fbdev: c2p - Extract common c2p core to c2p_core.h

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

1 files changed, 106 insertions, 0 deletions

diff --git a/drivers/video/c2p_core.h b/drivers/video/c2p_core.h
new file mode 100644
index 000000000000..3573cf723e43
--- /dev/null
+++ b/drivers/video/c2p_core.h
@@ -0,0 +1,106 @@
+/*
+ *  Fast C2P (Chunky-to-Planar) Conversion
+ *
+ *  Copyright (C) 2003-2008 Geert Uytterhoeven
+ *
+ *  NOTES:
+ *    - This code was inspired by Scout's C2P tutorial
+ *    - It assumes to run on a big endian system
+ *
+ *  This file is subject to the terms and conditions of the GNU General Public
+ *  License. See the file COPYING in the main directory of this archive
+ *  for more details.
+ */
+
+
+    /*
+     *  Basic transpose step
+     */
+
+static inline void _transp(u32 d[], unsigned int i1, unsigned int i2,
+                           unsigned int shift, u32 mask)
+{
+        u32 t = (d[i1] ^ (d[i2] >> shift)) & mask;
+
+        d[i1] ^= t;
+        d[i2] ^= t << shift;
+}
+
+
+extern void c2p_unsupported(void);
+
+static inline u32 get_mask(unsigned int n)
+{
+        switch (n) {
+        case 1:
+                return 0x55555555;
+
+        case 2:
+                return 0x33333333;
+
+        case 4:
+                return 0x0f0f0f0f;
+
+        case 8:
+                return 0x00ff00ff;
+
+        case 16:
+                return 0x0000ffff;
+        }
+
+        c2p_unsupported();
+        return 0;
+}
+
+
+    /*
+     *  Transpose operations on 8 32-bit words
+     */
+
+static inline void transp8(u32 d[], unsigned int n, unsigned int m)
+{
+        u32 mask = get_mask(n);
+
+        switch (m) {
+        case 1:
+                /* First n x 1 block */
+                _transp(d, 0, 1, n, mask);
+                /* Second n x 1 block */
+                _transp(d, 2, 3, n, mask);
+                /* Third n x 1 block */
+                _transp(d, 4, 5, n, mask);
+                /* Fourth n x 1 block */
+                _transp(d, 6, 7, n, mask);
+                return;
+
+        case 2:
+                /* First n x 2 block */
+                _transp(d, 0, 2, n, mask);
+                _transp(d, 1, 3, n, mask);
+                /* Second n x 2 block */
+                _transp(d, 4, 6, n, mask);
+                _transp(d, 5, 7, n, mask);
+                return;
+
+        case 4:
+                /* Single n x 4 block */
+                _transp(d, 0, 4, n, mask);
+                _transp(d, 1, 5, n, mask);
+                _transp(d, 2, 6, n, mask);
+                _transp(d, 3, 7, n, mask);
+                return;
+        }
+
+        c2p_unsupported();
+}
+
+
+    /*
+     *  Compose two values, using a bitmask as decision value
+     *  This is equivalent to (a & mask) | (b & ~mask)
+     */
+
+static inline u32 comp(u32 a, u32 b, u32 mask)
+{
+        return ((a ^ b) & mask) ^ b;
+}