cvm: initialize memory with random garbage

This should help spot bugs due to bad initialization.

cvm/vm.c

@@ -1,3 +1,4 @@
+#include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #include "vm.h"
@@ -284,8 +285,6 @@ VM* VM_init() {
         return NULL;
     }
     fseek(blkfp, 0, SEEK_SET);
-    // initialize memory
-    memset(vm.mem, 0, 0x10000);
     FILE *bfp = fopen(FBIN_PATH, "r");
     if (!bfp) {
         fprintf(stderr, "Can't open forth.bin\n");
@@ -298,6 +297,13 @@ VM* VM_init() {
         c = getc(bfp);
     }
     fclose(bfp);
+    // initialize rest of memory with random data. Many, many bugs we've seen in
+    // Collapse OS were caused by bad initialization and weren't reproducable
+    // in CVM because it has a neat zeroed-out memory. Let's make bugs easier
+    // to spot.
+    while (i<0x10000) {
+        vm.mem[i++] = random();
+    }
     vm.SP = SP_ADDR;
     vm.RS = RS_ADDR;
     vm.minSP = SP_ADDR;

cvm/xcomp.fs

@@ -6,23 +6,24 @@ RS_ADDR 0x80 - CONSTANT SYSVARS
 VARIABLE ORG
 CREATE BIN( 0 ,
 : PC H@ ORG @ - ;
+155 LOAD  ( ALLOT0 )
 262 LOAD  ( xcomp )
 270 LOAD  ( xcomp overrides )
 
 H@ ORG !
-ORG @ 0x0b + HERE !
+0x0b ALLOT0
 0 C, 0 C, ( EXIT )
-ORG @ 0x23 + HERE !
+0x16 ALLOT0
 0 C, 0x05 C, ( (n) )
-ORG @ 0x2b + HERE !
+0x6 ALLOT0
 0 C, 0x06 C, ( (s) )
-ORG @ 0x33 + HERE !
+0x6 ALLOT0
 0 C, 0x04 C, ( 2>R )
-ORG @ 0x3b + HERE !
+0x6 ALLOT0
 0 C, 0x01 C, ( (br) )
-ORG @ 0x3f + HERE !
+0x2 ALLOT0
 0 C, 0x02 C, ( (?br) )
-ORG @ 0x43 + HERE !
+0x2 ALLOT0
 0 C, 0x03 C, ( (loop) )
 ( END OF STABLE ABI )
 H@ 4 + XCURRENT ! ( make next CODE have 0 prev field )