1 /* $NetBSD: bzero.S,v 1.10 2009/12/14 02:53:52 matt Exp $ */
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35 #include <machine/asm.h>
36 __FBSDID("$FreeBSD$");
38 #if defined(LIBC_SCCS) && !defined(lint)
40 ASMSTR("from: @(#)bzero.s 8.1 (Berkeley) 6/4/93")
42 ASMSTR("$NetBSD: bzero.S,v 1.10 2009/12/14 02:53:52 matt Exp $")
44 #endif /* LIBC_SCCS and not lint */
46 #define _LOCORE /* XXX not really, just assembly-code source */
47 #include <machine/endian.h>
57 blt a1, 3*SZREG, smallclr # small amount to clear?
58 PTR_SUBU a3, zero, a0 # compute # bytes to word align address
60 beq a3, zero, 1f # skip if word aligned
61 PTR_SUBU a1, a1, a3 # subtract from remaining count
62 REG_SHI zero, 0(a0) # clear 1, 2, or 3 bytes to align
65 and v0, a1, SZREG-1 # compute number of words left
68 PTR_ADDU a3, a3, a0 # compute ending address
70 PTR_ADDU a0, a0, SZREG # clear words
71 bne a0, a3, 2b # unrolling loop doesnt help
72 REG_S zero, -SZREG(a0) # since we are limited by memory speed
75 PTR_ADDU a3, a1, a0 # compute ending address
77 PTR_ADDU a0, a0, 1 # clear bytes