| /* |
| * (c) Copyright 1986 HEWLETT-PACKARD COMPANY |
| * |
| * To anyone who acknowledges that this file is provided "AS IS" |
| * without any express or implied warranty: |
| * permission to use, copy, modify, and distribute this file |
| * for any purpose is hereby granted without fee, provided that |
| * the above copyright notice and this notice appears in all |
| * copies, and that the name of Hewlett-Packard Company not be |
| * used in advertising or publicity pertaining to distribution |
| * of the software without specific, written prior permission. |
| * Hewlett-Packard Company makes no representations about the |
| * suitability of this software for any purpose. |
| */ |
| |
| /* memcmp(s1, s2, n) */ |
| /* returns integer: < 0 iff s1 lexicographically less than s2 */ |
| /* > 0 iff s1 lexicographically greater than s2 */ |
| /* = 0 iff s1 lexicographically equal to s2 */ |
| /* = 0 iff s1 lexicographically equal to s2 */ |
| /* quit after n charachters */ |
| #ifndef _NAMESPACE_CLEAN |
| #define NOSECDEF /* prevents _memcmp from becoming primary entry */ |
| #endif |
| |
| #include "DEFS.h" |
| |
| #define s1 26 |
| #define s2 25 |
| #define tmp1 19 |
| #define s2word 20 |
| #define tmp3 21 |
| #define tmp7 22 |
| #define s1word 29 |
| #define save 1 |
| #define tmp6 23 |
| #define tmp5 28 |
| #define count 24 |
| |
| ENTRY(memcmp) |
| combt,<,n r0,count,search /*N <= 0 yields equality */ |
| b done /**/ |
| copy 0,ret0 /*return 0 (DELAY SLOT) */ |
| search: combf,=,n s1,s2,findout /*s1 != s2? */ |
| b done |
| copy 0,ret0 /*return 0 (delay slot) */ |
| findout: |
| comibf,=,n 0,s1,checks1 /*s1 == NULL? */ |
| ldbs 0(0,s2),ret0 /**/ |
| b done /*quit */ |
| sub 0,ret0,ret0 /*ret0 <- -*s2 */ |
| checks1: |
| comibf,=,n 0,s2,checkitout /*s2 == NULL? */ |
| b done /* quit */ |
| ldbs 0(0,s1),28 /* return *s1 */ |
| |
| checkitout: |
| extru s2,31,2,tmp1 /* Extract the low two bits of the s2. */ |
| extru s1,31,2,tmp5 /* Extract the low two bits of the s1 */ |
| sub,= tmp5,tmp1,tmp3 /* Are s1 & s2 aligned with each other? */ |
| b not_aligned /* It's more complicated (not_aligned) */ |
| dep 0,31,2,s1 /* Compute word address of s1 (DELAY SLOT) */ |
| dep 0,31,2,s2 /* Compute word address of s2 */ |
| ldwm 4(0,s1),s1word /* get next s1 word s1+=4 */ |
| combt,= tmp5,r0,skipmask /* skip masking, if we can */ |
| ldwm 4(0,s2),s2word /* get next s2 word s2+=4 (DELAY SLOT) */ |
| add tmp5,count,count /* bump count by the number of bytes */ |
| /* we are going to mask */ |
| sh3add tmp5,r0,save /* save now has number of bits to mask */ |
| mtctl save,11 |
| zvdepi -2,32,save /* load save with proper mask */ |
| or save,s1word,s1word /* mask s1word (s1) */ |
| or save,s2word,s2word /* mask s2word (s2) */ |
| |
| |
| skipmask: |
| combt,=,n s1word,s2word,checkN /* We may be done */ |
| |
| checkbyte: |
| extru s1word,7,8,tmp3 /* get first byte (character) */ |
| ckbyte2: extru s2word,7,8,tmp7 /* get first byte (character) */ |
| combf,= tmp3,tmp7,done /* quit if first byte is not equal */ |
| sub tmp3,tmp7,ret0 /* return difference (delay slot) */ |
| addibt,<=,n -1,count,done /* have we checked N chars? ret0 == 0 */ |
| extru s1word,15,8,tmp3 /* get second byte (character) */ |
| extru s2word,15,8,tmp7 /* get second byte (character) */ |
| combf,= tmp3,tmp7,done /* quit if second byte is not equal */ |
| sub tmp3,tmp7,ret0 /* return difference (delay slot) */ |
| addibt,<=,n -1,count,done /* have we checked N chars? */ |
| extru s1word,23,8,tmp3 /* get third byte (character) */ |
| extru s2word,23,8,tmp7 /* get third byte (character) */ |
| combf,= tmp3,tmp7,done /* done if third byte is not equal */ |
| sub tmp3,tmp7,ret0 /* return difference (delay slot) */ |
| addibt,<=,n -1,count,done /* have we checked N chars? */ |
| extru s1word,31,8,tmp3 /* get last byte (character) */ |
| extru s2word,31,8,tmp7 /* get last byte (character) */ |
| b done /* if we reach this point we know that */ |
| sub tmp3,tmp7,ret0 /* the last character in the word is */ |
| /* where the difference is, so return */ |
| /* the difference and we're outta here */ |
| |
| |
| checkN: |
| addibt,<=,n -4,count,zero /* have we checked N chars? */ |
| ldwm 4(0,s2),s2word /* get next s2 word s2+=4 */ |
| b skipmask /* keep checking */ |
| ldwm 4(0,s1),s1word /* get next s1 word s1+=4 */ |
| |
| |
| not_aligned: |
| dep r0,31,2,s2 /* Compute word address of s2 */ |
| combt,<,n r0,tmp3,shifts1 /* Do we shift s1 or s2 */ |
| sh3add tmp3,r0,tmp3 /* eight bits per byte so mul by 8 */ |
| ldwm 4(0,s1),s1word /* get first word of s1 */ |
| ldwm 4(0,s2),s2word /* get first word or s2 */ |
| combt,=,n r0,tmp5,masks2 /* Do we need to mask beginning of s1 */ |
| add tmp5,count,count /* bump count by the number of bytes */ |
| /* we are going to mask */ |
| sh3add tmp5,r0,save /* save now has number of bits to mask */ |
| mtctl save,11 |
| zvdepi -2,32,save /* load save with proper mask */ |
| or save,s1word,s1word /**/ |
| masks2: sh3add tmp1,r0,save /* save now has number of bits to mask */ |
| mtctl save,11 |
| zvdepi -2,32,save /* load save with proper mask */ |
| or save,s2word,s2word /**/ |
| subi 4,tmp1,tmp1 /* tmp1 now has the number of byte that */ |
| /* are valid in s2word before the vshd */ |
| mtctl tmp3,11 /* Move shift amount to CR11 */ |
| more: combt,<=,n count,tmp1,chunk1 /* Can we do the vshd? */ |
| ldwm 4(0,s2),tmp7 /* load second word to enable us to shift */ |
| vshd s2word,tmp7,s2word /**/ |
| combf,=,n s1word,s2word,ckbyte2 /**/ |
| extru s1word,7,8,tmp3 /* get first byte (DELAY SLOT) */ |
| addibt,<=,n -4,count,zero /* have we checked N chars? */ |
| copy tmp7,s2word /**/ |
| b more /* keep checking */ |
| ldwm 4(0,s1),s1word /* get next s1 (DELAY SLOT) */ |
| |
| chunk1: |
| vshd s2word,r0,s2word /* do an arithmetic shift left to position data */ |
| b ckbyte2 /**/ |
| extru s1word,7,8,tmp3 /**/ |
| |
| |
| shifts1: |
| sh3add tmp3,r0,tmp3 /* eight bits per byte so mul by 8 */ |
| sub r0,tmp3,tmp3 /* Get negative value for left shift */ |
| dep r0,31,2,s2 /* Compute word address of s2 */ |
| ldwm 4(0,s2),s2word /* get first word of s2 */ |
| ldwm 4(0,s1),s1word /* get first word or s1 */ |
| combt,=,n r0,tmp1,masks1 /*Do we need to mask beginning of s2 */ |
| add tmp1,count,count /*bump count by the number of bytes */ |
| /* we are going to mask */ |
| sh3add tmp1,r0,save /*save now has number of bits to mask */ |
| mtctl save,11 |
| zvdepi -2,32,save /*load save with proper mask */ |
| or save,s2word,s2word /**/ |
| masks1: sh3add tmp5,r0,save /*save now has number of bits to mask */ |
| mtctl save,11 |
| zvdepi -2,32,save /*load save with proper mask */ |
| or save,s1word,s1word /**/ |
| subi 4,tmp5,tmp5 /*tmp5 now has the number of byte that */ |
| /*are valid in s1word before the vshd */ |
| mtctl tmp3,11 /*Move shift amount to CR11 */ |
| more1: combt,<=,n count,tmp5,chunk2 /*Can we do the vshd? */ |
| ldwm 4(0,s1),tmp7 /*load second word to enable us to shift */ |
| vshd s1word,tmp7,s1word /**/ |
| combf,=,n s2word,s1word,ckbyte2 /**/ |
| extru s1word,7,8,tmp3 /*get first byte (DELAY SLOT) */ |
| addibt,<=,n -4,count,zero /*have we checked N chars? */ |
| copy tmp7,s1word /**/ |
| b more1 /*keep checking */ |
| ldwm 4(0,s2),s2word /*get next s2 (DELAY SLOT) */ |
| |
| chunk2: |
| vshd s1word,r0,s1word /**/ |
| b ckbyte2 /**/ |
| extru s1word,7,8,tmp3 /**/ |
| |
| zero: copy r0,ret0 |
| done: |
| EXIT(memcmp) |