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/*
* Ikarus Scheme -- A compiler for R6RS Scheme.
* Copyright (C) 2006,2007,2008 Abdulaziz Ghuloum
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifdef __CYGWIN__
#include <sys/mman.h>
#include <stdio.h>
#include <strings.h>
#include <errno.h>
#include <assert.h>
#define pagesize 4096
#define pageshift 12
#define segment_size (16*pagesize)
#define segment_shift (4+pageshift)
#include "ikarus-winmmap.h"
/* vim:syntax=c */
static unsigned short* table = 0;
static char* ap = 0;
static size_t as = 0;
static void*
do_mmap(size_t n){
void* x = mmap(0, n, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
if(x == (void*)-1){
fprintf(stderr, "failed to mmap: %s\n", strerror(errno));
exit(-1);
}
assert((((unsigned int)x) & (segment_size-1)) == 0);
return x;
}
static void
do_munmap(void* addr, size_t size){
int err = munmap(addr, size);
if(err){
fprintf(stderr, "failed to unmap\n");
exit(-1);
}
}
static void
init_table(){
assert(sizeof(unsigned short) == 2);
table = do_mmap(32*pagesize);
bzero(table, 32*pagesize);
}
void
win_munmap(char* addr, size_t size){
while(size){
unsigned int page = (((unsigned int) addr) >> pageshift);
unsigned int segment_index = page / 16;
unsigned int page_index = page & 15;
unsigned short alloc_bits = table[segment_index];
assert((alloc_bits & (1<<page_index)) == (1<<page_index));
unsigned int new_bits = alloc_bits & ~ (1 << page_index);
table[segment_index] = new_bits;
if(new_bits == 0){
do_munmap((void*)(segment_index*segment_size), segment_size);
}
size -= pagesize;
addr += pagesize;
}
}
char*
win_mmap(size_t size){
if(size <= as){
char* x = ap;
ap += size;
as -= size;
return x;
}
if(table == 0) init_table();
win_munmap(ap, as);
size_t segments = ((size+segment_size-1) >> segment_shift);
size_t aligned_size = segments << segment_shift;
char* addr = do_mmap(aligned_size);
unsigned int page = (((unsigned int) addr) >> pageshift);
unsigned int segment_index = page / 16;
int i;
for(i=0; i<segments; i++){
table[segment_index+i] = -1;
}
ap = addr + size;
as = aligned_size - size;
return addr;
}
#endif
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