    Unix V6 /usr/sys/ken/malloc.c

/*
* Structure of the coremap and swapmap
* arrays. Consists of non-zero count
* and base address of that many
* contiguous units.
* (The coremap unit is 64 bytes,
* the swapmap unit is 512 bytes)
* The addresses are increasing and
* the list is terminated with the
* first zero count.
*/
struct map
{
char *m_size;
};

/*
* Allocate size units from the given
* map. Return the base of the allocated
* space.
* Algorithm is first fit.
*/
malloc(mp, size)
struct map *mp;
{
register int a;
register struct map *bp;

for (bp = mp; bp->m_size; bp++) {
if (bp->m_size >= size) {
if ((bp->m_size =- size) == 0)
do {
bp++;
} while ((bp-1)->m_size = bp->m_size);
return(a);
}
}
return(0);
}

/*
* Free the previously allocated space aa
* of size units into the specified map.
* Sort aa into map and combine on
* one or both ends if possible.
*/
mfree(mp, size, aa)
struct map *mp;
{
register struct map *bp;
register int t;
register int a;

a = aa;
for (bp = mp; bp->m_addr<=a && bp->m_size!=0; bp++);
if (bp>mp && (bp-1)->m_addr+(bp-1)->m_size == a) {
(bp-1)->m_size =+ size;
if (a+size == bp->m_addr) {
(bp-1)->m_size =+ bp->m_size;
while (bp->m_size) {
bp++;
(bp-1)->m_size = bp->m_size;
}
}
} else {
if (a+size == bp->m_addr && bp->m_size) {
bp->m_size =+ size;
} else if (size) do {
a = t;
t = bp->m_size;
bp->m_size = size;
bp++;
} while (size = t);
}
}

unix-history/unix-v6/usr/sys/ken/malloc.c.txt · Последние изменения: 2006/07/26 07:34     Copyright (C) 1996-2013 Serge Vakulenko serge@vak.ru 