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Annotation of sys/dev/rasops/rasops_masks.h, Revision 1.1

1.1     ! nbrk        1: /*     $OpenBSD: rasops_masks.h,v 1.3 2006/08/04 06:28:10 miod Exp $ */
        !             2: /*     $NetBSD: rasops_masks.h,v 1.5 2000/06/13 13:37:01 ad Exp $      */
        !             3:
        !             4: /*-
        !             5:  * Copyright (c) 1999 The NetBSD Foundation, Inc.
        !             6:  * All rights reserved.
        !             7:  *
        !             8:  * This code is derived from software contributed to The NetBSD Foundation
        !             9:  * by Andrew Doran.
        !            10:  *
        !            11:  * Redistribution and use in source and binary forms, with or without
        !            12:  * modification, are permitted provided that the following conditions
        !            13:  * are met:
        !            14:  * 1. Redistributions of source code must retain the above copyright
        !            15:  *    notice, this list of conditions and the following disclaimer.
        !            16:  * 2. Redistributions in binary form must reproduce the above copyright
        !            17:  *    notice, this list of conditions and the following disclaimer in the
        !            18:  *    documentation and/or other materials provided with the distribution.
        !            19:  * 3. All advertising materials mentioning features or use of this software
        !            20:  *    must display the following acknowledgement:
        !            21:  *     This product includes software developed by the NetBSD
        !            22:  *     Foundation, Inc. and its contributors.
        !            23:  * 4. Neither the name of The NetBSD Foundation nor the names of its
        !            24:  *    contributors may be used to endorse or promote products derived
        !            25:  *    from this software without specific prior written permission.
        !            26:  *
        !            27:  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
        !            28:  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
        !            29:  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
        !            30:  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
        !            31:  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
        !            32:  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
        !            33:  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
        !            34:  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
        !            35:  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
        !            36:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
        !            37:  * POSSIBILITY OF SUCH DAMAGE.
        !            38:  */
        !            39:
        !            40: #ifndef _RASOPS_MASKS_H_
        !            41: #define _RASOPS_MASKS_H_ 1
        !            42:
        !            43: #include <sys/types.h>
        !            44: #include <machine/endian.h>
        !            45:
        !            46: /*
        !            47:  * Convenience macros. To get around the problem of dealing with properly
        !            48:  * ordered bits on little-endian machines, we just convert everything to
        !            49:  * big-endian and back again when we're done.
        !            50:  *
        !            51:  * MBL: move bits left
        !            52:  * MBR: move bits right
        !            53:  * MBE: make big-endian
        !            54:  */
        !            55:
        !            56: #define MBL(x,y)       ((y) > 31 ? 0 : (x) >> (y))
        !            57: #define MBR(x,y)       ((y) > 31 ? 0 : (x) << (y))
        !            58:
        !            59: #if BYTE_ORDER == BIG_ENDIAN
        !            60: #define MBE(x)         (x)
        !            61: #else
        !            62: #define MBE(x) \
        !            63: ({ \
        !            64:        u_int32_t tmp = (x); \
        !            65:        tmp = ((tmp >>  1) & 0x55555555) | ((tmp <<  1) & 0xaaaaaaaa); \
        !            66:        tmp = ((tmp >>  2) & 0x33333333) | ((tmp <<  2) & 0xcccccccc); \
        !            67:        tmp = ((tmp >>  4) & 0x0f0f0f0f) | ((tmp <<  4) & 0xf0f0f0f0); \
        !            68:        tmp = ((tmp >>  8) & 0x00ff00ff) | ((tmp <<  8) & 0xff00ff00); \
        !            69:        tmp = ((tmp >> 16) & 0x0000ffff) | ((tmp << 16) & 0xffff0000); \
        !            70:        tmp; \
        !            71: })
        !            72: #endif
        !            73:
        !            74: /*
        !            75:  * Using GETBITS() and PUTBITS() inside a loop mightn't be such a good idea.
        !            76:  * There's probably some CSE and strength-reduction that the compiler won't
        !            77:  * even think about - really should have a few assumptions/separate cases.
        !            78:  */
        !            79:
        !            80: /* Get a number of bits ( <= 32 ) from *sp and store in dw */
        !            81: #define GETBITS(sp, x, w, dw) do {                                     \
        !            82:        dw = MBL(*(sp), (x));                                           \
        !            83:        if (((x) + (w)) > 32)                                           \
        !            84:                dw |= (MBR((sp)[1], 32 - (x)));                         \
        !            85: } while(0);
        !            86:
        !            87: /* Put a number of bits ( <= 32 ) from sw to *dp */
        !            88: #define PUTBITS(sw, x, w, dp) do {                                     \
        !            89:        int n = (x) + (w) - 32;                                         \
        !            90:                                                                        \
        !            91:        if (n <= 0) {                                                   \
        !            92:                n = rasops_pmask[x & 31][w & 31];                       \
        !            93:                *(dp) = (*(dp) & ~n) | (MBR(sw, x) & n);                \
        !            94:        } else {                                                        \
        !            95:                *(dp) = (*(dp) & rasops_rmask[x]) | (MBR((sw), x));     \
        !            96:                (dp)[1] = ((dp)[1] & rasops_rmask[n]) |                 \
        !            97:                        (MBL(sw, 32-(x)) & rasops_lmask[n]);            \
        !            98:        }                                                               \
        !            99: } while(0);
        !           100:
        !           101: /* rasops_masks.c */
        !           102: #if BYTE_ORDER == BIG_ENDIAN
        !           103: extern const int32_t   rasops_lmask[32+1];
        !           104: extern const int32_t   rasops_rmask[32+1];
        !           105: extern const int32_t   rasops_pmask[32][32];
        !           106: #define        rasops_masks_init()     do { } while (0)
        !           107: #else
        !           108: extern int32_t rasops_lmask[32+1];
        !           109: extern int32_t rasops_rmask[32+1];
        !           110: extern int32_t rasops_pmask[32][32];
        !           111: void   rasops_masks_init(void);
        !           112: #endif
        !           113:
        !           114: #endif /* _RASOPS_MASKS_H_ */