Mail is a new hit parade of games.

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 ║ ─── MAIL ─── ║      
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 This section remains
empty  however, let's hope.
that everything will be OK.               
                                
 In the meantime, we’ll publish a new hit-
parade of games.                      
                                
 TOP tEN 'SPECtROPHOBY'         
                                
 1.UFO: Enemy unknown          
 2. Star Legacy            
 3.DIZZY 1-X2                   
 4.ELItE 2-3 (Novosibirsk)         
 5.ROBOCOP 1-3                  
 6.BAtMAN 1-3                   
 7.NIGEL MANSELL GP             
 8.tERMINAtOR 2                 
 9.SPACE CRUSADE                
10.LAZER SQUAD                  
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 ║ ─── SECRETS of tR-DOS ───  ║ 
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 When adapting shipments in games
many have probably encountered
a problem called IM2.
because  when accessing tR-DOSy with
turned onIM2 occurs
sanitization. This can be avoided by
in many ways:                
                                
1.At the beginning of the shipment subroutine
disable interrupt with command
IM1. and at the end turn it back on.
This is the most common and
simple way.2. Do this. so that when working
IM2 worked and tR-DOS. How is it
do? That's what we're up to today
We'll give you the answer.                    
                                
                                
 First, let's look at what's happening.
walks while processing an interrupt.
After the arrival of the pulse, the interruption
The microprocessor reads from
data bus bytes - interrupt vector
vania (with a standard tire -
this is #FF). 3atem from memory to hell
res.  formed by the vector pre-
tearing and the contents of the register I.
two bytes will be selected - address
interrupt processing routines
nia. But if the interruption came in
that moment.   when it works
tR-DOS. then transfer of control to
RAM area will automatically return
in its place the standard ROM ZX
Spectrum.  Upon completion of the
subroutine modification will occur
return to the main program.
However, about “replacing” the microprogram ROM
the processor will not recognize it. and instead of pro-
the operating conditions of the tR-DOS OS will be
"something" is executed from the OSZX
Spectrum. So. for that. to work
with second interrupt mode
need to somehow establish
twist  what is the current ROM?
included. At first glance, the question
Cha impossible. since the cross-
ROM flashings occur on the device -
but... However, you can use
differences in information in ROM and behind-
give different addresses to the subroutine
interrupt processing frame. For
this must be set in the registry
re I microprocessor number from 0
to #3F. then the address will be selected
from the ROM area. The most profitable
here the number is 9. I’ll explain now
why.  so for ROM ZX Spectrum
will be 65129(#FE82).  a for ROM
tR-DOS - 65535 (#FFFF) (and for
versions 5.01 and 5.03 and 5.04t).
This achieves the greatest con-
mectumoctb.                     
                                
                                
 now, when processing an interrupt,
tions with ZX ROM enabled
Spectrum interrupt will occur
go to the address 65129. and this
will be the main subroutine of the
interrupt operation. however if
everything is installed under a different ad-
res. then here you can put JP
ADDR. where ADDR is the real address
interrupt handling.   A at
included ROM tR-DOSinterrupt
will come to the address #FFFF and we will receive
There was only one byte. but this
quite enough. since there
you can write down the command code
JR(#18).  The offset will be taken
already from the ZX Spectrum ROM. and this
there will be a number #F3 (command code
DI).  this will make JR
65524. There are 11 bytes in the “recaptured”
you can place a subroutine
interrupt handling and return
tion in tR-DOS.                   
                                
 Here is the subroutine:      
                                
PUSH HL                    
LD HL.15663              
EX (SP).HL               
JP ADDR                  
where ADDR processing routine
interruptions.  In this case it is
will be 65129 (withI=9).          
                                
 And now to strengthen the math-
rial let's give an example. So we have: I=54(#36).     
First of all, we determine by what
the procedure is located at this address
interrupt handling. (help:
table of addresses of processing procedures
interrupt bots can be taken from
bookZX Spectrum & tR-DOScompany
PETER.   or in a three-volume edition
programming of the company INFORCOM).
So we got address #8603.
                                
now we write our
improvements:                      
                                
#FE86: #C30386 (JP #8603);      
#FFFF: #18 (JR 65524).          
#FFES: #E5212FЗDEЗC30386.       
                                
 And then in the main program
change the value I to #09. (this is
is done LD A.N:LD I.A where N as
once again it will be I).                 
                                
 Well then.perhaps that's all. In-
formation taken from the book ZX-Spec-
trum & tR-DOS from PETER.