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/* This file is derived from gcc-2.6.3/libgcc2.c, section L_clear_cache */
/* Copyright (C) 1989, 1992, 1993, 1994 Free Software Foundation, Inc.
This file is part of GNU CC.
GNU CC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GNU CC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
/* Clear part of an instruction cache. */
/* Our emphasis here is _not_ to clear as few cache lines as possible
* or with as few machine instructions as possible, but to do it _right_.
*/
/* This code is apparently untested!! */
#ifdef __m68k__
#ifdef NeXT
#define CLEAR_INSN_CACHE(BEG, END) \
asm volatile ("trap #2")
#endif
#endif
/* This is from Andreas Stolcke <stolcke@ICSI.Berkeley.EDU>. */
#if defined(__mips__) || defined(__mips64__)
#ifdef ultrix
#include <mips/cachectl.h>
#else
#include <sys/cachectl.h>
#endif
#define CLEAR_INSN_CACHE(BEG, END) \
cacheflush (BEG, END - BEG, BCACHE)
#endif
#ifdef __convex__
#define CLEAR_INSN_CACHE(BEG, END) \
asm ("pich")
#endif
void
__TR_clear_cache (beg, end)
char *beg, *end;
{
#ifdef CLEAR_INSN_CACHE
CLEAR_INSN_CACHE (beg, end);
#else
#ifdef INSN_CACHE_SIZE /* This is actually dead code!! */
#define INSN_CACHE_PLANE_SIZE (INSN_CACHE_SIZE / INSN_CACHE_DEPTH)
static char array[INSN_CACHE_SIZE + INSN_CACHE_PLANE_SIZE + INSN_CACHE_LINE_WIDTH];
static int initialized = 0;
int offset;
void *start_addr;
void *end_addr;
typedef (*function_ptr) ();
#if (INSN_CACHE_SIZE / INSN_CACHE_LINE_WIDTH) < 16
/* It's cheaper to clear the whole cache.
Put in a series of jump instructions so that calling the beginning
of the cache will clear the whole thing. */
if (! initialized)
{
int ptr = (((int) array + INSN_CACHE_LINE_WIDTH - 1)
& -INSN_CACHE_LINE_WIDTH);
int end_ptr = ptr + INSN_CACHE_SIZE;
while (ptr < end_ptr)
{
*(INSTRUCTION_TYPE *)ptr
= JUMP_AHEAD_INSTRUCTION + INSN_CACHE_LINE_WIDTH;
ptr += INSN_CACHE_LINE_WIDTH;
}
*(INSTRUCTION_TYPE *)(ptr - INSN_CACHE_LINE_WIDTH) = RETURN_INSTRUCTION;
initialized = 1;
}
/* Call the beginning of the sequence. */
(((function_ptr) (((int) array + INSN_CACHE_LINE_WIDTH - 1)
& -INSN_CACHE_LINE_WIDTH))
());
#else /* Cache is large. */
if (! initialized)
{
int ptr = (((int) array + INSN_CACHE_LINE_WIDTH - 1)
& -INSN_CACHE_LINE_WIDTH);
while (ptr < (int) array + sizeof array)
{
*(INSTRUCTION_TYPE *)ptr = RETURN_INSTRUCTION;
ptr += INSN_CACHE_LINE_WIDTH;
}
initialized = 1;
}
/* Find the location in array that occupies the same cache line as BEG. */
offset = ((int) beg & -INSN_CACHE_LINE_WIDTH) & (INSN_CACHE_PLANE_SIZE - 1);
start_addr = (((int) (array + INSN_CACHE_PLANE_SIZE - 1)
& -INSN_CACHE_PLANE_SIZE)
+ offset);
/* Compute the cache alignment of the place to stop clearing. */
#if 0 /* This is not needed for gcc's purposes. */
/* If the block to clear is bigger than a cache plane,
we clear the entire cache, and OFFSET is already correct. */
if (end < beg + INSN_CACHE_PLANE_SIZE)
#endif
offset = (((int) (end + INSN_CACHE_LINE_WIDTH - 1)
& -INSN_CACHE_LINE_WIDTH)
& (INSN_CACHE_PLANE_SIZE - 1));
#if INSN_CACHE_DEPTH > 1
end_addr = (start_addr & -INSN_CACHE_PLANE_SIZE) + offset;
if (end_addr <= start_addr)
end_addr += INSN_CACHE_PLANE_SIZE;
for (plane = 0; plane < INSN_CACHE_DEPTH; plane++)
{
int addr = start_addr + plane * INSN_CACHE_PLANE_SIZE;
int stop = end_addr + plane * INSN_CACHE_PLANE_SIZE;
while (addr != stop)
{
/* Call the return instruction at ADDR. */
((function_ptr) addr) ();
addr += INSN_CACHE_LINE_WIDTH;
}
}
#else /* just one plane */
do
{
/* Call the return instruction at START_ADDR. */
((function_ptr) start_addr) ();
start_addr += INSN_CACHE_LINE_WIDTH;
}
while ((start_addr % INSN_CACHE_SIZE) != offset);
#endif /* just one plane */
#endif /* Cache is large */
#endif /* Cache exists */
#endif /* CLEAR_INSN_CACHE */
}
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