/* * 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 (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved. */ /* * The ascii_strcasecmp() function is a case insensitive versions of strcmp(). * It assumes the ASCII character set and ignores differences in case * when comparing lower and upper case characters. In other words, it * behaves as if both strings had been converted to lower case using * tolower() in the "C" locale on each byte, and the results had then * been compared using strcmp(). * * The assembly code below is an optimized version of the following C * reference: * * static const char charmap[] = { * '\000', '\001', '\002', '\003', '\004', '\005', '\006', '\007', * '\010', '\011', '\012', '\013', '\014', '\015', '\016', '\017', * '\020', '\021', '\022', '\023', '\024', '\025', '\026', '\027', * '\030', '\031', '\032', '\033', '\034', '\035', '\036', '\037', * '\040', '\041', '\042', '\043', '\044', '\045', '\046', '\047', * '\050', '\051', '\052', '\053', '\054', '\055', '\056', '\057', * '\060', '\061', '\062', '\063', '\064', '\065', '\066', '\067', * '\070', '\071', '\072', '\073', '\074', '\075', '\076', '\077', * '\100', '\141', '\142', '\143', '\144', '\145', '\146', '\147', * '\150', '\151', '\152', '\153', '\154', '\155', '\156', '\157', * '\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167', * '\170', '\171', '\172', '\133', '\134', '\135', '\136', '\137', * '\140', '\141', '\142', '\143', '\144', '\145', '\146', '\147', * '\150', '\151', '\152', '\153', '\154', '\155', '\156', '\157', * '\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167', * '\170', '\171', '\172', '\173', '\174', '\175', '\176', '\177', * '\200', '\201', '\202', '\203', '\204', '\205', '\206', '\207', * '\210', '\211', '\212', '\213', '\214', '\215', '\216', '\217', * '\220', '\221', '\222', '\223', '\224', '\225', '\226', '\227', * '\230', '\231', '\232', '\233', '\234', '\235', '\236', '\237', * '\240', '\241', '\242', '\243', '\244', '\245', '\246', '\247', * '\250', '\251', '\252', '\253', '\254', '\255', '\256', '\257', * '\260', '\261', '\262', '\263', '\264', '\265', '\266', '\267', * '\270', '\271', '\272', '\273', '\274', '\275', '\276', '\277', * '\300', '\301', '\302', '\303', '\304', '\305', '\306', '\307', * '\310', '\311', '\312', '\313', '\314', '\315', '\316', '\317', * '\320', '\321', '\322', '\323', '\324', '\325', '\326', '\327', * '\330', '\331', '\332', '\333', '\334', '\335', '\336', '\337', * '\340', '\341', '\342', '\343', '\344', '\345', '\346', '\347', * '\350', '\351', '\352', '\353', '\354', '\355', '\356', '\357', * '\360', '\361', '\362', '\363', '\364', '\365', '\366', '\367', * '\370', '\371', '\372', '\373', '\374', '\375', '\376', '\377', * }; * * int * ascii_strcasecmp(const char *s1, const char *s2) * { * const unsigned char *cm = (const unsigned char *)charmap; * const unsigned char *us1 = (const unsigned char *)s1; * const unsigned char *us2 = (const unsigned char *)s2; * * while (cm[*us1] == cm[*us2++]) * if (*us1++ == '\0') * return (0); * return (cm[*us1] - cm[*(us2 - 1)]); * } * * The following algorithm, from a 1987 news posting by Alan Mycroft, is * used for finding null bytes in a word: * * #define has_null(word) ((word - 0x01010101) & (~word & 0x80808080)) * * The following algorithm is used for a wordwise tolower() operation: * * unsigned int * parallel_tolower (unsigned int x) * { * unsigned int p; * unsigned int q; * * unsigned int m1 = 0x80808080; * unsigned int m2 = 0x3f3f3f3f; * unsigned int m3 = 0x25252525; * * q = x & ~m1;// newb = byte & 0x7F * p = q + m2; // newb > 0x5A --> MSB set * q = q + m3; // newb < 0x41 --> MSB clear * p = p & ~q; // newb > 0x40 && newb < 0x5B --> MSB set * q = m1 & ~x;// byte < 0x80 --> 0x80 * q = p & q; // newb > 0x40 && newb < 0x5B && byte < 0x80 -> 0x80,else 0 * q = q >> 2; // newb > 0x40 && newb < 0x5B && byte < 0x80 -> 0x20,else 0 * return (x + q); // translate uppercase characters to lowercase * } * * Both algorithms have been tested exhaustively for all possible 2^32 inputs. */ #include <sys/asm_linkage.h> ! The first part of this algorithm walks through the beginning of ! both strings a byte at a time until the source ptr is aligned to ! a word boundary. During these steps, the bytes are translated to ! lower-case if they are upper-case, and are checked against ! the source string. ENTRY(ascii_strcasecmp) .align 32 save %sp, -SA(WINDOWSIZE), %sp subcc %i0, %i1, %i2 ! s1 == s2 ? bz,pn %ncc, .stringsequal ! yup, done, strings equal andcc %i0, 3, %i3 ! s1 word-aligned ? bz,pn %ncc, .s1aligned1 ! yup sethi %hi(0x80808080), %i4 ! start loading Mycroft's magic1 ldub [%i1 + %i2], %i0 ! s1[0] ldub [%i1], %g1 ! s2[0] sub %i0, 'A', %l0 ! transform for faster uppercase check sub %g1, 'A', %l1 ! transform for faster uppercase check cmp %l0, ('Z' - 'A') ! s1[0] uppercase? bleu,a .noxlate11 ! yes add %i0, ('a' - 'A'), %i0 ! s1[0] = tolower(s1[0]) .noxlate11: cmp %l1, ('Z' - 'A') ! s2[0] uppercase? bleu,a .noxlate12 ! yes add %g1, ('a' - 'A'), %g1 ! s2[0] = tolower(s2[0]) .noxlate12: subcc %i0, %g1, %i0 ! tolower(s1[0]) != tolower(s2[0]) ? bne,pn %ncc, .done ! yup, done inc %i1 ! s1++, s2++ addcc %i0, %g1, %i0 ! s1[0] == 0 ? bz,pn %ncc, .done ! yup, done, strings equal cmp %i3, 3 ! s1 aligned now? bz %ncc, .s1aligned2 ! yup sethi %hi(0x01010101), %i5 ! start loading Mycroft's magic2 ldub [%i1 + %i2], %i0 ! s1[1] ldub [%i1], %g1 ! s2[1] sub %i0, 'A', %l0 ! transform for faster uppercase check sub %g1, 'A', %l1 ! transform for faster uppercase check cmp %l0, ('Z' - 'A') ! s1[1] uppercase? bleu,a .noxlate21 ! yes add %i0, ('a' - 'A'), %i0 ! s1[1] = tolower(s1[1]) .noxlate21: cmp %l1, ('Z' - 'A') ! s2[1] uppercase? bleu,a .noxlate22 ! yes add %g1, ('a' - 'A'), %g1 ! s2[1] = tolower(s2[1]) .noxlate22: subcc %i0, %g1, %i0 ! tolower(s1[1]) != tolower(s2[1]) ? bne,pn %ncc, .done ! yup, done inc %i1 ! s1++, s2++ addcc %i0, %g1, %i0 ! s1[1] == 0 ? bz,pn %ncc, .done ! yup, done, strings equal cmp %i3, 2 ! s1 aligned now? bz %ncc, .s1aligned3 ! yup or %i4, %lo(0x80808080),%i4! finish loading Mycroft's magic1 ldub [%i1 + %i2], %i0 ! s1[2] ldub [%i1], %g1 ! s2[2] sub %i0, 'A', %l0 ! transform for faster uppercase check sub %g1, 'A', %l1 ! transform for faster uppercase check cmp %l0, ('Z' - 'A') ! s1[2] uppercase? bleu,a .noxlate31 ! yes add %i0, ('a' - 'A'), %i0 ! s1[2] = tolower(s1[2]) .noxlate31: cmp %l1, ('Z' - 'A') ! s2[2] uppercase? bleu,a .noxlate32 ! yes add %g1, ('a' - 'A'), %g1 ! s2[2] = tolower(s2[2]) .noxlate32: subcc %i0, %g1, %i0 ! tolower(s1[2]) != tolower(s2[2]) ? bne,pn %ncc, .done ! yup, done inc %i1 ! s1++, s2++ addcc %i0, %g1, %i0 ! s1[2] == 0 ? bz,pn %ncc, .done ! yup, done, strings equal or %i5, %lo(0x01010101),%i5! finish loading Mycroft's magic2 ba .s1aligned4 ! s1 aligned now andcc %i1, 3, %i3 ! s2 word-aligned ? ! Here, we initialize our checks for a zero byte and decide ! whether or not we can optimize further if we're fortunate ! enough to have a word aligned desintation .s1aligned1: sethi %hi(0x01010101), %i5 ! start loading Mycroft's magic2 .s1aligned2: or %i4, %lo(0x80808080),%i4! finish loading Mycroft's magic1 .s1aligned3: or %i5, %lo(0x01010101),%i5! finish loading Mycroft's magic2 andcc %i1, 3, %i3 ! s2 word aligned ? .s1aligned4: sethi %hi(0x3f3f3f3f), %l2 ! load m2 for parallel tolower() sethi %hi(0x25252525), %l3 ! load m3 for parallel tolower() or %l2, %lo(0x3f3f3f3f),%l2! finish loading m2 bz .word4 ! yup, s2 word-aligned or %l3, %lo(0x25252525),%l3! finish loading m3 add %i2, %i3, %i2 ! start adjusting offset s1-s2 sll %i3, 3, %l6 ! shift factor for left shifts andn %i1, 3, %i1 ! round s1 pointer down to next word sub %g0, %l6, %l7 ! shift factor for right shifts orn %i3, %g0, %i3 ! generate all ones lduw [%i1], %i0 ! new lower word from s2 srl %i3, %l6, %i3 ! mask for fixing up bytes sll %i0, %l6, %g1 ! partial unaligned word from s2 orn %i0, %i3, %i0 ! force start bytes to non-zero nop ! pad to align loop to 16-byte boundary nop ! pad to align loop to 16-byte boundary ! This is the comparision procedure used if the destination is not ! word aligned, if it is, we use word4 & cmp4 .cmp: andn %i4, %i0, %l4 ! ~word & 0x80808080 sub %i0, %i5, %l5 ! word - 0x01010101 andcc %l5, %l4, %g0 ! (word - 0x01010101) & ~word & 0x80808080 bz,a,pt %ncc, .doload ! null byte in previous aligned s2 word lduw [%i1 + 4], %i0 ! load next aligned word from s2 .doload: srl %i0, %l7, %i3 ! byte 1 from new aligned word from s2 or %g1, %i3, %g1 ! merge to get unaligned word from s2 lduw [%i1 + %i2], %i3 ! x1 = word from s1 andn %i3, %i4, %l0 ! q1 = x1 & ~m1 andn %g1, %i4, %l4 ! q2 = x2 & ~m1 add %l0, %l2, %l1 ! p1 = q1 + m2 add %l4, %l2, %l5 ! p2 = q2 + m2 add %l0, %l3, %l0 ! q1 = q1 + m3 add %l4, %l3, %l4 ! q2 = q2 + m3 andn %l1, %l0, %l1 ! p1 = p1 & ~q1 andn %l5, %l4, %l5 ! p2 = p2 & ~q2 andn %i4, %i3, %l0 ! q1 = m1 & ~x1 andn %i4, %g1, %l4 ! q2 = m1 & ~x2 and %l0, %l1, %l0 ! q1 = p1 & q1 and %l4, %l5, %l4 ! q2 = p2 & q2 srl %l0, 2, %l0 ! q1 = q1 >> 2 srl %l4, 2, %l4 ! q2 = q2 >> 2 add %l0, %i3, %i3 ! lowercase word from s1 add %l4, %g1, %g1 ! lowercase word from s2 cmp %i3, %g1 ! tolower(*s1) != tolower(*s2) ? bne %icc, .wordsdiffer ! yup, now find byte that is different add %i1, 4, %i1 ! s1+=4, s2+=4 andn %i4, %i3, %l4 ! ~word & 0x80808080 sub %i3, %i5, %l5 ! word - 0x01010101 andcc %l5, %l4, %g0 ! (word - 0x01010101) & ~word & 0x80808080 bz,pt %ncc, .cmp ! no null-byte in s1 yet sll %i0, %l6, %g1 ! partial unaligned word from s2 ! words are equal but the end of s1 has been reached ! this means the strings must be equal .stringsequal: ret ! return restore %g0, %g0, %o0 ! return 0, i.e. strings are equal nop ! pad ! we have a word aligned source and destination! This means ! things get to go fast! .word4: lduw [%i1 + %i2], %i3 ! x1 = word from s1 .cmp4: andn %i3, %i4, %l0 ! q1 = x1 & ~m1 lduw [%i1], %g1 ! x2 = word from s2 andn %g1, %i4, %l4 ! q2 = x2 & ~m1 add %l0, %l2, %l1 ! p1 = q1 + m2 add %l4, %l2, %l5 ! p2 = q2 + m2 add %l0, %l3, %l0 ! q1 = q1 + m3 add %l4, %l3, %l4 ! q2 = q2 + m3 andn %l1, %l0, %l1 ! p1 = p1 & ~q1 andn %l5, %l4, %l5 ! p2 = p2 & ~q2 andn %i4, %i3, %l0 ! q1 = m1 & ~x1 andn %i4, %g1, %l4 ! q2 = m1 & ~x2 and %l0, %l1, %l0 ! q1 = p1 & q1 and %l4, %l5, %l4 ! q2 = p2 & q2 srl %l0, 2, %l0 ! q1 = q1 >> 2 srl %l4, 2, %l4 ! q2 = q2 >> 2 add %l0, %i3, %i3 ! lowercase word from s1 add %l4, %g1, %g1 ! lowercase word from s2 cmp %i3, %g1 ! tolower(*s1) != tolower(*s2) ? bne,pn %icc, .wordsdiffer ! yup, now find mismatching character add %i1, 4, %i1 ! s1+=4, s2+=4 andn %i4, %i3, %l4 ! ~word & 0x80808080 sub %i3, %i5, %l5 ! word - 0x01010101 andcc %l5, %l4, %g0 ! (word - 0x01010101) & ~word & 0x80808080 bz,a,pt %icc, .cmp4 ! no null-byte in s1 yet lduw [%i1 + %i2], %i3 ! load word from s1 ! words are equal but the end of s1 has been reached ! this means the strings must be equal .stringsequal4: ret ! return restore %g0, %g0, %o0 ! return 0, i.e. strings are equal .wordsdiffer: srl %g1, 24, %i2 ! first byte of mismatching word in s2 srl %i3, 24, %i1 ! first byte of mismatching word in s1 subcc %i1, %i2, %i0 ! *s1-*s2 bnz,pn %ncc, .done ! bytes differ, return difference srl %g1, 16, %i2 ! second byte of mismatching word in s2 andcc %i1, 0xff, %i0 ! *s1 == 0 ? bz,pn %ncc, .done ! yup ! we know byte 1 is equal, so can compare bytes 1,2 as a group srl %i3, 16, %i1 ! second byte of mismatching word in s1 subcc %i1, %i2, %i0 ! *s1-*s2 bnz,pn %ncc, .done ! bytes differ, return difference srl %g1, 8, %i2 ! third byte of mismatching word in s2 andcc %i1, 0xff, %i0 ! *s1 == 0 ? bz,pn %ncc, .done ! yup ! we know bytes 1, 2 are equal, so can compare bytes 1,2,3 as a group srl %i3, 8, %i1 ! third byte of mismatching word in s1 subcc %i1, %i2, %i0 ! *s1-*s2 bnz,pn %ncc, .done ! bytes differ, return difference andcc %i1, 0xff, %g0 ! *s1 == 0 ? bz,pn %ncc, .stringsequal ! yup ! we know bytes 1,2,3 are equal, so can compare bytes 1,2,3,4 as group subcc %i3, %g1, %i0 ! *s1-*s2 bz,a .done ! bytes differ, return difference andcc %i3, 0xff, %i0 ! *s1 == 0 ? .done: ret ! return restore %i0, %g0, %o0 ! return tolower(*s1) - tolower(*s2) SET_SIZE(ascii_strcasecmp)