assembler routine for bcopy

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2 total messages Started by masscomp-request Sun, 07 Jun 1987 19:20

#35

Author: masscomp-request
Date: Sun, 07 Jun 1987 19:20

36 lines
1492 bytes

Here is an assembler routine to use in place of bcopy().

If you have assembler routines you'd like to share, please
send them to masscomp@soma.uucp.

Stan Barber
--------------------------------------------------------
| bcopy
| call from c just like the
| regular bcopy library routine.
| hopefully this one is much faster
|
| $Header: bcopy.s,v 1.1 87/06/06 17:35:10 sim Exp $
|
| By Stan Barber
| Copyright 1987 Stan Barber
| All Right Reserved. This code may be distributed freely
| as long as this copyright notice remains intact.
|
	.text
				| bcopy.c
	.globl	_bcopy
_bcopy:	link.w	a6,#0
				|
	move.l	(8,a6),a0	| load first pointer into a0
	move.l	(12,a6),a1	| load second pointer into a1
	move.l	(16,a6),d0	| load counter into d0
_bcp1:	move.b	(a0)+,(a1)+	| copy a byte from on to the other
				| and increment the pointer
	dbra	d0,_bcp1	| decrement the count and test
				| if still greater than zero 
				| branch back to the label
	unlk	a6
	rts
	.data
	.bss

Re: assembler routine for bcopy

#37

Author: Joe Buck
Date: Mon, 15 Jun 1987 09:20

14 lines
1280 bytes

In article <3130@soma.bcm.tmc.edu>, sob@soma.bcm.tmc.edu (Stan Barber) writes:
> Here is an assembler routine to use in place of bcopy().

It's fine as long as the number of bytes to copy is greater than
zero.  If given a zero length argument, it will copy 2^32 bytes!
The fix is easy: add a conditional branch after copying the
length argument to d0.
-- 
- Joe Buck    jbuck@epimass.EPI.COM  (in the brave new world of domains!)
		{seismo,ucbvax,sun,decwrl,<smart-site>}!epimass.epi.com!jbuck

[ARRGH! Thanks Joe. I forgot that....It has been a long time since I
write assembly... sigh-- sob]

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