| /* Optimized strcmp implementation for PowerPC. |
| Copyright (C) 1997, 1999, 2000, 2003 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| 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, write to the Free |
| Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. */ |
| |
| #include <sysdep.h> |
| #include <bp-sym.h> |
| #include <bp-asm.h> |
| |
| /* See strlen.s for comments on how the end-of-string testing works. */ |
| |
| /* int [r3] strcmp (const char *s1 [r3], const char *s2 [r4]) */ |
| |
| EALIGN (BP_SYM (strcmp), 4, 0) |
| |
| #define rTMP r0 |
| #define rRTN r3 |
| #define rSTR1 r3 /* first string arg */ |
| #define rSTR2 r4 /* second string arg */ |
| #if __BOUNDED_POINTERS__ |
| # define rHIGH1 r11 |
| # define rHIGH2 r12 |
| #endif |
| #define rWORD1 r5 /* current word in s1 */ |
| #define rWORD2 r6 /* current word in s2 */ |
| #define rFEFE r7 /* constant 0xfefefeff (-0x01010101) */ |
| #define r7F7F r8 /* constant 0x7f7f7f7f */ |
| #define rNEG r9 /* ~(word in s1 | 0x7f7f7f7f) */ |
| #define rBITDIF r10 /* bits that differ in s1 & s2 words */ |
| |
| CHECK_BOUNDS_LOW (rSTR1, rTMP, rHIGH1) |
| CHECK_BOUNDS_LOW (rSTR2, rTMP, rHIGH2) |
| |
| or rTMP, rSTR2, rSTR1 |
| clrlwi. rTMP, rTMP, 30 |
| lis rFEFE, -0x101 |
| bne L(unaligned) |
| |
| lwz rWORD1, 0(rSTR1) |
| lwz rWORD2, 0(rSTR2) |
| lis r7F7F, 0x7f7f |
| addi rFEFE, rFEFE, -0x101 |
| addi r7F7F, r7F7F, 0x7f7f |
| b L(g1) |
| |
| L(g0): lwzu rWORD1, 4(rSTR1) |
| bne cr1, L(different) |
| lwzu rWORD2, 4(rSTR2) |
| L(g1): add rTMP, rFEFE, rWORD1 |
| nor rNEG, r7F7F, rWORD1 |
| and. rTMP, rTMP, rNEG |
| cmpw cr1, rWORD1, rWORD2 |
| beq+ L(g0) |
| L(endstring): |
| /* OK. We've hit the end of the string. We need to be careful that |
| we don't compare two strings as different because of gunk beyond |
| the end of the strings... */ |
| and rTMP, r7F7F, rWORD1 |
| beq cr1, L(equal) |
| add rTMP, rTMP, r7F7F |
| xor. rBITDIF, rWORD1, rWORD2 |
| andc rNEG, rNEG, rTMP |
| blt- L(highbit) |
| cntlzw rBITDIF, rBITDIF |
| cntlzw rNEG, rNEG |
| addi rNEG, rNEG, 7 |
| cmpw cr1, rNEG, rBITDIF |
| sub rRTN, rWORD1, rWORD2 |
| bgelr+ cr1 |
| L(equal): |
| li rRTN, 0 |
| /* GKM FIXME: check high bounds. */ |
| blr |
| |
| L(different): |
| lwz rWORD1, -4(rSTR1) |
| xor. rBITDIF, rWORD1, rWORD2 |
| sub rRTN, rWORD1, rWORD2 |
| bgelr+ |
| L(highbit): |
| ori rRTN, rWORD2, 1 |
| /* GKM FIXME: check high bounds. */ |
| blr |
| |
| |
| /* Oh well. In this case, we just do a byte-by-byte comparison. */ |
| .align 4 |
| L(unaligned): |
| lbz rWORD1, 0(rSTR1) |
| lbz rWORD2, 0(rSTR2) |
| b L(u1) |
| |
| L(u0): lbzu rWORD1, 1(rSTR1) |
| bne- L(u4) |
| lbzu rWORD2, 1(rSTR2) |
| L(u1): cmpwi cr1, rWORD1, 0 |
| beq- cr1, L(u3) |
| cmpw rWORD1, rWORD2 |
| bne- L(u3) |
| lbzu rWORD1, 1(rSTR1) |
| lbzu rWORD2, 1(rSTR2) |
| cmpwi cr1, rWORD1, 0 |
| cmpw rWORD1, rWORD2 |
| bne+ cr1, L(u0) |
| L(u3): sub rRTN, rWORD1, rWORD2 |
| /* GKM FIXME: check high bounds. */ |
| blr |
| L(u4): lbz rWORD1, -1(rSTR1) |
| sub rRTN, rWORD1, rWORD2 |
| /* GKM FIXME: check high bounds. */ |
| blr |
| END (BP_SYM (strcmp)) |
| libc_hidden_builtin_def (strcmp) |
