3 files changed, 29 insertions, 2 deletions
diff --git a/kernel/console.rv b/kernel/console.rv
index a894141..a949cd2 100644
--- a/kernel/console.rv
+++ b/kernel/console.rv
@@ -3,7 +3,7 @@ const FH = 16           # glyph height in pixels (8x16 VGA bitmap font)
 const FG = 0xd0d0d0
 const CON_BG = 0x101018
 
-global con = { col = 0, row = 0, scale = 1 }
+global con = { col = 0, row = 0, scale = 1, cur_on = :true, blink = 0 }
 
 # cell size in pixels at the current zoom. named cell_* (not cw/ch) so they don't
 # collide with draw_glyph's `ch` character parameter.
@@ -65,5 +65,19 @@ global flush_console = fn() do
     con_putc(string.of_ascii(c))
     c = serial_next()
   end
+  # after any output the cursor is solid at the new head restart the blink phase
+  con.cur_on = :true
+  con.blink = 0
   cursor_paint(CUR)
 end
+
+# the PIT fires ~100x/sec
+# blink the cursor every 50 ticks (~2 Hz)
+global on_tick = fn(t) do
+  con.blink += 1
+  if con.blink >= 50 do
+    con.blink = 0
+    con.cur_on = not con.cur_on
+    cursor_paint(if con.cur_on CUR else CON_BG)
+  end
+end
diff --git a/kernel/input.rv b/kernel/input.rv
index fde962d..d069521 100644
--- a/kernel/input.rv
+++ b/kernel/input.rv
@@ -14,6 +14,15 @@ fn pic_remap() do
 end
 fn pic_unmask(line) outb(0x21, inb(0x21) band (255 bxor (1 shl line)))
 
+# 8253/8254 PIT channel 0, mode 3 (square wave)
+# divisor 11931 -> ~100 Hz (1193182 / 11931)
+# the ISR just counts ticks
+fn pit_init() do
+  outb(0x43, 0x36)
+  outb(0x40, 11931 band 0xff)
+  outb(0x40, (11931 shr 8) band 0xff)
+end
+
 # she stroke my keys till i handle
 # no fr this is just a key stroke handler
 global sh = { line = "", shift = :false }
diff --git a/kernel/main.rv b/kernel/main.rv
index d3f1b23..35413ef 100644
--- a/kernel/main.rv
+++ b/kernel/main.rv
@@ -1,6 +1,10 @@
 # kmain
 pic_remap()
-pic_unmask(1)
+pit_init()
+
+pic_unmask(0)   # PIT      (IRQ0) -> cursor blink / uptime
+pic_unmask(1)   # keyboard (IRQ1)
+
 cmd_clear()
 puts("revel shell, live in revo. type `help`\n> ")
 flush_console()