From 8caac67e05171dfa0e7e2f85529119553e14d9d1 Mon Sep 17 00:00:00 2001
From: "C. Guy Yarvin" <cgyarvin@gmail.com>
Date: Mon, 18 May 2015 10:07:42 -0700
Subject: [PATCH] Eliminated last direct pointers from piers.

---
 i/n/a.h |  8 +++-----
 i/n/u.h |  1 +
 n/j.c   |  4 ++--
 n/m.c   | 36 ++++++++++++++++++------------------
 n/t.c   |  6 +++---
 5 files changed, 27 insertions(+), 28 deletions(-)

diff --git a/i/n/a.h b/i/n/a.h
index 541e24e5f..23e62ebaf 100644
--- a/i/n/a.h
+++ b/i/n/a.h
@@ -98,11 +98,9 @@
     /* u3a_road: contiguous allocation and execution context.
     */
       typedef struct _u3a_road {
-        struct _u3a_road* par_u;              //  parent road
-
-        struct _u3a_road* kid_u;              //  child road list
-        struct _u3a_road* nex_u;              //  sibling road
-        struct _u3a_road* now_u;              //  current road pointer
+        u3p(struct _u3a_road) par_p;          //  parent road
+        u3p(struct _u3a_road) kid_p;          //  child road list
+        u3p(struct _u3a_road) nex_p;          //  sibling road
 
         u3p(c3_w) cap_p;                      //  top of transient region
         u3p(c3_w) hat_p;                      //  top of durable region
diff --git a/i/n/u.h b/i/n/u.h
index 9eb033ea3..46c9553af 100644
--- a/i/n/u.h
+++ b/i/n/u.h
@@ -104,5 +104,6 @@
     /* u3to(), u3of(): offset/pointer conversion.
     */
 #     define  u3to(type, x) ((type *) u3a_into(x))
+#     define  u3tn(type, x) (x == 0) ? (void *)0 :  ((type *) u3a_into(x))
 #     define  u3of(type, x) (u3a_outa((type *)x))
 
diff --git a/n/j.c b/n/j.c
index 0e6db22b2..acc70703a 100644
--- a/n/j.c
+++ b/n/j.c
@@ -209,8 +209,8 @@ u3j_find(u3_noun bat)
       return jaw;
     }
 
-    if ( rod_u->par_u ) {
-      rod_u = rod_u->par_u;
+    if ( rod_u->par_p ) {
+      rod_u = u3to(u3_road, rod_u->par_p);
     }
     else return u3_none;
   }
diff --git a/n/m.c b/n/m.c
index d99f6872d..d2c85dd4b 100644
--- a/n/m.c
+++ b/n/m.c
@@ -149,7 +149,7 @@ _cm_signal_handle_term(int x)
 {
   //  Ignore if we are using base memory from work memory, very rare.
   //
-  if ( (0 != u3H->rod_u.kid_u) && (&(u3H->rod_u) == u3R) ) {
+  if ( (0 != u3H->rod_u.kid_p) && (&(u3H->rod_u) == u3R) ) {
     _cm_emergency("ignored", c3__term);
   }
   else {
@@ -184,7 +184,7 @@ _cm_signal_reset(void)
   u3R = &u3H->rod_u;
   u3R->cap_p = u3R->mat_p;
   u3R->ear_p = 0;
-  u3R->kid_u = 0;
+  u3R->kid_p = 0;
 }
 
 /* _cm_stack_recover(): recover stack trace, with lacunae.
@@ -276,13 +276,13 @@ _cm_signal_recover(c3_l sig_l, u3_noun arg)
       u3R = &(u3H->rod_u);
       rod_u = u3R;
  
-      while ( rod_u->kid_u ) {
+      while ( rod_u->kid_p ) {
 #if 0
         fprintf(stderr, "collecting %d frames\r\n", 
-              u3kb_lent(rod_u->kid_u->bug.tax));
+              u3kb_lent((u3to(u3_road, rod_u->kid_p)->bug.tax));
 #endif
-        tax = u3kb_weld(_cm_stack_recover(rod_u->kid_u), tax);    
-        rod_u = rod_u->kid_u;
+        tax = u3kb_weld(_cm_stack_recover(u3to(u3_road, rod_u->kid_p)), tax);
+        rod_u = u3to(u3_road, rod_u->kid_p);
       }
     }
 
@@ -712,9 +712,9 @@ u3m_leap(c3_w pad_w)
   /* Attach the new road to its parents.
   */
   {
-    c3_assert(0 == u3R->kid_u);
-    rod_u->par_u = u3R;
-    u3R->kid_u = rod_u;
+    c3_assert(0 == u3R->kid_p);
+    rod_u->par_p = u3of(u3_road, u3R);
+    u3R->kid_p = u3of(u3_road, rod_u);
   }
 
   /* Set up the new road.
@@ -730,26 +730,26 @@ u3m_leap(c3_w pad_w)
 void
 u3m_fall()
 {
-  c3_assert(0 != u3R->par_u);
+  c3_assert(0 != u3R->par_p);
 
 #if 0
   fprintf(stderr, "fall: from %s %p, to %s %p (cap %p, was %p)\r\n",
           _(u3a_is_north(u3R)) ? "north" : "south",
           u3R,
           _(u3a_is_north(u3R)) ? "north" : "south",
-          u3R->par_u,
+          u3to(u3_road, u3R->par_p),
           u3R->hat_w,
           u3R->rut_w);
 #endif
 
   /* The new cap is the old hat - it's as simple as that.
   */
-  u3R->par_u->cap_p = u3R->hat_p;
+  u3to(u3_road, u3R->par_p)->cap_p = u3R->hat_p;
 
   /* And, we're back home.
   */
-  u3R = u3R->par_u;
-  u3R->kid_u = 0;
+  u3R = u3to(u3_road, u3R->par_p);
+  u3R->kid_p = 0;
 }
 
 /* u3m_hate(): new, integrated leap mechanism (enter).
@@ -951,8 +951,8 @@ u3m_soft_run(u3_noun fly,
   /* Configure the new road.
   */
   {
-    u3R->ski.flu = u3nc(fly, u3R->par_u->ski.flu);
-    u3R->pro.don = u3R->par_u->pro.don;
+    u3R->ski.flu = u3nc(fly, u3to(u3_road, u3R->par_p)->ski.flu);
+    u3R->pro.don = u3to(u3_road, u3R->par_p)->pro.don;
     u3R->bug.tax = 0;
   }
   u3t_on(coy_o);
@@ -1039,8 +1039,8 @@ u3m_soft_esc(u3_noun sam)
   /* Configure the new road.
   */
   {
-    u3R->ski.flu = u3t(u3R->par_u->ski.flu);
-    u3R->pro.don = u3R->par_u->pro.don;
+    u3R->ski.flu = u3t(u3to(u3_road, u3R->par_p)->ski.flu);
+    u3R->pro.don = u3to(u3_road, u3R->par_p)->pro.don;
     u3R->bug.tax = 0;
   }
 
diff --git a/n/t.c b/n/t.c
index eeefb0ca3..ff937334b 100644
--- a/n/t.c
+++ b/n/t.c
@@ -113,8 +113,8 @@ _t_jet_label(u3a_road* rod_u, u3_noun bat)
       return u3h(u3t(u3t(u3h(cax))));
     }
 
-    if ( rod_u->par_u ) {
-      rod_u = rod_u->par_u;
+    if ( rod_u->par_p ) {
+      rod_u = u3to(u3_road, rod_u->par_p);
     }
     else return u3_none;
   }
@@ -175,7 +175,7 @@ _t_samp_process(u3_road* rod_u)
       }
       don = u3t(don);
     }
-    rod_u = rod_u->par_u;
+    rod_u = u3tn(u3_road, rod_u->par_p);
   }
   u3z(muf);