diff --git a/src/gc.c b/src/gc.c
index 63d5c40f..bad30c9b 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -40,7 +40,7 @@ struct scm *g_cells;
 struct scm *g_news;
 
 SCM
-gc_init ()                      ///((internal))
+gc_init ()                      /*:((internal)) */
 {
 #if SYSTEM_LIBC
   ARENA_SIZE = 100000000;       // 2.3GiB
@@ -72,50 +72,50 @@ gc_init ()                      ///((internal))
 
   long arena_bytes = (ARENA_SIZE + JAM_SIZE) * sizeof (struct scm);
   void *a = malloc (arena_bytes + STACK_SIZE * sizeof (SCM));
-  g_cells = (struct scm *) a;
-  g_stack_array = (SCM *) (a + arena_bytes);
+  g_cells = a;
+  g_stack_array = a + arena_bytes;
 
   TYPE (0) = TVECTOR;
   LENGTH (0) = 1000;
   VECTOR (0) = 0;
-  g_cells++;
+  g_cells = g_cells + 1;
   TYPE (0) = TCHAR;
   VALUE (0) = 'c';
 
   // FIXME: remove MES_MAX_STRING, grow dynamically
-  g_buf = (char *) malloc (MAX_STRING);
+  g_buf = malloc (MAX_STRING);
 
   return 0;
 }
 
 SCM
-gc_init_news ()                 ///((internal))
+gc_init_news ()                 /*:((internal)) */
 {
   g_news = g_cells + g_free;
   NTYPE (0) = TVECTOR;
   NLENGTH (0) = 1000;
   NVECTOR (0) = 0;
-  g_news++;
+  g_news = g_news + 1;
   NTYPE (0) = TCHAR;
   NVALUE (0) = 'n';
   return 0;
 }
 
 SCM
-gc_up_arena ()                  ///((internal))
+gc_up_arena ()                  /*:((internal)) */
 {
   long old_arena_bytes = (ARENA_SIZE + JAM_SIZE) * sizeof (struct scm);
   if (ARENA_SIZE >> 1 < MAX_ARENA_SIZE >> 2)
     {
-      ARENA_SIZE <<= 1;
-      JAM_SIZE <<= 1;
-      GC_SAFETY <<= 1;
+      ARENA_SIZE = ARENA_SIZE << 1;
+      JAM_SIZE = JAM_SIZE << 1;
+      GC_SAFETY = GC_SAFETY << 1;
     }
   else
     ARENA_SIZE = MAX_ARENA_SIZE - JAM_SIZE;
   long arena_bytes = (ARENA_SIZE + JAM_SIZE) * sizeof (struct scm);
   void *p = realloc (g_cells - 1, arena_bytes + STACK_SIZE * sizeof (SCM));
-  if (!p)
+  if (p == 0)
     {
       eputs ("realloc failed, g_free=");
       eputs (itoa (g_free));
@@ -125,15 +125,15 @@ gc_up_arena ()                  ///((internal))
       assert (0);
       exit (1);
     }
-  g_cells = (struct scm *) p;
+  g_cells = p;
   memcpy (p + arena_bytes, p + old_arena_bytes, STACK_SIZE * sizeof (SCM));
-  g_cells++;
+  g_cells = g_cells + 1;
 
   return 0;
 }
 
 void
-gc_flip ()                      ///((internal))
+gc_flip ()                      /*:((internal)) */
 {
   if (g_debug > 2)
     {
@@ -147,17 +147,22 @@ gc_flip ()                      ///((internal))
 }
 
 SCM
-gc_copy (SCM old)               ///((internal))
+gc_copy (SCM old)               /*:((internal)) */
 {
   if (TYPE (old) == TBROKEN_HEART)
-    return g_cells[old].car;
-  SCM new = g_free++;
+    return CAR (old);
+  SCM new = g_free;
+  g_free = g_free + 1;
   g_news[new] = g_cells[old];
   if (NTYPE (new) == TSTRUCT || NTYPE (new) == TVECTOR)
     {
       NVECTOR (new) = g_free;
-      for (long i = 0; i < LENGTH (old); i++)
-        g_news[g_free++] = g_cells[VECTOR (old) + i];
+      long i;
+      for (i = 0; i < LENGTH (old); i = i + 1)
+        {
+          g_news[g_free] = g_cells[VECTOR (old) + i];
+          g_free = g_free + 1;
+        }
     }
   else if (NTYPE (new) == TBYTES)
     {
@@ -165,7 +170,7 @@ gc_copy (SCM old)               ///((internal))
       char *dest = NCBYTES (new);
       size_t length = NLENGTH (new);
       memcpy (dest, src, length + 1);
-      g_free += bytes_cells (length) - 1;
+      g_free = g_free + bytes_cells (length) - 1;
 
       if (g_debug > 4)
         {
@@ -189,21 +194,21 @@ gc_copy (SCM old)               ///((internal))
 }
 
 SCM
-gc_relocate_car (SCM new, SCM car)      ///((internal))
+gc_relocate_car (SCM new, SCM car)      /*:((internal)) */
 {
-  g_news[new].car = car;
+  NCAR (new) = car;
   return cell_unspecified;
 }
 
 SCM
-gc_relocate_cdr (SCM new, SCM cdr)      ///((internal))
+gc_relocate_cdr (SCM new, SCM cdr)      /*:((internal)) */
 {
-  g_news[new].cdr = cdr;
+  NCDR (new) = cdr;
   return cell_unspecified;
 }
 
 void
-gc_loop (SCM scan)              ///((internal))
+gc_loop (SCM scan)              /*:((internal)) */
 {
   SCM car;
   SCM cdr;
@@ -214,18 +219,19 @@ gc_loop (SCM scan)              ///((internal))
       if (NTYPE (scan) == TMACRO || NTYPE (scan) == TPAIR || NTYPE (scan) == TREF || scan == 1  // null
           || NTYPE (scan) == TVARIABLE)
         {
-          car = gc_copy (g_news[scan].car);
+          car = gc_copy (NCAR (scan));
           gc_relocate_car (scan, car);
         }
       if ((NTYPE (scan) == TCLOSURE || NTYPE (scan) == TCONTINUATION || NTYPE (scan) == TKEYWORD || NTYPE (scan) == TMACRO || NTYPE (scan) == TPAIR || NTYPE (scan) == TPORT || NTYPE (scan) == TSPECIAL || NTYPE (scan) == TSTRING || NTYPE (scan) == TSYMBOL || scan == 1     // null
-           || NTYPE (scan) == TVALUES) && g_news[scan].cdr)     // allow for 0 terminated list of symbols
+           || NTYPE (scan) == TVALUES)
+          && NCDR (scan))   // allow for 0 terminated list of symbols
         {
-          cdr = gc_copy (g_news[scan].cdr);
+          cdr = gc_copy (NCDR (scan));
           gc_relocate_cdr (scan, cdr);
         }
       if (NTYPE (scan) == TBYTES)
-        scan += bytes_cells (NLENGTH (scan)) - 1;
-      scan++;
+        scan = scan + bytes_cells (NLENGTH (scan)) - 1;
+      scan = scan + 1;
     }
   gc_flip ();
 }
@@ -239,7 +245,7 @@ gc_check ()
 }
 
 SCM
-gc_ ()                          ///((internal))
+gc_ ()                          /*:((internal)) */
 {
   gc_init_news ();
   if (g_debug == 2)
@@ -254,20 +260,16 @@ gc_ ()                          ///((internal))
     }
   g_free = 1;
 
-#if __MESC__
-  if (ARENA_SIZE < MAX_ARENA_SIZE && (long) g_news > 0)
-#else
   if (ARENA_SIZE < MAX_ARENA_SIZE && g_news > 0)
-#endif
     {
       if (g_debug == 2)
         eputs ("+");
       if (g_debug > 2)
         {
           eputs (" up[");
-          eputs (itoa ((unsigned long) g_cells));
+          eputs (itoa (g_cells));
           eputs (",");
-          eputs (itoa ((unsigned long) g_news));
+          eputs (itoa (g_news));
           eputs (":");
           eputs (itoa (ARENA_SIZE));
           eputs (",");
@@ -277,13 +279,14 @@ gc_ ()                          ///((internal))
       gc_up_arena ();
     }
 
-  for (long i = g_free; i < g_symbol_max; i++)
+  long i;
+  for (i = g_free; i < g_symbol_max; i = i + 1)
     gc_copy (i);
   g_symbols = gc_copy (g_symbols);
   g_macros = gc_copy (g_macros);
   g_ports = gc_copy (g_ports);
   m0 = gc_copy (m0);
-  for (long i = g_stack; i < STACK_SIZE; i++)
+  for (i = g_stack; i < STACK_SIZE; i = i + 1)
     g_stack_array[i] = gc_copy (g_stack_array[i]);
   gc_loop (1);
 }
@@ -315,20 +318,21 @@ gc ()
 }
 
 SCM
-gc_push_frame ()                ///((internal))
+gc_push_frame ()                /*:((internal)) */
 {
   if (g_stack < 5)
     assert (!"STACK FULL");
-  g_stack_array[--g_stack] = cell_f;
-  g_stack_array[--g_stack] = r0;
-  g_stack_array[--g_stack] = r1;
-  g_stack_array[--g_stack] = r2;
-  g_stack_array[--g_stack] = r3;
+  g_stack_array[g_stack - 1] = cell_f;
+  g_stack_array[g_stack - 2] = r0;
+  g_stack_array[g_stack - 3] = r1;
+  g_stack_array[g_stack - 4] = r2;
+  g_stack_array[g_stack - 5] = r3;
+  g_stack = g_stack - 5;
   return g_stack;
 }
 
 SCM
-gc_peek_frame ()                ///((internal))
+gc_peek_frame ()                /*:((internal)) */
 {
   r3 = g_stack_array[g_stack];
   r2 = g_stack_array[g_stack + 1];
@@ -338,9 +342,9 @@ gc_peek_frame ()                ///((internal))
 }
 
 SCM
-gc_pop_frame ()                 ///((internal))
+gc_pop_frame ()                 /*:((internal)) */
 {
   SCM x = gc_peek_frame ();
-  g_stack += 5;
+  g_stack = g_stack + 5;
   return x;
 }