1/* 2 * (c) Copyright 1986 HEWLETT-PACKARD COMPANY 3 * 4 * To anyone who acknowledges that this file is provided "AS IS" 5 * without any express or implied warranty: 6 * permission to use, copy, modify, and distribute this file 7 * for any purpose is hereby granted without fee, provided that 8 * the above copyright notice and this notice appears in all 9 * copies, and that the name of Hewlett-Packard Company not be 10 * used in advertising or publicity pertaining to distribution 11 * of the software without specific, written prior permission. 12 * Hewlett-Packard Company makes no representations about the 13 * suitability of this software for any purpose. 14 */ 15 16/* memcmp(s1, s2, n) */ 17/* returns integer: < 0 iff s1 lexicographically less than s2 */ 18/* > 0 iff s1 lexicographically greater than s2 */ 19/* = 0 iff s1 lexicographically equal to s2 */ 20/* = 0 iff s1 lexicographically equal to s2 */ 21/* quit after n charachters */ 22#include <picolibc.h> 23 24#ifndef _NAMESPACE_CLEAN 25#define NOSECDEF /* prevents _memcmp from becoming primary entry */ 26#endif 27 28#include "DEFS.h" 29 30#define s1 26 31#define s2 25 32#define tmp1 19 33#define s2word 20 34#define tmp3 21 35#define tmp7 22 36#define s1word 29 37#define save 1 38#define tmp6 23 39#define tmp5 28 40#define count 24 41 42ENTRY(memcmp) 43 combt,<,n r0,count,search /*N <= 0 yields equality */ 44 b done /**/ 45 copy 0,ret0 /*return 0 (DELAY SLOT) */ 46search: combf,=,n s1,s2,findout /*s1 != s2? */ 47 b done 48 copy 0,ret0 /*return 0 (delay slot) */ 49findout: 50 comibf,=,n 0,s1,checks1 /*s1 == NULL? */ 51 ldbs 0(0,s2),ret0 /**/ 52 b done /*quit */ 53 sub 0,ret0,ret0 /*ret0 <- -*s2 */ 54checks1: 55 comibf,=,n 0,s2,checkitout /*s2 == NULL? */ 56 b done /* quit */ 57 ldbs 0(0,s1),28 /* return *s1 */ 58 59checkitout: 60 extru s2,31,2,tmp1 /* Extract the low two bits of the s2. */ 61 extru s1,31,2,tmp5 /* Extract the low two bits of the s1 */ 62 sub,= tmp5,tmp1,tmp3 /* Are s1 & s2 aligned with each other? */ 63 b not_aligned /* It's more complicated (not_aligned) */ 64 dep 0,31,2,s1 /* Compute word address of s1 (DELAY SLOT) */ 65 dep 0,31,2,s2 /* Compute word address of s2 */ 66 ldwm 4(0,s1),s1word /* get next s1 word s1+=4 */ 67 combt,= tmp5,r0,skipmask /* skip masking, if we can */ 68 ldwm 4(0,s2),s2word /* get next s2 word s2+=4 (DELAY SLOT) */ 69 add tmp5,count,count /* bump count by the number of bytes */ 70 /* we are going to mask */ 71 sh3add tmp5,r0,save /* save now has number of bits to mask */ 72 mtctl save,11 73 zvdepi -2,32,save /* load save with proper mask */ 74 or save,s1word,s1word /* mask s1word (s1) */ 75 or save,s2word,s2word /* mask s2word (s2) */ 76 77 78skipmask: 79 combt,=,n s1word,s2word,checkN /* We may be done */ 80 81checkbyte: 82 extru s1word,7,8,tmp3 /* get first byte (character) */ 83ckbyte2: extru s2word,7,8,tmp7 /* get first byte (character) */ 84 combf,= tmp3,tmp7,done /* quit if first byte is not equal */ 85 sub tmp3,tmp7,ret0 /* return difference (delay slot) */ 86 addibt,<=,n -1,count,done /* have we checked N chars? ret0 == 0 */ 87 extru s1word,15,8,tmp3 /* get second byte (character) */ 88 extru s2word,15,8,tmp7 /* get second byte (character) */ 89 combf,= tmp3,tmp7,done /* quit if second byte is not equal */ 90 sub tmp3,tmp7,ret0 /* return difference (delay slot) */ 91 addibt,<=,n -1,count,done /* have we checked N chars? */ 92 extru s1word,23,8,tmp3 /* get third byte (character) */ 93 extru s2word,23,8,tmp7 /* get third byte (character) */ 94 combf,= tmp3,tmp7,done /* done if third byte is not equal */ 95 sub tmp3,tmp7,ret0 /* return difference (delay slot) */ 96 addibt,<=,n -1,count,done /* have we checked N chars? */ 97 extru s1word,31,8,tmp3 /* get last byte (character) */ 98 extru s2word,31,8,tmp7 /* get last byte (character) */ 99 b done /* if we reach this point we know that */ 100 sub tmp3,tmp7,ret0 /* the last character in the word is */ 101 /* where the difference is, so return */ 102 /* the difference and we're outta here */ 103 104 105checkN: 106 addibt,<=,n -4,count,zero /* have we checked N chars? */ 107 ldwm 4(0,s2),s2word /* get next s2 word s2+=4 */ 108 b skipmask /* keep checking */ 109 ldwm 4(0,s1),s1word /* get next s1 word s1+=4 */ 110 111 112not_aligned: 113 dep r0,31,2,s2 /* Compute word address of s2 */ 114 combt,<,n r0,tmp3,shifts1 /* Do we shift s1 or s2 */ 115 sh3add tmp3,r0,tmp3 /* eight bits per byte so mul by 8 */ 116 ldwm 4(0,s1),s1word /* get first word of s1 */ 117 ldwm 4(0,s2),s2word /* get first word or s2 */ 118 combt,=,n r0,tmp5,masks2 /* Do we need to mask beginning of s1 */ 119 add tmp5,count,count /* bump count by the number of bytes */ 120 /* we are going to mask */ 121 sh3add tmp5,r0,save /* save now has number of bits to mask */ 122 mtctl save,11 123 zvdepi -2,32,save /* load save with proper mask */ 124 or save,s1word,s1word /**/ 125masks2: sh3add tmp1,r0,save /* save now has number of bits to mask */ 126 mtctl save,11 127 zvdepi -2,32,save /* load save with proper mask */ 128 or save,s2word,s2word /**/ 129 subi 4,tmp1,tmp1 /* tmp1 now has the number of byte that */ 130 /* are valid in s2word before the vshd */ 131 mtctl tmp3,11 /* Move shift amount to CR11 */ 132more: combt,<=,n count,tmp1,chunk1 /* Can we do the vshd? */ 133 ldwm 4(0,s2),tmp7 /* load second word to enable us to shift */ 134 vshd s2word,tmp7,s2word /**/ 135 combf,=,n s1word,s2word,ckbyte2 /**/ 136 extru s1word,7,8,tmp3 /* get first byte (DELAY SLOT) */ 137 addibt,<=,n -4,count,zero /* have we checked N chars? */ 138 copy tmp7,s2word /**/ 139 b more /* keep checking */ 140 ldwm 4(0,s1),s1word /* get next s1 (DELAY SLOT) */ 141 142chunk1: 143 vshd s2word,r0,s2word /* do an arithmetic shift left to position data */ 144 b ckbyte2 /**/ 145 extru s1word,7,8,tmp3 /**/ 146 147 148shifts1: 149 sh3add tmp3,r0,tmp3 /* eight bits per byte so mul by 8 */ 150 sub r0,tmp3,tmp3 /* Get negative value for left shift */ 151 dep r0,31,2,s2 /* Compute word address of s2 */ 152 ldwm 4(0,s2),s2word /* get first word of s2 */ 153 ldwm 4(0,s1),s1word /* get first word or s1 */ 154 combt,=,n r0,tmp1,masks1 /*Do we need to mask beginning of s2 */ 155 add tmp1,count,count /*bump count by the number of bytes */ 156 /* we are going to mask */ 157 sh3add tmp1,r0,save /*save now has number of bits to mask */ 158 mtctl save,11 159 zvdepi -2,32,save /*load save with proper mask */ 160 or save,s2word,s2word /**/ 161masks1: sh3add tmp5,r0,save /*save now has number of bits to mask */ 162 mtctl save,11 163 zvdepi -2,32,save /*load save with proper mask */ 164 or save,s1word,s1word /**/ 165 subi 4,tmp5,tmp5 /*tmp5 now has the number of byte that */ 166 /*are valid in s1word before the vshd */ 167 mtctl tmp3,11 /*Move shift amount to CR11 */ 168more1: combt,<=,n count,tmp5,chunk2 /*Can we do the vshd? */ 169 ldwm 4(0,s1),tmp7 /*load second word to enable us to shift */ 170 vshd s1word,tmp7,s1word /**/ 171 combf,=,n s2word,s1word,ckbyte2 /**/ 172 extru s1word,7,8,tmp3 /*get first byte (DELAY SLOT) */ 173 addibt,<=,n -4,count,zero /*have we checked N chars? */ 174 copy tmp7,s1word /**/ 175 b more1 /*keep checking */ 176 ldwm 4(0,s2),s2word /*get next s2 (DELAY SLOT) */ 177 178chunk2: 179 vshd s1word,r0,s1word /**/ 180 b ckbyte2 /**/ 181 extru s1word,7,8,tmp3 /**/ 182 183zero: copy r0,ret0 184done: 185EXIT(memcmp) 186
