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+P6
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » Personal collection » Acorn ADFS disks » Electron_User_Group » EUG_38.ADF |
| Filename: | +P6 |
| Read OK: | ✔ |
| File size: | 0D5C bytes |
| Load address: | 2B204556 |
| Exec address: | D3650 |
Duplicates
There is 1 duplicate copy of this file in the archive:
- Personal collection » Acorn ADFS disks » Electron_User_Group » EUG_38.ADF » +P6
- Personal collection » Acorn hard disk » zipped_disks » elk03 » eug38/+P6
File contents
PIXEL-BY-PIXEL LAYOUT MEMORY FLOW
00008888 0 8
11119999 | |
2222AAAA | |
3333BBBB | |
4444CCCC | |
5555DDDD | |
6666EEEE \ / \ /
7777FFFF 7 F
Each of these sixteen bytes, as already discussed, contains four pixel
definitions. But within each byte's eight bits, they are not laid out as
you might at first imagine. If we call the four pixels A, B, C and D (A is
the left-most, D is the right-most), the layout is:
[MOST SIGNIFICANT] A1 B1 C1 D1 A0 B0 C0 D0 [LEAST SIGNIFICANT]
Where: A1: Most significant bit of A's definition } Two bit definition
A0: Least significant bit of A's definition } of pixel A
A simialar pattern holds for B, C and D.
EXAMPLE:
Let's suppose we want to set the colour of the left-most pixel in a byte
of a four-colour mode to be colour 3. We would use:
?address=(?address AND &77) OR &88
Explanation - The (?address AND &77) part clears the two bits defining the
pixel that we want to change. The OR &88 then sets the two bits that we
want to set. This way we ensure that when we are going say from colour 1
to colour 2, the least significant bit of the definition is cleared as
well as the most significant bit being set.
It is important to notice tha pattern in these bits - each pixel requires
a two bit definition, but these two bits are not next to each other in the
byte as one might expect - instead all of the high-bytes are stored
together, and all of the low-bytes are stored together.
SIXTEEN COLOUR MODES
The pattern for sixteen colour modes is very simialr to that found in four
colour modes, except that each byte can only store two pixels (each
occupies four bites). As with previous cases, the pixels are stored in a
number of vertical sweeps starting at the left of the character, and
moving right. This time four vertical sweeps are required to cover all of
the character (there are eight pixels across, and each sweep covers two of
them). The layout is shown below:
PIXEL-BY-PIXEL LAYOUT MEMORY FLOW
00880088 0 8 10 18
11991199 | | | |
22AA22AA | | | |
33BB33BB | | | |
44CC44CC | | | |
55DD55DD | | | |
66EE66EE \ / \ / \ / \ /
77FF77FF 7 F 17 1F
****
NB: Offsets given in hexadecinal. Values in the right half of the above
diagram (ie. the right four pixels, which have * underneath) should have
&10 added to them - only the least significant character of each
hexadecimal value is given. I am sure you can see my problem - the
hexadecimal values are two digits long, and I've only got one character in
which to put them!
The pattern of the layout of the pixel data in each of the bytes is also
similar to that for the four colour modes (the two pixels are A and B, and
each comprises of four bits 0-3, where 0 is least significant and 3 is
most significant).
[MOST SIGNIFICANT] A3 B3 A2 B2 A1 B1 A0 B0 [LEAST SIGNIFICANT]
Notice once again that bits defining the pixels A and B are not stored
together, but those defining the least/most significant bits are stored
together.
MORE ON THE SUBJECT ON SCREEN MEMORY IN NEXT EUG...
00000000 0d 50 49 58 45 4c 2d 42 59 2d 50 49 58 45 4c 20 |.PIXEL-BY-PIXEL | 00000010 4c 41 59 4f 55 54 20 20 20 20 20 4d 45 4d 4f 52 |LAYOUT MEMOR| 00000020 59 20 46 4c 4f 57 0d 0d 30 30 30 30 38 38 38 38 |Y FLOW..00008888| 00000030 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00000040 20 20 20 20 30 20 20 20 20 20 20 38 0d 31 31 31 | 0 8.111| 00000050 31 39 39 39 39 20 20 20 20 20 20 20 20 20 20 20 |19999 | 00000060 20 20 20 20 20 20 20 20 20 7c 20 20 20 20 20 20 | | | 00000070 7c 0d 32 32 32 32 41 41 41 41 20 20 20 20 20 20 ||.2222AAAA | 00000080 20 20 20 20 20 20 20 20 20 20 20 20 20 20 7c 20 | | | 00000090 20 20 20 20 20 7c 0d 33 33 33 33 42 42 42 42 20 | |.3333BBBB | 000000a0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 000000b0 20 20 20 7c 20 20 20 20 20 20 7c 0d 34 34 34 34 | | |.4444| 000000c0 43 43 43 43 20 20 20 20 20 20 20 20 20 20 20 20 |CCCC | 000000d0 20 20 20 20 20 20 20 20 7c 20 20 20 20 20 20 7c | | || 000000e0 0d 35 35 35 35 44 44 44 44 20 20 20 20 20 20 20 |.5555DDDD | 000000f0 20 20 20 20 20 20 20 20 20 20 20 20 20 7c 20 20 | | | 00000100 20 20 20 20 7c 0d 36 36 36 36 45 45 45 45 20 20 | |.6666EEEE | 00000110 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00000120 20 5c 20 2f 20 20 20 20 5c 20 2f 0d 37 37 37 37 | \ / \ /.7777| 00000130 46 46 46 46 20 20 20 20 20 20 20 20 20 20 20 20 |FFFF | 00000140 20 20 20 20 20 20 20 20 37 20 20 20 20 20 20 46 | 7 F| 00000150 0d 0d 45 61 63 68 20 6f 66 20 74 68 65 73 65 20 |..Each of these | 00000160 73 69 78 74 65 65 6e 20 62 79 74 65 73 2c 20 61 |sixteen bytes, a| 00000170 73 20 61 6c 72 65 61 64 79 20 64 69 73 63 75 73 |s already discus| 00000180 73 65 64 2c 20 63 6f 6e 74 61 69 6e 73 20 66 6f |sed, contains fo| 00000190 75 72 20 70 69 78 65 6c 0d 64 65 66 69 6e 69 74 |ur pixel.definit| 000001a0 69 6f 6e 73 2e 20 42 75 74 20 77 69 74 68 69 6e |ions. But within| 000001b0 20 65 61 63 68 20 62 79 74 65 27 73 20 65 69 67 | each byte's eig| 000001c0 68 74 20 62 69 74 73 2c 20 74 68 65 79 20 61 72 |ht bits, they ar| 000001d0 65 20 6e 6f 74 20 6c 61 69 64 20 6f 75 74 20 61 |e not laid out a| 000001e0 73 0d 79 6f 75 20 6d 69 67 68 74 20 61 74 20 66 |s.you might at f| 000001f0 69 72 73 74 20 69 6d 61 67 69 6e 65 2e 20 49 66 |irst imagine. If| 00000200 20 77 65 20 63 61 6c 6c 20 74 68 65 20 66 6f 75 | we call the fou| 00000210 72 20 70 69 78 65 6c 73 20 41 2c 20 42 2c 20 43 |r pixels A, B, C| 00000220 20 61 6e 64 20 44 20 28 41 20 69 73 0d 74 68 65 | and D (A is.the| 00000230 20 6c 65 66 74 2d 6d 6f 73 74 2c 20 44 20 69 73 | left-most, D is| 00000240 20 74 68 65 20 72 69 67 68 74 2d 6d 6f 73 74 29 | the right-most)| 00000250 2c 20 74 68 65 20 6c 61 79 6f 75 74 20 69 73 3a |, the layout is:| 00000260 0d 0d 5b 4d 4f 53 54 20 53 49 47 4e 49 46 49 43 |..[MOST SIGNIFIC| 00000270 41 4e 54 5d 20 20 41 31 20 42 31 20 43 31 20 44 |ANT] A1 B1 C1 D| 00000280 31 20 41 30 20 42 30 20 43 30 20 44 30 20 20 5b |1 A0 B0 C0 D0 [| 00000290 4c 45 41 53 54 20 53 49 47 4e 49 46 49 43 41 4e |LEAST SIGNIFICAN| 000002a0 54 5d 0d 0d 57 68 65 72 65 3a 20 41 31 3a 20 4d |T]..Where: A1: M| 000002b0 6f 73 74 20 73 69 67 6e 69 66 69 63 61 6e 74 20 |ost significant | 000002c0 62 69 74 20 6f 66 20 41 27 73 20 64 65 66 69 6e |bit of A's defin| 000002d0 69 74 69 6f 6e 20 20 7d 20 54 77 6f 20 62 69 74 |ition } Two bit| 000002e0 20 64 65 66 69 6e 69 74 69 6f 6e 0d 20 20 20 20 | definition. | 000002f0 20 20 20 41 30 3a 20 4c 65 61 73 74 20 73 69 67 | A0: Least sig| 00000300 6e 69 66 69 63 61 6e 74 20 62 69 74 20 6f 66 20 |nificant bit of | 00000310 41 27 73 20 64 65 66 69 6e 69 74 69 6f 6e 20 7d |A's definition }| 00000320 20 20 6f 66 20 70 69 78 65 6c 20 41 0d 0d 41 20 | of pixel A..A | 00000330 73 69 6d 69 61 6c 61 72 20 70 61 74 74 65 72 6e |simialar pattern| 00000340 20 68 6f 6c 64 73 20 66 6f 72 20 42 2c 20 43 20 | holds for B, C | 00000350 61 6e 64 20 44 2e 0d 0d 45 58 41 4d 50 4c 45 3a |and D...EXAMPLE:| 00000360 0d 0d 4c 65 74 27 73 20 73 75 70 70 6f 73 65 20 |..Let's suppose | 00000370 77 65 20 77 61 6e 74 20 74 6f 20 73 65 74 20 74 |we want to set t| 00000380 68 65 20 63 6f 6c 6f 75 72 20 6f 66 20 74 68 65 |he colour of the| 00000390 20 6c 65 66 74 2d 6d 6f 73 74 20 70 69 78 65 6c | left-most pixel| 000003a0 20 69 6e 20 61 20 62 79 74 65 0d 6f 66 20 61 20 | in a byte.of a | 000003b0 66 6f 75 72 2d 63 6f 6c 6f 75 72 20 6d 6f 64 65 |four-colour mode| 000003c0 20 74 6f 20 62 65 20 63 6f 6c 6f 75 72 20 33 2e | to be colour 3.| 000003d0 20 57 65 20 77 6f 75 6c 64 20 75 73 65 3a 0d 0d | We would use:..| 000003e0 3f 61 64 64 72 65 73 73 3d 28 3f 61 64 64 72 65 |?address=(?addre| 000003f0 73 73 20 41 4e 44 20 26 37 37 29 20 4f 52 20 26 |ss AND &77) OR &| 00000400 38 38 0d 0d 45 78 70 6c 61 6e 61 74 69 6f 6e 20 |88..Explanation | 00000410 2d 20 54 68 65 20 28 3f 61 64 64 72 65 73 73 20 |- The (?address | 00000420 41 4e 44 20 26 37 37 29 20 70 61 72 74 20 63 6c |AND &77) part cl| 00000430 65 61 72 73 20 74 68 65 20 74 77 6f 20 62 69 74 |ears the two bit| 00000440 73 20 64 65 66 69 6e 69 6e 67 20 74 68 65 0d 70 |s defining the.p| 00000450 69 78 65 6c 20 74 68 61 74 20 77 65 20 77 61 6e |ixel that we wan| 00000460 74 20 74 6f 20 63 68 61 6e 67 65 2e 20 54 68 65 |t to change. The| 00000470 20 4f 52 20 26 38 38 20 74 68 65 6e 20 73 65 74 | OR &88 then set| 00000480 73 20 74 68 65 20 74 77 6f 20 62 69 74 73 20 74 |s the two bits t| 00000490 68 61 74 20 77 65 0d 77 61 6e 74 20 74 6f 20 73 |hat we.want to s| 000004a0 65 74 2e 20 54 68 69 73 20 77 61 79 20 77 65 20 |et. This way we | 000004b0 65 6e 73 75 72 65 20 74 68 61 74 20 77 68 65 6e |ensure that when| 000004c0 20 77 65 20 61 72 65 20 67 6f 69 6e 67 20 73 61 | we are going sa| 000004d0 79 20 66 72 6f 6d 20 63 6f 6c 6f 75 72 20 31 0d |y from colour 1.| 000004e0 74 6f 20 63 6f 6c 6f 75 72 20 32 2c 20 74 68 65 |to colour 2, the| 000004f0 20 6c 65 61 73 74 20 73 69 67 6e 69 66 69 63 61 | least significa| 00000500 6e 74 20 62 69 74 20 6f 66 20 74 68 65 20 64 65 |nt bit of the de| 00000510 66 69 6e 69 74 69 6f 6e 20 69 73 20 63 6c 65 61 |finition is clea| 00000520 72 65 64 20 61 73 0d 77 65 6c 6c 20 61 73 20 74 |red as.well as t| 00000530 68 65 20 6d 6f 73 74 20 73 69 67 6e 69 66 69 63 |he most signific| 00000540 61 6e 74 20 62 69 74 20 62 65 69 6e 67 20 73 65 |ant bit being se| 00000550 74 2e 0d 0d 49 74 20 69 73 20 69 6d 70 6f 72 74 |t...It is import| 00000560 61 6e 74 20 74 6f 20 6e 6f 74 69 63 65 20 74 68 |ant to notice th| 00000570 61 20 70 61 74 74 65 72 6e 20 69 6e 20 74 68 65 |a pattern in the| 00000580 73 65 20 62 69 74 73 20 2d 20 65 61 63 68 20 70 |se bits - each p| 00000590 69 78 65 6c 20 72 65 71 75 69 72 65 73 0d 61 20 |ixel requires.a | 000005a0 74 77 6f 20 62 69 74 20 64 65 66 69 6e 69 74 69 |two bit definiti| 000005b0 6f 6e 2c 20 62 75 74 20 74 68 65 73 65 20 74 77 |on, but these tw| 000005c0 6f 20 62 69 74 73 20 61 72 65 20 6e 6f 74 20 6e |o bits are not n| 000005d0 65 78 74 20 74 6f 20 65 61 63 68 20 6f 74 68 65 |ext to each othe| 000005e0 72 20 69 6e 20 74 68 65 0d 62 79 74 65 20 61 73 |r in the.byte as| 000005f0 20 6f 6e 65 20 6d 69 67 68 74 20 65 78 70 65 63 | one might expec| 00000600 74 20 2d 20 69 6e 73 74 65 61 64 20 61 6c 6c 20 |t - instead all | 00000610 6f 66 20 74 68 65 20 68 69 67 68 2d 62 79 74 65 |of the high-byte| 00000620 73 20 61 72 65 20 73 74 6f 72 65 64 0d 74 6f 67 |s are stored.tog| 00000630 65 74 68 65 72 2c 20 61 6e 64 20 61 6c 6c 20 6f |ether, and all o| 00000640 66 20 74 68 65 20 6c 6f 77 2d 62 79 74 65 73 20 |f the low-bytes | 00000650 61 72 65 20 73 74 6f 72 65 64 20 74 6f 67 65 74 |are stored toget| 00000660 68 65 72 2e 0d 0d 53 49 58 54 45 45 4e 20 43 4f |her...SIXTEEN CO| 00000670 4c 4f 55 52 20 4d 4f 44 45 53 0d 0d 54 68 65 20 |LOUR MODES..The | 00000680 70 61 74 74 65 72 6e 20 66 6f 72 20 73 69 78 74 |pattern for sixt| 00000690 65 65 6e 20 63 6f 6c 6f 75 72 20 6d 6f 64 65 73 |een colour modes| 000006a0 20 69 73 20 76 65 72 79 20 73 69 6d 69 61 6c 72 | is very simialr| 000006b0 20 74 6f 20 74 68 61 74 20 66 6f 75 6e 64 20 69 | to that found i| 000006c0 6e 20 66 6f 75 72 0d 63 6f 6c 6f 75 72 20 6d 6f |n four.colour mo| 000006d0 64 65 73 2c 20 65 78 63 65 70 74 20 74 68 61 74 |des, except that| 000006e0 20 65 61 63 68 20 62 79 74 65 20 63 61 6e 20 6f | each byte can o| 000006f0 6e 6c 79 20 73 74 6f 72 65 20 74 77 6f 20 70 69 |nly store two pi| 00000700 78 65 6c 73 20 28 65 61 63 68 0d 6f 63 63 75 70 |xels (each.occup| 00000710 69 65 73 20 66 6f 75 72 20 62 69 74 65 73 29 2e |ies four bites).| 00000720 20 41 73 20 77 69 74 68 20 70 72 65 76 69 6f 75 | As with previou| 00000730 73 20 63 61 73 65 73 2c 20 74 68 65 20 70 69 78 |s cases, the pix| 00000740 65 6c 73 20 61 72 65 20 73 74 6f 72 65 64 20 69 |els are stored i| 00000750 6e 20 61 0d 6e 75 6d 62 65 72 20 6f 66 20 76 65 |n a.number of ve| 00000760 72 74 69 63 61 6c 20 73 77 65 65 70 73 20 73 74 |rtical sweeps st| 00000770 61 72 74 69 6e 67 20 61 74 20 74 68 65 20 6c 65 |arting at the le| 00000780 66 74 20 6f 66 20 74 68 65 20 63 68 61 72 61 63 |ft of the charac| 00000790 74 65 72 2c 20 61 6e 64 0d 6d 6f 76 69 6e 67 20 |ter, and.moving | 000007a0 72 69 67 68 74 2e 20 54 68 69 73 20 74 69 6d 65 |right. This time| 000007b0 20 66 6f 75 72 20 76 65 72 74 69 63 61 6c 20 73 | four vertical s| 000007c0 77 65 65 70 73 20 61 72 65 20 72 65 71 75 69 72 |weeps are requir| 000007d0 65 64 20 74 6f 20 63 6f 76 65 72 20 61 6c 6c 20 |ed to cover all | 000007e0 6f 66 0d 74 68 65 20 63 68 61 72 61 63 74 65 72 |of.the character| 000007f0 20 28 74 68 65 72 65 20 61 72 65 20 65 69 67 68 | (there are eigh| 00000800 74 20 70 69 78 65 6c 73 20 61 63 72 6f 73 73 2c |t pixels across,| 00000810 20 61 6e 64 20 65 61 63 68 20 73 77 65 65 70 20 | and each sweep | 00000820 63 6f 76 65 72 73 20 74 77 6f 20 6f 66 0d 74 68 |covers two of.th| 00000830 65 6d 29 2e 20 54 68 65 20 6c 61 79 6f 75 74 20 |em). The layout | 00000840 69 73 20 73 68 6f 77 6e 20 62 65 6c 6f 77 3a 0d |is shown below:.| 00000850 0d 50 49 58 45 4c 2d 42 59 2d 50 49 58 45 4c 20 |.PIXEL-BY-PIXEL | 00000860 4c 41 59 4f 55 54 20 20 20 4d 45 4d 4f 52 59 20 |LAYOUT MEMORY | 00000870 46 4c 4f 57 0d 0d 30 30 38 38 30 30 38 38 20 20 |FLOW..00880088 | 00000880 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 30 | 0| 00000890 20 20 20 20 20 38 20 20 20 20 31 30 20 20 20 20 | 8 10 | 000008a0 31 38 0d 31 31 39 39 31 31 39 39 20 20 20 20 20 |18.11991199 | 000008b0 20 20 20 20 20 20 20 20 20 20 20 20 7c 20 20 20 | | | 000008c0 20 20 7c 20 20 20 20 20 7c 20 20 20 20 20 7c 0d | | | |.| 000008d0 32 32 41 41 32 32 41 41 20 20 20 20 20 20 20 20 |22AA22AA | 000008e0 20 20 20 20 20 20 20 20 20 7c 20 20 20 20 20 7c | | || 000008f0 20 20 20 20 20 7c 20 20 20 20 20 7c 0d 33 33 42 | | |.33B| 00000900 42 33 33 42 42 20 20 20 20 20 20 20 20 20 20 20 |B33BB | 00000910 20 20 20 20 20 20 7c 20 20 20 20 20 7c 20 20 20 | | | | 00000920 20 20 7c 20 20 20 20 20 7c 0d 34 34 43 43 34 34 | | |.44CC44| 00000930 43 43 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |CC | 00000940 20 20 20 7c 20 20 20 20 20 7c 20 20 20 20 20 7c | | | || 00000950 20 20 20 20 20 7c 0d 35 35 44 44 35 35 44 44 20 | |.55DD55DD | 00000960 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00000970 7c 20 20 20 20 20 7c 20 20 20 20 20 7c 20 20 20 || | | | 00000980 20 20 7c 0d 36 36 45 45 36 36 45 45 20 20 20 20 | |.66EE66EE | 00000990 20 20 20 20 20 20 20 20 20 20 20 20 5c 20 2f 20 | \ / | 000009a0 20 20 5c 20 2f 20 20 20 5c 20 2f 20 20 20 5c 20 | \ / \ / \ | 000009b0 2f 0d 37 37 46 46 37 37 46 46 20 20 20 20 20 20 |/.77FF77FF | 000009c0 20 20 20 20 20 20 20 20 20 20 20 37 20 20 20 20 | 7 | 000009d0 20 46 20 20 20 20 31 37 20 20 20 20 31 46 0d 20 | F 17 1F. | 000009e0 20 20 20 2a 2a 2a 2a 0d 0d 4e 42 3a 20 4f 66 66 | ****..NB: Off| 000009f0 73 65 74 73 20 67 69 76 65 6e 20 69 6e 20 68 65 |sets given in he| 00000a00 78 61 64 65 63 69 6e 61 6c 2e 20 56 61 6c 75 65 |xadecinal. Value| 00000a10 73 20 69 6e 20 74 68 65 20 72 69 67 68 74 20 68 |s in the right h| 00000a20 61 6c 66 20 6f 66 20 74 68 65 20 61 62 6f 76 65 |alf of the above| 00000a30 0d 64 69 61 67 72 61 6d 20 28 69 65 2e 20 74 68 |.diagram (ie. th| 00000a40 65 20 72 69 67 68 74 20 66 6f 75 72 20 70 69 78 |e right four pix| 00000a50 65 6c 73 2c 20 77 68 69 63 68 20 68 61 76 65 20 |els, which have | 00000a60 2a 20 75 6e 64 65 72 6e 65 61 74 68 29 20 73 68 |* underneath) sh| 00000a70 6f 75 6c 64 20 68 61 76 65 0d 26 31 30 20 61 64 |ould have.&10 ad| 00000a80 64 65 64 20 74 6f 20 74 68 65 6d 20 2d 20 6f 6e |ded to them - on| 00000a90 6c 79 20 74 68 65 20 6c 65 61 73 74 20 73 69 67 |ly the least sig| 00000aa0 6e 69 66 69 63 61 6e 74 20 63 68 61 72 61 63 74 |nificant charact| 00000ab0 65 72 20 6f 66 20 65 61 63 68 0d 68 65 78 61 64 |er of each.hexad| 00000ac0 65 63 69 6d 61 6c 20 76 61 6c 75 65 20 69 73 20 |ecimal value is | 00000ad0 67 69 76 65 6e 2e 20 49 20 61 6d 20 73 75 72 65 |given. I am sure| 00000ae0 20 79 6f 75 20 63 61 6e 20 73 65 65 20 6d 79 20 | you can see my | 00000af0 70 72 6f 62 6c 65 6d 20 2d 20 74 68 65 0d 68 65 |problem - the.he| 00000b00 78 61 64 65 63 69 6d 61 6c 20 76 61 6c 75 65 73 |xadecimal values| 00000b10 20 61 72 65 20 74 77 6f 20 64 69 67 69 74 73 20 | are two digits | 00000b20 6c 6f 6e 67 2c 20 61 6e 64 20 49 27 76 65 20 6f |long, and I've o| 00000b30 6e 6c 79 20 67 6f 74 20 6f 6e 65 20 63 68 61 72 |nly got one char| 00000b40 61 63 74 65 72 20 69 6e 0d 77 68 69 63 68 20 74 |acter in.which t| 00000b50 6f 20 70 75 74 20 74 68 65 6d 21 0d 0d 54 68 65 |o put them!..The| 00000b60 20 70 61 74 74 65 72 6e 20 6f 66 20 74 68 65 20 | pattern of the | 00000b70 6c 61 79 6f 75 74 20 6f 66 20 74 68 65 20 70 69 |layout of the pi| 00000b80 78 65 6c 20 64 61 74 61 20 69 6e 20 65 61 63 68 |xel data in each| 00000b90 20 6f 66 20 74 68 65 20 62 79 74 65 73 20 69 73 | of the bytes is| 00000ba0 20 61 6c 73 6f 0d 73 69 6d 69 6c 61 72 20 74 6f | also.similar to| 00000bb0 20 74 68 61 74 20 66 6f 72 20 74 68 65 20 66 6f | that for the fo| 00000bc0 75 72 20 63 6f 6c 6f 75 72 20 6d 6f 64 65 73 20 |ur colour modes | 00000bd0 28 74 68 65 20 74 77 6f 20 70 69 78 65 6c 73 20 |(the two pixels | 00000be0 61 72 65 20 41 20 61 6e 64 20 42 2c 20 61 6e 64 |are A and B, and| 00000bf0 0d 65 61 63 68 20 63 6f 6d 70 72 69 73 65 73 20 |.each comprises | 00000c00 6f 66 20 66 6f 75 72 20 62 69 74 73 20 30 2d 33 |of four bits 0-3| 00000c10 2c 20 77 68 65 72 65 20 30 20 69 73 20 6c 65 61 |, where 0 is lea| 00000c20 73 74 20 73 69 67 6e 69 66 69 63 61 6e 74 20 61 |st significant a| 00000c30 6e 64 20 33 20 69 73 0d 6d 6f 73 74 20 73 69 67 |nd 3 is.most sig| 00000c40 6e 69 66 69 63 61 6e 74 29 2e 0d 0d 5b 4d 4f 53 |nificant)...[MOS| 00000c50 54 20 53 49 47 4e 49 46 49 43 41 4e 54 5d 20 20 |T SIGNIFICANT] | 00000c60 41 33 20 42 33 20 41 32 20 42 32 20 41 31 20 42 |A3 B3 A2 B2 A1 B| 00000c70 31 20 41 30 20 42 30 20 20 5b 4c 45 41 53 54 20 |1 A0 B0 [LEAST | 00000c80 53 49 47 4e 49 46 49 43 41 4e 54 5d 0d 0d 4e 6f |SIGNIFICANT]..No| 00000c90 74 69 63 65 20 6f 6e 63 65 20 61 67 61 69 6e 20 |tice once again | 00000ca0 74 68 61 74 20 62 69 74 73 20 64 65 66 69 6e 69 |that bits defini| 00000cb0 6e 67 20 74 68 65 20 70 69 78 65 6c 73 20 41 20 |ng the pixels A | 00000cc0 61 6e 64 20 42 20 61 72 65 20 6e 6f 74 20 73 74 |and B are not st| 00000cd0 6f 72 65 64 0d 74 6f 67 65 74 68 65 72 2c 20 62 |ored.together, b| 00000ce0 75 74 20 74 68 6f 73 65 20 64 65 66 69 6e 69 6e |ut those definin| 00000cf0 67 20 74 68 65 20 6c 65 61 73 74 2f 6d 6f 73 74 |g the least/most| 00000d00 20 73 69 67 6e 69 66 69 63 61 6e 74 20 62 69 74 | significant bit| 00000d10 73 20 61 72 65 20 73 74 6f 72 65 64 0d 74 6f 67 |s are stored.tog| 00000d20 65 74 68 65 72 2e 0d 0d 4d 4f 52 45 20 4f 4e 20 |ether...MORE ON | 00000d30 54 48 45 20 53 55 42 4a 45 43 54 20 4f 4e 20 53 |THE SUBJECT ON S| 00000d40 43 52 45 45 4e 20 4d 45 4d 4f 52 59 20 49 4e 20 |CREEN MEMORY IN | 00000d50 4e 45 58 54 20 45 55 47 2e 2e 2e 0d |NEXT EUG....| 00000d5c
+P6.m0
+P6.m1
+P6.m2
+P6.m4
+P6.m5
.