M69000 Asiliant Technologies, M69000 Datasheet - Page 285

• Manufacturer Part Number: M69000
• Manufacturer: Asiliant Technologies

Specifications of M69000

• Lead Free Status / Rohs Status: Supplier Unconfirmed

17-2
BR00
read/write at memory space offset 0x400000h
word or doubleword accessible
31-29
28-16
15-13
12-0
&+,36
31
15
Reserved
Reserved
(000)
(000)
Reserved
Destination Span
Reserved
Source Span
30
14
69000 Databook
Source and Destination Span Register
29
13
These bits always return 0 when read.
These 13 bits specify the span from the first byte in a scanline’s worth of destination data
to the first byte in the next scanline’s worth. In other words, these bits specify the amount
by which the destination address specified in BR07 should be incremented after a
scanline’s worth of destination data has been written to the destination in order to point to
where the first byte in the next scanline’s worth of destination data should be written.
If the destination data is to be contiguous (i.e., it will be a single unbroken block of data
where the last byte of a scanline’s worth of data is immediately followed by the first byte of
the next scanline’s worth), then the value of this span should be set equal to the number of
bytes in each scanline’s worth of destination data.
These bits always return 0 when read.
These 13 bits are used only when color source data is being used as an input in a BitBLT
operation. If the source data is monochrome, or no source data is to be used, then the
BitBLT engine will ignore the value carried by these bits.
When color source data is read from the frame buffer, these 13 bits specify the span from
the first byte in a scanline’s worth of color source data to the first byte in the next scanline’s
worth. In other words, these bits specify the amount by which the source address specified
in BR06 should be incremented after a scanline’s worth of color source data has been read
from the frame buffer in order to point to where the first byte in the next scanline’s worth of
color source data should be read.
When the host CPU provides the color source data through the BitBLT data port, these 13
bits specify the number of bytes to be counted from the first byte in one scanline’s worth of
color source data to the first byte in the next scanline’s worth.
If the color source data is contiguous (i.e., it is a single unbroken block of data where the
last byte of a scanline’s worth of data is immediately followed by the first byte of the next
scanline’s worth), then the value of this span should be set equal to the number of bytes in
each scanline’s worth of color source data.
28
12
27
11
26
10
Subject to Change Without Notice
25
9
BitBLT Registers
24
8
(x:xxxx:xxxx:xxxx)
(x:xxxx:xxxx:xxxx)
23
Destination Span
7
Source Span
22
6
21
5
20
4
19
3
Revision 1.3 8/31/98
18
2
17
1
16
0