NAME
        BltBitMap -- move a rectangular region of bits in a bitmap.

   SYNOPSIS
        planecnt = BltBitMap(SrcBitMap, SrcX, SrcY, DstBitMap,
        D0                   A0         D0:16 D1:16 A1
            DstX, DstY, SizeX, SizeY, Minterm, Mask [, TempA])
            D2:16 D3:16 D4:16  D5:16  D6:8     D7:8   [A2]

        ULONG BltBitMap(struct bitmap *, word, word, struct bitmap *,
            WORD, WORD, WORD, WORD, ubyte, ubyte, uword *);

   FUNCTION
        Perform non-destructive blits to move a rectangle from one
        area in a bitmap to another area, which can be on a different
        bitmap.
        This blit is assumed to be friendly: no error conditions (e.g.
        a rectangle outside the bitmap bounds) are tested or reported.

   INPUTS
        SrcBitMap, DstBitMap - the BitMap(s) containing the
              rectangles
            - the planes copied from the source to the destination are
              only those whose plane numbers are identical and less
              than the minimum Depth of either bitmap and whose mask
              bit for that plane is non-zero.
            - as a special case, if a plane pointer in the SrcBitMap
              is zero, it acts as a pointer to a plane of all zeros, and
              if the plane pointer is 0xffffffff, it acts as a pointer
              to a plane of all ones.  (Note: new for V36)
            - SrcBitMap and DstBitMap can be identical if they point
              to actual planes.
        SrcX, SrcY - the x and y coordinates of the upper left corner
            of the source rectangle.  Valid range is positive
            signed integer such that the raster word's offset
            0..(32767-Size)
        DstX, DstY - the x and y coordinates of the upper left
            corner of the destination for the rectangle.  Valid
            range is as for Src.
        SizeX, SizeY - the size of the rectangle to be moved.  Valid
            range is (X: 1..976; Y: 1..1023 such that final raster
            word's offset is 0..32767)
        Minterm - the logic function to apply to the rectangle when
            A is non-zero (i.e. within the rectangle).  B is the
            source rectangle and C, D is the destination for the
            rectangle.
            - $0C0 is a vanilla copy
            - $030 inverts the source before the copy
            - $050 ignores the source and inverts the destination
            - see the hardware reference manual for other combinations
        Mask - the write mask to apply to this operation.  Bits set
            indicate the corresponding planes (if not greater than
            the minimum plane count) are to participate in the
            operation.  Typically this is set to 0xff.
        TempA - If the copy overlaps exactly to the left or right
            (i.e. the scan line addresses overlap), and TempA is
            non-zero, it points to enough chip accessible memory
            to hold a line of A source for the blit (ie CHIP RAM).
            BltBitMap will allocate (and free) the needed TempA if
            none is provided and one is needed.  Blit overlap is
            determined from the relation of the first non-masked
            planes in the source and destination bit maps.

   RESULTS
        planecnt - the number of planes actually involved in the blit.

   NOTES
        o   This function may use the blitter.

   SEE ALSO
        clipblit()  graphics/gfx.h  hardware/blit.h