60 lines
1.3 KiB
C
60 lines
1.3 KiB
C
/* go-memclr.c -- clear a memory buffer
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Copyright 2016 The Go Authors. All rights reserved.
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Use of this source code is governed by a BSD-style
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license that can be found in the LICENSE file. */
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#include "runtime.h"
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void memclrNoHeapPointers(void *, uintptr)
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__asm__ (GOSYM_PREFIX "runtime.memclrNoHeapPointers")
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__attribute__ ((no_split_stack));
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void
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memclrNoHeapPointers (void *p1, uintptr len)
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{
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#if !defined(__PPC64__)
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__builtin_memset(p1, 0, len);
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#else
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int64 rem,drem,i;
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uint64 offset;
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volatile uint64 *vp;
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if (len == 0) {
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return;
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}
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rem = len;
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offset = (uint64)p1 % 8;
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// This memset is OK since it can't contain
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// an 8 byte aligned pointer.
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if ((rem < 8) || (offset > 0 && offset+rem <= 16)) {
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__builtin_memset(p1, 0, rem);
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return;
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}
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// Move initial bytes to get to 8 byte boundary
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if (offset > 0) {
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__builtin_memset(p1, 0, 8-offset);
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p1 = (void*)((char*)p1+8-offset);
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rem -= 8-offset;
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}
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// If at least 8 bytes left, clear
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drem = rem>>3;
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vp = (volatile uint64*)(p1);
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// Without the use of volatile here, the compiler
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// might convert the loop into a memset.
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for (i=0; i<drem; i++) {
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*vp = 0;
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vp++;
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rem -= 8;
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}
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p1 = (void*)((char*)p1 + 8*drem);
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// Clear any remaining
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if (rem > 0) {
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__builtin_memset (p1, 0, rem);
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}
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#endif
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}
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