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Annotation of researchv9/X11/src/X.V11R1/server/ddx/mfb/maskbits.h, revision 1.1

1.1     ! root        1: /***********************************************************
        !             2: Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts,
        !             3: and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
        !             4: 
        !             5:                         All Rights Reserved
        !             6: 
        !             7: Permission to use, copy, modify, and distribute this software and its 
        !             8: documentation for any purpose and without fee is hereby granted, 
        !             9: provided that the above copyright notice appear in all copies and that
        !            10: both that copyright notice and this permission notice appear in 
        !            11: supporting documentation, and that the names of Digital or MIT not be
        !            12: used in advertising or publicity pertaining to distribution of the
        !            13: software without specific, written prior permission.  
        !            14: 
        !            15: DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
        !            16: ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
        !            17: DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
        !            18: ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
        !            19: WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
        !            20: ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
        !            21: SOFTWARE.
        !            22: 
        !            23: ******************************************************************/
        !            24: /* $Header: maskbits.h,v 1.6 87/09/12 23:46:43 toddb Exp $ */
        !            25: #include "X.h"
        !            26: #include "Xmd.h"
        !            27: #include "servermd.h"
        !            28: 
        !            29: extern int starttab[];
        !            30: extern int endtab[];
        !            31: extern int startpartial[];
        !            32: extern int endpartial[];
        !            33: extern int rmask[32];
        !            34: extern int mask[32];
        !            35: 
        !            36: 
        !            37: /* the following notes use the following conventions:
        !            38: SCREEN LEFT                            SCREEN RIGHT
        !            39: in this file and maskbits.c, left and right refer to screen coordinates,
        !            40: NOT bit numbering in registers.
        !            41: 
        !            42: starttab[n] 
        !            43:        bits[0,n-1] = 0 bits[n,31] = 1
        !            44: endtab[n] =
        !            45:        bits[0,n-1] = 1 bits[n,31] = 0
        !            46: 
        !            47: startpartial[], endpartial[]
        !            48:        these are used as accelerators for doing putbits and masking out
        !            49: bits that are all contained between longword boudaries.  the extra
        !            50: 256 bytes of data seems a small price to pay -- code is smaller,
        !            51: and narrow things (e.g. window borders) go faster.
        !            52: 
        !            53: the names may seem misleading; they are derived not from which end
        !            54: of the word the bits are turned on, but at which end of a scanline
        !            55: the table tends to be used.
        !            56: 
        !            57: look at the tables and macros to understand boundary conditions.
        !            58: (careful readers will note that starttab[n] = ~endtab[n] for n != 0)
        !            59: 
        !            60: -----------------------------------------------------------------------
        !            61: these two macros depend on the screen's bit ordering.
        !            62: in both of them x is a screen position.  they are used to
        !            63: combine bits collected from multiple longwords into a
        !            64: single destination longword, and to unpack a single
        !            65: source longword into multiple destinations.
        !            66: 
        !            67: SCRLEFT(dst, x)
        !            68:        takes dst[x, 32] and moves them to dst[0, 32-x]
        !            69:        the contents of the rest of dst are 0 ONLY IF
        !            70:        dst is UNSIGNED.
        !            71:        this is a right shift on LSBFirst (forward-thinking)
        !            72:        machines like the VAX, and left shift on MSBFirst
        !            73:        (backwards) machines like the 680x0 and pc/rt.
        !            74: 
        !            75: SCRRIGHT(dst, x)
        !            76:        takes dst[0,x] and moves them to dst[32-x, 32]
        !            77:        the contents of the rest of dst are 0 ONLY IF
        !            78:        dst is UNSIGNED.
        !            79:        this is a left shift on LSBFirst, right shift
        !            80:        on MSBFirst.
        !            81: 
        !            82: 
        !            83: the remaining macros are cpu-independent; all bit order dependencies
        !            84: are built into the tables and the two macros above.
        !            85: 
        !            86: maskbits(x, w, startmask, endmask, nlw)
        !            87:        for a span of width w starting at position x, returns
        !            88: a mask for ragged bits at start, mask for ragged bits at end,
        !            89: and the number of whole longwords between the ends.
        !            90: 
        !            91: maskpartialbits(x, w, mask)
        !            92:        works like maskbits(), except all the bits are in the
        !            93:        same longword (i.e. (x&0x1f + w) <= 32)
        !            94: 
        !            95: mask32bits(x, w, startmask, endmask, nlw)
        !            96:        as maskbits, but does not calculate nlw.  it is used by
        !            97:        mfbGlyphBlt to put down glyphs <= 32 bits wide.
        !            98: 
        !            99: -------------------------------------------------------------------
        !           100: 
        !           101: NOTE
        !           102:        any pointers passe to the following 4 macros are
        !           103:        guranteed to be 32-bit aligned.
        !           104:        The only non-32-bit-aligned references ever made are
        !           105:        to font glyphs, and those are made with getleftbits()
        !           106:        and getshiftedleftbits (qq.v.)
        !           107: 
        !           108: getbits(psrc, x, w, dst)
        !           109:        starting at position x in psrc (x < 32), collect w
        !           110:        bits and put them in the screen left portion of dst.
        !           111:        psrc is a longword pointer.  this may span longword boundaries.
        !           112:        it special-cases fetching all w bits from one longword.
        !           113: 
        !           114:        +--------+--------+             +--------+
        !           115:        |    | m |n|      |     ==>     | m |n|  |
        !           116:        +--------+--------+             +--------+
        !           117:            x      x+w                  0     w
        !           118:        psrc     psrc+1                 dst
        !           119:                        m = 32 - x
        !           120:                        n = w - m
        !           121: 
        !           122:        implementation:
        !           123:        get m bits, move to screen-left of dst, zeroing rest of dst;
        !           124:        get n bits from next word, move screen-right by m, zeroing
        !           125:                 lower m bits of word.
        !           126:        OR the two things together.
        !           127: 
        !           128: putbits(src, x, w, pdst)
        !           129:        starting at position x in pdst, put down the screen-leftmost
        !           130:        w bits of src.  pdst is a longword pointer.  this may
        !           131:        span longword boundaries.
        !           132:        it special-cases putting all w bits into the same longword.
        !           133: 
        !           134:        +--------+                      +--------+--------+
        !           135:        | m |n|  |              ==>     |    | m |n|      |
        !           136:        +--------+                      +--------+--------+
        !           137:        0     w                              x     x+w
        !           138:        dst                             pdst     pdst+1
        !           139:                        m = 32 - x
        !           140:                        n = w - m
        !           141: 
        !           142:        implementation:
        !           143:        get m bits, shift screen-right by x, zero screen-leftmost x
        !           144:                bits; zero rightmost m bits of *pdst and OR in stuff
        !           145:                from before the semicolon.
        !           146:        shift src screen-left by m, zero bits n-32;
        !           147:                zero leftmost n bits of *(pdst+1) and OR in the
        !           148:                stuff from before the semicolon.
        !           149: 
        !           150: putbitsrop(src, x, w, pdst, ROP)
        !           151:        like putbits but calls DoRop with the rasterop ROP (see mfb.h for
        !           152:        DoRop)
        !           153: 
        !           154: putbitsrrop(src, x, w, pdst, ROP)
        !           155:        like putbits but calls DoRRop with the reduced rasterop ROP 
        !           156:        (see mfb.h for DoRRop)
        !           157: 
        !           158: -----------------------------------------------------------------------
        !           159:        The two macros below are used only for getting bits from glyphs
        !           160: in fonts, and glyphs in fonts are gotten only with the following two
        !           161: mcros.
        !           162:        You should tune these macros toyour font format and cpu
        !           163: byte ordering.
        !           164: 
        !           165: NOTE
        !           166: getleftbits(psrc, w, dst)
        !           167:        get the leftmost w (w<=32) bits from *psrc and put them
        !           168:        in dst.  this is used by the mfbGlyphBlt code for glyphs
        !           169:        <=32 bits wide.
        !           170:        psrc is declared (unsigned char *)
        !           171: 
        !           172:        psrc is NOT guaranteed to be 32-bit aligned.  on  many
        !           173:        machines this will cause problems, so there are several
        !           174:        versions of this macro.
        !           175: 
        !           176:        this macro is called ONLY for getting bits from font glyphs,
        !           177:        and depends on the server-natural font padding.
        !           178: 
        !           179:        for blazing text performance, you want this macro
        !           180:        to touch memory as infrequently as possible (e.g.
        !           181:        fetch longwords) and as efficiently as possible
        !           182:        (e.g. don't fetch misaligned longwords)
        !           183: 
        !           184: getshiftedleftbits(psrc, offset, w, dst)
        !           185:        used by the font code; like getleftbits, but shifts the
        !           186:        bits SCRLEFT by offset.
        !           187:        this is implemented portably, calling getleftbits()
        !           188:        and SCRLEFT().
        !           189:        psrc is declared (unsigned char *).
        !           190: */
        !           191: 
        !           192: #if (BITMAP_BIT_ORDER == MSBFirst)     /* pc/rt, 680x0 */
        !           193: #define SCRLEFT(lw, n) ((lw) << (n))
        !           194: #define SCRRIGHT(lw, n)        ((lw) >> (n))
        !           195: #else                                  /* vax, intel */
        !           196: #define SCRLEFT(lw, n) ((lw) >> (n))
        !           197: #define SCRRIGHT(lw, n)        ((lw) << (n))
        !           198: #endif
        !           199: 
        !           200: 
        !           201: #define maskbits(x, w, startmask, endmask, nlw) \
        !           202:     startmask = starttab[(x)&0x1f]; \
        !           203:     endmask = endtab[((x)+(w)) & 0x1f]; \
        !           204:     if (startmask) \
        !           205:        nlw = (((w) - (32 - ((x)&0x1f))) >> 5); \
        !           206:     else \
        !           207:        nlw = (w) >> 5;
        !           208: 
        !           209: #define maskpartialbits(x, w, mask) \
        !           210:     mask = startpartial[(x) & 0x1f] & endpartial[((x) + (w)) & 0x1f];
        !           211: 
        !           212: #define mask32bits(x, w, startmask, endmask) \
        !           213:     startmask = starttab[(x)&0x1f]; \
        !           214:     endmask = endtab[((x)+(w)) & 0x1f];
        !           215: 
        !           216: 
        !           217: #define getbits(psrc, x, w, dst) \
        !           218: if ( ((x) + (w)) <= 32) \
        !           219: { \
        !           220:     dst = SCRLEFT(*(psrc), (x)); \
        !           221: } \
        !           222: else \
        !           223: { \
        !           224:     int m; \
        !           225:     m = 32-(x); \
        !           226:     dst = (SCRLEFT(*(psrc), (x)) & endtab[m]) | \
        !           227:          (SCRRIGHT(*((psrc)+1), m) & starttab[m]); \
        !           228: }
        !           229: 
        !           230: 
        !           231: #define putbits(src, x, w, pdst) \
        !           232: if ( ((x)+(w)) <= 32) \
        !           233: { \
        !           234:     int tmpmask; \
        !           235:     maskpartialbits((x), (w), tmpmask); \
        !           236:     *(pdst) = (*(pdst) & ~tmpmask) | (SCRRIGHT(src, x) & tmpmask); \
        !           237: } \
        !           238: else \
        !           239: { \
        !           240:     int m; \
        !           241:     int n; \
        !           242:     m = 32-(x); \
        !           243:     n = (w) - m; \
        !           244:     *(pdst) = (*(pdst) & endtab[x]) | (SCRRIGHT(src, x) & starttab[x]); \
        !           245:     *((pdst)+1) = (*((pdst)+1) & starttab[n]) | (SCRLEFT(src, m) & endtab[n]); \
        !           246: }
        !           247: 
        !           248: #define putbitsrop(src, x, w, pdst, rop) \
        !           249: if ( ((x)+(w)) <= 32) \
        !           250: { \
        !           251:     int tmpmask; \
        !           252:     int t1, t2; \
        !           253:     maskpartialbits((x), (w), tmpmask); \
        !           254:     t1 = SCRRIGHT((src), (x)); \
        !           255:     t2 = DoRop(rop, t1, *(pdst)); \
        !           256:     *(pdst) = (*(pdst) & ~tmpmask) | (t2 & tmpmask); \
        !           257: } \
        !           258: else \
        !           259: { \
        !           260:     int m; \
        !           261:     int n; \
        !           262:     int t1, t2; \
        !           263:     m = 32-(x); \
        !           264:     n = (w) - m; \
        !           265:     t1 = SCRRIGHT((src), (x)); \
        !           266:     t2 = DoRop(rop, t1, *(pdst)); \
        !           267:     *(pdst) = (*(pdst) & endtab[x]) | (t2 & starttab[x]); \
        !           268:     t1 = SCRLEFT((src), m); \
        !           269:     t2 = DoRop(rop, t1, *((pdst) + 1)); \
        !           270:     *((pdst)+1) = (*((pdst)+1) & starttab[n]) | (t2 & endtab[n]); \
        !           271: }
        !           272: 
        !           273: #define putbitsrrop(src, x, w, pdst, rop) \
        !           274: if ( ((x)+(w)) <= 32) \
        !           275: { \
        !           276:     int tmpmask; \
        !           277:     int t1, t2; \
        !           278:     maskpartialbits((x), (w), tmpmask); \
        !           279:     t1 = SCRRIGHT((src), (x)); \
        !           280:     t2 = DoRRop(rop, t1, *(pdst)); \
        !           281:     *(pdst) = (*(pdst) & ~tmpmask) | (t2 & tmpmask); \
        !           282: } \
        !           283: else \
        !           284: { \
        !           285:     int m; \
        !           286:     int n; \
        !           287:     int t1, t2; \
        !           288:     m = 32-(x); \
        !           289:     n = (w) - m; \
        !           290:     t1 = SCRRIGHT((src), (x)); \
        !           291:     t2 = DoRRop(rop, t1, *(pdst)); \
        !           292:     *(pdst) = (*(pdst) & endtab[x]) | (t2 & starttab[x]); \
        !           293:     t1 = SCRLEFT((src), m); \
        !           294:     t2 = DoRRop(rop, t1, *((pdst) + 1)); \
        !           295:     *((pdst)+1) = (*((pdst)+1) & starttab[n]) | (t2 & endtab[n]); \
        !           296: }
        !           297: 
        !           298: #if GETLEFTBITS_ALIGNMENT == 1
        !           299: #define getleftbits(psrc, w, dst)      getbits(psrc, 0, w, dst)
        !           300: #endif /* GETLEFTBITS_ALIGNMENT == 1 */
        !           301: 
        !           302: #if GETLEFTBITS_ALIGNMENT == 2
        !           303: #define getleftbits(psrc, w, dst) \
        !           304:     { \
        !           305:        if ( ((int)(psrc)) & 0x01 ) \
        !           306:                getbits( ((unsigned int *)((int)(psrc))-1), 8, (w), (dst) ); \
        !           307:        else
        !           308:                getbits(psrc, 0, w, dst)
        !           309:     }
        !           310: #endif /* GETLEFTBITS_ALIGNMENT == 2 */
        !           311: 
        !           312: #if GETLEFTBITS_ALIGNMENT == 4
        !           313: #define getleftbits(psrc, w, dst) \
        !           314:     { \
        !           315:        int off; \
        !           316:        off = ( ((int)(psrc)) & 0x03) << 3; \
        !           317:        getbits( \
        !           318:                (unsigned int *)( ((int)(psrc)) &~0x03), \
        !           319:                (off), (w), (dst) \
        !           320:               ); \
        !           321:     }
        !           322: #endif /* GETLEFTBITS_ALIGNMENT == 4 */
        !           323: 
        !           324: 
        !           325: #define getshiftedleftbits(psrc, offset, w, dst) \
        !           326:        getleftbits((psrc), (w), (dst)); \
        !           327:        dst = SCRLEFT((dst), (offset));
        !           328: 
        !           329: 

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