| /* |
| * strcpy |
| * |
| * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| * See https://llvm.org/LICENSE.txt for license information. |
| * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| */ |
| |
| #if defined (__thumb2__) && !defined (__thumb__) |
| |
| /* For GLIBC: |
| #include <string.h> |
| #include <memcopy.h> |
| |
| #undef strcmp |
| */ |
| |
| #ifdef __thumb2__ |
| #define magic1(REG) "#0x01010101" |
| #define magic2(REG) "#0x80808080" |
| #else |
| #define magic1(REG) #REG |
| #define magic2(REG) #REG ", lsl #7" |
| #endif |
| |
| char* __attribute__((naked)) |
| __strcpy_arm (char* dst, const char* src) |
| { |
| __asm__ ( |
| "pld [r1, #0]\n\t" |
| "eor r2, r0, r1\n\t" |
| "mov ip, r0\n\t" |
| "tst r2, #3\n\t" |
| "bne 4f\n\t" |
| "tst r1, #3\n\t" |
| "bne 3f\n" |
| "5:\n\t" |
| # ifndef __thumb2__ |
| "str r5, [sp, #-4]!\n\t" |
| "mov r5, #0x01\n\t" |
| "orr r5, r5, r5, lsl #8\n\t" |
| "orr r5, r5, r5, lsl #16\n\t" |
| # endif |
| |
| "str r4, [sp, #-4]!\n\t" |
| "tst r1, #4\n\t" |
| "ldr r3, [r1], #4\n\t" |
| "beq 2f\n\t" |
| "sub r2, r3, "magic1(r5)"\n\t" |
| "bics r2, r2, r3\n\t" |
| "tst r2, "magic2(r5)"\n\t" |
| "itt eq\n\t" |
| "streq r3, [ip], #4\n\t" |
| "ldreq r3, [r1], #4\n" |
| "bne 1f\n\t" |
| /* Inner loop. We now know that r1 is 64-bit aligned, so we |
| can safely fetch up to two words. This allows us to avoid |
| load stalls. */ |
| ".p2align 2\n" |
| "2:\n\t" |
| "pld [r1, #8]\n\t" |
| "ldr r4, [r1], #4\n\t" |
| "sub r2, r3, "magic1(r5)"\n\t" |
| "bics r2, r2, r3\n\t" |
| "tst r2, "magic2(r5)"\n\t" |
| "sub r2, r4, "magic1(r5)"\n\t" |
| "bne 1f\n\t" |
| "str r3, [ip], #4\n\t" |
| "bics r2, r2, r4\n\t" |
| "tst r2, "magic2(r5)"\n\t" |
| "itt eq\n\t" |
| "ldreq r3, [r1], #4\n\t" |
| "streq r4, [ip], #4\n\t" |
| "beq 2b\n\t" |
| "mov r3, r4\n" |
| "1:\n\t" |
| # ifdef __ARMEB__ |
| "rors r3, r3, #24\n\t" |
| # endif |
| "strb r3, [ip], #1\n\t" |
| "tst r3, #0xff\n\t" |
| # ifdef __ARMEL__ |
| "ror r3, r3, #8\n\t" |
| # endif |
| "bne 1b\n\t" |
| "ldr r4, [sp], #4\n\t" |
| # ifndef __thumb2__ |
| "ldr r5, [sp], #4\n\t" |
| # endif |
| "BX LR\n" |
| |
| /* Strings have the same offset from word alignment, but it's |
| not zero. */ |
| "3:\n\t" |
| "tst r1, #1\n\t" |
| "beq 1f\n\t" |
| "ldrb r2, [r1], #1\n\t" |
| "strb r2, [ip], #1\n\t" |
| "cmp r2, #0\n\t" |
| "it eq\n" |
| "BXEQ LR\n" |
| "1:\n\t" |
| "tst r1, #2\n\t" |
| "beq 5b\n\t" |
| "ldrh r2, [r1], #2\n\t" |
| # ifdef __ARMEB__ |
| "tst r2, #0xff00\n\t" |
| "iteet ne\n\t" |
| "strneh r2, [ip], #2\n\t" |
| "lsreq r2, r2, #8\n\t" |
| "streqb r2, [ip]\n\t" |
| "tstne r2, #0xff\n\t" |
| # else |
| "tst r2, #0xff\n\t" |
| "itet ne\n\t" |
| "strneh r2, [ip], #2\n\t" |
| "streqb r2, [ip]\n\t" |
| "tstne r2, #0xff00\n\t" |
| # endif |
| "bne 5b\n\t" |
| "BX LR\n" |
| |
| /* src and dst do not have a common word-alignment. Fall back to |
| byte copying. */ |
| "4:\n\t" |
| "ldrb r2, [r1], #1\n\t" |
| "strb r2, [ip], #1\n\t" |
| "cmp r2, #0\n\t" |
| "bne 4b\n\t" |
| "BX LR"); |
| } |
| /* For GLIBC: libc_hidden_builtin_def (strcpy) */ |
| |
| #endif /* defined (__thumb2__) && !defined (__thumb__) */ |
