/* $NetBSD: bzero.S,v 1.8 2003/08/07 16:42:16 agc) ASMSTR("from: @(#)bzero.s 8.1 (Berkeley) 6/4/93") ASMSTR("$NetBSD: bzero.S,v 1.8 2003/08/07 16:42:16 agc Exp $") #endif /* LIBC_SCCS and not lint */ #define _LOCORE /* XXX not really, just assembly-code source */ #include <machine/endian.h> #ifdef __ABICALLS__ .abicalls #endif /* bzero(s1, n) */ LEAF(bzero) .set noreorder blt a1, 12, smallclr # small amount to clear? subu a3, zero, a0 # compute # bytes to word align address and a3, a3, 3 beq a3, zero, 1f # skip if word aligned subu a1, a1, a3 # subtract from remaining count SWHI zero, 0(a0) # clear 1, 2, or 3 bytes to align addu a0, a0, a3 1: and v0, a1, 3 # compute number of words left subu a3, a1, v0 move a1, v0 addu a3, a3, a0 # compute ending address 2: addu a0, a0, 4 # clear words bne a0, a3, 2b # unrolling loop doesnt help sw zero, -4(a0) # since we are limited by memory speed smallclr: ble a1, zero, 2f addu a3, a1, a0 # compute ending address 1: addu a0, a0, 1 # clear bytes bne a0, a3, 1b sb zero, -1(a0) 2: j ra nop END(bzero)