ref: 56a22259605107b053e6b22b125fb93afd725641
parent: ff7b906c28f2707f0ad7736738495a42a3b23ce8
author: mkf <mkf@cloud9p.org>
date: Fri Nov 17 04:29:35 EST 2023
add pc/mem.c
--- /dev/null
+++ b/pc/mem.c
@@ -1,0 +1,71 @@
+#include <u.h>
+#include <libc.h>
+#include <mem.h>
+#include <err.h>
+
+/* does first fit, returns index of that part of memory in memap */
+int
+
+_malloc(uint16 size)
+{+ int i, j;
+ uint16 fmem; /* number of free segments */
+
+ if(size > MEM_MAX * BLOCKSIZE)
+ return NO_MEM;
+
+ i = 0;
+ fmem = 0;
+ while(i < MEM_MAX * (1024 / BLOCKSIZE))
+ {+ if(memap[i] == FREE)
+ {+ fmem++;
+ if(fmem == size+1) /* one bit for padding */
+ {+
+ /* we are done here, give address */
+ for(int j = i ; j > i - size; j--)
+ memap[j] = TAKEN;
+ return i - size;
+ }
+ }
+ else
+ {+ fmem = 0; /* we need contigus(?) memory */
+ }
+ i++;
+ }
+
+
+ return NO_MEM;
+}
+
+void*
+malloc(uint16 size)
+{+ int t;
+
+ if(size == 0)
+ return nil;
+
+ t = _malloc(size);
+ if(t == NO_MEM)
+ return nil;
+
+ return (void*)(t * ( BLOCKSIZE ) + MEM_BEG);
+}
+
+int
+free(void *mem)
+{+ int i;
+
+ i = (((int)(mem) - MEM_BEG ) / BLOCKSIZE)+1;
+ while(memap[i])
+ {+ memap[i] = 0;
+ i++;
+ }
+ return OK;
+}