logohack exit on escape

[bootcensus] / src / video_asm.s

diff --git a/src/video_asm.s b/src/video_asm.s
new file mode 100644 (file)
index 0000000..1f7995c
--- /dev/null
+++ b/src/video_asm.s
@@ -0,0 +1,27 @@
+# pcboot - bootable PC demo/game kernel
+# Copyright (C) 2018  John Tsiombikas <nuclear@member.fsf.org>
+# 
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY, without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+       .text
+
+       .global wait_vsync
+wait_vsync:
+       mov $0x3da, %dx
+0:     in %dx, %al
+       and $8, %al
+       jnz 0b
+0:     in %dx, %al
+       and $8, %al
+       jz 0b
+       ret