From af5522ca0114d12d0b70dc91c0b4ed409591ff61 Mon Sep 17 00:00:00 2001
From: Henri Vasserman <henv@hot.ee>
Date: Sat, 10 Apr 2021 22:30:51 +0300
Subject: [PATCH] initial commit

---
 .gitignore     |   1 +
 CMakeLists.txt |  13 +++
 EGA8x8.c       | 187 ++++++++++++++++++++++++++++++++++++++++++
 EGA8x8.h       |   7 ++
 font.c         |  33 ++++++++
 font.h         |   9 ++
 xormod.c       | 217 +++++++++++++++++++++++++++++++++++++++++++++++++
 7 files changed, 467 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 CMakeLists.txt
 create mode 100644 EGA8x8.c
 create mode 100644 EGA8x8.h
 create mode 100644 font.c
 create mode 100644 font.h
 create mode 100644 xormod.c

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..567609b
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+build/
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..d6c7ba0
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,13 @@
+cmake_minimum_required(VERSION 3.18)
+
+project(xormod C)
+
+find_package(SDL2)
+
+add_executable(xormod
+    "xormod.c"
+    "font.c"
+    "EGA8x8.c"
+)
+
+target_link_libraries(xormod SDL2::SDL2)
diff --git a/EGA8x8.c b/EGA8x8.c
new file mode 100644
index 0000000..8bdd871
--- /dev/null
+++ b/EGA8x8.c
@@ -0,0 +1,187 @@
+unsigned char font_data[] = {
+  0x42, 0x4d, 0x82, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x82, 0x00,
+  0x00, 0x00, 0x6c, 0x00, 0x00, 0x00, 0x80, 0x00, 0x00, 0x00, 0x80, 0x00,
+  0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08,
+  0x00, 0x00, 0x13, 0x0b, 0x00, 0x00, 0x13, 0x0b, 0x00, 0x00, 0x02, 0x00,
+  0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x42, 0x47, 0x52, 0x73, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0xff, 0x00, 0xff, 0x00, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x18, 0x70, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1c, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0xfc, 0xfc, 0xfc, 0x18, 0xd8, 0x30, 0x00, 0x00, 0x00,
+  0x00, 0x3c, 0x00, 0x00, 0x00, 0x00, 0xfc, 0x00, 0x00, 0x00, 0x18, 0xd8,
+  0x30, 0xdc, 0x00, 0x00, 0x00, 0x6c, 0x00, 0x00, 0x3c, 0x00, 0x00, 0x30,
+  0x60, 0x18, 0x18, 0x18, 0x00, 0x76, 0x00, 0x18, 0x18, 0xec, 0x6c, 0x78,
+  0x3c, 0x00, 0xfc, 0x30, 0x30, 0x30, 0x18, 0x18, 0xfc, 0x00, 0x38, 0x18,
+  0x00, 0x0c, 0x6c, 0x60, 0x3c, 0x00, 0x00, 0xfc, 0x18, 0x60, 0x1b, 0x18,
+  0x00, 0xdc, 0x6c, 0x00, 0x00, 0x0c, 0x6c, 0x30, 0x3c, 0x00, 0xfc, 0x30,
+  0x30, 0x30, 0x1b, 0x18, 0x30, 0x76, 0x6c, 0x00, 0x00, 0x0c, 0x6c, 0x18,
+  0x00, 0x00, 0x00, 0x30, 0x60, 0x18, 0x0e, 0x18, 0x30, 0x00, 0x38, 0x00,
+  0x00, 0x0f, 0x78, 0x70, 0x00, 0x00, 0x00, 0xc0, 0x00, 0x00, 0x00, 0x00,
+  0xc0, 0x00, 0xfc, 0x00, 0x00, 0x00, 0x00, 0xc0, 0x00, 0x00, 0x76, 0xc0,
+  0xc0, 0x6c, 0xfc, 0x70, 0x60, 0x18, 0x30, 0x38, 0xee, 0x78, 0x00, 0x60,
+  0x38, 0xcc, 0xdc, 0xf8, 0xc0, 0x6c, 0xcc, 0xd8, 0x7c, 0x18, 0x78, 0x6c,
+  0x6c, 0xcc, 0x7e, 0x7e, 0x60, 0xcc, 0xc8, 0xcc, 0xc0, 0x6c, 0x60, 0xd8,
+  0x66, 0x18, 0xcc, 0xc6, 0x6c, 0xcc, 0xdb, 0xdb, 0xc0, 0xcc, 0xdc, 0xf8,
+  0xc0, 0x6c, 0x30, 0xd8, 0x66, 0x18, 0xcc, 0xfe, 0xc6, 0x7c, 0xdb, 0xdb,
+  0xf8, 0xcc, 0x76, 0xcc, 0xcc, 0x6c, 0x60, 0x7e, 0x66, 0xdc, 0x78, 0xc6,
+  0xc6, 0x18, 0x7e, 0x7e, 0xc0, 0xcc, 0x00, 0x78, 0xfc, 0xfe, 0xcc, 0x00,
+  0x66, 0x76, 0x30, 0x6c, 0x6c, 0x30, 0x00, 0x0c, 0x60, 0xcc, 0x00, 0x00,
+  0x00, 0x00, 0xfc, 0x00, 0x00, 0x00, 0xfc, 0x38, 0x38, 0x1c, 0x00, 0x06,
+  0x38, 0x78, 0x00, 0x18, 0x36, 0x00, 0x00, 0x18, 0x36, 0x36, 0x18, 0x00,
+  0x18, 0xff, 0xff, 0xf0, 0x0f, 0x00, 0x00, 0x18, 0x36, 0x00, 0x00, 0x18,
+  0x36, 0x36, 0x18, 0x00, 0x18, 0xff, 0xff, 0xf0, 0x0f, 0x00, 0x00, 0x18,
+  0x36, 0x00, 0x00, 0x18, 0x36, 0x36, 0x18, 0x00, 0x18, 0xff, 0xff, 0xf0,
+  0x0f, 0x00, 0xff, 0xff, 0xff, 0x3f, 0x1f, 0x1f, 0x3f, 0xff, 0xff, 0xf8,
+  0x1f, 0xff, 0xff, 0xf0, 0x0f, 0x00, 0x36, 0x00, 0x00, 0x36, 0x18, 0x18,
+  0x00, 0x36, 0x18, 0x18, 0x00, 0xff, 0x00, 0xf0, 0x0f, 0xff, 0x36, 0xff,
+  0x00, 0x36, 0x1f, 0x1f, 0x00, 0x36, 0xff, 0x18, 0x00, 0xff, 0x00, 0xf0,
+  0x0f, 0xff, 0x36, 0x00, 0x00, 0x36, 0x18, 0x00, 0x00, 0x36, 0x18, 0x18,
+  0x00, 0xff, 0x00, 0xf0, 0x0f, 0xff, 0x36, 0x00, 0x00, 0x36, 0x18, 0x00,
+  0x00, 0x36, 0x18, 0x18, 0x00, 0xff, 0x00, 0xf0, 0x0f, 0xff, 0x00, 0x00,
+  0x18, 0x18, 0x00, 0x18, 0x18, 0x36, 0x00, 0x36, 0x00, 0x36, 0x36, 0x00,
+  0x36, 0x00, 0x00, 0x00, 0x18, 0x18, 0x00, 0x18, 0x18, 0x36, 0x00, 0x36,
+  0x00, 0x36, 0x36, 0x00, 0x36, 0x00, 0x00, 0x00, 0x18, 0x18, 0x00, 0x18,
+  0x18, 0x36, 0x00, 0x36, 0x00, 0x36, 0x36, 0x00, 0x36, 0x00, 0x1f, 0xff,
+  0xff, 0x1f, 0xff, 0xff, 0x1f, 0x37, 0x3f, 0x37, 0xff, 0xf7, 0x37, 0xff,
+  0xf7, 0xff, 0x18, 0x18, 0x00, 0x18, 0x00, 0x18, 0x18, 0x36, 0x30, 0x30,
+  0x00, 0x00, 0x30, 0x00, 0x00, 0x00, 0x18, 0x18, 0x00, 0x18, 0x00, 0x18,
+  0x1f, 0x36, 0x37, 0x3f, 0xf7, 0xff, 0x37, 0xff, 0xf7, 0xff, 0x18, 0x18,
+  0x00, 0x18, 0x00, 0x18, 0x18, 0x36, 0x36, 0x00, 0x36, 0x00, 0x36, 0x00,
+  0x36, 0x18, 0x18, 0x18, 0x00, 0x18, 0x00, 0x18, 0x18, 0x36, 0x36, 0x00,
+  0x36, 0x00, 0x36, 0x00, 0x36, 0x18, 0x88, 0xaa, 0xee, 0x18, 0x18, 0x18,
+  0x36, 0x36, 0x18, 0x36, 0x36, 0x36, 0x00, 0x00, 0x00, 0x18, 0x22, 0x55,
+  0xdb, 0x18, 0x18, 0x18, 0x36, 0x36, 0x18, 0x36, 0x36, 0x36, 0x00, 0x00,
+  0x00, 0x18, 0x88, 0xaa, 0x77, 0x18, 0x18, 0x18, 0x36, 0x36, 0x18, 0x36,
+  0x36, 0x36, 0x00, 0x00, 0x00, 0x18, 0x22, 0x55, 0xdb, 0x18, 0xf8, 0xf8,
+  0xf6, 0xfe, 0xf8, 0xf6, 0x36, 0xf6, 0xfe, 0xfe, 0xf8, 0xf8, 0x88, 0xaa,
+  0xee, 0x18, 0x18, 0x18, 0x36, 0x00, 0x18, 0x06, 0x36, 0x06, 0x06, 0x36,
+  0x18, 0x00, 0x22, 0x55, 0xdb, 0x18, 0x18, 0xf8, 0x36, 0x00, 0xf8, 0xf6,
+  0x36, 0xfe, 0xf6, 0x36, 0xf8, 0x00, 0x88, 0xaa, 0x77, 0x18, 0x18, 0x18,
+  0x36, 0x00, 0x00, 0x36, 0x36, 0x00, 0x36, 0x36, 0x18, 0x00, 0x22, 0x55,
+  0xdb, 0x18, 0x18, 0x18, 0x36, 0x00, 0x00, 0x36, 0x36, 0x00, 0x36, 0x36,
+  0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x0f, 0x03, 0x00, 0x00, 0x00, 0x7e, 0x78, 0x78, 0x7e, 0xcc, 0xcc,
+  0x00, 0x00, 0x78, 0x00, 0x00, 0xcc, 0xcf, 0x18, 0x00, 0x00, 0xcc, 0x30,
+  0xcc, 0xcc, 0xcc, 0xdc, 0x7e, 0x7c, 0xcc, 0xc0, 0x0c, 0x66, 0x6f, 0x18,
+  0x33, 0xcc, 0x7c, 0x30, 0xcc, 0xcc, 0xcc, 0xfc, 0x00, 0x00, 0xc0, 0xc0,
+  0x0c, 0x33, 0x37, 0x18, 0x66, 0x66, 0x0c, 0x30, 0x78, 0xcc, 0xf8, 0xec,
+  0x3e, 0x38, 0x60, 0xfc, 0xfc, 0xde, 0xdb, 0x18, 0xcc, 0x33, 0x78, 0x70,
+  0x00, 0x00, 0x00, 0xcc, 0x6c, 0x6c, 0x30, 0x00, 0x00, 0xcc, 0xcc, 0x00,
+  0x66, 0x66, 0x00, 0x00, 0x1c, 0x1c, 0xf8, 0x00, 0x6c, 0x6c, 0x00, 0x00,
+  0x00, 0xc6, 0xc6, 0x18, 0x33, 0xcc, 0x1c, 0x38, 0x00, 0x00, 0x00, 0xfc,
+  0x3c, 0x38, 0x30, 0x00, 0x00, 0xc3, 0xc3, 0x18, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf8, 0x00, 0x00, 0x18, 0x00, 0x30,
+  0xc7, 0x70, 0xfc, 0x7f, 0xce, 0x78, 0x78, 0x78, 0x7e, 0x7e, 0x0c, 0x18,
+  0x78, 0x18, 0xfc, 0x30, 0xc6, 0xd8, 0x60, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc,
+  0xcc, 0xcc, 0x7c, 0x3c, 0xcc, 0x7e, 0xe6, 0xfc, 0xcf, 0x18, 0x78, 0x7f,
+  0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0x66, 0xcc, 0xc0, 0x60, 0x30,
+  0xc6, 0x18, 0x60, 0x0c, 0xfe, 0x78, 0x78, 0x78, 0xcc, 0xcc, 0xcc, 0x66,
+  0xcc, 0xc0, 0xf0, 0xfc, 0xfa, 0x3c, 0xfc, 0x7f, 0xcc, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x3c, 0xcc, 0x7e, 0x64, 0x78, 0xcc, 0x18, 0x00, 0x00,
+  0x6c, 0xcc, 0xcc, 0xe0, 0xcc, 0xe0, 0xcc, 0x18, 0x00, 0x18, 0x6c, 0xcc,
+  0xcc, 0x1b, 0x1c, 0x00, 0x3e, 0x78, 0x00, 0x00, 0x78, 0x00, 0x00, 0xc3,
+  0xcc, 0x18, 0x38, 0xcc, 0xf8, 0x0e, 0x78, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x38, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x7e,
+  0x78, 0x3f, 0x7e, 0x7e, 0x7e, 0x0c, 0x3c, 0x78, 0x78, 0x78, 0x3c, 0x78,
+  0xc6, 0xcc, 0x18, 0xcc, 0xc0, 0x66, 0xcc, 0xcc, 0xcc, 0x78, 0x60, 0xc0,
+  0xc0, 0x30, 0x18, 0x30, 0xc6, 0xfc, 0x78, 0xcc, 0xfc, 0x3e, 0x7c, 0x7c,
+  0x7c, 0xc0, 0x7e, 0xfc, 0xfc, 0x30, 0x18, 0x30, 0xfe, 0xcc, 0xcc, 0xcc,
+  0xcc, 0x06, 0x0c, 0x0c, 0x0c, 0xc0, 0x66, 0xcc, 0xcc, 0x30, 0x18, 0x30,
+  0xc6, 0x78, 0xc0, 0x00, 0x78, 0x3c, 0x78, 0x78, 0x78, 0x78, 0x3c, 0x78,
+  0x78, 0x70, 0x38, 0x70, 0x6c, 0x00, 0xcc, 0xcc, 0x00, 0xc3, 0x00, 0x00,
+  0x30, 0x00, 0xc3, 0x00, 0x00, 0x00, 0xc6, 0x00, 0x38, 0x30, 0x78, 0x00,
+  0x1c, 0x7e, 0xcc, 0xe0, 0x30, 0x00, 0x7e, 0xcc, 0xe0, 0xcc, 0x7c, 0xe0,
+  0xc6, 0x30, 0xf0, 0x1e, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf8,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x60, 0x0c, 0xf0, 0xf8, 0x18, 0x76,
+  0x30, 0x6c, 0xc6, 0x0c, 0xfc, 0x1c, 0x18, 0xe0, 0x00, 0xfe, 0x7c, 0x7c,
+  0x60, 0x0c, 0x34, 0xcc, 0x78, 0xfe, 0x6c, 0x7c, 0x64, 0x30, 0x18, 0x30,
+  0x00, 0xc6, 0x66, 0xcc, 0x66, 0x78, 0x30, 0xcc, 0xcc, 0xfe, 0x38, 0xcc,
+  0x30, 0x30, 0x18, 0x30, 0x00, 0xc6, 0x66, 0xcc, 0x76, 0xc0, 0x30, 0xcc,
+  0xcc, 0xd6, 0x6c, 0xcc, 0x98, 0xe0, 0x00, 0x1c, 0x00, 0x6c, 0xdc, 0x76,
+  0xdc, 0x7c, 0x7c, 0xcc, 0xcc, 0xc6, 0xc6, 0xcc, 0xfc, 0x30, 0x18, 0x30,
+  0x00, 0x38, 0x00, 0x00, 0x00, 0x00, 0x30, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x30, 0x18, 0x30, 0xdc, 0x10, 0x00, 0x00, 0x00, 0x00, 0x10, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x1c, 0x18, 0xe0, 0x76, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0xf8, 0x00, 0x00, 0x78, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x76, 0xdc, 0x78, 0x76, 0x78, 0xf0, 0x0c, 0xe6, 0x78,
+  0xcc, 0xe6, 0x78, 0xc6, 0xcc, 0x78, 0x00, 0xcc, 0x66, 0xcc, 0xcc, 0xc0,
+  0x60, 0x7c, 0x66, 0x30, 0xcc, 0x6c, 0x30, 0xd6, 0xcc, 0xcc, 0x00, 0x7c,
+  0x66, 0xc0, 0xcc, 0xfc, 0x60, 0xcc, 0x66, 0x30, 0x0c, 0x78, 0x30, 0xfe,
+  0xcc, 0xcc, 0x00, 0x0c, 0x7c, 0xcc, 0x7c, 0xcc, 0xf0, 0xcc, 0x76, 0x30,
+  0x0c, 0x6c, 0x30, 0xfe, 0xcc, 0xcc, 0x18, 0x78, 0x60, 0x78, 0x0c, 0x78,
+  0x60, 0x76, 0x6c, 0x70, 0x0c, 0x66, 0x30, 0xcc, 0xf8, 0x78, 0x30, 0x00,
+  0x60, 0x00, 0x0c, 0x00, 0x6c, 0x00, 0x60, 0x00, 0x00, 0x60, 0x30, 0x00,
+  0x00, 0x00, 0x30, 0x00, 0xe0, 0x00, 0x1c, 0x00, 0x38, 0x00, 0xe0, 0x30,
+  0x0c, 0xe0, 0x70, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xf0, 0x1c,
+  0xe6, 0x78, 0x78, 0xfc, 0x30, 0xc6, 0xc6, 0x78, 0xfe, 0x78, 0x02, 0x78,
+  0x00, 0x00, 0x60, 0x78, 0x66, 0xcc, 0x30, 0xcc, 0x78, 0xee, 0x6c, 0x30,
+  0x66, 0x60, 0x06, 0x18, 0x00, 0x00, 0x60, 0xdc, 0x6c, 0x1c, 0x30, 0xcc,
+  0xcc, 0xfe, 0x38, 0x30, 0x32, 0x60, 0x0c, 0x18, 0x00, 0x00, 0x7c, 0xcc,
+  0x7c, 0x70, 0x30, 0xcc, 0xcc, 0xd6, 0x38, 0x78, 0x18, 0x60, 0x18, 0x18,
+  0xc6, 0x00, 0x66, 0xcc, 0x66, 0xe0, 0x30, 0xcc, 0xcc, 0xc6, 0x6c, 0xcc,
+  0x8c, 0x60, 0x30, 0x18, 0x6c, 0x00, 0x66, 0xcc, 0x66, 0xcc, 0xb4, 0xcc,
+  0xcc, 0xc6, 0xc6, 0xcc, 0xc6, 0x60, 0x60, 0x18, 0x38, 0x00, 0xfc, 0x78,
+  0xfc, 0x78, 0xfc, 0xcc, 0xcc, 0xc6, 0xc6, 0xcc, 0xfe, 0x78, 0xc0, 0x78,
+  0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x78, 0xcc, 0xfc, 0x3c, 0xf8, 0xfe,
+  0xf0, 0x3e, 0xcc, 0x78, 0x78, 0xe6, 0xfe, 0xc6, 0xc6, 0x38, 0xc0, 0xcc,
+  0x66, 0x66, 0x6c, 0x62, 0x60, 0x66, 0xcc, 0x30, 0xcc, 0x66, 0x66, 0xc6,
+  0xc6, 0x6c, 0xde, 0xfc, 0x66, 0xc0, 0x66, 0x68, 0x68, 0xce, 0xcc, 0x30,
+  0xcc, 0x6c, 0x62, 0xd6, 0xce, 0xc6, 0xde, 0xcc, 0x7c, 0xc0, 0x66, 0x78,
+  0x78, 0xc0, 0xfc, 0x30, 0x0c, 0x78, 0x60, 0xfe, 0xde, 0xc6, 0xde, 0xcc,
+  0x66, 0xc0, 0x66, 0x68, 0x68, 0xc0, 0xcc, 0x30, 0x0c, 0x6c, 0x60, 0xfe,
+  0xf6, 0xc6, 0xc6, 0x78, 0x66, 0x66, 0x6c, 0x62, 0x62, 0x66, 0xcc, 0x30,
+  0x0c, 0x66, 0x60, 0xee, 0xe6, 0x6c, 0x7c, 0x30, 0xfc, 0x3c, 0xf8, 0xfe,
+  0xfe, 0x3c, 0xcc, 0x78, 0x1e, 0xe6, 0xf0, 0xc6, 0xc6, 0x38, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x60, 0x00, 0x00,
+  0x00, 0x00, 0x7c, 0xfc, 0xfc, 0x78, 0x1e, 0x78, 0x78, 0x30, 0x78, 0x70,
+  0x30, 0x30, 0x18, 0x00, 0x60, 0x30, 0xe6, 0x30, 0xcc, 0xcc, 0x0c, 0xcc,
+  0xcc, 0x30, 0xcc, 0x18, 0x30, 0x30, 0x30, 0xfc, 0x30, 0x00, 0xf6, 0x30,
+  0x60, 0x0c, 0xfe, 0x0c, 0xcc, 0x30, 0xcc, 0x0c, 0x00, 0x00, 0x60, 0x00,
+  0x18, 0x30, 0xde, 0x30, 0x38, 0x38, 0xcc, 0x0c, 0xf8, 0x18, 0x78, 0x7c,
+  0x00, 0x00, 0xc0, 0x00, 0x0c, 0x18, 0xce, 0x30, 0x0c, 0x0c, 0x6c, 0xf8,
+  0xc0, 0x0c, 0xcc, 0xcc, 0x30, 0x30, 0x60, 0xfc, 0x18, 0x0c, 0xc6, 0x70,
+  0xcc, 0xcc, 0x3c, 0xc0, 0x60, 0xcc, 0xcc, 0xcc, 0x30, 0x30, 0x30, 0x00,
+  0x30, 0xcc, 0x7c, 0x30, 0x78, 0x78, 0x1c, 0xfc, 0x38, 0xfc, 0x78, 0x78,
+  0x00, 0x00, 0x18, 0x00, 0x60, 0x78, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x30,
+  0x00, 0x6c, 0x30, 0xc6, 0x76, 0x00, 0x18, 0x60, 0x00, 0x00, 0x30, 0x00,
+  0x30, 0x80, 0x00, 0x00, 0x00, 0x6c, 0xf8, 0x66, 0xcc, 0x00, 0x30, 0x30,
+  0x66, 0x30, 0x30, 0x00, 0x30, 0xc0, 0x00, 0x30, 0x00, 0xfe, 0x0c, 0x30,
+  0xdc, 0x00, 0x60, 0x18, 0x3c, 0x30, 0x00, 0x00, 0x00, 0x60, 0x00, 0x30,
+  0x00, 0x6c, 0x78, 0x18, 0x76, 0x00, 0x60, 0x18, 0xff, 0xfc, 0x00, 0xfc,
+  0x00, 0x30, 0x00, 0x78, 0x6c, 0xfe, 0xc0, 0xcc, 0x38, 0xc0, 0x60, 0x18,
+  0x3c, 0x30, 0x00, 0x00, 0x00, 0x18, 0x00, 0x78, 0x6c, 0x6c, 0x7c, 0xc6,
+  0x6c, 0x60, 0x30, 0x30, 0x66, 0x30, 0x00, 0x00, 0x00, 0x0c, 0x00, 0x30,
+  0x6c, 0x6c, 0x30, 0x00, 0x38, 0x60, 0x18, 0x60, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x06, 0x00, 0x00, 0x18, 0x00, 0x00, 0x78, 0x00, 0xff, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0x02, 0x3c, 0x66, 0x1b, 0xcc,
+  0x7e, 0x18, 0x18, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xe0, 0x0e,
+  0x7e, 0x00, 0x1b, 0x38, 0x7e, 0x3c, 0x18, 0x3c, 0x18, 0x30, 0xfe, 0x24,
+  0xff, 0x18, 0xf8, 0x3e, 0x18, 0x66, 0x1b, 0x6c, 0x7e, 0x7e, 0x18, 0x7e,
+  0x0c, 0x60, 0xc0, 0x66, 0xff, 0x3c, 0xfe, 0xfe, 0x18, 0x66, 0x7b, 0x6c,
+  0x00, 0x18, 0x18, 0x18, 0xfe, 0xfe, 0xc0, 0xff, 0x7e, 0x7e, 0xf8, 0x3e,
+  0x7e, 0x66, 0xdb, 0x38, 0x00, 0x7e, 0x7e, 0x18, 0x0c, 0x60, 0xc0, 0x66,
+  0x3c, 0xff, 0xe0, 0x0e, 0x3c, 0x66, 0xdb, 0x63, 0x00, 0x3c, 0x3c, 0x18,
+  0x18, 0x30, 0x00, 0x24, 0x18, 0xff, 0x80, 0x02, 0x18, 0x66, 0x7f, 0x3e,
+  0x00, 0x18, 0x18, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x7e,
+  0x7e, 0x00, 0x00, 0x7c, 0x7c, 0x00, 0xff, 0x00, 0xff, 0x78, 0x18, 0xe0,
+  0xc0, 0x99, 0x00, 0x81, 0xff, 0x10, 0x10, 0x38, 0x38, 0x00, 0xff, 0x3c,
+  0xc3, 0xcc, 0x7e, 0xf0, 0xe6, 0x5a, 0x00, 0x99, 0xe7, 0x38, 0x38, 0x7c,
+  0x7c, 0x18, 0xe7, 0x66, 0x99, 0xcc, 0x18, 0x70, 0x67, 0x3c, 0x00, 0xbd,
+  0xc3, 0x7c, 0x7c, 0xfe, 0xfe, 0x3c, 0xc3, 0x42, 0xbd, 0xcc, 0x3c, 0x30,
+  0x63, 0xe7, 0x00, 0x81, 0xff, 0xfe, 0xfe, 0xfe, 0x7c, 0x3c, 0xc3, 0x42,
+  0xbd, 0x7d, 0x66, 0x30, 0x63, 0xe7, 0x00, 0xa5, 0xdb, 0xfe, 0x7c, 0x38,
+  0x38, 0x18, 0xe7, 0x66, 0x99, 0x0f, 0x66, 0x3f, 0x7f, 0x3c, 0x00, 0x81,
+  0xff, 0xfe, 0x38, 0x7c, 0x10, 0x00, 0xff, 0x3c, 0xc3, 0x07, 0x66, 0x33,
+  0x63, 0x5a, 0x00, 0x7e, 0x7e, 0x6c, 0x10, 0x38, 0x10, 0x00, 0xff, 0x00,
+  0xff, 0x0f, 0x3c, 0x3f, 0x7f, 0x99
+};
+unsigned int font_data_len = 2178;
+unsigned int font_w = 8;
+unsigned int font_h = 8;
\ No newline at end of file
diff --git a/EGA8x8.h b/EGA8x8.h
new file mode 100644
index 0000000..92e7d06
--- /dev/null
+++ b/EGA8x8.h
@@ -0,0 +1,7 @@
+#pragma once
+
+extern unsigned char font_data[];
+extern unsigned int font_data_len;
+
+extern unsigned int font_w;
+extern unsigned int font_h;
diff --git a/font.c b/font.c
new file mode 100644
index 0000000..24695a2
--- /dev/null
+++ b/font.c
@@ -0,0 +1,33 @@
+#include "EGA8x8.h"
+
+#include <SDL2/SDL.h>
+
+SDL_Texture *load_font(SDL_Renderer *renderer) {
+    SDL_Surface *s = SDL_LoadBMP_RW(SDL_RWFromConstMem(font_data, font_data_len), 1);
+    SDL_SetColorKey(s, SDL_TRUE, SDL_MapRGB(s->format, 255, 0, 255));
+    SDL_Texture *font_texture = SDL_CreateTextureFromSurface(renderer, s);
+    SDL_FreeSurface(s);
+    return font_texture;
+}
+
+void draw_text(SDL_Renderer *renderer, SDL_Texture *font,
+    char *text, size_t len, int x, int y, uint8_t r, uint8_t g, uint8_t b) {
+    if (font == NULL) return;
+    SDL_SetTextureColorMod(font, r, g, b);    
+    SDL_Rect src = { .w = font_w, .h = font_h },
+             dst = { .x = x, .y = y, .w = font_w, .h = font_h };
+    for (size_t i = 0; i < len; i++) {
+        char c = text[i];
+        if (c == 0) break;
+        if (c == '\n') {
+            dst.x = x;
+            dst.y += font_h;
+            continue;
+        }
+        src.x = (c & 0xf) * font_w;
+        src.y = (c >> 4) * font_h;
+        SDL_RenderCopy(renderer, font, &src, &dst);
+        dst.x += font_w;
+    }
+    
+}
diff --git a/font.h b/font.h
new file mode 100644
index 0000000..e175ba9
--- /dev/null
+++ b/font.h
@@ -0,0 +1,9 @@
+#pragma once
+
+#include <SDL2/SDL.h>
+
+#define RC(r, c) (c)*font_w, (r)*font_h
+
+SDL_Texture *load_font(SDL_Renderer *renderer);
+void draw_text(SDL_Renderer *renderer, SDL_Texture *font,
+    char *text, size_t len, int x, int y, uint8_t r, uint8_t g, uint8_t b);
diff --git a/xormod.c b/xormod.c
new file mode 100644
index 0000000..a91d6d7
--- /dev/null
+++ b/xormod.c
@@ -0,0 +1,217 @@
+#include "font.h"
+#include "EGA8x8.h"
+
+#include <stdio.h>
+#include <SDL2/SDL.h>
+
+#define SWAP(a, b) ({ \
+    __typeof(a) tmp = (a); \
+    (a) = (b); \
+    (b) = tmp; \
+})
+
+typedef struct {
+    int x1;
+    int y1;
+    int x2;
+    int y2;
+    int w;
+    int h;
+    SDL_Surface *surface;
+    SDL_Texture *texture;
+    uint32_t *pixels;
+    uint32_t color;
+} Picture;
+
+static void Picture_render(Picture *p, SDL_Renderer *rend);
+static Picture *Picture_new(SDL_Renderer *rend,
+    int x, int y, int w, int h, uint32_t color) {
+    
+    Picture *p = calloc(1, sizeof(Picture));
+
+    p->x1 = x;
+    p->x2 = x + w;
+    p->y1 = y;
+    p->y2 = y + h;
+    p->w = w;
+    p->h = h;
+    p->pixels = malloc(w * h * sizeof(uint32_t));
+    p->color = color;
+
+    p->surface = SDL_CreateRGBSurfaceWithFormatFrom(
+        p->pixels, w, h, 32, w * sizeof(uint32_t),
+        SDL_PIXELFORMAT_RGBA32);
+
+    Picture_render(p, rend);
+    return p;
+}
+
+typedef uint32_t uint32_4 __attribute__ ((vector_size (4 * sizeof(uint32_t))));
+
+static void Picture_render(Picture *p, SDL_Renderer *rend) {
+
+    for (int j = p->y1, r = 0; j < p->y2; j++) {
+        uint32_4 y = {j, j, j, j};
+        for (int i = p->x1; i < p->x2; i+=4, r+=4) {
+            uint32_4 x = {i, i + 1, i + 2, i + 3};
+            uint32_4 z = (x ^ y) % 9;
+            uint32_4 f = (z==0) & p->color;
+            memcpy(&p->pixels[r], (uint32_t*)&f, sizeof(f));
+        }
+
+    }
+
+    if (p->texture) SDL_DestroyTexture(p->texture);
+    p->texture = SDL_CreateTextureFromSurface(rend, p->surface);
+    SDL_SetTextureBlendMode(p->texture, SDL_BLENDMODE_NONE);
+}
+
+static void Picture_move(Picture *p, int x, int y) {
+    p->x1 += x;
+    p->x2 += x;
+    p->y1 += y;
+    p->y2 += y;
+}
+
+struct int2 { int x; int y; };
+
+int main() {
+
+    unsigned w = 1280, h = 720;
+
+    if (SDL_Init(SDL_INIT_VIDEO) != 0) {
+        fprintf(stderr, "Can't init: %s\n", SDL_GetError());
+        return -1;
+    }
+
+    SDL_Window *window = SDL_CreateWindow("xormod",
+        SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, w, h,
+        SDL_WINDOW_OPENGL /*SDL_WINDOW_FULLSCREEN */);
+    if (window == NULL) {
+        fprintf(stderr, "Can't open window: %s\n", SDL_GetError());
+        return -1;
+    }
+
+    SDL_GetWindowSize(window, &w, &h);
+
+    SDL_Renderer *rend = SDL_CreateRenderer(window, -1,
+        /*SDL_RENDERER_PRESENTVSYNC | */SDL_RENDERER_ACCELERATED);
+
+    SDL_Texture *font = load_font(rend);
+
+    Picture *pictures[4];
+    enum { P_TOPLEFT, P_TOPRGHT, P_BOTLEFT, P_BOTRGHT };
+
+    pictures[P_TOPLEFT] = Picture_new(rend, 0, 0, w, h, 0xff7fffff);
+    pictures[P_TOPRGHT] = Picture_new(rend, w, 0, w, h, 0xffff7fff);
+    pictures[P_BOTLEFT] = Picture_new(rend, 0, h, w, h, 0xffffff7f);
+    pictures[P_BOTRGHT] = Picture_new(rend, w, h, w, h, 0xff7fff7f);
+
+    struct int2 off = { 0,  0 };
+    struct int2 mouse_prev = { -1, -1 };
+    int running = 1;
+    while (running) {
+        const uint8_t *keys = SDL_GetKeyboardState(NULL);
+        if (keys[SDL_SCANCODE_ESCAPE] || keys[SDL_SCANCODE_Q]) {
+            break;
+        }
+        if (keys[SDL_SCANCODE_LEFT]) {
+            off.x -= 5;
+        }
+        if (keys[SDL_SCANCODE_RIGHT]) {
+            off.x += 5;
+        }
+        if (keys[SDL_SCANCODE_UP]) {
+            off.y -= 5;
+        }
+        if (keys[SDL_SCANCODE_DOWN]) {
+            off.y += 5;
+        }
+        
+        struct int2 mouse;
+        if (SDL_GetMouseState(&mouse.x, &mouse.y) & SDL_BUTTON(SDL_BUTTON_LEFT)) {
+            if (mouse_prev.x != -1 ) {
+                off.x -= mouse.x - mouse_prev.x;
+                off.y -= mouse.y - mouse_prev.y;
+            }
+            mouse_prev = mouse;
+        } else if (mouse_prev.x != -1) {
+            mouse_prev = (struct int2) { -1, -1 };
+        }
+
+        if (off.y < pictures[P_TOPLEFT]->y1) {
+            SWAP(pictures[P_TOPLEFT], pictures[P_BOTLEFT]);
+            SWAP(pictures[P_TOPRGHT], pictures[P_BOTRGHT]);
+            Picture_move(pictures[P_TOPLEFT], 0, -2*h);
+            Picture_move(pictures[P_TOPRGHT], 0, -2*h);
+            Picture_render(pictures[P_TOPLEFT], rend);
+            Picture_render(pictures[P_TOPRGHT], rend);
+        }
+        if (off.x < pictures[P_TOPLEFT]->x1) {
+            SWAP(pictures[P_TOPLEFT], pictures[P_TOPRGHT]);
+            SWAP(pictures[P_BOTLEFT], pictures[P_BOTRGHT]);
+            Picture_move(pictures[P_TOPLEFT], -2*w, 0);
+            Picture_move(pictures[P_BOTLEFT], -2*w, 0);
+            Picture_render(pictures[P_TOPLEFT], rend);
+            Picture_render(pictures[P_BOTLEFT], rend);
+        }
+        if (off.y > pictures[P_BOTRGHT]->y1) {
+            SWAP(pictures[P_TOPLEFT], pictures[P_BOTLEFT]);
+            SWAP(pictures[P_TOPRGHT], pictures[P_BOTRGHT]);
+            Picture_move(pictures[P_BOTLEFT], 0, 2*h);
+            Picture_move(pictures[P_BOTRGHT], 0, 2*h);
+            Picture_render(pictures[P_BOTLEFT], rend);
+            Picture_render(pictures[P_BOTRGHT], rend);
+        }
+        if (off.x > pictures[P_BOTRGHT]->x1) {
+            SWAP(pictures[P_TOPLEFT], pictures[P_TOPRGHT]);
+            SWAP(pictures[P_BOTLEFT], pictures[P_BOTRGHT]);
+            Picture_move(pictures[P_TOPRGHT], 2*w, 0);
+            Picture_move(pictures[P_BOTRGHT], 2*w, 0);
+            Picture_render(pictures[P_TOPRGHT], rend);
+            Picture_render(pictures[P_BOTRGHT], rend);
+        }
+
+        //SDL_SetRenderDrawColor(rend, 0, 0, 0, 255);
+        //SDL_RenderClear(rend);
+
+        for (int i = 0; i < 4; i++) {
+            Picture *p = pictures[i];
+            SDL_Rect dst = {
+                p->x1 - off.x, p->y1 - off.y, w, h,
+            };
+            SDL_RenderCopy(rend, p->texture, NULL, &dst);
+        }
+
+        //char buf[72];
+        //SDL_SetRenderDrawColor(rend, 0, 0, 0, 255);
+        //SDL_RenderFillRect(rend, &(SDL_Rect) { 0, 0, sizeof(buf)*font_w, 7*font_h });
+
+        //size_t len = snprintf(buf, sizeof(buf), "off.x: %d, off.y: %d", off.x, off.y);
+        //draw_text(rend, font, buf, len, RC(1, 1), 255, 255, 255);
+
+        //char *q[] = {"TL", "TR", "BL", "BR"};
+        //for (int i = 0; i < 4; i++) {
+        //    Picture *p = pictures[i];
+        //    len = snprintf(buf, sizeof(buf), "%s| x1: %05d, x2: %05d, y1: %05d, y2: %05d, p: %p",
+        //        q[i], p->x1, p->x2, p->y1, p->y2, p);
+        //    draw_text(rend, font, buf, len, RC(2+i, 1), 255, 255, 255);
+        //}
+
+        SDL_RenderPresent(rend);
+
+        SDL_Event e;
+        while (SDL_PollEvent(&e)) {
+            if (e.type == SDL_QUIT) {
+                running = 0;
+            }
+        }
+    }
+
+    SDL_DestroyRenderer(rend);
+    SDL_DestroyWindow(window);
+    SDL_Quit();
+
+    return 0;
+
+}