/* SPDX-License-Identifier: GPL-2.0-only */ /* * linux/arch/arm/lib/memset.S * * Copyright (C) 1995-2000 Russell King * * ASM optimised string functions */ #include <linux/linkage.h> #include <asm/assembler.h> #include <asm/unwind.h> .text .align 5 ENTRY(__memset) ENTRY(mmioset) WEAK(memset) UNWIND( .fnstart ) and r1, r1, #255 @ cast to unsigned char ands r3, r0, #3 @ 1 unaligned? mov ip, r0 @ preserve r0 as return value bne 6f @ 1 /* * we know that the pointer in ip is aligned to a word boundary. */ 1: orr r1, r1, r1, lsl #8 orr r1, r1, r1, lsl #16 mov r3, r1 7: cmp r2, #16 blt 4f UNWIND( .fnend ) #if ! CALGN(1)+0 /* * We need 2 extra registers for this loop - use r8 and the LR */ UNWIND( .fnstart ) UNWIND( .save {r8, lr} ) stmfd sp!, {r8, lr} mov r8, r1 mov lr, r3 2: subs r2, r2, #64 stmiage ip!, {r1, r3, r8, lr} @ 64 bytes at a time. stmiage ip!, {r1, r3, r8, lr} stmiage ip!, {r1, r3, r8, lr} stmiage ip!, {r1, r3, r8, lr} bgt 2b ldmfdeq sp!, {r8, pc} @ Now <64 bytes to go. /* * No need to correct the count; we're only testing bits from now on */ tst r2, #32 stmiane ip!, {r1, r3, r8, lr} stmiane ip!, {r1, r3, r8, lr} tst r2, #16 stmiane ip!, {r1, r3, r8, lr} ldmfd sp!, {r8, lr} UNWIND( .fnend ) #else /* * This version aligns the destination pointer in order to write * whole cache lines at once. */ UNWIND( .fnstart ) UNWIND( .save {r4-r8, lr} ) stmfd sp!, {r4-r8, lr} mov r4, r1 mov r5, r3 mov r6, r1 mov r7, r3 mov r8, r1 mov lr, r3 cmp r2, #96 tstgt ip, #31 ble 3f and r8, ip, #31 rsb r8, r8, #32 sub r2, r2, r8 movs r8, r8, lsl #(32 - 4) stmiacs ip!, {r4, r5, r6, r7} stmiami ip!, {r4, r5} tst r8, #(1 << 30) mov r8, r1 strne r1, [ip], #4 3: subs r2, r2, #64 stmiage ip!, {r1, r3-r8, lr} stmiage ip!, {r1, r3-r8, lr} bgt 3b ldmfdeq sp!, {r4-r8, pc} tst r2, #32 stmiane ip!, {r1, r3-r8, lr} tst r2, #16 stmiane ip!, {r4-r7} ldmfd sp!, {r4-r8, lr} UNWIND( .fnend ) #endif UNWIND( .fnstart ) 4: tst r2, #8 stmiane ip!, {r1, r3} tst r2, #4 strne r1, [ip], #4 /* * When we get here, we've got less than 4 bytes to set. We * may have an unaligned pointer as well. */ 5: tst r2, #2 strbne r1, [ip], #1 strbne r1, [ip], #1 tst r2, #1 strbne r1, [ip], #1 ret lr 6: subs r2, r2, #4 @ 1 do we have enough blt 5b @ 1 bytes to align with? cmp r3, #2 @ 1 strblt r1, [ip], #1 @ 1 strble r1, [ip], #1 @ 1 strb r1, [ip], #1 @ 1 add r2, r2, r3 @ 1 (r2 = r2 - (4 - r3)) b 1b UNWIND( .fnend ) ENDPROC(memset) ENDPROC(mmioset) ENDPROC(__memset) ENTRY(__memset32) UNWIND( .fnstart ) mov r3, r1 @ copy r1 to r3 and fall into memset64 UNWIND( .fnend ) ENDPROC(__memset32) ENTRY(__memset64) UNWIND( .fnstart ) mov ip, r0 @ preserve r0 as return value b 7b @ jump into the middle of memset UNWIND( .fnend ) ENDPROC(__memset64)