diff options
Diffstat (limited to 'sysdeps/powerpc/powerpc64/power9/strncmp.S')
| -rw-r--r-- | sysdeps/powerpc/powerpc64/power9/strncmp.S | 379 |
1 files changed, 379 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc64/power9/strncmp.S b/sysdeps/powerpc/powerpc64/power9/strncmp.S new file mode 100644 index 0000000000..40be98ff45 --- /dev/null +++ b/sysdeps/powerpc/powerpc64/power9/strncmp.S @@ -0,0 +1,379 @@ +/* Optimized strncmp 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> + +/* Implements the function + + int [r3] strncmp (const char *s1 [r3], const char *s2 [r4], size_t [r5] n) + + The implementation uses unaligned doubleword access to avoid specialized + code paths depending of data alignment for first 32 bytes and uses + vectorised loops after that. */ + +#ifndef STRNCMP +# define STRNCMP strncmp +#endif + +/* 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: \ + cmplw cr6, r5, r11; \ + ble cr6, 2f; \ + addi r6, reg2, 16; \ + lvx v9, 0, r6; \ +2: \ + vperm reg1, v9, reg1, reg3; + +/* TODO: change this to .machine power9 when minimum binutils + is upgraded to 2.27. */ + .machine power7 +ENTRY_TOCLESS (STRNCMP, 4) + /* Check if size is 0. */ + cmpdi cr0, r5, 0 + beq cr0, L(ret0) + li r0, 0 + + /* Check if [s1]+32 or [s2]+32 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 32. */ + rldicl r8, r3, 0, 52 + cmpldi cr7, r8, 4096-32 + bgt cr7, L(pagecross) + rldicl r9, r4, 0, 52 + cmpldi cr7, r9, 4096-32 + bgt cr7, L(pagecross) + + /* For short strings up to 32 bytes, load both s1 and s2 using + unaligned dwords and compare. */ + + ld r7, 0(r3) + ld r9, 0(r4) + li r8, 0 + cmpb r8, r7, r8 + cmpb r6, r7, r9 + orc. r8, r8, r6 + bne cr0, L(different1) + + /* If the strings compared are equal, but size is less or equal + to 8, return 0. */ + cmpldi cr7, r5, 8 + li r9, 0 + ble cr7, L(ret1) + addi r5, r5, -8 + + ld r7, 8(r3) + ld r9, 8(r4) + cmpb r8, r7, r8 + cmpb r6, r7, r9 + orc. r8, r8, r6 + bne cr0, L(different1) + cmpldi cr7, r5, 8 + mr r9, r8 + ble cr7, L(ret1) + /* Update pointers and size. */ + addi r5, r5, -8 + addi r3, r3, 16 + addi r4, r4, 16 + + ld r7, 0(r3) + ld r9, 0(r4) + li r8, 0 + cmpb r8, r7, r8 + cmpb r6, r7, r9 + orc. r8, r8, r6 + bne cr0, L(different1) + cmpldi cr7, r5, 8 + li r9, 0 + ble cr7, L(ret1) + addi r5, r5, -8 + + ld r7, 8(r3) + ld r9, 8(r4) + cmpb r8, r7, r8 + cmpb r6, r7, r9 + orc. r8, r8, r6 + bne cr0, L(different1) + cmpldi cr7, r5, 8 + mr r9, r8 + ble cr7, L(ret1) + + /* Update pointers and size. */ + addi r5, r5, -8 + addi r3, r3, 16 + addi r4, r4, 16 +L(align): + /* Now it has checked for first 32 bytes, align source1 to doubleword + and adjust source2 address. */ + vspltisb v0, 0 + vspltisb v2, -1 + or r6, r4, r3 + andi. r6, r6, 0xF + beq cr0, L(aligned) + lvsr v6, 0, r4 /* Compute mask. */ + clrldi r6, r4, 60 + subfic r11, r6, 16 + andi. r6, r3, 0xF + beq cr0, L(s1_align) + /* Both s1 and s2 are unaligned. */ + GET16BYTES(v5, r4, v6) + lvsr v10, 0, r3 /* Compute mask. */ + clrldi r6, r3, 60 + subfic r11, r6, 16 + GET16BYTES(v4, r3, v10) + VCMPNEZB(v7, v5, v4) + beq cr6, L(match) + b L(different) + + /* Align s1 to qw and adjust s2 address. */ + .align 4 +L(match): + cmpldi cr7, r5, 16 + ble cr7, L(ret0) + subf r5, r11, r5 + add r3, r3, r11 + add r4, r4, r11 + andi. r11, r4, 0xF + beq cr0, L(aligned) + lvsr v6, 0, r4 + clrldi r6, r4, 60 + subfic r11, r6, 16 + /* There are 2 loops depending on the input alignment. + Each loop gets 16 bytes from s1 and s2, checks for null + and compares them. Loops until a mismatch or null occurs. */ +L(s1_align): + lvx v4, 0, r3 + GET16BYTES(v5, r4, v6) + VCMPNEZB(v7, v5, v4) + bne cr6, L(different) + cmpldi cr7, r5, 16 + ble cr7, L(ret0) + addi r5, r5, -16 + addi r3, r3, 16 + addi r4, r4, 16 + + lvx v4, 0, r3 + GET16BYTES(v5, r4, v6) + VCMPNEZB(v7, v5, v4) + bne cr6, L(different) + cmpldi cr7, r5, 16 + ble cr7, L(ret0) + addi r5, r5, -16 + addi r3, r3, 16 + addi r4, r4, 16 + + lvx v4, 0, r3 + GET16BYTES(v5, r4, v6) + VCMPNEZB(v7, v5, v4) + bne cr6, L(different) + cmpldi cr7, r5, 16 + ble cr7, L(ret0) + addi r5, r5, -16 + addi r3, r3, 16 + addi r4, r4, 16 + + lvx v4, 0, r3 + GET16BYTES(v5, r4, v6) + VCMPNEZB(v7, v5, v4) + bne cr6, L(different) + cmpldi cr7, r5, 16 + ble cr7, L(ret0) + addi r5, r5, -16 + addi r3, r3, 16 + addi r4, r4, 16 + b L(s1_align) + .align 4 +L(aligned): + lvx v4, 0, r3 + lvx v5, 0, r4 + VCMPNEZB(v7, v5, v4) + bne cr6, L(different) + cmpldi cr7, r5, 16 + ble cr7, L(ret0) + addi r5, r5, -16 + addi r3, r3, 16 + addi r4, r4, 16 + + lvx v4, 0, r3 + lvx v5, 0, r4 + VCMPNEZB(v7, v5, v4) + bne cr6, L(different) + cmpldi cr7, r5, 16 + ble cr7, L(ret0) + addi r5, r5, -16 + addi r3, r3, 16 + addi r4, r4, 16 + + lvx v4, 0, r3 + lvx v5, 0, r4 + VCMPNEZB(v7, v5, v4) + bne cr6, L(different) + cmpldi cr7, r5, 16 + ble cr7, L(ret0) + addi r5, r5, -16 + addi r3, r3, 16 + addi r4, r4, 16 + + lvx v4, 0, r3 + lvx v5, 0, r4 + VCMPNEZB(v7, v5, v4) + bne cr6, L(different) + cmpldi cr7, r5, 16 + ble cr7, L(ret0) + addi r5, r5, -16 + addi r3, r3, 16 + addi r4, r4, 16 + b L(aligned) + /* Calculate and return the difference. */ +L(different): + VCTZLSBB(r6, v7) + cmplw cr7, r5, r6 + ble cr7, L(ret0) + VEXTUBRX(r5, r6, v4) + VEXTUBRX(r4, r6, v5) + subf r3, r4, r5 + extsw r3, r3 + blr + + .align 4 +L(ret0): + li r9, 0 +L(ret1): + mr r3, r9 + blr + + /* The code now checks if r8 and r5 are different by issuing a + cmpb and shifts the result based on its output: + + leadzero = (__builtin_ffsl (z1) - 1); + leadzero = leadzero > (n-1)*8 ? (n-1)*8 : leadzero; + r1 = (r1 >> leadzero) & 0xFFUL; + r2 = (r2 >> leadzero) & 0xFFUL; + return r1 - r2; */ + + .align 4 +L(different1): + neg r11, r8 + sldi r5, r5, 3 + and r8, r11, r8 + addi r5, r5, -8 + cntlzd r8, r8 + subfic r8, r8, 63 + extsw r8, r8 + cmpld cr7, r8, r5 + ble cr7, L(different2) + mr r8, r5 +L(different2): + extsw r8, r8 + srd r7, r7, r8 + srd r9, r9, r8 + rldicl r3, r7, 0, 56 + rldicl r9, r9, 0, 56 + subf r9, r9, 3 + extsw r9, r9 + mr r3, r9 + blr + + /* 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. */ + .align 4 +L(pagecross): + lbz r7, 0(r3) + lbz r9, 0(r4) + subfic r8, r8,4095 + cmplw cr7, r9, r7 + bne cr7, L(byte_ne_3) + cmpdi cr7, r9, 0 + beq cr7, L(byte_ne_0) + addi r5, r5, -1 + subf r7, r8, r5 + subf r9, r7, r5 + addi r9, r9, 1 + mtctr r9 + b L(pagecross_loop1) + + .align 4 +L(pagecross_loop0): + beq cr7, L(ret0) + lbz r9, 0(r3) + lbz r8, 0(r4) + addi r5, r5, -1 + cmplw cr7, r9, r8 + cmpdi cr5, r9, 0 + bne cr7, L(byte_ne_2) + beq cr5, L(byte_ne_0) +L(pagecross_loop1): + cmpdi cr7, r5, 0 + addi r3, r3, 1 + addi r4, r4, 1 + bdnz L(pagecross_loop0) + cmpdi cr7, r7, 0 + li r9, 0 + bne+ cr7, L(align) + b L(ret1) + + .align 4 +L(byte_ne_0): + li r7, 0 +L(byte_ne_1): + subf r9, r9, r7 + extsw r9, r9 + b L(ret1) + + .align 4 +L(byte_ne_2): + extsw r7, r9 + mr r9, r8 + b L(byte_ne_1) +L(byte_ne_3): + extsw r7, r7 + b L(byte_ne_1) +END(STRNCMP) +libc_hidden_builtin_def(strncmp) +#else +#include <sysdeps/powerpc/powerpc64/power8/strncmp.S> +#endif |