| /* Compare two strings for differences. |
| For SPARC v9. |
| Copyright (C) 2011-2014 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by David S. Miller <davem@davemloft.net> |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <sysdep.h> |
| #include <asm/asi.h> |
| |
| #ifndef XCC |
| .register %g2, #scratch |
| .register %g3, #scratch |
| .register %g6, #scratch |
| #endif |
| |
| #define rSTR1 %o0 |
| #define rSTR2 %o1 |
| #define r0101 %o2 /* 0x0101010101010101 */ |
| #define r8080 %o3 /* 0x8080808080808080 */ |
| #define rSTRXOR %o4 |
| #define rWORD1 %o5 |
| #define rTMP1 %g1 |
| #define rTMP2 %g2 |
| #define rWORD2 %g3 |
| #define rSLL %g4 |
| #define rSRL %g5 |
| #define rBARREL %g6 |
| |
| /* There are two cases, either the two pointers are aligned |
| * identically or they are not. If they have the same |
| * alignment we can use the normal full speed loop. Otherwise |
| * we have to use the barrel-shifter version. |
| */ |
| |
| .text |
| .align 32 |
| ENTRY(strcmp) |
| or rSTR2, rSTR1, rTMP1 |
| sethi %hi(0x80808080), r8080 |
| |
| andcc rTMP1, 0x7, %g0 |
| bne,pn %icc, .Lmaybe_barrel_shift |
| or r8080, %lo(0x80808080), r8080 |
| ldx [rSTR1], rWORD1 |
| |
| sub rSTR2, rSTR1, rSTR2 |
| sllx r8080, 32, rTMP1 |
| |
| ldx [rSTR1 + rSTR2], rWORD2 |
| or r8080, rTMP1, r8080 |
| |
| ba,pt %xcc, .Laligned_loop_entry |
| srlx r8080, 7, r0101 |
| |
| .align 32 |
| .Laligned_loop_entry: |
| .Laligned_loop: |
| add rSTR1, 8, rSTR1 |
| |
| sub rWORD1, r0101, rTMP2 |
| xorcc rWORD1, rWORD2, rSTRXOR |
| bne,pn %xcc, .Lcommon_endstring |
| |
| andn r8080, rWORD1, rTMP1 |
| |
| ldxa [rSTR1] ASI_PNF, rWORD1 |
| andcc rTMP1, rTMP2, %g0 |
| be,a,pt %xcc, .Laligned_loop |
| |
| ldxa [rSTR1 + rSTR2] ASI_PNF, rWORD2 |
| |
| .Lcommon_equal: |
| retl |
| mov 0, %o0 |
| |
| /* All loops terminate here once they find an unequal word. |
| * If a zero byte appears in the word before the first unequal |
| * byte, we must report zero. Otherwise we report '1' or '-1' |
| * depending upon whether the first mis-matching byte is larger |
| * in the first string or the second, respectively. |
| * |
| * First we compute a 64-bit mask value that has "0x01" in |
| * each byte where a zero exists in rWORD1. rSTRXOR holds the |
| * value (rWORD1 ^ rWORD2). Therefore, if considered as an |
| * unsigned quantity, our "0x01" mask value is "greater than" |
| * rSTRXOR then a zero terminating byte comes first and |
| * therefore we report '0'. |
| * |
| * The formula for this mask is: |
| * |
| * mask_tmp1 = ~rWORD1 & 0x8080808080808080; |
| * mask_tmp2 = ((rWORD1 & 0x7f7f7f7f7f7f7f7f) + |
| * 0x7f7f7f7f7f7f7f7f); |
| * |
| * mask = ((mask_tmp1 & ~mask_tmp2) >> 7); |
| */ |
| .Lcommon_endstring: |
| andn rWORD1, r8080, rTMP2 |
| or r8080, 1, %o1 |
| |
| mov 1, %o0 |
| sub rTMP2, %o1, rTMP2 |
| |
| cmp rWORD1, rWORD2 |
| andn rTMP1, rTMP2, rTMP1 |
| |
| movleu %xcc, -1, %o0 |
| srlx rTMP1, 7, rTMP1 |
| |
| cmp rTMP1, rSTRXOR |
| retl |
| movgu %xcc, 0, %o0 |
| |
| .Lmaybe_barrel_shift: |
| sub rSTR2, rSTR1, rSTR2 |
| sllx r8080, 32, rTMP1 |
| |
| or r8080, rTMP1, r8080 |
| and rSTR1, 0x7, rTMP2 |
| |
| srlx r8080, 7, r0101 |
| andn rSTR1, 0x7, rSTR1 |
| |
| ldxa [rSTR1] ASI_PNF, rWORD1 |
| andcc rSTR2, 0x7, rSLL |
| sll rTMP2, 3, rSTRXOR |
| |
| bne,pn %icc, .Lneed_barrel_shift |
| mov -1, rTMP1 |
| ldxa [rSTR1 + rSTR2] ASI_PNF, rBARREL |
| |
| srlx rTMP1, rSTRXOR, rTMP2 |
| |
| orn rWORD1, rTMP2, rWORD1 |
| ba,pt %xcc, .Laligned_loop_entry |
| orn rBARREL, rTMP2, rWORD2 |
| |
| .Lneed_barrel_shift: |
| sllx rSLL, 3, rSLL |
| andn rSTR2, 0x7, rSTR2 |
| |
| ldxa [rSTR1 + rSTR2] ASI_PNF, rBARREL |
| mov 64, rTMP2 |
| sub rTMP2, rSLL, rSRL |
| |
| srlx rTMP1, rSTRXOR, rTMP1 |
| add rSTR2, 8, rSTR2 |
| |
| orn rWORD1, rTMP1, rWORD1 |
| sllx rBARREL, rSLL, rWORD2 |
| ldxa [rSTR1 + rSTR2] ASI_PNF, rBARREL |
| |
| add rSTR1, 8, rSTR1 |
| sub rWORD1, r0101, rTMP2 |
| |
| srlx rBARREL, rSRL, rSTRXOR |
| |
| or rWORD2, rSTRXOR, rWORD2 |
| |
| orn rWORD2, rTMP1, rWORD2 |
| ba,pt %xcc, .Lbarrel_shift_loop_entry |
| andn r8080, rWORD1, rTMP1 |
| |
| .Lbarrel_shift_loop: |
| sllx rBARREL, rSLL, rWORD2 |
| ldxa [rSTR1 + rSTR2] ASI_PNF, rBARREL |
| |
| add rSTR1, 8, rSTR1 |
| sub rWORD1, r0101, rTMP2 |
| |
| srlx rBARREL, rSRL, rSTRXOR |
| andn r8080, rWORD1, rTMP1 |
| |
| or rWORD2, rSTRXOR, rWORD2 |
| |
| .Lbarrel_shift_loop_entry: |
| xorcc rWORD1, rWORD2, rSTRXOR |
| bne,pn %xcc, .Lcommon_endstring |
| |
| andcc rTMP1, rTMP2, %g0 |
| be,a,pt %xcc, .Lbarrel_shift_loop |
| ldxa [rSTR1] ASI_PNF, rWORD1 |
| |
| retl |
| mov 0, %o0 |
| END(strcmp) |
| libc_hidden_builtin_def (strcmp) |
