diff --git a/src/libdraw/md-draw.c b/src/libdraw/md-draw.c
new file mode 100644
index 0000000..d0f2d4f
--- /dev/null
+++ b/src/libdraw/md-draw.c
@@ -0,0 +1,2487 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+#include <memdraw.h>
+
+int drawdebug;
+static int	tablesbuilt;
+
+/* perfect approximation to NTSC = .299r+.587g+.114b when 0 ≤ r,g,b < 256 */
+#define RGB2K(r,g,b)	((156763*(r)+307758*(g)+59769*(b))>>19)
+
+/*
+ * for 0 ≤ x ≤ 255*255, (x*0x0101+0x100)>>16 is a perfect approximation.
+ * for 0 ≤ x < (1<<16), x/255 = ((x+1)*0x0101)>>16 is a perfect approximation.
+ * the last one is perfect for all up to 1<<16, avoids a multiply, but requires a rathole.
+ */
+/* #define DIV255(x) (((x)*257+256)>>16)  */
+#define DIV255(x) ((((x)+1)*257)>>16)
+/* #define DIV255(x) (tmp=(x)+1, (tmp+(tmp>>8))>>8) */
+
+#define MUL(x, y, t)	(t = (x)*(y)+128, (t+(t>>8))>>8)
+#define MASK13	0xFF00FF00
+#define MASK02	0x00FF00FF
+#define MUL13(a, x, t)		(t = (a)*(((x)&MASK13)>>8)+128, ((t+((t>>8)&MASK02))>>8)&MASK02)
+#define MUL02(a, x, t)		(t = (a)*(((x)&MASK02)>>0)+128, ((t+((t>>8)&MASK02))>>8)&MASK02)
+#define MUL0123(a, x, s, t)	((MUL13(a, x, s)<<8)|MUL02(a, x, t))
+
+#define MUL2(u, v, x, y)	(t = (u)*(v)+(x)*(y)+256, (t+(t>>8))>>8)
+
+static void mktables(void);
+typedef int Subdraw(Memdrawparam*);
+static Subdraw chardraw, alphadraw, memoptdraw;
+
+static Memimage*	memones;
+static Memimage*	memzeros;
+Memimage *memwhite;
+Memimage *memblack;
+Memimage *memtransparent;
+Memimage *memopaque;
+
+int	__ifmt(Fmt*);
+
+void
+memimageinit(void)
+{
+	static int didinit = 0;
+
+	if(didinit)
+		return;
+
+	didinit = 1;
+
+	mktables();
+	_memmkcmap();
+
+	fmtinstall('R', Rfmt); 
+	fmtinstall('P', Pfmt);
+	fmtinstall('b', __ifmt);
+
+	memones = allocmemimage(Rect(0,0,1,1), GREY1);
+	memones->flags |= Frepl;
+	memones->clipr = Rect(-0x3FFFFFF, -0x3FFFFFF, 0x3FFFFFF, 0x3FFFFFF);
+	*byteaddr(memones, ZP) = ~0;
+
+	memzeros = allocmemimage(Rect(0,0,1,1), GREY1);
+	memzeros->flags |= Frepl;
+	memzeros->clipr = Rect(-0x3FFFFFF, -0x3FFFFFF, 0x3FFFFFF, 0x3FFFFFF);
+	*byteaddr(memzeros, ZP) = 0;
+
+	if(memones == nil || memzeros == nil)
+		assert(0 /*cannot initialize memimage library */);	/* RSC BUG */
+
+	memwhite = memones;
+	memblack = memzeros;
+	memopaque = memones;
+	memtransparent = memzeros;
+}
+
+u32int _imgtorgba(Memimage*, u32int);
+u32int _rgbatoimg(Memimage*, u32int);
+u32int _pixelbits(Memimage*, Point);
+
+#define DBG if(0)
+static Memdrawparam par;
+
+Memdrawparam*
+_memimagedrawsetup(Memimage *dst, Rectangle r, Memimage *src, Point p0, Memimage *mask, Point p1, int op)
+{
+	if(mask == nil)
+		mask = memopaque;
+
+DBG	print("memimagedraw %p/%luX %R @ %p %p/%luX %P %p/%luX %P... ", dst, dst->chan, r, dst->data->bdata, src, src->chan, p0, mask, mask->chan, p1);
+
+	if(drawclip(dst, &r, src, &p0, mask, &p1, &par.sr, &par.mr) == 0){
+//		if(drawdebug)
+//			iprint("empty clipped rectangle\n");
+		return nil;
+	}
+
+	if(op < Clear || op > SoverD){
+//		if(drawdebug)
+//			iprint("op out of range: %d\n", op);
+		return nil;
+	}
+
+	par.op = op;
+	par.dst = dst;
+	par.r = r;
+	par.src = src;
+	/* par.sr set by drawclip */
+	par.mask = mask;
+	/* par.mr set by drawclip */
+
+	par.state = 0;
+	if(src->flags&Frepl){
+		par.state |= Replsrc;
+		if(Dx(src->r)==1 && Dy(src->r)==1){
+			par.sval = pixelbits(src, src->r.min);
+			par.state |= Simplesrc;
+			par.srgba = _imgtorgba(src, par.sval);
+			par.sdval = _rgbatoimg(dst, par.srgba);
+			if((par.srgba&0xFF) == 0 && (op&DoutS)){
+//				if (drawdebug) iprint("fill with transparent source\n");
+				return nil;	/* no-op successfully handled */
+			}
+		}
+	}
+
+	if(mask->flags & Frepl){
+		par.state |= Replmask;
+		if(Dx(mask->r)==1 && Dy(mask->r)==1){
+			par.mval = pixelbits(mask, mask->r.min);
+			if(par.mval == 0 && (op&DoutS)){
+//				if(drawdebug) iprint("fill with zero mask\n");
+				return nil;	/* no-op successfully handled */
+			}
+			par.state |= Simplemask;
+			if(par.mval == ~0)
+				par.state |= Fullmask;
+			par.mrgba = _imgtorgba(mask, par.mval);
+		}
+	}
+
+//	if(drawdebug)
+//		iprint("dr %R sr %R mr %R...", r, par.sr, par.mr);
+DBG print("draw dr %R sr %R mr %R %lux\n", r, par.sr, par.mr, par.state);
+
+	return &par;
+}
+
+void
+_memimagedraw(Memdrawparam *par)
+{
+	/*
+	 * Now that we've clipped the parameters down to be consistent, we 
+	 * simply try sub-drawing routines in order until we find one that was able
+	 * to handle us.  If the sub-drawing routine returns zero, it means it was
+	 * unable to satisfy the request, so we do not return.
+	 */
+
+	/*
+	 * Hardware support.  Each video driver provides this function,
+	 * which checks to see if there is anything it can help with.
+	 * There could be an if around this checking to see if dst is in video memory.
+	 */
+DBG print("test hwdraw\n");
+	if(hwdraw(par)){
+//if(drawdebug) iprint("hw handled\n");
+DBG print("hwdraw handled\n");
+		return;
+	}
+	/*
+	 * Optimizations using memmove and memset.
+	 */
+DBG print("test memoptdraw\n");
+	if(memoptdraw(par)){
+//if(drawdebug) iprint("memopt handled\n");
+DBG print("memopt handled\n");
+		return;
+	}
+
+	/*
+	 * Character drawing.
+	 * Solid source color being painted through a boolean mask onto a high res image.
+	 */
+DBG print("test chardraw\n");
+	if(chardraw(par)){
+//if(drawdebug) iprint("chardraw handled\n");
+DBG print("chardraw handled\n");
+		return;
+	}
+
+	/*
+	 * General calculation-laden case that does alpha for each pixel.
+	 */
+DBG print("do alphadraw\n");
+	alphadraw(par);
+//if(drawdebug) iprint("alphadraw handled\n");
+DBG print("alphadraw handled\n");
+}
+#undef DBG
+
+/*
+ * Clip the destination rectangle further based on the properties of the 
+ * source and mask rectangles.  Once the destination rectangle is properly
+ * clipped, adjust the source and mask rectangles to be the same size.
+ * Then if source or mask is replicated, move its clipped rectangle
+ * so that its minimum point falls within the repl rectangle.
+ *
+ * Return zero if the final rectangle is null.
+ */
+int
+drawclip(Memimage *dst, Rectangle *r, Memimage *src, Point *p0, Memimage *mask, Point *p1, Rectangle *sr, Rectangle *mr)
+{
+	Point rmin, delta;
+	int splitcoords;
+	Rectangle omr;
+
+	if(r->min.x>=r->max.x || r->min.y>=r->max.y)
+		return 0;
+	splitcoords = (p0->x!=p1->x) || (p0->y!=p1->y);
+	/* clip to destination */
+	rmin = r->min;
+	if(!rectclip(r, dst->r) || !rectclip(r, dst->clipr))
+		return 0;
+	/* move mask point */
+	p1->x += r->min.x-rmin.x;
+	p1->y += r->min.y-rmin.y;
+	/* move source point */
+	p0->x += r->min.x-rmin.x;
+	p0->y += r->min.y-rmin.y;
+	/* map destination rectangle into source */
+	sr->min = *p0;
+	sr->max.x = p0->x+Dx(*r);
+	sr->max.y = p0->y+Dy(*r);
+	/* sr is r in source coordinates; clip to source */
+	if(!(src->flags&Frepl) && !rectclip(sr, src->r))
+		return 0;
+	if(!rectclip(sr, src->clipr))
+		return 0;
+	/* compute and clip rectangle in mask */
+	if(splitcoords){
+		/* move mask point with source */
+		p1->x += sr->min.x-p0->x;
+		p1->y += sr->min.y-p0->y;
+		mr->min = *p1;
+		mr->max.x = p1->x+Dx(*sr);
+		mr->max.y = p1->y+Dy(*sr);
+		omr = *mr;
+		/* mr is now rectangle in mask; clip it */
+		if(!(mask->flags&Frepl) && !rectclip(mr, mask->r))
+			return 0;
+		if(!rectclip(mr, mask->clipr))
+			return 0;
+		/* reflect any clips back to source */
+		sr->min.x += mr->min.x-omr.min.x;
+		sr->min.y += mr->min.y-omr.min.y;
+		sr->max.x += mr->max.x-omr.max.x;
+		sr->max.y += mr->max.y-omr.max.y;
+		*p1 = mr->min;
+	}else{
+		if(!(mask->flags&Frepl) && !rectclip(sr, mask->r))
+			return 0;
+		if(!rectclip(sr, mask->clipr))
+			return 0;
+		*p1 = sr->min;
+	}
+
+	/* move source clipping back to destination */
+	delta.x = r->min.x - p0->x;
+	delta.y = r->min.y - p0->y;
+	r->min.x = sr->min.x + delta.x;
+	r->min.y = sr->min.y + delta.y;
+	r->max.x = sr->max.x + delta.x;
+	r->max.y = sr->max.y + delta.y;
+
+	/* move source rectangle so sr->min is in src->r */
+	if(src->flags&Frepl) {
+		delta.x = drawreplxy(src->r.min.x, src->r.max.x, sr->min.x) - sr->min.x;
+		delta.y = drawreplxy(src->r.min.y, src->r.max.y, sr->min.y) - sr->min.y;
+		sr->min.x += delta.x;
+		sr->min.y += delta.y;
+		sr->max.x += delta.x;
+		sr->max.y += delta.y;
+	}
+	*p0 = sr->min;
+
+	/* move mask point so it is in mask->r */
+	*p1 = drawrepl(mask->r, *p1);
+	mr->min = *p1;
+	mr->max.x = p1->x+Dx(*sr);
+	mr->max.y = p1->y+Dy(*sr);
+
+	assert(Dx(*sr) == Dx(*mr) && Dx(*mr) == Dx(*r));
+	assert(Dy(*sr) == Dy(*mr) && Dy(*mr) == Dy(*r));
+	assert(ptinrect(*p0, src->r));
+	assert(ptinrect(*p1, mask->r));
+	assert(ptinrect(r->min, dst->r));
+
+	return 1;
+}
+
+/*
+ * Conversion tables.
+ */
+static uchar replbit[1+8][256];		/* replbit[x][y] is the replication of the x-bit quantity y to 8-bit depth */
+static uchar conv18[256][8];		/* conv18[x][y] is the yth pixel in the depth-1 pixel x */
+static uchar conv28[256][4];		/* ... */
+static uchar conv48[256][2];
+
+/*
+ * bitmap of how to replicate n bits to fill 8, for 1 ≤ n ≤ 8.
+ * the X's are where to put the bottom (ones) bit of the n-bit pattern.
+ * only the top 8 bits of the result are actually used.
+ * (the lower 8 bits are needed to get bits in the right place
+ * when n is not a divisor of 8.)
+ *
+ * Should check to see if its easier to just refer to replmul than
+ * use the precomputed values in replbit.  On PCs it may well
+ * be; on machines with slow multiply instructions it probably isn't.
+ */
+#define a ((((((((((((((((0
+#define X *2+1)
+#define _ *2)
+static int replmul[1+8] = {
+	0,
+	a X X X X X X X X X X X X X X X X,
+	a _ X _ X _ X _ X _ X _ X _ X _ X,
+	a _ _ X _ _ X _ _ X _ _ X _ _ X _,
+	a _ _ _ X _ _ _ X _ _ _ X _ _ _ X,
+	a _ _ _ _ X _ _ _ _ X _ _ _ _ X _,
+	a _ _ _ _ _ X _ _ _ _ _ X _ _ _ _, 
+	a _ _ _ _ _ _ X _ _ _ _ _ _ X _ _,
+	a _ _ _ _ _ _ _ X _ _ _ _ _ _ _ X,
+};
+#undef a
+#undef X
+#undef _
+
+static void
+mktables(void)
+{
+	int i, j, mask, sh, small;
+		
+	if(tablesbuilt)
+		return;
+
+	fmtinstall('R', Rfmt);
+	fmtinstall('P', Pfmt);
+	tablesbuilt = 1;
+
+	/* bit replication up to 8 bits */
+	for(i=0; i<256; i++){
+		for(j=0; j<=8; j++){	/* j <= 8 [sic] */
+			small = i & ((1<<j)-1);
+			replbit[j][i] = (small*replmul[j])>>8;
+		}
+	}
+
+	/* bit unpacking up to 8 bits, only powers of 2 */
+	for(i=0; i<256; i++){
+		for(j=0, sh=7, mask=1; j<8; j++, sh--)
+			conv18[i][j] = replbit[1][(i>>sh)&mask];
+
+		for(j=0, sh=6, mask=3; j<4; j++, sh-=2)
+			conv28[i][j] = replbit[2][(i>>sh)&mask];
+
+		for(j=0, sh=4, mask=15; j<2; j++, sh-=4)
+			conv48[i][j] = replbit[4][(i>>sh)&mask];
+	}
+}
+
+static uchar ones = 0xff;
+
+/*
+ * General alpha drawing case.  Can handle anything.
+ */
+typedef struct	Buffer	Buffer;
+struct Buffer {
+	/* used by most routines */
+	uchar	*red;
+	uchar	*grn;
+	uchar	*blu;
+	uchar	*alpha;
+	uchar	*grey;
+	u32int	*rgba;
+	int	delta;	/* number of bytes to add to pointer to get next pixel to the right */
+
+	/* used by boolcalc* for mask data */
+	uchar	*m;		/* ptr to mask data r.min byte; like p->bytermin */
+	int		mskip;	/* no. of left bits to skip in *m */
+	uchar	*bm;		/* ptr to mask data img->r.min byte; like p->bytey0s */
+	int		bmskip;	/* no. of left bits to skip in *bm */
+	uchar	*em;		/* ptr to mask data img->r.max.x byte; like p->bytey0e */
+	int		emskip;	/* no. of right bits to skip in *em */
+};
+
+typedef struct	Param	Param;
+typedef Buffer	Readfn(Param*, uchar*, int);
+typedef void	Writefn(Param*, uchar*, Buffer);
+typedef Buffer	Calcfn(Buffer, Buffer, Buffer, int, int, int);
+
+enum {
+	MAXBCACHE = 16
+};
+
+/* giant rathole to customize functions with */
+struct Param {
+	Readfn	*replcall;
+	Readfn	*greymaskcall;	
+	Readfn	*convreadcall;
+	Writefn	*convwritecall;
+
+	Memimage *img;
+	Rectangle	r;
+	int	dx;	/* of r */
+	int	needbuf;
+	int	convgrey;
+	int	alphaonly;
+
+	uchar	*bytey0s;		/* byteaddr(Pt(img->r.min.x, img->r.min.y)) */
+	uchar	*bytermin;	/* byteaddr(Pt(r.min.x, img->r.min.y)) */
+	uchar	*bytey0e;		/* byteaddr(Pt(img->r.max.x, img->r.min.y)) */
+	int		bwidth;
+
+	int	replcache;	/* if set, cache buffers */
+	Buffer	bcache[MAXBCACHE];
+	u32int	bfilled;
+	uchar	*bufbase;
+	int	bufoff;
+	int	bufdelta;
+
+	int	dir;
+
+	int	convbufoff;
+	uchar	*convbuf;
+	Param	*convdpar;
+	int	convdx;
+};
+
+static uchar *drawbuf;
+static int	ndrawbuf;
+static int	mdrawbuf;
+static Param spar, mpar, dpar;	/* easier on the stacks */
+static Readfn	greymaskread, replread, readptr;
+static Writefn	nullwrite;
+static Calcfn	alphacalc0, alphacalc14, alphacalc2810, alphacalc3679, alphacalc5, alphacalc11, alphacalcS;
+static Calcfn	boolcalc14, boolcalc236789, boolcalc1011;
+
+static Readfn*	readfn(Memimage*);
+static Readfn*	readalphafn(Memimage*);
+static Writefn*	writefn(Memimage*);
+
+static Calcfn*	boolcopyfn(Memimage*, Memimage*);
+static Readfn*	convfn(Memimage*, Param*, Memimage*, Param*);
+
+static Calcfn *alphacalc[Ncomp] = 
+{
+	alphacalc0,		/* Clear */
+	alphacalc14,		/* DoutS */
+	alphacalc2810,		/* SoutD */
+	alphacalc3679,		/* DxorS */
+	alphacalc14,		/* DinS */
+	alphacalc5,		/* D */
+	alphacalc3679,		/* DatopS */
+	alphacalc3679,		/* DoverS */
+	alphacalc2810,		/* SinD */
+	alphacalc3679,		/* SatopD */
+	alphacalc2810,		/* S */
+	alphacalc11,		/* SoverD */
+};
+
+static Calcfn *boolcalc[Ncomp] =
+{
+	alphacalc0,		/* Clear */
+	boolcalc14,		/* DoutS */
+	boolcalc236789,		/* SoutD */
+	boolcalc236789,		/* DxorS */
+	boolcalc14,		/* DinS */
+	alphacalc5,		/* D */
+	boolcalc236789,		/* DatopS */
+	boolcalc236789,		/* DoverS */
+	boolcalc236789,		/* SinD */
+	boolcalc236789,		/* SatopD */
+	boolcalc1011,		/* S */
+	boolcalc1011,		/* SoverD */
+};
+
+static int
+allocdrawbuf(void)
+{
+	uchar *p;
+
+	if(ndrawbuf > mdrawbuf){
+		p = realloc(drawbuf, ndrawbuf);
+		if(p == nil){
+			werrstr("memimagedraw out of memory");
+			return -1;
+		}
+		drawbuf = p;
+		mdrawbuf = ndrawbuf;
+	}
+	return 0;
+}
+
+static Param
+getparam(Memimage *img, Rectangle r, int convgrey, int needbuf)
+{
+	Param p;
+	int nbuf;
+
+	memset(&p, 0, sizeof p);
+
+	p.img = img;
+	p.r = r;
+	p.dx = Dx(r);
+	p.needbuf = needbuf;
+	p.convgrey = convgrey;
+
+	assert(img->r.min.x <= r.min.x && r.min.x < img->r.max.x);
+
+	p.bytey0s = byteaddr(img, Pt(img->r.min.x, img->r.min.y));
+	p.bytermin = byteaddr(img, Pt(r.min.x, img->r.min.y));
+	p.bytey0e = byteaddr(img, Pt(img->r.max.x, img->r.min.y));
+	p.bwidth = sizeof(u32int)*img->width;
+
+	assert(p.bytey0s <= p.bytermin && p.bytermin <= p.bytey0e);
+
+	if(p.r.min.x == p.img->r.min.x)
+		assert(p.bytermin == p.bytey0s);
+
+	nbuf = 1;
+	if((img->flags&Frepl) && Dy(img->r) <= MAXBCACHE && Dy(img->r) < Dy(r)){
+		p.replcache = 1;
+		nbuf = Dy(img->r);
+	}
+	p.bufdelta = 4*p.dx;
+	p.bufoff = ndrawbuf;
+	ndrawbuf += p.bufdelta*nbuf;
+
+	return p;
+}
+
+static void
+clipy(Memimage *img, int *y)
+{
+	int dy;
+
+	dy = Dy(img->r);
+	if(*y == dy)
+		*y = 0;
+	else if(*y == -1)
+		*y = dy-1;
+	assert(0 <= *y && *y < dy);
+}
+
+static void
+dumpbuf(char *s, Buffer b, int n)
+{
+	int i;
+	uchar *p;
+	
+	print("%s", s);
+	for(i=0; i<n; i++){
+		print(" ");
+		if(p=b.grey){
+			print(" k%.2uX", *p);
+			b.grey += b.delta;
+		}else{	
+			if(p=b.red){
+				print(" r%.2uX", *p);
+				b.red += b.delta;
+			}
+			if(p=b.grn){
+				print(" g%.2uX", *p);
+				b.grn += b.delta;
+			}
+			if(p=b.blu){
+				print(" b%.2uX", *p);
+				b.blu += b.delta;
+			}
+		}
+		if((p=b.alpha) != &ones){
+			print(" α%.2uX", *p);
+			b.alpha += b.delta;
+		}
+	}
+	print("\n");
+}
+
+/*
+ * For each scan line, we expand the pixels from source, mask, and destination
+ * into byte-aligned red, green, blue, alpha, and grey channels.  If buffering is not
+ * needed and the channels were already byte-aligned (grey8, rgb24, rgba32, rgb32),
+ * the readers need not copy the data: they can simply return pointers to the data.
+ * If the destination image is grey and the source is not, it is converted using the NTSC
+ * formula.
+ *
+ * Once we have all the channels, we call either rgbcalc or greycalc, depending on 
+ * whether the destination image is color.  This is allowed to overwrite the dst buffer (perhaps
+ * the actual data, perhaps a copy) with its result.  It should only overwrite the dst buffer
+ * with the same format (i.e. red bytes with red bytes, etc.)  A new buffer is returned from
+ * the calculator, and that buffer is passed to a function to write it to the destination.
+ * If the buffer is already pointing at the destination, the writing function is a no-op.
+ */
+#define DBG if(0)
+static int
+alphadraw(Memdrawparam *par)
+{
+	int isgrey, starty, endy, op;
+	int needbuf, dsty, srcy, masky;
+	int y, dir, dx, dy;
+	Buffer bsrc, bdst, bmask;
+	Readfn *rdsrc, *rdmask, *rddst;
+	Calcfn *calc;
+	Writefn *wrdst;
+	Memimage *src, *mask, *dst;
+	Rectangle r, sr, mr;
+
+	r = par->r;
+	dx = Dx(r);
+	dy = Dy(r);
+
+	ndrawbuf = 0;
+
+	src = par->src;
+	mask = par->mask;	
+	dst = par->dst;
+	sr = par->sr;
+	mr = par->mr;
+	op = par->op;
+
+	isgrey = dst->flags&Fgrey;
+
+	/*
+	 * Buffering when src and dst are the same bitmap is sufficient but not 
+	 * necessary.  There are stronger conditions we could use.  We could
+	 * check to see if the rectangles intersect, and if simply moving in the
+	 * correct y direction can avoid the need to buffer.
+	 */
+	needbuf = (src->data == dst->data);
+
+	spar = getparam(src, sr, isgrey, needbuf);
+	dpar = getparam(dst, r, isgrey, needbuf);
+	mpar = getparam(mask, mr, 0, needbuf);
+
+	dir = (needbuf && byteaddr(dst, r.min) > byteaddr(src, sr.min)) ? -1 : 1;
+	spar.dir = mpar.dir = dpar.dir = dir;
+
+	/*
+	 * If the mask is purely boolean, we can convert from src to dst format
+	 * when we read src, and then just copy it to dst where the mask tells us to.
+	 * This requires a boolean (1-bit grey) mask and lack of a source alpha channel.
+	 *
+	 * The computation is accomplished by assigning the function pointers as follows:
+	 *	rdsrc - read and convert source into dst format in a buffer
+	 * 	rdmask - convert mask to bytes, set pointer to it
+	 * 	rddst - fill with pointer to real dst data, but do no reads
+	 *	calc - copy src onto dst when mask says to.
+	 *	wrdst - do nothing
+	 * This is slightly sleazy, since things aren't doing exactly what their names say,
+	 * but it avoids a fair amount of code duplication to make this a case here
+	 * rather than have a separate booldraw.
+	 */
+//if(drawdebug) iprint("flag %lud mchan %lux=?%x dd %d\n", src->flags&Falpha, mask->chan, GREY1, dst->depth);
+	if(!(src->flags&Falpha) && mask->chan == GREY1 && dst->depth >= 8 && op == SoverD){
+//if(drawdebug) iprint("boolcopy...");
+		rdsrc = convfn(dst, &dpar, src, &spar);
+		rddst = readptr;
+		rdmask = readfn(mask);
+		calc = boolcopyfn(dst, mask);
+		wrdst = nullwrite;
+	}else{
+		/* usual alphadraw parameter fetching */
+		rdsrc = readfn(src);
+		rddst = readfn(dst);
+		wrdst = writefn(dst);
+		calc = alphacalc[op];
+
+		/*
+		 * If there is no alpha channel, we'll ask for a grey channel
+		 * and pretend it is the alpha.
+		 */
+		if(mask->flags&Falpha){
+			rdmask = readalphafn(mask);
+			mpar.alphaonly = 1;
+		}else{
+			mpar.greymaskcall = readfn(mask);
+			mpar.convgrey = 1;
+			rdmask = greymaskread;
+
+			/*
+			 * Should really be above, but then boolcopyfns would have
+			 * to deal with bit alignment, and I haven't written that.
+			 *
+			 * This is a common case for things like ellipse drawing.
+			 * When there's no alpha involved and the mask is boolean,
+			 * we can avoid all the division and multiplication.
+			 */
+			if(mask->chan == GREY1 && !(src->flags&Falpha))
+				calc = boolcalc[op];
+			else if(op == SoverD && !(src->flags&Falpha))
+				calc = alphacalcS;
+		}
+	}
+
+	/*
+	 * If the image has a small enough repl rectangle,
+	 * we can just read each line once and cache them.
+	 */
+	if(spar.replcache){
+		spar.replcall = rdsrc;
+		rdsrc = replread;
+	}
+	if(mpar.replcache){
+		mpar.replcall = rdmask;
+		rdmask = replread;
+	}
+
+	if(allocdrawbuf() < 0)
+		return 0;
+
+	/*
+	 * Before we were saving only offsets from drawbuf in the parameter
+	 * structures; now that drawbuf has been grown to accomodate us,
+	 * we can fill in the pointers.
+	 */
+	spar.bufbase = drawbuf+spar.bufoff;
+	mpar.bufbase = drawbuf+mpar.bufoff;
+	dpar.bufbase = drawbuf+dpar.bufoff;
+	spar.convbuf = drawbuf+spar.convbufoff;
+
+	if(dir == 1){
+		starty = 0;
+		endy = dy;
+	}else{
+		starty = dy-1;
+		endy = -1;
+	}
+
+	/*
+	 * srcy, masky, and dsty are offsets from the top of their
+	 * respective Rectangles.  they need to be contained within
+	 * the rectangles, so clipy can keep them there without division.
+ 	 */
+	srcy = (starty + sr.min.y - src->r.min.y)%Dy(src->r);
+	masky = (starty + mr.min.y - mask->r.min.y)%Dy(mask->r);
+	dsty = starty + r.min.y - dst->r.min.y;
+
+	assert(0 <= srcy && srcy < Dy(src->r));
+	assert(0 <= masky && masky < Dy(mask->r));
+	assert(0 <= dsty && dsty < Dy(dst->r));
+
+	for(y=starty; y!=endy; y+=dir, srcy+=dir, masky+=dir, dsty+=dir){
+		clipy(src, &srcy);
+		clipy(dst, &dsty);
+		clipy(mask, &masky);
+
+		bsrc = rdsrc(&spar, spar.bufbase, srcy);
+DBG print("[");
+		bmask = rdmask(&mpar, mpar.bufbase, masky);
+DBG print("]\n");
+		bdst = rddst(&dpar, dpar.bufbase, dsty);
+DBG		dumpbuf("src", bsrc, dx);
+DBG		dumpbuf("mask", bmask, dx);
+DBG		dumpbuf("dst", bdst, dx);
+		bdst = calc(bdst, bsrc, bmask, dx, isgrey, op);
+		wrdst(&dpar, dpar.bytermin+dsty*dpar.bwidth, bdst);
+	}
+
+	return 1;
+}
+#undef DBG
+
+static Buffer
+alphacalc0(Buffer bdst, Buffer b1, Buffer b2, int dx, int grey, int op)
+{
+	USED(grey);
+	USED(op);
+	memset(bdst.rgba, 0, dx*bdst.delta);
+	return bdst;
+}
+
+static Buffer
+alphacalc14(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
+{
+	Buffer obdst;
+	int fd, sadelta;
+	int i, sa, ma, q;
+	u32int s, t;
+
+	obdst = bdst;
+	sadelta = bsrc.alpha == &ones ? 0 : bsrc.delta;
+	q = bsrc.delta == 4 && bdst.delta == 4;
+
+	for(i=0; i<dx; i++){
+		sa = *bsrc.alpha;
+		ma = *bmask.alpha;
+		fd = MUL(sa, ma, t);
+		if(op == DoutS)
+			fd = 255-fd;
+
+		if(grey){
+			*bdst.grey = MUL(fd, *bdst.grey, t);
+			bsrc.grey += bsrc.delta;
+			bdst.grey += bdst.delta;
+		}else{
+			if(q){
+				*bdst.rgba = MUL0123(fd, *bdst.rgba, s, t);
+				bsrc.rgba++;
+				bdst.rgba++;
+				bsrc.alpha += sadelta;
+				bmask.alpha += bmask.delta;
+				continue;
+			}
+			*bdst.red = MUL(fd, *bdst.red, t);
+			*bdst.grn = MUL(fd, *bdst.grn, t);
+			*bdst.blu = MUL(fd, *bdst.blu, t);
+			bsrc.red += bsrc.delta;
+			bsrc.blu += bsrc.delta;
+			bsrc.grn += bsrc.delta;
+			bdst.red += bdst.delta;
+			bdst.blu += bdst.delta;
+			bdst.grn += bdst.delta;
+		}
+		if(bdst.alpha != &ones){
+			*bdst.alpha = MUL(fd, *bdst.alpha, t);
+			bdst.alpha += bdst.delta;
+		}
+		bmask.alpha += bmask.delta;
+		bsrc.alpha += sadelta;
+	}
+	return obdst;
+}
+
+static Buffer
+alphacalc2810(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
+{
+	Buffer obdst;
+	int fs, sadelta;
+	int i, ma, da, q;
+	u32int s, t;
+
+	obdst = bdst;
+	sadelta = bsrc.alpha == &ones ? 0 : bsrc.delta;
+	q = bsrc.delta == 4 && bdst.delta == 4;
+
+	for(i=0; i<dx; i++){
+		ma = *bmask.alpha;
+		da = *bdst.alpha;
+		if(op == SoutD)
+			da = 255-da;
+		fs = ma;
+		if(op != S)
+			fs = MUL(fs, da, t);
+
+		if(grey){
+			*bdst.grey = MUL(fs, *bsrc.grey, t);
+			bsrc.grey += bsrc.delta;
+			bdst.grey += bdst.delta;
+		}else{
+			if(q){
+				*bdst.rgba = MUL0123(fs, *bsrc.rgba, s, t);
+				bsrc.rgba++;
+				bdst.rgba++;
+				bmask.alpha += bmask.delta;
+				bdst.alpha += bdst.delta;
+				continue;
+			}
+			*bdst.red = MUL(fs, *bsrc.red, t);
+			*bdst.grn = MUL(fs, *bsrc.grn, t);
+			*bdst.blu = MUL(fs, *bsrc.blu, t);
+			bsrc.red += bsrc.delta;
+			bsrc.blu += bsrc.delta;
+			bsrc.grn += bsrc.delta;
+			bdst.red += bdst.delta;
+			bdst.blu += bdst.delta;
+			bdst.grn += bdst.delta;
+		}
+		if(bdst.alpha != &ones){
+			*bdst.alpha = MUL(fs, *bsrc.alpha, t);
+			bdst.alpha += bdst.delta;
+		}
+		bmask.alpha += bmask.delta;
+		bsrc.alpha += sadelta;
+	}
+	return obdst;
+}
+
+static Buffer
+alphacalc3679(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
+{
+	Buffer obdst;
+	int fs, fd, sadelta;
+	int i, sa, ma, da, q;
+	u32int s, t, u, v;
+
+	obdst = bdst;
+	sadelta = bsrc.alpha == &ones ? 0 : bsrc.delta;
+	q = bsrc.delta == 4 && bdst.delta == 4;
+
+	for(i=0; i<dx; i++){
+		sa = *bsrc.alpha;
+		ma = *bmask.alpha;
+		da = *bdst.alpha;
+		if(op == SatopD)
+			fs = MUL(ma, da, t);
+		else
+			fs = MUL(ma, 255-da, t);
+		if(op == DoverS)
+			fd = 255;
+		else{
+			fd = MUL(sa, ma, t);
+			if(op != DatopS)
+				fd = 255-fd;
+		}
+
+		if(grey){
+			*bdst.grey = MUL(fs, *bsrc.grey, s)+MUL(fd, *bdst.grey, t);
+			bsrc.grey += bsrc.delta;
+			bdst.grey += bdst.delta;
+		}else{
+			if(q){
+				*bdst.rgba = MUL0123(fs, *bsrc.rgba, s, t)+MUL0123(fd, *bdst.rgba, u, v);
+				bsrc.rgba++;
+				bdst.rgba++;
+				bsrc.alpha += sadelta;
+				bmask.alpha += bmask.delta;
+				bdst.alpha += bdst.delta;
+				continue;
+			}
+			*bdst.red = MUL(fs, *bsrc.red, s)+MUL(fd, *bdst.red, t);
+			*bdst.grn = MUL(fs, *bsrc.grn, s)+MUL(fd, *bdst.grn, t);
+			*bdst.blu = MUL(fs, *bsrc.blu, s)+MUL(fd, *bdst.blu, t);
+			bsrc.red += bsrc.delta;
+			bsrc.blu += bsrc.delta;
+			bsrc.grn += bsrc.delta;
+			bdst.red += bdst.delta;
+			bdst.blu += bdst.delta;
+			bdst.grn += bdst.delta;
+		}
+		if(bdst.alpha != &ones){
+			*bdst.alpha = MUL(fs, sa, s)+MUL(fd, da, t);
+			bdst.alpha += bdst.delta;
+		}
+		bmask.alpha += bmask.delta;
+		bsrc.alpha += sadelta;
+	}
+	return obdst;
+}
+
+static Buffer
+alphacalc5(Buffer bdst, Buffer b1, Buffer b2, int dx, int grey, int op)
+{
+	USED(dx);
+	USED(grey);
+	USED(op);
+	return bdst;
+}
+
+static Buffer
+alphacalc11(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
+{
+	Buffer obdst;
+	int fd, sadelta;
+	int i, sa, ma, q;
+	u32int s, t, u, v;
+
+	USED(op);
+	obdst = bdst;
+	sadelta = bsrc.alpha == &ones ? 0 : bsrc.delta;
+	q = bsrc.delta == 4 && bdst.delta == 4;
+
+	for(i=0; i<dx; i++){
+		sa = *bsrc.alpha;
+		ma = *bmask.alpha;
+		fd = 255-MUL(sa, ma, t);
+
+		if(grey){
+			*bdst.grey = MUL(ma, *bsrc.grey, s)+MUL(fd, *bdst.grey, t);
+			bsrc.grey += bsrc.delta;
+			bdst.grey += bdst.delta;
+		}else{
+			if(q){
+				*bdst.rgba = MUL0123(ma, *bsrc.rgba, s, t)+MUL0123(fd, *bdst.rgba, u, v);
+				bsrc.rgba++;
+				bdst.rgba++;
+				bsrc.alpha += sadelta;
+				bmask.alpha += bmask.delta;
+				continue;
+			}
+			*bdst.red = MUL(ma, *bsrc.red, s)+MUL(fd, *bdst.red, t);
+			*bdst.grn = MUL(ma, *bsrc.grn, s)+MUL(fd, *bdst.grn, t);
+			*bdst.blu = MUL(ma, *bsrc.blu, s)+MUL(fd, *bdst.blu, t);
+			bsrc.red += bsrc.delta;
+			bsrc.blu += bsrc.delta;
+			bsrc.grn += bsrc.delta;
+			bdst.red += bdst.delta;
+			bdst.blu += bdst.delta;
+			bdst.grn += bdst.delta;
+		}
+		if(bdst.alpha != &ones){
+			*bdst.alpha = MUL(ma, sa, s)+MUL(fd, *bdst.alpha, t);
+			bdst.alpha += bdst.delta;
+		}
+		bmask.alpha += bmask.delta;
+		bsrc.alpha += sadelta;
+	}
+	return obdst;
+}
+
+/*
+not used yet
+source and mask alpha 1
+static Buffer
+alphacalcS0(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
+{
+	Buffer obdst;
+	int i;
+
+	USED(op);
+	obdst = bdst;
+	if(bsrc.delta == bdst.delta){
+		memmove(bdst.rgba, bsrc.rgba, dx*bdst.delta);
+		return obdst;
+	}
+	for(i=0; i<dx; i++){
+		if(grey){
+			*bdst.grey = *bsrc.grey;
+			bsrc.grey += bsrc.delta;
+			bdst.grey += bdst.delta;
+		}else{
+			*bdst.red = *bsrc.red;
+			*bdst.grn = *bsrc.grn;
+			*bdst.blu = *bsrc.blu;
+			bsrc.red += bsrc.delta;
+			bsrc.blu += bsrc.delta;
+			bsrc.grn += bsrc.delta;
+			bdst.red += bdst.delta;
+			bdst.blu += bdst.delta;
+			bdst.grn += bdst.delta;
+		}
+		if(bdst.alpha != &ones){
+			*bdst.alpha = 255;
+			bdst.alpha += bdst.delta;
+		}
+	}
+	return obdst;
+}
+*/
+
+/* source alpha 1 */
+static Buffer
+alphacalcS(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
+{
+	Buffer obdst;
+	int fd;
+	int i, ma;
+	u32int s, t;
+
+	USED(op);
+	obdst = bdst;
+
+	for(i=0; i<dx; i++){
+		ma = *bmask.alpha;
+		fd = 255-ma;
+
+		if(grey){
+			*bdst.grey = MUL(ma, *bsrc.grey, s)+MUL(fd, *bdst.grey, t);
+			bsrc.grey += bsrc.delta;
+			bdst.grey += bdst.delta;
+		}else{
+			*bdst.red = MUL(ma, *bsrc.red, s)+MUL(fd, *bdst.red, t);
+			*bdst.grn = MUL(ma, *bsrc.grn, s)+MUL(fd, *bdst.grn, t);
+			*bdst.blu = MUL(ma, *bsrc.blu, s)+MUL(fd, *bdst.blu, t);
+			bsrc.red += bsrc.delta;
+			bsrc.blu += bsrc.delta;
+			bsrc.grn += bsrc.delta;
+			bdst.red += bdst.delta;
+			bdst.blu += bdst.delta;
+			bdst.grn += bdst.delta;
+		}
+		if(bdst.alpha != &ones){
+			*bdst.alpha = ma+MUL(fd, *bdst.alpha, t);
+			bdst.alpha += bdst.delta;
+		}
+		bmask.alpha += bmask.delta;
+	}
+	return obdst;
+}
+
+static Buffer
+boolcalc14(Buffer bdst, Buffer b1, Buffer bmask, int dx, int grey, int op)
+{
+	Buffer obdst;
+	int i, ma, zero;
+
+	obdst = bdst;
+
+	for(i=0; i<dx; i++){
+		ma = *bmask.alpha;
+		zero = ma ? op == DoutS : op == DinS;
+
+		if(grey){
+			if(zero)
+				*bdst.grey = 0;
+			bdst.grey += bdst.delta;
+		}else{
+			if(zero)
+				*bdst.red = *bdst.grn = *bdst.blu = 0;
+			bdst.red += bdst.delta;
+			bdst.blu += bdst.delta;
+			bdst.grn += bdst.delta;
+		}
+		bmask.alpha += bmask.delta;
+		if(bdst.alpha != &ones){
+			if(zero)
+				*bdst.alpha = 0;
+			bdst.alpha += bdst.delta;
+		}
+	}
+	return obdst;
+}
+
+static Buffer
+boolcalc236789(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
+{
+	Buffer obdst;
+	int fs, fd;
+	int i, ma, da, zero;
+	u32int s, t;
+
+	obdst = bdst;
+	zero = !(op&1);
+
+	for(i=0; i<dx; i++){
+		ma = *bmask.alpha;
+		da = *bdst.alpha;
+		fs = da;
+		if(op&2)
+			fs = 255-da;
+		fd = 0;
+		if(op&4)
+			fd = 255;
+
+		if(grey){
+			if(ma)
+				*bdst.grey = MUL(fs, *bsrc.grey, s)+MUL(fd, *bdst.grey, t);
+			else if(zero)
+				*bdst.grey = 0;
+			bsrc.grey += bsrc.delta;
+			bdst.grey += bdst.delta;
+		}else{
+			if(ma){
+				*bdst.red = MUL(fs, *bsrc.red, s)+MUL(fd, *bdst.red, t);
+				*bdst.grn = MUL(fs, *bsrc.grn, s)+MUL(fd, *bdst.grn, t);
+				*bdst.blu = MUL(fs, *bsrc.blu, s)+MUL(fd, *bdst.blu, t);
+			}
+			else if(zero)
+				*bdst.red = *bdst.grn = *bdst.blu = 0;
+			bsrc.red += bsrc.delta;
+			bsrc.blu += bsrc.delta;
+			bsrc.grn += bsrc.delta;
+			bdst.red += bdst.delta;
+			bdst.blu += bdst.delta;
+			bdst.grn += bdst.delta;
+		}
+		bmask.alpha += bmask.delta;
+		if(bdst.alpha != &ones){
+			if(ma)
+				*bdst.alpha = fs+MUL(fd, da, t);
+			else if(zero)
+				*bdst.alpha = 0;
+			bdst.alpha += bdst.delta;
+		}
+	}
+	return obdst;
+}
+
+static Buffer
+boolcalc1011(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
+{
+	Buffer obdst;
+	int i, ma, zero;
+
+	obdst = bdst;
+	zero = !(op&1);
+
+	for(i=0; i<dx; i++){
+		ma = *bmask.alpha;
+
+		if(grey){
+			if(ma)
+				*bdst.grey = *bsrc.grey;
+			else if(zero)
+				*bdst.grey = 0;
+			bsrc.grey += bsrc.delta;
+			bdst.grey += bdst.delta;
+		}else{
+			if(ma){
+				*bdst.red = *bsrc.red;
+				*bdst.grn = *bsrc.grn;
+				*bdst.blu = *bsrc.blu;
+			}
+			else if(zero)
+				*bdst.red = *bdst.grn = *bdst.blu = 0;
+			bsrc.red += bsrc.delta;
+			bsrc.blu += bsrc.delta;
+			bsrc.grn += bsrc.delta;
+			bdst.red += bdst.delta;
+			bdst.blu += bdst.delta;
+			bdst.grn += bdst.delta;
+		}
+		bmask.alpha += bmask.delta;
+		if(bdst.alpha != &ones){
+			if(ma)
+				*bdst.alpha = 255;
+			else if(zero)
+				*bdst.alpha = 0;
+			bdst.alpha += bdst.delta;
+		}
+	}
+	return obdst;
+}
+/*
+ * Replicated cached scan line read.  Call the function listed in the Param,
+ * but cache the result so that for replicated images we only do the work once.
+ */
+static Buffer
+replread(Param *p, uchar *s, int y)
+{
+	Buffer *b;
+
+	USED(s);
+	b = &p->bcache[y];
+	if((p->bfilled & (1<<y)) == 0){
+		p->bfilled |= 1<<y;
+		*b = p->replcall(p, p->bufbase+y*p->bufdelta, y);
+	}
+	return *b;
+}
+
+/*
+ * Alpha reading function that simply relabels the grey pointer.
+ */
+static Buffer
+greymaskread(Param *p, uchar *buf, int y)
+{
+	Buffer b;
+
+	b = p->greymaskcall(p, buf, y);
+	b.alpha = b.grey;
+	return b;
+}
+
+#define DBG if(0)
+static Buffer
+readnbit(Param *p, uchar *buf, int y)
+{
+	Buffer b;
+	Memimage *img;
+	uchar *repl, *r, *w, *ow, bits;
+	int i, n, sh, depth, x, dx, npack, nbits;
+
+	b.rgba = (u32int*)buf;
+	b.grey = w = buf;
+	b.red = b.blu = b.grn = w;
+	b.alpha = &ones;
+	b.delta = 1;
+
+	dx = p->dx;
+	img = p->img;
+	depth = img->depth;
+	repl = &replbit[depth][0];
+	npack = 8/depth;
+	sh = 8-depth;
+
+	/* copy from p->r.min.x until end of repl rectangle */
+	x = p->r.min.x;
+	n = dx;
+	if(n > p->img->r.max.x - x)
+		n = p->img->r.max.x - x;
+
+	r = p->bytermin + y*p->bwidth;
+DBG print("readnbit dx %d %p=%p+%d*%d, *r=%d fetch %d ", dx, r, p->bytermin, y, p->bwidth, *r, n);
+	bits = *r++;
+	nbits = 8;
+	if(i=x&(npack-1)){
+DBG print("throwaway %d...", i);
+		bits <<= depth*i;
+		nbits -= depth*i;
+	}
+	for(i=0; i<n; i++){
+		if(nbits == 0){
+DBG print("(%.2ux)...", *r);
+			bits = *r++;
+			nbits = 8;
+		}
+		*w++ = repl[bits>>sh];
+DBG print("bit %x...", repl[bits>>sh]);
+		bits <<= depth;
+		nbits -= depth;
+	}
+	dx -= n;
+	if(dx == 0)
+		return b;
+
+	assert(x+i == p->img->r.max.x);
+
+	/* copy from beginning of repl rectangle until where we were before. */
+	x = p->img->r.min.x;
+	n = dx;
+	if(n > p->r.min.x - x)
+		n = p->r.min.x - x;
+
+	r = p->bytey0s + y*p->bwidth;
+DBG print("x=%d r=%p...", x, r);
+	bits = *r++;
+	nbits = 8;
+	if(i=x&(npack-1)){
+		bits <<= depth*i;
+		nbits -= depth*i;
+	}
+DBG print("nbits=%d...", nbits);
+	for(i=0; i<n; i++){
+		if(nbits == 0){
+			bits = *r++;
+			nbits = 8;
+		}
+		*w++ = repl[bits>>sh];
+DBG print("bit %x...", repl[bits>>sh]);
+		bits <<= depth;
+		nbits -= depth;
+DBG print("bits %x nbits %d...", bits, nbits);
+	}
+	dx -= n;
+	if(dx == 0)
+		return b;
+
+	assert(dx > 0);
+	/* now we have exactly one full scan line: just replicate the buffer itself until we are done */
+	ow = buf;
+	while(dx--)
+		*w++ = *ow++;
+
+	return b;
+}
+#undef DBG
+
+#define DBG if(0)
+static void
+writenbit(Param *p, uchar *w, Buffer src)
+{
+	uchar *r;
+	u32int bits;
+	int i, sh, depth, npack, nbits, x, ex;
+
+	assert(src.grey != nil && src.delta == 1);
+
+	x = p->r.min.x;
+	ex = x+p->dx;
+	depth = p->img->depth;
+	npack = 8/depth;
+
+	i=x&(npack-1);
+	bits = i ? (*w >> (8-depth*i)) : 0;
+	nbits = depth*i;
+	sh = 8-depth;
+	r = src.grey;
+
+	for(; x<ex; x++){
+		bits <<= depth;
+DBG print(" %x", *r);
+		bits |= (*r++ >> sh);
+		nbits += depth;
+		if(nbits == 8){
+			*w++ = bits;
+			nbits = 0;
+		}
+	}
+
+	if(nbits){
+		sh = 8-nbits;
+		bits <<= sh;
+		bits |= *w & ((1<<sh)-1);
+		*w = bits;
+	}
+DBG print("\n");
+	return;
+}
+#undef DBG
+
+static Buffer
+readcmap(Param *p, uchar *buf, int y)
+{
+	Buffer b;
+	int a, convgrey, copyalpha, dx, i, m;
+	uchar *q, *cmap, *begin, *end, *r, *w;
+
+	begin = p->bytey0s + y*p->bwidth;
+	r = p->bytermin + y*p->bwidth;
+	end = p->bytey0e + y*p->bwidth;
+	cmap = p->img->cmap->cmap2rgb;
+	convgrey = p->convgrey;
+	copyalpha = (p->img->flags&Falpha) ? 1 : 0;
+
+	w = buf;
+	dx = p->dx;
+	if(copyalpha){
+		b.alpha = buf++;
+		a = p->img->shift[CAlpha]/8;
+		m = p->img->shift[CMap]/8;
+		for(i=0; i<dx; i++){
+			*w++ = r[a];
+			q = cmap+r[m]*3;
+			r += 2;
+			if(r == end)
+				r = begin;
+			if(convgrey){
+				*w++ = RGB2K(q[0], q[1], q[2]);
+			}else{
+				*w++ = q[2];	/* blue */
+				*w++ = q[1];	/* green */
+				*w++ = q[0];	/* red */
+			}
+		}
+	}else{
+		b.alpha = &ones;
+		for(i=0; i<dx; i++){
+			q = cmap+*r++*3;
+			if(r == end)
+				r = begin;
+			if(convgrey){
+				*w++ = RGB2K(q[0], q[1], q[2]);
+			}else{
+				*w++ = q[2];	/* blue */
+				*w++ = q[1];	/* green */
+				*w++ = q[0];	/* red */
+			}
+		}
+	}
+
+	b.rgba = (u32int*)(buf-copyalpha);
+
+	if(convgrey){
+		b.grey = buf;
+		b.red = b.blu = b.grn = buf;
+		b.delta = 1+copyalpha;
+	}else{
+		b.blu = buf;
+		b.grn = buf+1;
+		b.red = buf+2;
+		b.grey = nil;
+		b.delta = 3+copyalpha;
+	}
+	return b;
+}
+
+static void
+writecmap(Param *p, uchar *w, Buffer src)
+{
+	uchar *cmap, *red, *grn, *blu;
+	int i, dx, delta;
+
+	cmap = p->img->cmap->rgb2cmap;
+	
+	delta = src.delta;
+	red= src.red;
+	grn = src.grn;
+	blu = src.blu;
+
+	dx = p->dx;
+	for(i=0; i<dx; i++, red+=delta, grn+=delta, blu+=delta)
+		*w++ = cmap[(*red>>4)*256+(*grn>>4)*16+(*blu>>4)];
+}
+
+#define DBG if(0)
+static Buffer
+readbyte(Param *p, uchar *buf, int y)
+{
+	Buffer b;
+	Memimage *img;
+	int dx, isgrey, convgrey, alphaonly, copyalpha, i, nb;
+	uchar *begin, *end, *r, *w, *rrepl, *grepl, *brepl, *arepl, *krepl;
+	uchar ured, ugrn, ublu;
+	u32int u;
+
+	img = p->img;
+	begin = p->bytey0s + y*p->bwidth;
+	r = p->bytermin + y*p->bwidth;
+	end = p->bytey0e + y*p->bwidth;
+
+	w = buf;
+	dx = p->dx;
+	nb = img->depth/8;
+
+	convgrey = p->convgrey;	/* convert rgb to grey */
+	isgrey = img->flags&Fgrey;
+	alphaonly = p->alphaonly;
+	copyalpha = (img->flags&Falpha) ? 1 : 0;
+
+DBG print("copyalpha %d alphaonly %d convgrey %d isgrey %d\n", copyalpha, alphaonly, convgrey, isgrey);
+	/* if we can, avoid processing everything */
+	if(!(img->flags&Frepl) && !convgrey && (img->flags&Fbytes)){
+		memset(&b, 0, sizeof b);
+		if(p->needbuf){
+			memmove(buf, r, dx*nb);
+			r = buf;
+		}
+		b.rgba = (u32int*)r;
+		if(copyalpha)
+			b.alpha = r+img->shift[CAlpha]/8;
+		else
+			b.alpha = &ones;
+		if(isgrey){
+			b.grey = r+img->shift[CGrey]/8;
+			b.red = b.grn = b.blu = b.grey;
+		}else{
+			b.red = r+img->shift[CRed]/8;
+			b.grn = r+img->shift[CGreen]/8;
+			b.blu = r+img->shift[CBlue]/8;
+		}
+		b.delta = nb;
+		return b;
+	}
+
+DBG print("2\n");
+	rrepl = replbit[img->nbits[CRed]];
+	grepl = replbit[img->nbits[CGreen]];
+	brepl = replbit[img->nbits[CBlue]];
+	arepl = replbit[img->nbits[CAlpha]];
+	krepl = replbit[img->nbits[CGrey]];
+
+	for(i=0; i<dx; i++){
+		u = r[0] | (r[1]<<8) | (r[2]<<16) | (r[3]<<24);
+		if(copyalpha) {
+			*w++ = arepl[(u>>img->shift[CAlpha]) & img->mask[CAlpha]];
+DBG print("a %x\n", w[-1]);
+		}
+
+		if(isgrey)
+			*w++ = krepl[(u >> img->shift[CGrey]) & img->mask[CGrey]];
+		else if(!alphaonly){
+			ured = rrepl[(u >> img->shift[CRed]) & img->mask[CRed]];
+			ugrn = grepl[(u >> img->shift[CGreen]) & img->mask[CGreen]];
+			ublu = brepl[(u >> img->shift[CBlue]) & img->mask[CBlue]];
+			if(convgrey){
+DBG print("g %x %x %x\n", ured, ugrn, ublu);
+				*w++ = RGB2K(ured, ugrn, ublu);
+DBG print("%x\n", w[-1]);
+			}else{
+				*w++ = brepl[(u >> img->shift[CBlue]) & img->mask[CBlue]];
+				*w++ = grepl[(u >> img->shift[CGreen]) & img->mask[CGreen]];
+				*w++ = rrepl[(u >> img->shift[CRed]) & img->mask[CRed]];
+			}
+		}
+		r += nb;
+		if(r == end)
+			r = begin;
+	}
+	
+	b.alpha = copyalpha ? buf : &ones;
+	b.rgba = (u32int*)buf;
+	if(alphaonly){
+		b.red = b.grn = b.blu = b.grey = nil;
+		if(!copyalpha)
+			b.rgba = nil;
+		b.delta = 1;
+	}else if(isgrey || convgrey){
+		b.grey = buf+copyalpha;
+		b.red = b.grn = b.blu = buf+copyalpha;
+		b.delta = copyalpha+1;
+DBG print("alpha %x grey %x\n", b.alpha ? *b.alpha : 0xFF, *b.grey);
+	}else{
+		b.blu = buf+copyalpha;
+		b.grn = buf+copyalpha+1;
+		b.grey = nil;
+		b.red = buf+copyalpha+2;
+		b.delta = copyalpha+3;
+	}
+	return b;
+}
+#undef DBG
+
+#define DBG if(0)
+static void
+writebyte(Param *p, uchar *w, Buffer src)
+{
+	Memimage *img;
+	int i, isalpha, isgrey, nb, delta, dx, adelta;
+	uchar ff, *red, *grn, *blu, *grey, *alpha;
+	u32int u, mask;
+
+	img = p->img;
+
+	red = src.red;
+	grn = src.grn;
+	blu = src.blu;
+	alpha = src.alpha;
+	delta = src.delta;
+	grey = src.grey;
+	dx = p->dx;
+
+	nb = img->depth/8;
+	mask = (nb==4) ? 0 : ~((1<<img->depth)-1);
+
+	isalpha = img->flags&Falpha;
+	isgrey = img->flags&Fgrey;
+	adelta = src.delta;
+
+	if(isalpha && (alpha == nil || alpha == &ones)){
+		ff = 0xFF;
+		alpha = &ff;
+		adelta = 0;
+	}
+
+	for(i=0; i<dx; i++){
+		u = w[0] | (w[1]<<8) | (w[2]<<16) | (w[3]<<24);
+DBG print("u %.8lux...", u);
+		u &= mask;
+DBG print("&mask %.8lux...", u);
+		if(isgrey){
+			u |= ((*grey >> (8-img->nbits[CGrey])) & img->mask[CGrey]) << img->shift[CGrey];
+DBG print("|grey %.8lux...", u);
+			grey += delta;
+		}else{
+			u |= ((*red >> (8-img->nbits[CRed])) & img->mask[CRed]) << img->shift[CRed];
+			u |= ((*grn >> (8-img->nbits[CGreen])) & img->mask[CGreen]) << img->shift[CGreen];
+			u |= ((*blu >> (8-img->nbits[CBlue])) & img->mask[CBlue]) << img->shift[CBlue];
+			red += delta;
+			grn += delta;
+			blu += delta;
+DBG print("|rgb %.8lux...", u);
+		}
+
+		if(isalpha){
+			u |= ((*alpha >> (8-img->nbits[CAlpha])) & img->mask[CAlpha]) << img->shift[CAlpha];
+			alpha += adelta;
+DBG print("|alpha %.8lux...", u);
+		}
+
+		w[0] = u;
+		w[1] = u>>8;
+		w[2] = u>>16;
+		w[3] = u>>24;
+		w += nb;
+	}
+}
+#undef DBG
+
+static Readfn*
+readfn(Memimage *img)
+{
+	if(img->depth < 8)
+		return readnbit;
+	if(img->nbits[CMap] == 8)
+		return readcmap;
+	return readbyte;
+}
+
+static Readfn*
+readalphafn(Memimage *m)
+{
+	USED(m);
+	return readbyte;
+}
+
+static Writefn*
+writefn(Memimage *img)
+{
+	if(img->depth < 8)
+		return writenbit;
+	if(img->chan == CMAP8)
+		return writecmap;
+	return writebyte;
+}
+
+static void
+nullwrite(Param *p, uchar *s, Buffer b)
+{
+	USED(p);
+	USED(s);
+}
+
+static Buffer
+readptr(Param *p, uchar *s, int y)
+{
+	Buffer b;
+	uchar *q;
+
+	USED(s);
+	q = p->bytermin + y*p->bwidth;
+	b.red = q;	/* ptr to data */
+	b.grn = b.blu = b.grey = b.alpha = nil;
+	b.rgba = (u32int*)q;
+	b.delta = p->img->depth/8;
+	return b;
+}
+
+static Buffer
+boolmemmove(Buffer bdst, Buffer bsrc, Buffer b1, int dx, int i, int o)
+{
+	USED(i);
+	USED(o);
+	memmove(bdst.red, bsrc.red, dx*bdst.delta);
+	return bdst;
+}
+
+static Buffer
+boolcopy8(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int i, int o)
+{
+	uchar *m, *r, *w, *ew;
+
+	USED(i);
+	USED(o);
+	m = bmask.grey;
+	w = bdst.red;
+	r = bsrc.red;
+	ew = w+dx;
+	for(; w < ew; w++,r++)
+		if(*m++)
+			*w = *r;
+	return bdst;	/* not used */
+}
+
+static Buffer
+boolcopy16(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int i, int o)
+{
+	uchar *m;
+	ushort *r, *w, *ew;
+
+	USED(i);
+	USED(o);
+	m = bmask.grey;
+	w = (ushort*)bdst.red;
+	r = (ushort*)bsrc.red;
+	ew = w+dx;
+	for(; w < ew; w++,r++)
+		if(*m++)
+			*w = *r;
+	return bdst;	/* not used */
+}
+
+static Buffer
+boolcopy24(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int i, int o)
+{
+	uchar *m;
+	uchar *r, *w, *ew;
+
+	USED(i);
+	USED(o);
+	m = bmask.grey;
+	w = bdst.red;
+	r = bsrc.red;
+	ew = w+dx*3;
+	while(w < ew){
+		if(*m++){
+			*w++ = *r++;
+			*w++ = *r++;
+			*w++ = *r++;
+		}else{
+			w += 3;
+			r += 3;
+		}
+	}
+	return bdst;	/* not used */
+}
+
+static Buffer
+boolcopy32(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int i, int o)
+{
+	uchar *m;
+	u32int *r, *w, *ew;
+
+	USED(i);
+	USED(o);
+	m = bmask.grey;
+	w = (u32int*)bdst.red;
+	r = (u32int*)bsrc.red;
+	ew = w+dx;
+	for(; w < ew; w++,r++)
+		if(*m++)
+			*w = *r;
+	return bdst;	/* not used */
+}
+
+static Buffer
+genconv(Param *p, uchar *buf, int y)
+{
+	Buffer b;
+	int nb;
+	uchar *r, *w, *ew;
+
+	/* read from source into RGB format in convbuf */
+	b = p->convreadcall(p, p->convbuf, y);
+
+	/* write RGB format into dst format in buf */
+	p->convwritecall(p->convdpar, buf, b);
+
+	if(p->convdx){
+		nb = p->convdpar->img->depth/8;
+		r = buf;
+		w = buf+nb*p->dx;
+		ew = buf+nb*p->convdx;
+		while(w<ew)
+			*w++ = *r++;
+	}
+
+	b.red = buf;
+	b.blu = b.grn = b.grey = b.alpha = nil;
+	b.rgba = (u32int*)buf;
+	b.delta = 0;
+	
+	return b;
+}
+
+static Readfn*
+convfn(Memimage *dst, Param *dpar, Memimage *src, Param *spar)
+{
+	if(dst->chan == src->chan && !(src->flags&Frepl)){
+//if(drawdebug) iprint("readptr...");
+		return readptr;
+	}
+
+	if(dst->chan==CMAP8 && (src->chan==GREY1||src->chan==GREY2||src->chan==GREY4)){
+		/* cheat because we know the replicated value is exactly the color map entry. */
+//if(drawdebug) iprint("Readnbit...");
+		return readnbit;
+	}
+
+	spar->convreadcall = readfn(src);
+	spar->convwritecall = writefn(dst);
+	spar->convdpar = dpar;
+
+	/* allocate a conversion buffer */
+	spar->convbufoff = ndrawbuf;
+	ndrawbuf += spar->dx*4;
+
+	if(spar->dx > Dx(spar->img->r)){
+		spar->convdx = spar->dx;
+		spar->dx = Dx(spar->img->r);
+	}
+
+//if(drawdebug) iprint("genconv...");
+	return genconv;
+}
+
+/*
+ * Do NOT call this directly.  pixelbits is a wrapper
+ * around this that fetches the bits from the X server
+ * when necessary.
+ */
+u32int
+_pixelbits(Memimage *i, Point pt)
+{
+	uchar *p;
+	u32int val;
+	int off, bpp, npack;
+
+	val = 0;
+	p = byteaddr(i, pt);
+	switch(bpp=i->depth){
+	case 1:
+	case 2:
+	case 4:
+		npack = 8/bpp;
+		off = pt.x%npack;
+		val = p[0] >> bpp*(npack-1-off);
+		val &= (1<<bpp)-1;
+		break;
+	case 8:
+		val = p[0];
+		break;
+	case 16:
+		val = p[0]|(p[1]<<8);
+		break;
+	case 24:
+		val = p[0]|(p[1]<<8)|(p[2]<<16);
+		break;
+	case 32:
+		val = p[0]|(p[1]<<8)|(p[2]<<16)|(p[3]<<24);
+		break;
+	}
+	while(bpp<32){
+		val |= val<<bpp;
+		bpp *= 2;
+	}
+	return val;
+}
+
+static Calcfn*
+boolcopyfn(Memimage *img, Memimage *mask)
+{
+	if(mask->flags&Frepl && Dx(mask->r)==1 && Dy(mask->r)==1 && pixelbits(mask, mask->r.min)==~0)
+		return boolmemmove;
+
+	switch(img->depth){
+	case 8:
+		return boolcopy8;
+	case 16:
+		return boolcopy16;
+	case 24:
+		return boolcopy24;
+	case 32:
+		return boolcopy32;
+	default:
+		assert(0 /* boolcopyfn */);
+	}
+	return nil;
+}
+
+/*
+ * Optimized draw for filling and scrolling; uses memset and memmove.
+ */
+static void
+memsets(void *vp, ushort val, int n)
+{
+	ushort *p, *ep;
+
+	p = vp;
+	ep = p+n;
+	while(p<ep)
+		*p++ = val;
+}
+
+static void
+memsetl(void *vp, u32int val, int n)
+{
+	u32int *p, *ep;
+
+	p = vp;
+	ep = p+n;
+	while(p<ep)
+		*p++ = val;
+}
+
+static void
+memset24(void *vp, u32int val, int n)
+{
+	uchar *p, *ep;
+	uchar a,b,c;
+
+	p = vp;
+	ep = p+3*n;
+	a = val;
+	b = val>>8;
+	c = val>>16;
+	while(p<ep){
+		*p++ = a;
+		*p++ = b;
+		*p++ = c;
+	}
+}
+
+u32int
+_imgtorgba(Memimage *img, u32int val)
+{
+	uchar r, g, b, a;
+	int nb, ov, v;
+	u32int chan;
+	uchar *p;
+
+	a = 0xFF;
+	r = g = b = 0xAA;	/* garbage */
+	for(chan=img->chan; chan; chan>>=8){
+		nb = NBITS(chan);
+		ov = v = val&((1<<nb)-1);
+		val >>= nb;
+
+		while(nb < 8){
+			v |= v<<nb;
+			nb *= 2;
+		}
+		v >>= (nb-8);
+
+		switch(TYPE(chan)){
+		case CRed:
+			r = v;
+			break;
+		case CGreen:
+			g = v;
+			break;
+		case CBlue:
+			b = v;
+			break;
+		case CAlpha:
+			a = v;
+			break;
+		case CGrey:
+			r = g = b = v;
+			break;
+		case CMap:
+			p = img->cmap->cmap2rgb+3*ov;
+			r = *p++;
+			g = *p++;	
+			b = *p;
+			break;
+		}
+	}
+	return (r<<24)|(g<<16)|(b<<8)|a;	
+}
+
+u32int
+_rgbatoimg(Memimage *img, u32int rgba)
+{
+	u32int chan;
+	int d, nb;
+	u32int v;
+	uchar *p, r, g, b, a, m;
+
+	v = 0;
+	r = rgba>>24;
+	g = rgba>>16;
+	b = rgba>>8;
+	a = rgba;
+	d = 0;
+	for(chan=img->chan; chan; chan>>=8){
+		nb = NBITS(chan);
+		switch(TYPE(chan)){
+		case CRed:
+			v |= (r>>(8-nb))<<d;
+			break;
+		case CGreen:
+			v |= (g>>(8-nb))<<d;
+			break;
+		case CBlue:
+			v |= (b>>(8-nb))<<d;
+			break;
+		case CAlpha:
+			v |= (a>>(8-nb))<<d;
+			break;
+		case CMap:
+			p = img->cmap->rgb2cmap;
+			m = p[(r>>4)*256+(g>>4)*16+(b>>4)];
+			v |= (m>>(8-nb))<<d;
+			break;
+		case CGrey:
+			m = RGB2K(r,g,b);
+			v |= (m>>(8-nb))<<d;
+			break;
+		}
+		d += nb;
+	}
+//	print("rgba2img %.8lux = %.*lux\n", rgba, 2*d/8, v);
+	return v;
+}
+
+#define DBG if(0)
+static int
+memoptdraw(Memdrawparam *par)
+{
+	int m, y, dy, dx, op;
+	u32int v;
+	Memimage *src;
+	Memimage *dst;
+
+	dx = Dx(par->r);
+	dy = Dy(par->r);
+	src = par->src;
+	dst = par->dst;
+	op = par->op;
+
+DBG print("state %lux mval %lux dd %d\n", par->state, par->mval, dst->depth);
+	/*
+	 * If we have an opaque mask and source is one opaque pixel we can convert to the
+	 * destination format and just replicate with memset.
+	 */
+	m = Simplesrc|Simplemask|Fullmask;
+	if((par->state&m)==m && (par->srgba&0xFF) == 0xFF && (op ==S || op == SoverD)){
+		uchar *dp, p[4];
+		int d, dwid, ppb, np, nb;
+		uchar lm, rm;
+
+DBG print("memopt, dst %p, dst->data->bdata %p\n", dst, dst->data->bdata);
+		dwid = dst->width*sizeof(u32int);
+		dp = byteaddr(dst, par->r.min);
+		v = par->sdval;
+DBG print("sdval %lud, depth %d\n", v, dst->depth);
+		switch(dst->depth){
+		case 1:
+		case 2:
+		case 4:
+			for(d=dst->depth; d<8; d*=2)
+				v |= (v<<d);
+			ppb = 8/dst->depth;	/* pixels per byte */
+			m = ppb-1;
+			/* left edge */
+			np = par->r.min.x&m;		/* no. pixels unused on left side of word */
+			dx -= (ppb-np);
+			nb = 8 - np * dst->depth;		/* no. bits used on right side of word */
+			lm = (1<<nb)-1;
+DBG print("np %d x %d nb %d lm %ux ppb %d m %ux\n", np, par->r.min.x, nb, lm, ppb, m);	
+
+			/* right edge */
+			np = par->r.max.x&m;	/* no. pixels used on left side of word */
+			dx -= np;
+			nb = 8 - np * dst->depth;		/* no. bits unused on right side of word */
+			rm = ~((1<<nb)-1);
+DBG print("np %d x %d nb %d rm %ux ppb %d m %ux\n", np, par->r.max.x, nb, rm, ppb, m);	
+
+DBG print("dx %d Dx %d\n", dx, Dx(par->r));
+			/* lm, rm are masks that are 1 where we should touch the bits */
+			if(dx < 0){	/* just one byte */
+				lm &= rm;
+				for(y=0; y<dy; y++, dp+=dwid)
+					*dp ^= (v ^ *dp) & lm;
+			}else if(dx == 0){	/* no full bytes */
+				if(lm)
+					dwid--;
+
+				for(y=0; y<dy; y++, dp+=dwid){
+					if(lm){
+DBG print("dp %p v %lux lm %ux (v ^ *dp) & lm %lux\n", dp, v, lm, (v^*dp)&lm);
+						*dp ^= (v ^ *dp) & lm;
+						dp++;
+					}
+					*dp ^= (v ^ *dp) & rm;
+				}
+			}else{		/* full bytes in middle */
+				dx /= ppb;
+				if(lm)
+					dwid--;
+				dwid -= dx;
+
+				for(y=0; y<dy; y++, dp+=dwid){
+					if(lm){
+						*dp ^= (v ^ *dp) & lm;
+						dp++;
+					}
+					memset(dp, v, dx);
+					dp += dx;
+					*dp ^= (v ^ *dp) & rm;
+				}
+			}
+			return 1;
+		case 8:
+			for(y=0; y<dy; y++, dp+=dwid)
+				memset(dp, v, dx);
+			return 1;
+		case 16:
+			p[0] = v;		/* make little endian */
+			p[1] = v>>8;
+			v = *(ushort*)p;
+DBG print("dp=%p; dx=%d; for(y=0; y<%d; y++, dp+=%d)\nmemsets(dp, v, dx);\n",
+	dp, dx, dy, dwid);
+			for(y=0; y<dy; y++, dp+=dwid)
+				memsets(dp, v, dx);
+			return 1;
+		case 24:
+			for(y=0; y<dy; y++, dp+=dwid)
+				memset24(dp, v, dx);
+			return 1;
+		case 32:
+			p[0] = v;		/* make little endian */
+			p[1] = v>>8;
+			p[2] = v>>16;
+			p[3] = v>>24;
+			v = *(u32int*)p;
+			for(y=0; y<dy; y++, dp+=dwid)
+				memsetl(dp, v, dx);
+			return 1;
+		default:
+			assert(0 /* bad dest depth in memoptdraw */);
+		}
+	}
+
+	/*
+	 * If no source alpha, an opaque mask, we can just copy the
+	 * source onto the destination.  If the channels are the same and
+	 * the source is not replicated, memmove suffices.
+	 */
+	m = Simplemask|Fullmask;
+	if((par->state&(m|Replsrc))==m && src->depth >= 8 
+	&& src->chan == dst->chan && !(src->flags&Falpha) && (op == S || op == SoverD)){
+		uchar *sp, *dp;
+		long swid, dwid, nb;
+		int dir;
+
+		if(src->data == dst->data && byteaddr(dst, par->r.min) > byteaddr(src, par->sr.min))
+			dir = -1;
+		else
+			dir = 1;
+
+		swid = src->width*sizeof(u32int);
+		dwid = dst->width*sizeof(u32int);
+		sp = byteaddr(src, par->sr.min);
+		dp = byteaddr(dst, par->r.min);
+		if(dir == -1){
+			sp += (dy-1)*swid;
+			dp += (dy-1)*dwid;
+			swid = -swid;
+			dwid = -dwid;
+		}
+		nb = (dx*src->depth)/8;
+		for(y=0; y<dy; y++, sp+=swid, dp+=dwid)
+			memmove(dp, sp, nb);
+		return 1;
+	}
+
+	/*
+	 * If we have a 1-bit mask, 1-bit source, and 1-bit destination, and
+	 * they're all bit aligned, we can just use bit operators.  This happens
+	 * when we're manipulating boolean masks, e.g. in the arc code.
+	 */
+	if((par->state&(Simplemask|Simplesrc|Replmask|Replsrc))==0 
+	&& dst->chan==GREY1 && src->chan==GREY1 && par->mask->chan==GREY1 
+	&& (par->r.min.x&7)==(par->sr.min.x&7) && (par->r.min.x&7)==(par->mr.min.x&7)){
+		uchar *sp, *dp, *mp;
+		uchar lm, rm;
+		long swid, dwid, mwid;
+		int i, x, dir;
+
+		sp = byteaddr(src, par->sr.min);
+		dp = byteaddr(dst, par->r.min);
+		mp = byteaddr(par->mask, par->mr.min);
+		swid = src->width*sizeof(u32int);
+		dwid = dst->width*sizeof(u32int);
+		mwid = par->mask->width*sizeof(u32int);
+
+		if(src->data == dst->data && byteaddr(dst, par->r.min) > byteaddr(src, par->sr.min)){
+			dir = -1;
+		}else
+			dir = 1;
+
+		lm = 0xFF>>(par->r.min.x&7);
+		rm = 0xFF<<(8-(par->r.max.x&7));
+		dx -= (8-(par->r.min.x&7)) + (par->r.max.x&7);
+
+		if(dx < 0){	/* one byte wide */
+			lm &= rm;
+			if(dir == -1){
+				dp += dwid*(dy-1);
+				sp += swid*(dy-1);
+				mp += mwid*(dy-1);
+				dwid = -dwid;
+				swid = -swid;
+				mwid = -mwid;
+			}
+			for(y=0; y<dy; y++){
+				*dp ^= (*dp ^ *sp) & *mp & lm;
+				dp += dwid;
+				sp += swid;
+				mp += mwid;
+			}
+			return 1;
+		}
+
+		dx /= 8;
+		if(dir == 1){
+			i = (lm!=0)+dx+(rm!=0);
+			mwid -= i;
+			swid -= i;
+			dwid -= i;
+			for(y=0; y<dy; y++, dp+=dwid, sp+=swid, mp+=mwid){
+				if(lm){
+					*dp ^= (*dp ^ *sp++) & *mp++ & lm;
+					dp++;
+				}
+				for(x=0; x<dx; x++){
+					*dp ^= (*dp ^ *sp++) & *mp++;
+					dp++;
+				}
+				if(rm){
+					*dp ^= (*dp ^ *sp++) & *mp++ & rm;
+					dp++;
+				}
+			}
+			return 1;
+		}else{
+		/* dir == -1 */
+			i = (lm!=0)+dx+(rm!=0);
+			dp += dwid*(dy-1)+i-1;
+			sp += swid*(dy-1)+i-1;
+			mp += mwid*(dy-1)+i-1;
+			dwid = -dwid+i;
+			swid = -swid+i;
+			mwid = -mwid+i;
+			for(y=0; y<dy; y++, dp+=dwid, sp+=swid, mp+=mwid){
+				if(rm){
+					*dp ^= (*dp ^ *sp--) & *mp-- & rm;
+					dp--;
+				}
+				for(x=0; x<dx; x++){
+					*dp ^= (*dp ^ *sp--) & *mp--;
+					dp--;
+				}
+				if(lm){
+					*dp ^= (*dp ^ *sp--) & *mp-- & lm;
+					dp--;
+				}
+			}
+		}
+		return 1;
+	}
+	return 0;	
+}
+#undef DBG
+
+/*
+ * Boolean character drawing.
+ * Solid opaque color through a 1-bit greyscale mask.
+ */
+#define DBG if(0)
+static int
+chardraw(Memdrawparam *par)
+{
+	u32int bits;
+	int i, ddepth, dy, dx, x, bx, ex, y, npack, bsh, depth, op;
+	u32int v, maskwid, dstwid;
+	uchar *wp, *rp, *q, *wc;
+	ushort *ws;
+	u32int *wl;
+	uchar sp[4];
+	Rectangle r, mr;
+	Memimage *mask, *src, *dst;
+
+if(0) if(drawdebug) iprint("chardraw? mf %lux md %d sf %lux dxs %d dys %d dd %d ddat %p sdat %p\n",
+		par->mask->flags, par->mask->depth, par->src->flags, 
+		Dx(par->src->r), Dy(par->src->r), par->dst->depth, par->dst->data, par->src->data);
+
+	mask = par->mask;
+	src = par->src;
+	dst = par->dst;
+	r = par->r;
+	mr = par->mr;
+	op = par->op;
+
+	if((par->state&(Replsrc|Simplesrc|Replmask)) != (Replsrc|Simplesrc)
+	|| mask->depth != 1 || src->flags&Falpha || dst->depth<8 || dst->data==src->data
+	|| op != SoverD)
+		return 0;
+
+//if(drawdebug) iprint("chardraw...");
+
+	depth = mask->depth;
+	maskwid = mask->width*sizeof(u32int);
+	rp = byteaddr(mask, mr.min);
+	npack = 8/depth;
+	bsh = (mr.min.x % npack) * depth;
+
+	wp = byteaddr(dst, r.min);
+	dstwid = dst->width*sizeof(u32int);
+DBG print("bsh %d\n", bsh);
+	dy = Dy(r);
+	dx = Dx(r);
+
+	ddepth = dst->depth;
+
+	/*
+	 * for loop counts from bsh to bsh+dx
+	 *
+	 * we want the bottom bits to be the amount
+	 * to shift the pixels down, so for n≡0 (mod 8) we want 
+	 * bottom bits 7.  for n≡1, 6, etc.
+	 * the bits come from -n-1.
+	 */
+
+	bx = -bsh-1;
+	ex = -bsh-1-dx;
+	SET(bits);
+	v = par->sdval;
+
+	/* make little endian */
+	sp[0] = v;
+	sp[1] = v>>8;
+	sp[2] = v>>16;
+	sp[3] = v>>24;
+
+//print("sp %x %x %x %x\n", sp[0], sp[1], sp[2], sp[3]);
+	for(y=0; y<dy; y++, rp+=maskwid, wp+=dstwid){
+		q = rp;
+		if(bsh)
+			bits = *q++;
+		switch(ddepth){
+		case 8:
+//if(drawdebug) iprint("8loop...");
+			wc = wp;
+			for(x=bx; x>ex; x--, wc++){
+				i = x&7;
+				if(i == 8-1)
+					bits = *q++;
+DBG print("bits %lux sh %d...", bits, i);
+				if((bits>>i)&1)
+					*wc = v;
+			}
+			break;
+		case 16:
+			ws = (ushort*)wp;
+			v = *(ushort*)sp;
+			for(x=bx; x>ex; x--, ws++){
+				i = x&7;
+				if(i == 8-1)
+					bits = *q++;
+DBG print("bits %lux sh %d...", bits, i);
+				if((bits>>i)&1)
+					*ws = v;
+			}
+			break;
+		case 24:
+			wc = wp;
+			for(x=bx; x>ex; x--, wc+=3){
+				i = x&7;
+				if(i == 8-1)
+					bits = *q++;
+DBG print("bits %lux sh %d...", bits, i);
+				if((bits>>i)&1){
+					wc[0] = sp[0];
+					wc[1] = sp[1];
+					wc[2] = sp[2];
+				}
+			}
+			break;
+		case 32:
+			wl = (u32int*)wp;
+			v = *(u32int*)sp;
+			for(x=bx; x>ex; x--, wl++){
+				i = x&7;
+				if(i == 8-1)
+					bits = *q++;
+DBG iprint("bits %lux sh %d...", bits, i);
+				if((bits>>i)&1)
+					*wl = v;
+			}
+			break;
+		}
+	}
+
+DBG print("\n");	
+	return 1;	
+}
+#undef DBG
+
+
+/*
+ * Fill entire byte with replicated (if necessary) copy of source pixel,
+ * assuming destination ldepth is >= source ldepth.
+ *
+ * This code is just plain wrong for >8bpp.
+ *
+u32int
+membyteval(Memimage *src)
+{
+	int i, val, bpp;
+	uchar uc;
+
+	unloadmemimage(src, src->r, &uc, 1);
+	bpp = src->depth;
+	uc <<= (src->r.min.x&(7/src->depth))*src->depth;
+	uc &= ~(0xFF>>bpp);
+	* pixel value is now in high part of byte. repeat throughout byte 
+	val = uc;
+	for(i=bpp; i<8; i<<=1)
+		val |= val>>i;
+	return val;
+}
+ * 
+ */
+
+void
+_memfillcolor(Memimage *i, u32int val)
+{
+	u32int bits;
+	int d, y;
+	uchar p[4];
+
+	if(val == DNofill)
+		return;
+
+	bits = _rgbatoimg(i, val);
+	switch(i->depth){
+	case 24:	/* 24-bit images suck */
+		for(y=i->r.min.y; y<i->r.max.y; y++)
+			memset24(byteaddr(i, Pt(i->r.min.x, y)), bits, Dx(i->r));
+		break;
+	default:	/* 1, 2, 4, 8, 16, 32 */
+		for(d=i->depth; d<32; d*=2)
+			bits = (bits << d) | bits;
+		p[0] = bits;		/* make little endian */
+		p[1] = bits>>8;
+		p[2] = bits>>16;
+		p[3] = bits>>24;
+		bits = *(u32int*)p;
+		memsetl(wordaddr(i, i->r.min), bits, i->width*Dy(i->r));
+		break;
+	}
+}
+