| /* Optimized strchr implementation for PowerPC64/POWER8. |
| Copyright (C) 2016-2018 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, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <sysdep.h> |
| |
| #ifdef USE_AS_STRCHRNUL |
| # ifndef STRCHRNUL |
| # define FUNC_NAME __strchrnul |
| # else |
| # define FUNC_NAME STRCHRNUL |
| # endif |
| #else |
| # ifndef STRCHR |
| # define FUNC_NAME strchr |
| # else |
| # define FUNC_NAME STRCHR |
| # endif |
| #endif /* !USE_AS_STRCHRNUL */ |
| |
| /* int [r3] strchr (char *s [r3], int c [r4]) */ |
| /* TODO: change these to the actual instructions when the minimum required |
| binutils allows it. */ |
| #define MTVRD(v,r) .long (0x7c000167 | ((v)<<(32-11)) | ((r)<<(32-16))) |
| #define MFVRD(r,v) .long (0x7c000067 | ((v)<<(32-11)) | ((r)<<(32-16))) |
| #define VBPERMQ(t,a,b) .long (0x1000054c \ |
| | ((t)<<(32-11)) \ |
| | ((a)<<(32-16)) \ |
| | ((b)<<(32-21)) ) |
| /* TODO: change this to .machine power8 when the minimum required binutils |
| allows it. */ |
| .machine power7 |
| ENTRY_TOCLESS (FUNC_NAME) |
| CALL_MCOUNT 2 |
| dcbt 0,r3 |
| clrrdi r8,r3,3 /* Align the address to doubleword boundary. */ |
| cmpdi cr7,r4,0 |
| ld r12,0(r8) /* Load doubleword from memory. */ |
| li r0,0 /* Doubleword with null chars to use |
| with cmpb. */ |
| |
| rlwinm r6,r3,3,26,28 /* Calculate padding. */ |
| |
| beq cr7,L(null_match) |
| |
| /* Replicate byte to doubleword. */ |
| insrdi r4,r4,8,48 |
| insrdi r4,r4,16,32 |
| insrdi r4,r4,32,0 |
| |
| /* Now r4 has a doubleword of c bytes and r0 has |
| a doubleword of null bytes. */ |
| |
| cmpb r10,r12,r4 /* Compare each byte against c byte. */ |
| cmpb r11,r12,r0 /* Compare each byte against null byte. */ |
| |
| /* Move the doublewords left and right to discard the bits that are |
| not part of the string and bring them back as zeros. */ |
| #ifdef __LITTLE_ENDIAN__ |
| srd r10,r10,r6 |
| srd r11,r11,r6 |
| sld r10,r10,r6 |
| sld r11,r11,r6 |
| #else |
| sld r10,r10,r6 |
| sld r11,r11,r6 |
| srd r10,r10,r6 |
| srd r11,r11,r6 |
| #endif |
| or r5,r10,r11 /* OR the results to speed things up. */ |
| cmpdi cr7,r5,0 /* If r5 == 0, no c or null bytes |
| have been found. */ |
| bne cr7,L(done) |
| |
| mtcrf 0x01,r8 |
| |
| /* Are we now aligned to a doubleword boundary? If so, skip to |
| the main loop. Otherwise, go through the alignment code. */ |
| |
| bt 28,L(loop) |
| |
| /* Handle WORD2 of pair. */ |
| ldu r12,8(r8) |
| cmpb r10,r12,r4 |
| cmpb r11,r12,r0 |
| or r5,r10,r11 |
| cmpdi cr7,r5,0 |
| bne cr7,L(done) |
| b L(loop) /* We branch here (rather than falling through) |
| to skip the nops due to heavy alignment |
| of the loop below. */ |
| |
| .p2align 5 |
| L(loop): |
| /* Load two doublewords, compare and merge in a |
| single register for speed. This is an attempt |
| to speed up the null-checking process for bigger strings. */ |
| ld r12,8(r8) |
| ldu r9,16(r8) |
| cmpb r10,r12,r4 |
| cmpb r11,r12,r0 |
| cmpb r6,r9,r4 |
| cmpb r7,r9,r0 |
| or r5,r10,r11 |
| or r9,r6,r7 |
| or r12,r5,r9 |
| cmpdi cr7,r12,0 |
| beq cr7,L(vector) |
| /* OK, one (or both) of the doublewords contains a c/null byte. Check |
| the first doubleword and decrement the address in case the first |
| doubleword really contains a c/null byte. */ |
| |
| cmpdi cr6,r5,0 |
| addi r8,r8,-8 |
| bne cr6,L(done) |
| |
| /* The c/null byte must be in the second doubleword. Adjust the |
| address again and move the result of cmpb to r10 so we can calculate |
| the pointer. */ |
| |
| mr r10,r6 |
| mr r11,r7 |
| addi r8,r8,8 |
| #ifdef USE_AS_STRCHRNUL |
| mr r5, r9 |
| #endif |
| /* r10/r11 have the output of the cmpb instructions, that is, |
| 0xff in the same position as the c/null byte in the original |
| doubleword from the string. Use that to calculate the pointer. */ |
| L(done): |
| #ifdef USE_AS_STRCHRNUL |
| mr r10, r5 |
| #endif |
| #ifdef __LITTLE_ENDIAN__ |
| addi r3,r10,-1 |
| andc r3,r3,r10 |
| popcntd r0,r3 |
| # ifndef USE_AS_STRCHRNUL |
| addi r4,r11,-1 |
| andc r4,r4,r11 |
| cmpld cr7,r3,r4 |
| bgt cr7,L(no_match) |
| # endif |
| #else |
| cntlzd r0,r10 /* Count leading zeros before c matches. */ |
| # ifndef USE_AS_STRCHRNUL |
| cmpld cr7,r11,r10 |
| bgt cr7,L(no_match) |
| # endif |
| #endif |
| srdi r0,r0,3 /* Convert leading zeros to bytes. */ |
| add r3,r8,r0 /* Return address of the matching c byte |
| or null in case c was not found. */ |
| blr |
| |
| /* Check the first 32B in GPR's and move to vectorized loop. */ |
| .p2align 5 |
| L(vector): |
| addi r3, r8, 8 |
| andi. r10, r3, 31 |
| bne cr0, L(loop) |
| vspltisb v0, 0 |
| /* Precompute vbpermq constant. */ |
| vspltisb v10, 3 |
| lvsl v11, r0, r0 |
| vslb v10, v11, v10 |
| MTVRD(v1,r4) |
| li r5, 16 |
| vspltb v1, v1, 7 |
| /* Compare 32 bytes in each loop. */ |
| L(continue): |
| lvx v4, 0, r3 |
| lvx v5, r3, r5 |
| vcmpequb v2, v0, v4 |
| vcmpequb v3, v0, v5 |
| vcmpequb v6, v1, v4 |
| vcmpequb v7, v1, v5 |
| vor v8, v2, v3 |
| vor v9, v6, v7 |
| vor v11, v8, v9 |
| vcmpequb. v11, v0, v11 |
| addi r3, r3, 32 |
| blt cr6, L(continue) |
| /* One (or both) of the quadwords contains a c/null byte. */ |
| addi r3, r3, -32 |
| #ifndef USE_AS_STRCHRNUL |
| vcmpequb. v11, v0, v9 |
| blt cr6, L(no_match) |
| #endif |
| /* Permute the first bit of each byte into bits 48-63. */ |
| VBPERMQ(v2, v2, v10) |
| VBPERMQ(v3, v3, v10) |
| VBPERMQ(v6, v6, v10) |
| VBPERMQ(v7, v7, v10) |
| /* Shift each component into its correct position for merging. */ |
| #ifdef __LITTLE_ENDIAN__ |
| vsldoi v3, v3, v3, 2 |
| vsldoi v7, v7, v7, 2 |
| #else |
| vsldoi v2, v2, v2, 6 |
| vsldoi v3, v3, v3, 4 |
| vsldoi v6, v6, v6, 6 |
| vsldoi v7, v7, v7, 4 |
| #endif |
| |
| /* Merge the results and move to a GPR. */ |
| vor v1, v3, v2 |
| vor v2, v6, v7 |
| vor v4, v1, v2 |
| MFVRD(r5, v4) |
| #ifdef __LITTLE_ENDIAN__ |
| addi r6, r5, -1 |
| andc r6, r6, r5 |
| popcntd r6, r6 |
| #else |
| cntlzd r6, r5 /* Count leading zeros before the match. */ |
| #endif |
| add r3, r3, r6 /* Compute final length. */ |
| /* Return NULL if null found before c. */ |
| #ifndef USE_AS_STRCHRNUL |
| lbz r4, 0(r3) |
| cmpdi cr7, r4, 0 |
| beq cr7, L(no_match) |
| #endif |
| blr |
| |
| #ifndef USE_AS_STRCHRNUL |
| .align 4 |
| L(no_match): |
| li r3,0 |
| blr |
| #endif |
| |
| /* We are here because strchr was called with a null byte. */ |
| .align 4 |
| L(null_match): |
| /* r0 has a doubleword of null bytes. */ |
| |
| cmpb r5,r12,r0 /* Compare each byte against null bytes. */ |
| |
| /* Move the doublewords left and right to discard the bits that are |
| not part of the string and bring them back as zeros. */ |
| #ifdef __LITTLE_ENDIAN__ |
| srd r5,r5,r6 |
| sld r5,r5,r6 |
| #else |
| sld r5,r5,r6 |
| srd r5,r5,r6 |
| #endif |
| cmpdi cr7,r5,0 /* If r10 == 0, no c or null bytes |
| have been found. */ |
| bne cr7,L(done_null) |
| |
| mtcrf 0x01,r8 |
| |
| /* Are we now aligned to a quadword boundary? If so, skip to |
| the main loop. Otherwise, go through the alignment code. */ |
| |
| bt 28,L(loop_null) |
| |
| /* Handle WORD2 of pair. */ |
| ldu r12,8(r8) |
| cmpb r5,r12,r0 |
| cmpdi cr7,r5,0 |
| bne cr7,L(done_null) |
| b L(loop_null) /* We branch here (rather than falling through) |
| to skip the nops due to heavy alignment |
| of the loop below. */ |
| |
| /* Main loop to look for the end of the string. Since it's a |
| small loop (< 8 instructions), align it to 32-bytes. */ |
| .p2align 5 |
| L(loop_null): |
| /* Load two doublewords, compare and merge in a |
| single register for speed. This is an attempt |
| to speed up the null-checking process for bigger strings. */ |
| ld r12,8(r8) |
| ldu r11,16(r8) |
| cmpb r5,r12,r0 |
| cmpb r10,r11,r0 |
| or r6,r5,r10 |
| cmpdi cr7,r6,0 |
| beq cr7,L(vector1) |
| |
| /* OK, one (or both) of the doublewords contains a null byte. Check |
| the first doubleword and decrement the address in case the first |
| doubleword really contains a null byte. */ |
| |
| cmpdi cr6,r5,0 |
| addi r8,r8,-8 |
| bne cr6,L(done_null) |
| |
| /* The null byte must be in the second doubleword. Adjust the address |
| again and move the result of cmpb to r10 so we can calculate the |
| pointer. */ |
| |
| mr r5,r10 |
| addi r8,r8,8 |
| |
| /* r5 has the output of the cmpb instruction, that is, it contains |
| 0xff in the same position as the null byte in the original |
| doubleword from the string. Use that to calculate the pointer. */ |
| L(done_null): |
| #ifdef __LITTLE_ENDIAN__ |
| addi r0,r5,-1 |
| andc r0,r0,r5 |
| popcntd r0,r0 |
| #else |
| cntlzd r0,r5 /* Count leading zeros before the match. */ |
| #endif |
| srdi r0,r0,3 /* Convert leading zeros to bytes. */ |
| add r3,r8,r0 /* Return address of the matching null byte. */ |
| blr |
| .p2align 5 |
| L(vector1): |
| addi r3, r8, 8 |
| andi. r10, r3, 31 |
| bne cr0, L(loop_null) |
| vspltisb v8, -1 |
| vspltisb v0, 0 |
| vspltisb v10, 3 |
| lvsl v11, r0, r0 |
| vslb v10, v11, v10 |
| li r5, 16 |
| L(continue1): |
| lvx v4, 0, r3 |
| lvx v5, r3, r5 |
| vcmpequb v2, v0, v4 |
| vcmpequb v3, v0, v5 |
| vor v8, v2, v3 |
| vcmpequb. v11, v0, v8 |
| addi r3, r3, 32 |
| blt cr6, L(continue1) |
| addi r3, r3, -32 |
| L(end1): |
| VBPERMQ(v2, v2, v10) |
| VBPERMQ(v3, v3, v10) |
| /* Shift each component into its correct position for merging. */ |
| #ifdef __LITTLE_ENDIAN__ |
| vsldoi v3, v3, v3, 2 |
| #else |
| vsldoi v2, v2, v2, 6 |
| vsldoi v3, v3, v3, 4 |
| #endif |
| |
| /* Merge the results and move to a GPR. */ |
| vor v4, v3, v2 |
| MFVRD(r5, v4) |
| #ifdef __LITTLE_ENDIAN__ |
| addi r6, r5, -1 |
| andc r6, r6, r5 |
| popcntd r6, r6 |
| #else |
| cntlzd r6, r5 /* Count leading zeros before the match. */ |
| #endif |
| add r3, r3, r6 /* Compute final length. */ |
| blr |
| END (FUNC_NAME) |
| |
| #ifndef USE_AS_STRCHRNUL |
| weak_alias (strchr, index) |
| libc_hidden_builtin_def (strchr) |
| #endif |
