1c32c7ac7Sbostic/*- 2c32c7ac7Sbostic * Copyright (c) 1991 The Regents of the University of California. 3c32c7ac7Sbostic * All rights reserved. 4c32c7ac7Sbostic * 5c32c7ac7Sbostic * This code is derived from software contributed to Berkeley by 6c32c7ac7Sbostic * Ralph Campbell. 7c32c7ac7Sbostic * 8c32c7ac7Sbostic * %sccs.include.redist.c% 9c32c7ac7Sbostic */ 10c32c7ac7Sbostic 11*a839bd66Sralph#include <machine/machAsmDefs.h> 12c32c7ac7Sbostic 13c821a74bSbostic#if defined(LIBC_SCCS) && !defined(lint) 14*a839bd66Sralph ASMSTR("@(#)bzero.s 5.3 (Berkeley) 07/26/92") 15c821a74bSbostic#endif /* LIBC_SCCS and not lint */ 16c821a74bSbostic 17c32c7ac7Sbostic/* bzero(s1, n) */ 18c32c7ac7Sbostic 19c32c7ac7SbosticLEAF(bzero) 20c32c7ac7Sbostic .set noreorder 21c32c7ac7Sbostic blt a1, 12, smallclr # small amount to clear? 22c32c7ac7Sbostic subu a3, zero, a0 # compute # bytes to word align address 23c32c7ac7Sbostic and a3, a3, 3 24c32c7ac7Sbostic beq a3, zero, 1f # skip if word aligned 25c32c7ac7Sbostic subu a1, a1, a3 # subtract from remaining count 26c32c7ac7Sbostic swr zero, 0(a0) # clear 1, 2, or 3 bytes to align 27c32c7ac7Sbostic addu a0, a0, a3 28c32c7ac7Sbostic1: 29c32c7ac7Sbostic and v0, a1, 3 # compute number of words left 30c32c7ac7Sbostic subu a3, a1, v0 31c32c7ac7Sbostic move a1, v0 32c32c7ac7Sbostic addu a3, a3, a0 # compute ending address 33c32c7ac7Sbostic2: 34c32c7ac7Sbostic addu a0, a0, 4 # clear words 35c32c7ac7Sbostic bne a0, a3, 2b # unrolling loop doesn't help 36c32c7ac7Sbostic sw zero, -4(a0) # since we're limited by memory speed 37c32c7ac7Sbosticsmallclr: 38c32c7ac7Sbostic ble a1, zero, 2f 39c32c7ac7Sbostic addu a3, a1, a0 # compute ending address 40c32c7ac7Sbostic1: 41c32c7ac7Sbostic addu a0, a0, 1 # clear bytes 42c32c7ac7Sbostic bne a0, a3, 1b 43c32c7ac7Sbostic sb zero, -1(a0) 44c32c7ac7Sbostic2: 45c32c7ac7Sbostic j ra 46c32c7ac7Sbostic nop 47c32c7ac7SbosticEND(bzero) 48