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| /* SPDX-License-Identifier: GPL-2.0-only */
| /*
| * User string length functions for kernel
| *
| * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
| */
|
| #define isrc r0
| #define max r1 /* Do not change! */
|
| #define end r2
| #define tmp1 r3
|
| #define obo r6 /* off-by-one */
| #define start r7
| #define mod8 r8
| #define dbuf r15:14
| #define dcmp r13:12
|
| /*
| * The vector mask version of this turned out *really* badly.
| * The hardware loop version also turned out *really* badly.
| * Seems straight pointer arithmetic basically wins here.
| */
|
| #define fname __strnlen_user
|
| .text
| .global fname
| .type fname, @function
| .p2align 5 /* why? */
| fname:
| {
| mod8 = and(isrc,#7);
| end = add(isrc,max);
| start = isrc;
| }
| {
| P0 = cmp.eq(mod8,#0);
| mod8 = and(end,#7);
| dcmp = #0;
| if (P0.new) jump:t dw_loop; /* fire up the oven */
| }
|
| alignment_loop:
| fail_1: {
| tmp1 = memb(start++#1);
| }
| {
| P0 = cmp.eq(tmp1,#0);
| if (P0.new) jump:nt exit_found;
| P1 = cmp.gtu(end,start);
| mod8 = and(start,#7);
| }
| {
| if (!P1) jump exit_error; /* hit the end */
| P0 = cmp.eq(mod8,#0);
| }
| {
| if (!P0) jump alignment_loop;
| }
|
|
|
| dw_loop:
| fail_2: {
| dbuf = memd(start);
| obo = add(start,#1);
| }
| {
| P0 = vcmpb.eq(dbuf,dcmp);
| }
| {
| tmp1 = P0;
| P0 = cmp.gtu(end,start);
| }
| {
| tmp1 = ct0(tmp1);
| mod8 = and(end,#7);
| if (!P0) jump end_check;
| }
| {
| P0 = cmp.eq(tmp1,#32);
| if (!P0.new) jump:nt exit_found;
| if (!P0.new) start = add(obo,tmp1);
| }
| {
| start = add(start,#8);
| jump dw_loop;
| } /* might be nice to combine these jumps... */
|
|
| end_check:
| {
| P0 = cmp.gt(tmp1,mod8);
| if (P0.new) jump:nt exit_error; /* neverfound! */
| start = add(obo,tmp1);
| }
|
| exit_found:
| {
| R0 = sub(start,isrc);
| jumpr R31;
| }
|
| exit_error:
| {
| R0 = add(max,#1);
| jumpr R31;
| }
|
| /* Uh, what does the "fixup" return here? */
| .falign
| fix_1:
| {
| R0 = #0;
| jumpr R31;
| }
|
| .size fname,.-fname
|
|
| .section __ex_table,"a"
| .long fail_1,fix_1
| .long fail_2,fix_1
| .previous
|
|
