2 example: 24 bpp (packed) mode, 2 pixel end and start, 2 example: 24 bpp (packed) mode -9 – Cirrus Logic EP93xx User Manual
Page 273: 2 pixel end and start -9, Table 8-9. transfer example 2 -9, Table 8-10. transfer example 3 -9, Table 8-11. transfer example 4 -9, Table 8-12. transfer example 5 -9, Table 8-9
DS785UM1
8-9
Copyright 2007 Cirrus Logic
Graphics Accelerator
EP93xx User’s Guide
8
8
8
If a Block Copy starts at pixel 3 and 10 pixels are to be copied, the
register
would be loaded with 0x3 (4 words - 1 word = 0x3). The pixels fetched are highlighted in
.
8.5.1.2 Example: 24 BPP (packed) mode
If a Block Copy starts at pixel 0 and copies 5 pixels, the
register would be
filled with 0x3. This is because the first four pixels consume 3 words and the 5th pixel
consumes part of 1 word. This is a total of 4 words. So, the word width is 4 words - 1 word =
0x3. The pixels fetched are highlighted in
If a Block Copy starts at pixel 2 and copies 6 pixels, the
register would be
filled with 0x4. This is because the 1st pixel consumes part of the 1st word and the 4
remaining pixels consume the next 4 words. So, the word width is 5 words - 1 word = 0x4.
The pixels fetched are highlighted in
.
8.5.2 Pixel End and Start
Two registers are used to control where in a word the first and last pixels reside. This is
required since in all color depths more than 1 pixel can reside in a word of memory. This fact
requires that the programmer provide the hardware with the exact information of where in a
32-bit word a pixel starts or ends. One register,
, is used for the source
Table 8-9. Transfer Example 2
Address
31
0
31
0
31
0
31
0
0x0000 -
0x000C
FF
EE
DD
CC
BB
AA
99
88
77
66
55
44
33
22
11
00
Table 8-10. Transfer Example 3
Address
31
0
31
0
31
0
31
0
0x0000 -
0x000C
FF
EE
DD
CC
BB
AA
99
88
77
66
55
44
33
22
11
00
Table 8-11. Transfer Example 4
Address
31
0
31
0
31
0
31
0
0x0000 -
0x000C
55
44
44
44
33
33
33
22
22
22
11
11
11
00
00
00
Table 8-12. Transfer Example 5
Address
31
0
31
0
31
0
31
0
0x0000 -
0x000C
55
44
44
44
33
33
33
22
22
22
11
11
11
00
00
00
0x0010 -
0x001C
AA
AA
99
99
99
88
88
88
77
77
77
66
66
66
55
55