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