sys/netiso/xebec/malloc.c

   1 /*      $NetBSD: malloc.c,v 1.11 2009/03/14 21:04:25 dsl Exp $  */
   2
   3 /*
   4  * This code is such a kludge that I don't want to put my name on it.
   5  * It was a ridiculously fast hack and needs rewriting.
   6  * However it does work...
   7  */
   8
   9 /*
  10  * a simple malloc
  11  * it might be brain-damaged but for the purposes of xebec
  12  * it's a whole lot faster than the c library malloc
  13  */
  14
  15 #include <sys/cdefs.h>
  16 __KERNEL_RCSID(0, "$NetBSD: malloc.c,v 1.11 2009/03/14 21:04:25 dsl Exp $");
  17
  18 #include <stdio.h>
  19 #include "malloc.h"
  20 #include "debug.h"
  21 #include "main.h"
  22 #define CHUNKSIZE 4096*2
  23
  24 static char *hiwat, *highend;
  25 int bytesmalloced=0;
  26 int byteswasted = 0;
  27
  28 void
  29 init_alloc(void)
  30 {
  31 #ifdef LINT
  32         hiwat = 0;
  33         highend = 0;
  34 #else /* !LINT */
  35         extern char *sbrk();
  36
  37         hiwat = (char *) sbrk(0);
  38         hiwat = (char *)((unsigned)(hiwat + 3) & ~0x3);
  39         highend = hiwat;
  40 #endif /* LINT */
  41 }
  42
  43 void
  44 HIWAT(char *s)
  45 {
  46         IFDEBUG(M)
  47                 fprintf(stdout, "HIWAT %p  %s\n", hiwat,s);
  48                 fflush(stdout);
  49         ENDDEBUG
  50 }
  51
  52 #define MIN(x,y) ((x<y)?x:y)
  53
  54 char *Malloc(x)
  55 int x;
  56 {
  57         char *c;
  58         extern char *sbrk();
  59         static int firsttime=1;
  60         int total = x;
  61         int first_iter = 1;
  62         char *returnvalue;
  63
  64         IFDEBUG(N)
  65                 fprintf(stdout, "Malloc 0x%x, %d, bytesmalloced %d\n",
  66                         total,total, bytesmalloced);
  67                 fflush(stdout);
  68         ENDDEBUG
  69         IFDEBUG(M)
  70                 fprintf(stdout, "Malloc 0x%x, %d, hiwat %p\n",
  71                         total,total, hiwat);
  72                 fflush(stdout);
  73         ENDDEBUG
  74         if(firsttime) {
  75                 hiwat = sbrk(0);
  76                 if(((unsigned)(hiwat) & 0x3)) {
  77                         bytesmalloced = 4 - (int) ((unsigned)(hiwat) & 0x3);
  78                         hiwat = sbrk( bytesmalloced );
  79                 } else
  80                         bytesmalloced = 0;
  81                 firsttime = 0;
  82                 highend = hiwat;
  83         }
  84         while( total ) {
  85                 x = MIN(CHUNKSIZE, total);
  86                 if(total != x)  {
  87                         IFDEBUG(N)
  88                                 fprintf(stdout, "BIG Malloc tot %d, x %d, left %d net %d\n",
  89                                         total,x, total-x, bytesmalloced);
  90                                 fflush(stdout);
  91                         ENDDEBUG
  92                 }
  93                 if ( (hiwat + x) > highend) {
  94                         c = sbrk(CHUNKSIZE);
  95                         IFDEBUG(M)
  96                                 fprintf(stdout, "hiwat %p, x 0x%x, highend %p, c %p\n",
  97                                                 hiwat, x, highend, c);
  98                                 fflush(stdout);
  99                         ENDDEBUG
 100                         if( c == (char *) -1 ) {
 101                                 fprintf(stderr, "Ran out of memory!\n");
 102                                 Exit(-1);
 103                         }
 104                         if(first_iter) {
 105                                 returnvalue = c;
 106                                 first_iter = 0;
 107                         }
 108                         bytesmalloced +=  CHUNKSIZE;
 109                         IFDEBUG(m)
 110                                 if (highend != c) {
 111                                         fprintf(OUT, "warning: %d wasted bytes!\n", highend - hiwat);
 112                                 fprintf(OUT, " chunksize 0x%x,  x 0x%x \n", CHUNKSIZE, x);
 113                                 }
 114                         ENDDEBUG
 115                         highend = c + CHUNKSIZE;
 116                         hiwat = c;
 117                 }
 118                 c = hiwat;
 119                 if(first_iter) {
 120                         returnvalue = c;
 121                         first_iter = 0;
 122                 }
 123                 hiwat += x;
 124                 total -= x;
 125         }
 126         if((unsigned)hiwat & 0x3) {
 127                 byteswasted += (int)((unsigned)(hiwat) & 0x3);
 128                 hiwat = (char *)((unsigned)(hiwat + 3) & ~0x3);
 129         }
 130         IFDEBUG(M)
 131                 fprintf(stdout, "Malloc = %p, bytesm 0x%x, wasted 0x%x, hiwat %p\n",
 132                         returnvalue, bytesmalloced, byteswasted, hiwat);
 133         ENDDEBUG
 134         IFDEBUG(N)
 135                 fprintf(stdout, "Malloc returns %p, sbrk(0) %p\n", returnvalue, sbrk(0));
 136                 fflush(stdout);
 137         ENDDEBUG
 138         return(returnvalue);
 139 }
 140