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Annotation of sys/dev/rasops/rasops_masks.h, Revision 1.1.1.1

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_ */