Shadow: Add c2p core

Add Chunky-to-Planar core functionality, to be used by the Atari and Amiga
(interleaved) bitplanes code.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Keith Packard <keithp@keithp.com>

miext/shadow/c2p_core.h

@@ -0,0 +1,184 @@
+/*
+ *  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
+ *
+ *  Permission to use, copy, modify, distribute, and sell this software and its
+ *  documentation for any purpose is hereby granted without fee, provided that
+ *  the above copyright notice appear in all copies and that both that
+ *  copyright notice and this permission notice appear in supporting
+ *  documentation, and that the name of Geert Uytterhoeven not be used in
+ *  advertising or publicity pertaining to distribution of the software without
+ *  specific, written prior permission.  Geert Uytterhoeven makes no
+ *  representations about the suitability of this software for any purpose.  It
+ *  is provided "as is" without express or implied warranty.
+ *
+ *  GEERT UYTTERHOEVEN DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ *  INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ *  EVENT SHALL GEERT UYTTERHOEVEN BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ *  CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ *  DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ *  TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ *  PERFORMANCE OF THIS SOFTWARE.
+ */
+
+
+    /*
+     *  Basic transpose step
+     */
+
+static inline void _transp(CARD32 d[], unsigned int i1, unsigned int i2,
+                           unsigned int shift, CARD32 mask)
+{
+    CARD32 t = (d[i1] ^ (d[i2] >> shift)) & mask;
+
+    d[i1] ^= t;
+    d[i2] ^= t << shift;
+}
+
+
+extern void c2p_unsupported(void);
+
+static inline CARD32 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(CARD32 d[], unsigned int n, unsigned int m)
+{
+    CARD32 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();
+}
+
+
+    /*
+     *  Transpose operations on 4 32-bit words
+     */
+
+static inline void transp4(CARD32 d[], unsigned int n, unsigned int m)
+{
+    CARD32 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);
+        return;
+
+    case 2:
+        /* Single n x 2 block */
+        _transp(d, 0, 2, n, mask);
+        _transp(d, 1, 3, n, mask);
+        return;
+    }
+
+    c2p_unsupported();
+}
+
+
+    /*
+     *  Transpose operations on 4 32-bit words (reverse order)
+     */
+
+static inline void transp4x(CARD32 d[], unsigned int n, unsigned int m)
+{
+    CARD32 mask = get_mask(n);
+
+    switch (m) {
+    case 2:
+        /* Single n x 2 block */
+        _transp(d, 2, 0, n, mask);
+        _transp(d, 3, 1, n, mask);
+        return;
+    }
+
+    c2p_unsupported();
+}
+
+
+    /*
+     *  Transpose operations on 2 32-bit words
+     */
+
+static inline void transp2(CARD32 d[], unsigned int n)
+{
+    CARD32 mask = get_mask(n);
+
+    /* Single n x 1 block */
+    _transp(d, 0, 1, n, mask);
+    return;
+}
+
+
+    /*
+     *  Transpose operations on 2 32-bit words (reverse order)
+     */
+
+static inline void transp2x(CARD32 d[], unsigned int n)
+{
+    CARD32 mask = get_mask(n);
+
+    /* Single n x 1 block */
+    _transp(d, 1, 0, n, mask);
+    return;
+}