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1.8 ADVANCED PROGRAMMING.
This section introduces one new command and some other programming
aspects which you may find useful.
The new command is:-
|ASKRAM, [ enquiry ], ( variable ]
The command allows certain constants to be found by the program you are
writing. For example it can return the number of banks available to the
program as this will change depending on whether you are using the 64K
RAM pack or the 256K RAM pack. The 'enquiry' value is a number 1 to 3 which
selects what you want to know. The answer is placed in an INTEGER variable
defined by the second parameter.
1000 a%=0 : |ASKRAM, 1, @a% .. will assign a% to the amount of RAM
1100 a%=0 : |ASKRAM, 2, @a% .. will assign a% to the number of banks
1200 a%=0 : |ASKRAM, 3, @a% .. will set a% to 0 or 1 depending on
whether there is a problem with the RAM
The last command can be used to make sure the RAM is there and ready to
use if in your programs you do not want to have to load the RSX loader
first. It is possible to load just the RSX machine code on its own:-
20 MODE 1 : PRINT "Program Loading!"
30 I=HIMEM
40 MEMORY 9999
50 LOAD "rsx", 10000
60 I=I-( PEEK(10004) + PEEK(10005)*256+1)
70 POKE 10002, I-INT(I/256)*256
80 POKE 10003, INT(I/256)
90 PRINT CHR$(30);CHR$(21);
100 CALL 10000
110 PRINT CHR$(30);CHR$(6);
120 a%=0 : |ASKRAM, 3, @a%
130 IF a% THEN PRINT "RAM is faulty" : END
140 CLEAR : MEMORY PEEK(10002) + PEEK(10003)*256-1
160 CHAIN "part2"
The
program
above
memory. Nothing will be printed on the screen unless the RAM proves to be
faulty or not even there! The program 'part2' would be the bulk of the
program. Loading the program in two parts saves reloading the RSX code
every time the program is run.
The code has to be loaded in at 10000 in memory before it is relocated for
use. The 16 bit value in locations 10002 and 10003 is the place you want
the code to be located at. Another 16 bit value in locations 10004 and
10005 contains the length of the code which is moved higher in memory.
Nearly 1K of the program is only needed once - the relocation and the RAM
test programs, and hence this part is not moved higher in RAM.
will
load
the
-13-
RSX
machine
code
and
put
it
into
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