Odyssey Magazine #02 14 июля 1997

Программирование

Assembler - Is it possible to throw a screen (6144 bytes) per tick.

Educational program: DR.S. you're wrong!
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(C) 1997 Phantom Lord
Music by Shov


 Greetings in the new section of our magazine.
The idea of ​​establishing such a column appeared after
reading at the Kharkov ZX Power Journal
articles Likbez "where the author tries to convince novice 
programmers" that throw 6144 bytes per tick 
nevozmozhno.Vozmutilo me is that I get - "A beginning 
programmer, because I believe that this can be done. The most 
interesting thing that I did it! But everything is in order. 


  Thus, in the ZX Power # 1 painted all is well. Resulted in 
several well-known methods: 

1. POP HL

        LD (ADR), HL


2. LD SP, STEK1

        POP HL

        ...

        LD SP, STEK

        PUSH HL

        ....



  Indeed, in such a way imprint
picture of one tick is impossible, but because
this is not the fastest ways to print!

 I propose a counterexample for Authors ZX Power, and I hope 
they will correct their error.



        LD SP, # 5800

        LD HL, # XXXX

        PUSH HL

        .... 3072 times

        LD HL, # XXXX

        PUSH HL



 Now calculate:


        LD SP, # 5800 - 1910 takts CPU

        LD HL, # XXXX - 10 takts

        PUSH HL - 11 takts


 Total:


        10 + (10 +11) * 3072 = 64522 cycles!



  Of course, we can say that it was not
convenient first image thus placed among the medley, and LD HL 
PUSH HL, but Why not do for the sake of speed! As you can see

all quite fit into one screen clock.
You can even hook up and the music that
were sold in the last part ETUDE
demo, published in the last issue of our magazine.

 I beg you not to evaluate this material as the arrival on the 
manufacturers ZX Power. All errors are the authors and are 
likely to have its found without us. We can only add

a few words to address INFORKOM'a.
Probably seen in the ZX-REVIEW 1 / 2 for 1997.
So there is advertising ZX P. hello where lines from different 
articles in the magazine. There where row and from literacy 
classes, which once again shows that Inforkom continues to 
write unverified information to the end. And yet

say that the Spectrum is held on Inforkome ... (But this is 
probably already a topic of another conversation.)


 And a bit of useful information.

 I recently wrote introchku and slightly off the chair
did not fall when changing the 1950 RES 50-SET
files of mine was to slow down. After
small-scale experiments revealed that
Team RES XX, (HL) takes 15 cycles,
and somewhere 14-14.5! Maybe it depends on
the type of computer, but the fact that SCORP'e
so - it's a fact!


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