�  OSbits Module B/osb01
(�  Introduction to the BBC Assembler
�  Version 1.0 - 17.8.86
( 
2*KEY1MO.3|M|NL.|M
< 
Fosasci=&FFE3
Pcode% = &3000
Z 
d� pass%=0 � 3 � 3
nP%=code%
x 
�[OPT pass%
�DLDX #0       \ We use the X register as an offset, starting at 0
� 
�A.loop        \ The start of the loop that prints out the text
�=LDA text,X   \ Load A with the contents of address text+X
�?JSR osasci   \ This is an built in subroutine that prints A
�1INX          \ Increase the value of X by one
�8CMP #13      \ Compare A with 13 (a carriage return)
�CBNE loop     \ If A not equal to 13 then branch to label 'loop'
� 
�"RTS          \ Return to Basic
� 
�B.text        \ Use the $ indirection operator to put text here

]

�

 

",$P%="Hello World, this is machine code!"

,� code%
�

00000000  0d 00 0a 1c f4 20 20 4f  53 62 69 74 73 20 4d 6f  |.....  OSbits Mo|
00000010  64 75 6c 65 20 42 2f 6f  73 62 30 31 0d 00 14 28  |dule B/osb01...(|
00000020  f4 20 20 49 6e 74 72 6f  64 75 63 74 69 6f 6e 20  |.  Introduction |
00000030  74 6f 20 74 68 65 20 42  42 43 20 41 73 73 65 6d  |to the BBC Assem|
00000040  62 6c 65 72 0d 00 1e 1c  f4 20 20 56 65 72 73 69  |bler.....  Versi|
00000050  6f 6e 20 31 2e 30 20 2d  20 31 37 2e 38 2e 38 36  |on 1.0 - 17.8.86|
00000060  0d 00 28 05 20 0d 00 32  15 2a 4b 45 59 31 4d 4f  |..(. ..2.*KEY1MO|
00000070  2e 33 7c 4d 7c 4e 4c 2e  7c 4d 0d 00 3c 05 20 0d  |.3|M|NL.|M..<. .|
00000080  00 46 10 6f 73 61 73 63  69 3d 26 46 46 45 33 0d  |.F.osasci=&FFE3.|
00000090  00 50 11 63 6f 64 65 25  20 3d 20 26 33 30 30 30  |.P.code% = &3000|
000000a0  0d 00 5a 05 20 0d 00 64  15 e3 20 70 61 73 73 25  |..Z. ..d.. pass%|
000000b0  3d 30 20 b8 20 33 20 88  20 33 0d 00 6e 0c 50 25  |=0 . 3 . 3..n.P%|
000000c0  3d 63 6f 64 65 25 0d 00  78 05 20 0d 00 82 0e 5b  |=code%..x. ....[|
000000d0  4f 50 54 20 70 61 73 73  25 0d 00 8c 44 4c 44 58  |OPT pass%...DLDX|
000000e0  20 23 30 20 20 20 20 20  20 20 5c 20 57 65 20 75  | #0       \ We u|
000000f0  73 65 20 74 68 65 20 58  20 72 65 67 69 73 74 65  |se the X registe|
00000100  72 20 61 73 20 61 6e 20  6f 66 66 73 65 74 2c 20  |r as an offset, |
00000110  73 74 61 72 74 69 6e 67  20 61 74 20 30 0d 00 96  |starting at 0...|
00000120  05 20 0d 00 a0 41 2e 6c  6f 6f 70 20 20 20 20 20  |. ...A.loop     |
00000130  20 20 20 5c 20 54 68 65  20 73 74 61 72 74 20 6f  |   \ The start o|
00000140  66 20 74 68 65 20 6c 6f  6f 70 20 74 68 61 74 20  |f the loop that |
00000150  70 72 69 6e 74 73 20 6f  75 74 20 74 68 65 20 74  |prints out the t|
00000160  65 78 74 0d 00 aa 3d 4c  44 41 20 74 65 78 74 2c  |ext...=LDA text,|
00000170  58 20 20 20 5c 20 4c 6f  61 64 20 41 20 77 69 74  |X   \ Load A wit|
00000180  68 20 74 68 65 20 63 6f  6e 74 65 6e 74 73 20 6f  |h the contents o|
00000190  66 20 61 64 64 72 65 73  73 20 74 65 78 74 2b 58  |f address text+X|
000001a0  0d 00 b4 3f 4a 53 52 20  6f 73 61 73 63 69 20 20  |...?JSR osasci  |
000001b0  20 5c 20 54 68 69 73 20  69 73 20 61 6e 20 62 75  | \ This is an bu|
000001c0  69 6c 74 20 69 6e 20 73  75 62 72 6f 75 74 69 6e  |ilt in subroutin|
000001d0  65 20 74 68 61 74 20 70  72 69 6e 74 73 20 41 0d  |e that prints A.|
000001e0  00 be 31 49 4e 58 20 20  20 20 20 20 20 20 20 20  |..1INX          |
000001f0  5c 20 49 6e 63 72 65 61  73 65 20 74 68 65 20 76  |\ Increase the v|
00000200  61 6c 75 65 20 6f 66 20  58 20 62 79 20 6f 6e 65  |alue of X by one|
00000210  0d 00 c8 38 43 4d 50 20  23 31 33 20 20 20 20 20  |...8CMP #13     |
00000220  20 5c 20 43 6f 6d 70 61  72 65 20 41 20 77 69 74  | \ Compare A wit|
00000230  68 20 31 33 20 28 61 20  63 61 72 72 69 61 67 65  |h 13 (a carriage|
00000240  20 72 65 74 75 72 6e 29  0d 00 d2 43 42 4e 45 20  | return)...CBNE |
00000250  6c 6f 6f 70 20 20 20 20  20 5c 20 49 66 20 41 20  |loop     \ If A |
00000260  6e 6f 74 20 65 71 75 61  6c 20 74 6f 20 31 33 20  |not equal to 13 |
00000270  74 68 65 6e 20 62 72 61  6e 63 68 20 74 6f 20 6c  |then branch to l|
00000280  61 62 65 6c 20 27 6c 6f  6f 70 27 0d 00 dc 05 20  |abel 'loop'.... |
00000290  0d 00 e6 22 52 54 53 20  20 20 20 20 20 20 20 20  |..."RTS         |
000002a0  20 5c 20 52 65 74 75 72  6e 20 74 6f 20 42 61 73  | \ Return to Bas|
000002b0  69 63 0d 00 f0 05 20 0d  00 fa 42 2e 74 65 78 74  |ic.... ...B.text|
000002c0  20 20 20 20 20 20 20 20  5c 20 55 73 65 20 74 68  |        \ Use th|
000002d0  65 20 24 20 69 6e 64 69  72 65 63 74 69 6f 6e 20  |e $ indirection |
000002e0  6f 70 65 72 61 74 6f 72  20 74 6f 20 70 75 74 20  |operator to put |
000002f0  74 65 78 74 20 68 65 72  65 0d 01 04 05 5d 0d 01  |text here....]..|
00000300  0e 05 ed 0d 01 18 05 20  0d 01 22 2c 24 50 25 3d  |....... ..",$P%=|
00000310  22 48 65 6c 6c 6f 20 57  6f 72 6c 64 2c 20 74 68  |"Hello World, th|
00000320  69 73 20 69 73 20 6d 61  63 68 69 6e 65 20 63 6f  |is is machine co|
00000330  64 65 21 22 0d 01 2c 0b  d6 20 63 6f 64 65 25 0d  |de!"..,.. code%.|
00000340  ff                                                |.|
00000341