/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2008 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ .file "strncmp.s" /* * strncmp(s1, s2, n) * * Compare strings (at most n bytes): s1>s2: >0 s1==s2: 0 s1 ENTRY(strncmp) save %sp, -SA(WINDOWSIZE), %sp cmp %i2, 8 blu,a .cmp_bytes ! for small counts go do bytes sub %i0, %i1, %i0 ! delay slot, get diff from s1 - s2 andcc %i0, 3, %g0 ! is s1 aligned 1: bz .iss2 ! if so go check s2 andcc %i1, 3, %i3 ! is s2 aligned deccc %i2 ! --n >= 0 ? bcs .doneq nop ! delay slot ldub [%i0], %i4 ! else cmp one byte ldub [%i1], %i5 inc %i0 cmp %i4, %i5 bne .noteqb inc %i1 tst %i4 ! terminating zero bnz 1b andcc %i0, 3, %g0 b,a .doneq .iss2: set 0x7efefeff, %l6 set 0x81010100, %l7 sethi %hi(0xff000000), %l0 ! masks to test for terminating null sethi %hi(0x00ff0000), %l1 srl %l1, 8, %l2 ! generate 0x0000ff00 mask bz .w4cmp ! if s2 word aligned, compare words cmp %i3, 2 ! check if s2 half aligned be .w2cmp cmp %i3, 1 ! check if aligned to 1 or 3 bytes .w3cmp: ldub [%i1], %i5 inc 1, %i1 be .w1cmp sll %i5, 24, %i5 sub %i0, %i1, %i0 2: deccc 4, %i2 ! n >= 4 ? bgeu,a 3f ld [%i1], %i3 ! delay slot dec %i1 ! reset s2 inc %i0 ! reset s1 diff b .cmp_bytes ! do a byte at a time if n < 4 inc 4, %i2 3: ld [%i0 + %i1], %i4 inc 4, %i1 srl %i3, 8, %l4 ! merge with the other half or %l4, %i5, %i5 cmp %i4, %i5 be 1f add %i4, %l6, %l3 b,a .noteq 1: xor %l3, %i4, %l3 and %l3, %l7, %l3 cmp %l3, %l7 be,a 2b sll %i3, 24, %i5 ! ! For 7-bit characters, we know one of the bytes is zero, but for ! 8-bit characters, the zero detection algorithm gives some false ! triggers ... check every byte individually. ! andcc %i4, %l0, %g0 ! check if first byte was zero bnz 1f andcc %i4, %l1, %g0 ! check if second byte was zero b,a .doneq 1: bnz 1f andcc %i4, %l2, %g0 ! check if third byte was zero b,a .doneq 1: bnz 1f andcc %i4, 0xff, %g0 ! check if last byte is zero b,a .doneq 1: bnz 2b sll %i3, 24, %i5 b,a .doneq .w1cmp: clr %l4 lduh [%i1], %l4 inc 2, %i1 sll %l4, 8, %l4 or %i5, %l4, %i5 sub %i0, %i1, %i0 3: deccc 4, %i2 ! n >= 4 ? bgeu,a 4f ld [%i1], %i3 ! delay slot dec 3, %i1 ! reset s2 inc 3, %i0 ! reset s1 diff b .cmp_bytes ! do a byte at a time if n < 4 inc 4, %i2 4: ld [%i0 + %i1], %i4 inc 4, %i1 srl %i3, 24, %l4 ! merge with the other half or %l4, %i5, %i5 cmp %i4, %i5 be 1f add %i4, %l6, %l3 b,a .noteq 1: xor %l3, %i4, %l3 and %l3, %l7, %l3 cmp %l3, %l7 be,a 3b sll %i3, 8, %i5 andcc %i4, %l0, %g0 ! check if first byte was zero bnz 1f andcc %i4, %l1, %g0 ! check if second byte was zero b,a .doneq 1: bnz 1f andcc %i4, %l2, %g0 ! check if third byte was zero b,a .doneq 1: bnz 1f andcc %i4, 0xff, %g0 ! check if last byte is zero b,a .doneq 1: bnz 3b sll %i3, 8, %i5 b,a .doneq .w2cmp: lduh [%i1], %i5 ! read a halfword to align s2 inc 2, %i1 sll %i5, 16, %i5 sub %i0, %i1, %i0 4: deccc 4, %i2 ! n >= 4 ? bgeu,a 5f ld [%i1], %i3 ! delay slot dec 2, %i1 ! reset s2 inc 2, %i0 ! reset s1 diff b .cmp_bytes ! do a byte at a time if n < 4 inc 4, %i2 ! delay slot 5: ld [%i1 + %i0], %i4 ! read a word from s2 inc 4, %i1 srl %i3, 16, %l4 ! merge with the other half or %l4, %i5, %i5 cmp %i4, %i5 be 1f add %i4, %l6, %l3 b,a .noteq 1: xor %l3, %i4, %l3 ! are any bytes 0? and %l3, %l7, %l3 cmp %l3, %l7 be,a 4b sll %i3, 16, %i5 andcc %i4, %l0, %g0 ! check if first byte was zero bnz 1f andcc %i4, %l1, %g0 ! check if second byte was zero b,a .doneq 1: bnz 1f andcc %i4, %l2, %g0 ! check if third byte was zero b,a .doneq 1: bnz 1f andcc %i4, 0xff, %g0 ! check if last byte is zero b,a .doneq 1: bnz 4b sll %i3, 16, %i5 b,a .doneq .w4cmp: sub %i0, %i1, %i0 ld [%i1], %i5 ! read a word from s1 5: cmp %i2,0 be,a .doneq nop ld [%i1], %i5 ! read a word from s1 deccc 4, %i2 ! n >= 4 ? bcs,a .cmp_bytes ! do a byte at a time if n < 4 inc 4, %i2 ld [%i1 + %i0], %i4 ! read a word from s2 cmp %i4, %i5 inc 4, %i1 be 1f add %i4, %l6, %l3 b,a .noteq 1: xor %l3, %i4, %l3 and %l3, %l7, %l3 cmp %l3, %l7 be,a 5b nop andcc %i4, %l0, %g0 ! check if first byte was zero bnz 1f andcc %i4, %l1, %g0 ! check if second byte was zero b,a .doneq 1: bnz 1f andcc %i4, %l2, %g0 ! check if third byte was zero b,a .doneq 1: bnz 1f andcc %i4, 0xff, %g0 ! check if last byte is zero b,a .doneq 1: bnz,a 5b ld [%i1], %i5 .doneq: ret restore %g0, %g0, %o0 ! equal return zero .noteq: srl %i4, 24, %l4 srl %i5, 24, %l5 subcc %l4, %l5, %i0 bne 6f andcc %l4, 0xff, %g0 bz .doneq sll %i4, 8, %l4 sll %i5, 8, %l5 srl %l4, 24, %l4 srl %l5, 24, %l5 subcc %l4, %l5, %i0 bne 6f andcc %l4, 0xff, %g0 bz .doneq sll %i4, 16, %l4 sll %i5, 16, %l5 srl %l4, 24, %l4 srl %l5, 24, %l5 subcc %l4, %l5, %i0 bne 6f andcc %l4, 0xff, %g0 bz .doneq nop .noteqb: and %i4, 0xff, %l4 and %i5, 0xff, %l5 subcc %l4, %l5, %i0 6: ret restore %i0, %g0, %o0 ! Do a byte by byte comparison, disregarding alignments .cmp_bytes: deccc %i2 ! --n >= 0 ? 1: bcs .doneq nop ! delay slot ldub [%i1 + %i0], %i4 ! read a word from s1 ldub [%i1], %i5 ! read a word from s2 inc %i1 cmp %i4, %i5 bne .noteqb tst %i4 ! terminating zero bnz 1b deccc %i2 ! --n >= 0 b,a .doneq SET_SIZE(strncmp)