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