+        full_update = 1;
+    }
 
     depth_index = get_depth_index(s->ds);
     if (cw == 16)
@@ -1420,7 +1428,8 @@ static void vga_draw_text(VGACommonState *s, int full_update)
                                     font_ptr, cheight, fgcol, bgcol, dup9);
                 }
                 if (src == cursor_ptr &&
-                    !(s->cr[VGA_CRTC_CURSOR_START] & 0x20)) {
+                    !(s->cr[VGA_CRTC_CURSOR_START] & 0x20) &&
+                    s->cursor_blink_state != 0) {
                     int line_start, line_last, h;
                     /* draw the cursor */
                     line_start = s->cr[VGA_CRTC_CURSOR_START] & 0x1f;
@@ -1884,6 +1893,9 @@ static void vga_update_display(void *opaque)
         }
         if (graphic_mode != s->graphic_mode) {
             s->graphic_mode = graphic_mode;
+            s->cursor_blink_time =
+                qemu_get_clock_ms(vm_clock) + VGA_TEXT_CURSOR_PERIOD;
+            s->cursor_blink_state = 1;
             full_update = 1;
         }
         switch(graphic_mode) {
diff --git a/hw/vga_int.h b/hw/vga_int.h
index 3b38764..c374474 100644
--- a/hw/vga_int.h
+++ b/hw/vga_int.h
@@ -156,6 +156,8 @@ typedef struct VGACommonState {
     uint32_t last_scr_width, last_scr_height; /* in pixels */
     uint32_t last_depth; /* in bits */
     uint8_t cursor_start, cursor_end;
+    int cursor_blink_state;
+    int64_t cursor_blink_time;
     uint32_t cursor_offset;
     unsigned int (*rgb_to_pixel)(unsigned int r,
                                  unsigned int g, unsigned b);
-- 
1.7.3.4