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Diffstat (limited to 'sysdeps/powerpc/powerpc64/power9/strcmp.S')
| -rw-r--r-- | sysdeps/powerpc/powerpc64/power9/strcmp.S | 268 |
1 files changed, 268 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc64/power9/strcmp.S b/sysdeps/powerpc/powerpc64/power9/strcmp.S new file mode 100644 index 0000000000..98243a9d51 --- /dev/null +++ b/sysdeps/powerpc/powerpc64/power9/strcmp.S @@ -0,0 +1,268 @@ +/* Optimized strcmp implementation for PowerPC64/POWER9. + 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/>. */ +#ifdef __LITTLE_ENDIAN__ +#include <sysdep.h> + +#ifndef STRCMP +# define STRCMP strcmp +#endif + +/* Implements the function + + int [r3] strcmp (const char *s1 [r3], const char *s2 [r4]) + + The implementation uses unaligned doubleword access for first 32 bytes + as in POWER8 patch and uses vectorised loops after that. */ + +/* TODO: Change this to actual instructions when minimum binutils is upgraded + to 2.27. Macros are defined below for these newer instructions in order + to maintain compatibility. */ +# define VCTZLSBB(r,v) .long (0x10010602 | ((r)<<(32-11)) | ((v)<<(32-21))) + +# define VEXTUBRX(t,a,b) .long (0x1000070d \ + | ((t)<<(32-11)) \ + | ((a)<<(32-16)) \ + | ((b)<<(32-21)) ) + +# define VCMPNEZB(t,a,b) .long (0x10000507 \ + | ((t)<<(32-11)) \ + | ((a)<<(32-16)) \ + | ((b)<<(32-21)) ) + +/* Get 16 bytes for unaligned case. + reg1: Vector to hold next 16 bytes. + reg2: Address to read from. + reg3: Permute control vector. */ +# define GET16BYTES(reg1, reg2, reg3) \ + lvx reg1, 0, reg2; \ + vperm v8, v2, reg1, reg3; \ + vcmpequb. v8, v0, v8; \ + beq cr6, 1f; \ + vspltisb v9, 0; \ + b 2f; \ + .align 4; \ +1: \ + addi r6, reg2, 16; \ + lvx v9, 0, r6; \ +2: \ + vperm reg1, v9, reg1, reg3; + +/* TODO: change this to .machine power9 when the minimum required binutils + allows it. */ + + .machine power7 +ENTRY_TOCLESS (STRCMP, 4) + li r0, 0 + + /* Check if [s1]+16 or [s2]+16 will cross a 4K page boundary using + the code: + + (((size_t) s1) % PAGE_SIZE > (PAGE_SIZE - ITER_SIZE)) + + with PAGE_SIZE being 4096 and ITER_SIZE begin 16. */ + + rldicl r7, r3, 0, 52 + rldicl r9, r4, 0, 52 + cmpldi cr7, r7, 4096-16 + bgt cr7, L(pagecross_check) + cmpldi cr5, r9, 4096-16 + bgt cr5, L(pagecross_check) + + /* For short strings up to 16 bytes, load both s1 and s2 using + unaligned dwords and compare. */ + ld r8, 0(r3) + ld r10, 0(r4) + cmpb r12, r8, r0 + cmpb r11, r8, r10 + orc. r9, r12, r11 + bne cr0, L(different_nocmpb) + + ld r8, 8(r3) + ld r10, 8(r4) + cmpb r12, r8, r0 + cmpb r11, r8, r10 + orc. r9, r12, r11 + bne cr0, L(different_nocmpb) + + addi r7, r3, 16 + addi r4, r4, 16 + +L(align): + /* Now it has checked for first 16 bytes. */ + vspltisb v0, 0 + vspltisb v2, -1 + lvsr v6, 0, r4 /* Compute mask. */ + or r5, r4, r7 + andi. r5, r5, 0xF + beq cr0, L(aligned) + andi. r5, r7, 0xF + beq cr0, L(s1_align) + lvsr v10, 0, r7 /* Compute mask. */ + + /* Both s1 and s2 are unaligned. */ + GET16BYTES(v4, r7, v10) + GET16BYTES(v5, r4, v6) + VCMPNEZB(v7, v5, v4) + beq cr6, L(match) + b L(different) + + /* Align s1 to qw and adjust s2 address. */ + .align 4 +L(match): + clrldi r6, r7, 60 + subfic r5, r6, 16 + add r7, r7, r5 + add r4, r4, r5 + andi. r5, r4, 0xF + beq cr0, L(aligned) + lvsr v6, 0, r4 + /* There are 2 loops depending on the input alignment. + Each loop gets 16 bytes from s1 and s2 and compares. + Loop until a mismatch or null occurs. */ +L(s1_align): + lvx v4, r7, r0 + GET16BYTES(v5, r4, v6) + VCMPNEZB(v7, v5, v4) + addi r7, r7, 16 + addi r4, r4, 16 + bne cr6, L(different) + + lvx v4, r7, r0 + GET16BYTES(v5, r4, v6) + VCMPNEZB(v7, v5, v4) + addi r7, r7, 16 + addi r4, r4, 16 + bne cr6, L(different) + + lvx v4, r7, r0 + GET16BYTES(v5, r4, v6) + VCMPNEZB(v7, v5, v4) + addi r7, r7, 16 + addi r4, r4, 16 + bne cr6, L(different) + + lvx v4, r7, r0 + GET16BYTES(v5, r4, v6) + VCMPNEZB(v7, v5, v4) + addi r7, r7, 16 + addi r4, r4, 16 + beq cr6, L(s1_align) + b L(different) + + .align 4 +L(aligned): + lvx v4, 0, r7 + lvx v5, 0, r4 + VCMPNEZB(v7, v5, v4) + addi r7, r7, 16 + addi r4, r4, 16 + bne cr6, L(different) + + lvx v4, 0, r7 + lvx v5, 0, r4 + VCMPNEZB(v7, v5, v4) + addi r7, r7, 16 + addi r4, r4, 16 + bne cr6, L(different) + + lvx v4, 0, r7 + lvx v5, 0, r4 + VCMPNEZB(v7, v5, v4) + addi r7, r7, 16 + addi r4, r4, 16 + bne cr6, L(different) + + lvx v4, 0, r7 + lvx v5, 0, r4 + VCMPNEZB(v7, v5, v4) + addi r7, r7, 16 + addi r4, r4, 16 + beq cr6, L(aligned) + + /* Calculate and return the difference. */ +L(different): + VCTZLSBB(r6, v7) + VEXTUBRX(r5, r6, v4) + VEXTUBRX(r4, r6, v5) + subf r3, r4, r5 + extsw r3, r3 + blr + + .align 4 +L(different_nocmpb): + neg r3, r9 + and r9, r9, r3 + cntlzd r9, r9 + subfic r9, r9, 63 + srd r3, r8, r9 + srd r10, r10, r9 + rldicl r10, r10, 0, 56 + rldicl r3, r3, 0, 56 + subf r3, r10, r3 + extsw r3, r3 + blr + + .align 4 +L(pagecross_check): + subfic r9, r9, 4096 + subfic r7, r7, 4096 + cmpld cr7, r7, r9 + bge cr7, L(pagecross) + mr r7, r9 + + /* If unaligned 16 bytes reads across a 4K page boundary, it uses + a simple byte a byte comparison until the page alignment for s1 + is reached. */ +L(pagecross): + add r7, r3, r7 + subf r9, r3, r7 + mtctr r9 + + .align 4 +L(pagecross_loop): + /* Loads a byte from s1 and s2, compare if *s1 is equal to *s2 + and if *s1 is '\0'. */ + lbz r9, 0(r3) + lbz r10, 0(r4) + addi r3, r3, 1 + addi r4, r4, 1 + cmplw cr7, r9, r10 + cmpdi cr5, r9, r0 + bne cr7, L(pagecross_ne) + beq cr5, L(pagecross_nullfound) + bdnz L(pagecross_loop) + b L(align) + + .align 4 +L(pagecross_ne): + extsw r3, r9 + mr r9, r10 +L(pagecross_retdiff): + subf r9, r9, r3 + extsw r3, r9 + blr + + .align 4 +L(pagecross_nullfound): + li r3, 0 + b L(pagecross_retdiff) +END (STRCMP) +libc_hidden_builtin_def (strcmp) +#else +#include <sysdeps/powerpc/powerpc64/power8/strcmp.S> +#endif |