NYYRIKKI: ehm, totally unreadable... Wasn't that the idea of obfuscation? ANyway, it will get you guys loads of extra space, that was the idea. Not just because it is possible.

Here is yet another entry...

This program can be used to change CPU mode on MSX tR.

3608 DEFUSR=-32749:IFUSR(0)THENLINE>2COPY0&H80F6OR384BASE!!

Change number after "LINE>" like this:
0 = Z80 (ROM)
1 = R800 (ROM)
2 = R800 (DRAM)

This program has also another special feature... If you save this program with .COM extention, you can use it on MSX-DOS as well.

Example:

SAVE"R800.COM"
_SYSTEM
R800

Here is version, that should not give me minus points as it works from any address...

8728 DEFUSR=38+PEEK(-2442)+PEEK(-2441)*256:IFUSR(0)THENLINE>2COPY0&H80F6OR384BASE!!

Hehe, I was just thinking you wouldn't get any bonus points but then you came up with an even more insane version

/me drops his jaw to on the floor...

My MSX started to smell funny after I ran your entry

Ok, here is the latest version

8728 DEFUSR=38+PEEK(-2442)+PEEK(-2441)*256:IFUSR(0)THENLINE>2COPY0&H80F6OR384ALLYOURBASEAREBELONGTOUS!

Dvik: You really should not eat on top of your MSX

hehe ^_^

Say euhm.. Nyrikki... could you explain how the $#%*&$* this works? I'm clueless

I think he reads the pointer to the basic program (#f676 + 256*#f677), then add a offset of 38 bytes(used by the real basic program) and then executes a clever Z80 code defined with BASIC tokens and data.

Yes it isn't really an MSX basic program. It is just a reverse basic of a small program that sets the CPU mode. Asembler code is usually not allowed in basic contests so I doubt that this entry would count although the idea is brilliant and the entry looks very good

I'll explain...

In DOS the BASIC header, lenght of the line and line number cause following program appear:

RST #38 ; Just a fake interrupt
LD C,B
LD A,B
JR #127 ; This is the address where actual program will be loaded in DOS

DEFUSR=38+PEEK(-2442)+PEEK(-2441)*256:IFUSR(0)THEN

This is pure BASIC. Because this program does not change the output of USR, 0 will be returned back and as we know 0 = False, so rest of the line will not be executed in BASIC.

THENLINE>2COPY0&H80F6OR384

This is the ML program, in assembler it would look like this:

XOR A
XOR #13
SUB #11
INC C
OR #80
RST #30
DB #1C ; A bit weird looking Slot ID, but it works as bits 0,1 and 7 are 0
DW #180


ALLYOURBASEAREBELONGTOUS!

Just "BASE" is important here (RET) rest is just pure humor


Ps. Dvik: Assembler is allowed in this compo (rules are on page 1)

Thanks for the explanation, I ran the program in a debugger and got the assembler listing and kindof figured out how it worked.
It is a very clever program and I like it a lot (and I missed the asm rule, sorry)

dvik/Nyyrikki - Can we expect more updates to Rally-X?

(never mind...)