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mcgeezer · 27 July 2021, 22:17

Hi all,

I'm not too familiar with exact cycle count timings but I'm looking for a fast way to multiply a number by 200, return value can be within 64Kb.

At the moment I have.

Code:

	lea	.mulu200(pc),a3
	add.w	d2,d2
	move.w	(a3,d2.w),d2
.
.
.

.mulu200:	
	rept	256
	dc.w	REPTN*200
	endr

I'm assuming this will be faster than a mulu #200,d2 which I recall takes something like 70 cycles?

Any faster ways you guys can think of?

Thanks,
Graeme

27 July 2021, 22:17	#1
mcgeezer Registered User Join Date: Oct 2017 Location: Sunderland, England Posts: 2,702	Fastest way to multiply by 200? Hi all, I'm not too familiar with exact cycle count timings but I'm looking for a fast way to multiply a number by 200, return value can be within 64Kb. At the moment I have. Code: lea .mulu200(pc),a3 add.w d2,d2 move.w (a3,d2.w),d2 . . . .mulu200: rept 256 dc.w REPTN*200 endr I'm assuming this will be faster than a mulu #200,d2 which I recall takes something like 70 cycles? Any faster ways you guys can think of? Thanks, Graeme