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Diffstat (limited to 'cfb/cfbrrop.c')
| -rw-r--r-- | cfb/cfbrrop.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/cfb/cfbrrop.c b/cfb/cfbrrop.c new file mode 100644 index 000000000..69ec0278d --- /dev/null +++ b/cfb/cfbrrop.c @@ -0,0 +1,221 @@ +/* + * $Xorg: cfbrrop.c,v 1.4 2001/02/09 02:04:38 xorgcvs Exp $ + * +Copyright 1989, 1998 The Open Group + +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. + +The above copyright notice and this permission notice shall be included in +all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN +AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN +CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + +Except as contained in this notice, the name of The Open Group shall not be +used in advertising or otherwise to promote the sale, use or other dealings +in this Software without prior written authorization from The Open Group. + * + * Author: Keith Packard, MIT X Consortium + */ + +/* cfb reduced rasterop computations */ + +#include "X.h" +#include "Xmd.h" +#include "Xproto.h" +#include "cfb.h" +#include "cfbmskbits.h" + +/* A description: + * + * There are four possible operations on each bit in the destination word, + * + * 1 2 3 4 + * + * 0 0 0 1 1 + * 1 0 1 0 1 + * + * On examination of the reduced rop equation (dst = (dst & and) ^ xor), + * these four fall to reduced rops as follows: + * + * and 0 1 1 0 + * xor 0 0 1 1 + * + * or, (if 'and' is expensive) (dst = (dst | or) ^ xor) + * + * or 1 0 0 1 + * xor 1 0 1 0 + * + * The trouble with using this later equation is that trivial + * rasterop reduction is more difficult; some common rasterops + * use complicated expressions of xor/and instead of the simple + * ones while other common rasterops are not made any simpler: + * + * GXcopy: *dst = ~xor instead of *dst = xor + * GXand: *dst = *dst & ~or instead of *dst = *dst & and + * GXor: *dst = *dst | or instead of *dst = *dst | xor + * GXxor: *dst = *dst ^ xor instead of *dst = *dst ^ xor + * + * If you're really set on using this second mechanism, the changes + * are pretty simple. + * + * All that remains is to provide a mechanism for computing and/xor values + * based on the raster op and foreground value. + * + * The 16 rops fall as follows, with the associated reduced + * rop and/xor and or/xor values. The values in parenthesis following the + * reduced values gives an equation using the source value for + * the reduced value, and is one of {0, src, ~src, 1} as appropriate. + * + * clear and andReverse copy + * src 0 1 0 1 0 1 0 1 + * dst 0 0 0 0 0 0 0 0 1 0 0 1 + * 1 0 0 1 0 1 1 0 0 1 0 1 + * + * and 0 0 (0) 0 1 (src) 0 1 (src) 0 0 (0) + * xor 0 0 (0) 0 0 (0) 0 1 (src) 0 1 (src) + * + * or 1 1 (1) 1 0 (~src) 1 0 (~src) 1 1 (1) + * xor 1 1 (1) 1 0 (~src) 1 1 (1) 1 0 (~src) + * + * andInverted noop xor or + * src 0 1 0 1 0 1 0 1 + * dst 0 0 0 0 0 0 0 0 1 0 0 1 + * 1 1 0 1 1 1 1 1 0 1 1 1 + * + * and 1 0 (~src) 1 1 (1) 1 1 (1) 1 0 (~src) + * xor 0 0 (0) 0 0 (0) 0 1 (src) 0 1 (src) + * + * or 0 1 (src) 0 0 (0) 0 0 (0) 0 1 (src) + * xor 0 1 (src) 0 0 (0) 0 1 (src) 0 0 (0) + * + * nor equiv invert orReverse + * src 0 1 0 1 0 1 0 1 + * dst 0 1 0 0 1 0 0 1 1 0 1 1 + * 1 0 0 1 0 1 1 0 0 1 0 1 + * + * and 1 0 (~src) 1 1 (1) 1 1 (1) 1 0 (~src) + * xor 1 0 (~src) 1 0 (~src) 1 1 (1) 1 1 (1) + * + * or 0 1 (src) 0 0 (0) 0 0 (0) 0 1 (src) + * xor 1 1 (1) 1 0 (~src) 1 1 (1) 1 0 (~src) + * + * copyInverted orInverted nand set + * src 0 1 0 1 0 1 0 1 + * dst 0 1 0 0 1 0 0 1 1 0 1 1 + * 1 1 0 1 1 1 1 1 0 1 1 1 + * + * and 0 0 (0) 0 1 (src) 0 1 (src) 0 0 (0) + * xor 1 0 (~src) 1 0 (~src) 1 1 (1) 1 1 (1) + * + * or 1 1 (1) 1 0 (~src) 1 0 (~src) 1 1 (1) + * xor 0 1 (src) 0 0 (0) 0 1 (src) 0 0 (0) + */ + +int +cfbReduceRasterOp (rop, fg, pm, andp, xorp) + int rop; + unsigned long fg, pm; + unsigned long *andp, *xorp; +{ + unsigned long and, xor; + int rrop; + + fg = PFILL (fg); + pm = PFILL (pm); + switch (rop) + { + case GXclear: + and = 0; + xor = 0; + break; + case GXand: + and = fg; + xor = 0; + break; + case GXandReverse: + and = fg; + xor = fg; + break; + case GXcopy: + and = 0; + xor = fg; + break; + case GXandInverted: + and = ~fg; + xor = 0; + break; + case GXnoop: + and = ~0; + xor = 0; + break; + case GXxor: + and = ~0; + xor = fg; + break; + case GXor: + and = ~fg; + xor = fg; + break; + case GXnor: + and = ~fg; + xor = ~fg; + break; + case GXequiv: + and = ~0; + xor = ~fg; + break; + case GXinvert: + and = ~0; + xor = ~0; + break; + case GXorReverse: + and = ~fg; + xor = ~0; + break; + case GXcopyInverted: + and = 0; + xor = ~fg; + break; + case GXorInverted: + and = fg; + xor = ~fg; + break; + case GXnand: + and = fg; + xor = ~0; + break; + case GXset: + and = 0; + xor = ~0; + break; + } + and |= ~pm; + xor &= pm; + *andp = and; + *xorp = xor; + /* check for some special cases to reduce computation */ + if (and == 0) + rrop = GXcopy; + /* nothing checks for GXnoop + else if (and == ~0 && xor == 0) + rrop = GXnoop; + */ + else if (and == ~0) + rrop = GXxor; + else if (xor == 0) + rrop = GXand; + else if ( (and ^ xor) == ~0) /* fix XBUG 6541 */ + rrop = GXor; + else + rrop = GXset; /* rop not reduced */ + return rrop; +} |