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Old 10 December 2018, 19:37   #941
Don_Adan
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Quote:
Originally Posted by Hedeon View Post
What?! Close the longest troll.thread?? Nooo...
Right, dont close this thread. I always want to hear about advantages x86 code over 68k code. And maybe litwr will be soon very good 68k coder. Learning 68k coding is easy enough.
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Old 10 December 2018, 19:53   #942
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Does it matter though? Yes, especially if there is a vulnerability that can be exploited in the host hypervisor via the guest.

Last edited by ross; 10 December 2018 at 20:04. Reason: small removal ;)
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Old 11 December 2018, 16:46   #943
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Originally Posted by ross View Post
It means not understanding how server farms work today and what it means to have a virtual machine run by a complete stranger.
Detect and abuse are one step away..
Intel created the UMIP or User mode Instruction Prevention extension to stop abuse of the SMSW instruction (and some others) _outside_ the virtualization problem.
Sure one could applaud their determination of keeping backwards compatibility with crazy design decisions for the 80286, but couldn't they have added this extension with the 80386 instead of waiting 34 years(!) to patch a known problem?!?

It's just another of those things with x86 that doesn't make sense.
Quote:
Heard by chance of Meltdown and Spectre and their consequences?
Spectre and Meltdown use completely unrelated mechanisms?
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Old 11 December 2018, 18:15   #944
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Spectre and Meltdown use completely unrelated mechanisms?
Right, Meltdown seems to affect only Intel processors and *fully* (HW support) virtualized machines are not affected.
More problematic are Spectre vulnerabilities (bounds check bypass and branch target injection) that can cross between VMs..
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Old 11 December 2018, 19:23   #945
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Ok, how about this: https://projecteuler.net/problem=25

And here is my implementation (noob on asm)
Code:
	;; vasmm68k_mot -Fhunkexe -o euler25 euler25.asm
DIGITS = 1000
NUMSTORAGE = DIGITS/2
        opt x+
	lea.l	-NUMSTORAGE(sp),sp
	move.l	sp,a1
	lea.l	-NUMSTORAGE(sp),sp
	move.l	sp,a2
	lea.l	-NUMSTORAGE(sp),sp
	move.l	sp,a3

	;; clear the numbers
	move.l	a3,a0
	moveq	#0,d0
	move.w	#(3*NUMSTORAGE)/4-1,d1
.clrloop
	move.l	d0,(a0)+
	dbra	d1,.clrloop

	;; init *a1 and *a2 to 1
	moveq	#1,d0
	move.b	d0,NUMSTORAGE-1(a1)
	move.b	d0,NUMSTORAGE-1(a2)
	moveq	#2,d0	; d0 will hold the term-number we are now calculating
	moveq	#1-1,d7		;number of pair of digits, normalised for dbra

	;; n1 ->
	;; n2 ->
	;; n3 ->
	;; n1 ->
	;; n2 ->
	;; n3 ->
	
	;; addfib n1,n2,n3  n3 = n1 + n2
addfib:	MACRO
	addq	#1,d0		;increase the term-number
	;; move num2 to num3
	moveq	#NUMSTORAGE/4-1,d1
	move.l	\2,a4
	move.l	\3,a5
mvloop\@
	move.l	(a4)+,(a5)+
	dbra	d1,mvloop\@

	lea.l	NUMSTORAGE(\1),a4
	lea.l	NUMSTORAGE(\3),a5
	move.w	d7,d1
addloop\@
	abcd	-(a4),-(a5)
	dbra	d1,addloop\@
	bcc.s	nocarry\@
	move.b	#1,-(a5)	
	addq	#1,d7
nocarry\@
	cmp.b	#9,(\3)
	bgt.s	done
	ENDM

loop:	
	addfib a1,a2,a3
	addfib a2,a3,a1
	addfib a3,a1,a2
	bra	loop
	
done:	
	lea.l	3*NUMSTORAGE(sp),sp
	rts
224 bytes.
After you run it, type set in shell and see the answer in RC.
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Old 11 December 2018, 22:58   #946
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I've just finished a 44 bytes version (no bss space, only code and stack usage).
I publish it or wait a bit for someone different result? (I love this little competitions )
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Old 11 December 2018, 23:46   #947
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Originally Posted by ross View Post
I've just finished a 44 bytes version (no bss space, only code and stack usage).
I publish it or wait a bit for someone different result? (I love this little competitions )
lol, 44 bytes?

Man, I knew I was noob. I didn't knew I was that much of a noob though
Well played, sir!
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Old 11 December 2018, 23:53   #948
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lol, 44 bytes?

Man, I knew I was noob. I didn't knew I was that much of a noob though
Well played, sir!
Uh sorry! I've not counted rts!
So actually 46

Just curious, i've not assembled your source.
What's your result?

Mine is 4782.
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Old 11 December 2018, 23:58   #949
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Originally Posted by ross View Post
Uh sorry! I've not counted rts!
So actually 46

Just curious, i've not assembled your source.
What's your result?

Mine is 4782.
4782 indeed.
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Old 12 December 2018, 00:26   #950
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Originally Posted by ross View Post
I've just finished a 44 bytes version (no bss space, only code and stack usage).
The no bss space got me wondering
Umm, what's the final executable size?
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Old 12 December 2018, 00:35   #951
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Originally Posted by alkis View Post
The no bss space got me wondering
Umm, what's the final executable size?
84: header(36)+code(46)+pad(2)
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Old 12 December 2018, 01:16   #952
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code 94, final exe 132

Code:
	;; vasmm68k_mot -Fhunkexe -o euler25 euler25.asm
DIGITS = 1000
NUMSTORAGE = DIGITS/2
	opt x+
	
	lea.l	-NUMSTORAGE(sp),sp
	move.l	sp,a1
	lea.l	-NUMSTORAGE(sp),sp
	move.l	sp,a2
	lea.l	-NUMSTORAGE(sp),sp
	move.l	sp,a3


	;; init *a1 and *a2 to 1
	moveq	#1,d0
	move.b	d0,NUMSTORAGE-1(a1)
	move.b	d0,NUMSTORAGE-1(a2)
	move.b	d0,(a2)
	moveq	#2,d0	; d0 will hold the term-number we are now calculating
	moveq	#1-1,d7		;number of pair of digits, normalised for dbra

loop:
	addq	#1,d0
	
	lea.l	NUMSTORAGE(a2),a6
	lea.l	NUMSTORAGE(a1),a4
	lea.l	NUMSTORAGE(a3),a5

	move.w	d7,d1
	
digloop:
	move.b	-(a6),-1(a5)
	abcd	-(a4),-(a5)
	scc	d2
	move.b	(a6),(a4)
	move.b	(a5),(a6)
	dbra	d1,digloop
	tst.b	d2
	bne.s	nocarry
	move.b	#1,-(a6)
	move.b	#0,-(a4)
	addq	#1,d7
nocarry:
	cmp.b	#9,(a2)
	bgt.s	done
	bra.s	loop
done:	
	lea.l	3*NUMSTORAGE(sp),sp
	rts
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Old 12 December 2018, 01:37   #953
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Originally Posted by alkis View Post
code 94, final exe 132
Much better.

If you only look at the formula you see that at step n you need to sum n-1 to n-2.
But you have to actually think about what does it represent the Fibonacci sequence: a recurrence relation.
So if you use n-2 as the current n..
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Old 12 December 2018, 14:02   #954
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At 46 right now, gonna keep trying. Out of curiosity, I have 18 instructions.
Awaiting meynaf's 44 ;P...
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Old 12 December 2018, 14:12   #955
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At 46 right now, gonna keep trying. Out of curiosity, I have 18 instructions.
Awaiting meynaf's 44 ;P...
There is a 44 bytes possibility but is forbidden with scheduler active
The 44 bytes code is 16 instructions.

My 46 bytes version is 18 instructions, like yours.
But probably there are more possibilities to do it in 46 bytes.

And yes as usual when meynaf will see my code i'm expecting a 2 bytes strip
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Old 12 December 2018, 14:21   #956
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Out of curiosity
I have a curiosity too.

Since I wanted to find a way to use the link instruction (I committed myself to using it at all costs!), did you accidentally use it too?
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Old 12 December 2018, 14:51   #957
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Yeah, I'm using link.
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Old 12 December 2018, 15:14   #958
meynaf
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Quote:
Originally Posted by a/b View Post
Awaiting meynaf's 44 ;P...
44 bytes for what ?
Does it include displaying the number ?


Quote:
Originally Posted by ross View Post
And yes as usual when meynaf will see my code i'm expecting a 2 bytes strip
Maybe, maybe not. I have bigger things on the fire currently.
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Old 12 December 2018, 16:29   #959
ross
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44 bytes for what ?
Does it include displaying the number ?
Nope, a simple return code displayed on CLI (so a value in d0.l at exit).

Quote:
Maybe, maybe not. I have bigger things on the fire currently.
Yep, don't distract yourself
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Old 12 December 2018, 16:47   #960
meynaf
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Nope, a simple return code displayed on CLI (so a value in d0.l at exit).
Ok then, let's go.
Code:
 move.l #4782,d0
 rts

(What ? It gives the right result, no ?)
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