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Article #33627Re: ASSEMBLY MOVE/CLEAR/SET/COMPARE ROUTINES (was Clearing memory chain)
From: Eric Gisin
Date: Tue, 16 Aug 1988 23:09
Date: Tue, 16 Aug 1988 23:09
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Why do so many people think movem is faster than the more straight-forward loop of move.l's? copying 12 long words with movem (a0)+,regs; movem regs,(a1); add.l Rn,a1" takes 242 cycles on the 68000, while 12 successive "move.l (a0)+, (a1)+" takes 240 cycles. (timings derived from Motorola'a 68000 manual) when copying fewer words, move.l is even better. the move.l appoach does not require saving and restoring all your registers, and can be coded in C with decent compilers.
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!water!watmath!egisin From: egisin@watmath.waterloo.edu (Eric Gisin) Newsgroups: comp.sys.atari.st Subject: Re: ASSEMBLY MOVE/CLEAR/SET/COMPARE ROUTINES (was Clearing memory chain) Summary: movem is slower that move.l Message-ID: <20383@watmath.waterloo.edu> Date: 16 Aug 88 23:09:22 GMT References: <8808160343.AA10248@cory.Berkeley.EDU> Organization: U of Waterloo, Ontario Lines: 11