Graphic Orders
BLT2F_XHD
MOTOROLA
MC68322 USER’S MANUAL
13-29
BLT2F_XHD
Expanded Source, Halftone, Destination bitBLT to Banded Bitmap
The BLT2F_XHD graphic order transfers a low resolution source frame to a destination
frame and applies a halftone bitmap in the process. Before being combined with the
destination, the source frame is scaled to match the resolution of the destination bitmap,
which results in an intermediate expanded source bitmap. The pixels of the expanded
source, halftone, and destination bit maps are combined as specified by the Boolean code
set in the last SET_BOOL_SHD order. The SET_HTBMAP graphic order must previously
define the halftone bitmap dimensions. During the processing of halftones, wrapping occurs
at the edges of the bitmap and this results in horizontal and vertical replication (tiling) of the
bitmap to cover the entire destination frame area. The DA parameter specifies the physical
bit address of the destination frame. It must point to the upper left corner of the destination
frame. The destination frame will be packed since its warp is assumed to equal FW.
The FW and FH parameters define the area of the destination bitmap on which the operation
is performed. FW is the frame width in bits and at a maximum equals the quantity
W
× (XMUL + 1) where W is the width of the unexpanded source bitmap. FH is the frame
height in scanlines and at a maximum equals the quantity H
× (YMUL + 1) where H is the
height of the unexpanded source bitmap. Specifying FW and FH as defined above causes
the entire expanded source image to be combined with the destination bitmap. Specifying
an FW and/or FH value less than the values defined by the above equations causes only a
portion of the expanded source frame to be applied to the destination. When used in
combination with XOFF and YOFF, clipping can be affected at any or all extents of the
expanded source bitmap.
The SA parameter defines the unexpanded source bitmap bit address. It must point to the
upper left corner of the bitmap. The warp of the bitmap is set by the SW parameter. This
value is added to SA to locate the beginning of each successive scanline. Note that the
source warp set by the SET_SBMAP graphic order has no effect on this graphic order.
PARAMETERS
SIZE
DESCRIPTION
0x17
0x00
DA
FW
FH
SA
SW
XOFF:XMUL
YOFF:YMUL
HXR
HYR
HA
Byte
Long Word
Word
Long Word
Word
Two 4-bit Fields
Word
Long Word
BLT2F_XHD Opcode.
Reserved.
Destination physical bit address.
Destination frame width in bits.
Destination frame height in scanlines.
Unexpanded source physical bit address.
Unexpanded source frame warp in bits.
X offset and X multiplier in bits.
Y offset and Y multiplier in scanlines.
Halftone X remainder.
Halftone Y remainder.
Halftone physical bit address of the starting pixel.