From 51f730c2b01de31f973bbca9e96485c66db68e92 Mon Sep 17 00:00:00 2001
From: Raymond Toy <toy.raymond@gmail.com>
Date: Sat, 2 Jan 2021 14:11:17 -0800
Subject: [PATCH] Remove PAGE_WRITE_PROTECT_CLEARED and MASK.

This macro and mask is only used once to set the bit (near line 498).
It's not read anywhere, so remove it.

Addresses #89.
---
 src/lisp/gencgc.c |  1 -
 src/lisp/gencgc.h | 10 ----------
 2 files changed, 11 deletions(-)

diff --git a/src/lisp/gencgc.c b/src/lisp/gencgc.c
index 204a298f3..e2b9cd0f0 100644
--- a/src/lisp/gencgc.c
+++ b/src/lisp/gencgc.c
@@ -495,7 +495,6 @@ gc_write_barrier(void *addr)
     /* Un-protect the page */
     os_protect((os_vm_address_t) page_address(page_index), GC_PAGE_SIZE, OS_VM_PROT_ALL);
     page_table[page_index].flags &= ~PAGE_WRITE_PROTECTED_MASK;
-    page_table[page_index].flags |= PAGE_WRITE_PROTECT_CLEARED_MASK;
 
     return 1;
 }
diff --git a/src/lisp/gencgc.h b/src/lisp/gencgc.h
index a7ce03afe..363736fa9 100644
--- a/src/lisp/gencgc.h
+++ b/src/lisp/gencgc.h
@@ -45,16 +45,6 @@ int gc_write_barrier(void *);
 #define PAGE_WRITE_PROTECTED(page) \
 	(page_table[page].flags & PAGE_WRITE_PROTECTED_MASK)
 
-/*
- * This flag is set when the above write protect flag is clear by the
- * sigbus handler. This is useful for re-scavenging pages that are
- * written during a GC.
- */
-
-#define PAGE_WRITE_PROTECT_CLEARED_MASK	0x00000020
-#define PAGE_WRITE_PROTECT_CLEARED(page) \
-	(page_table[page].flags & PAGE_WRITE_PROTECT_CLEARED_MASK)
-
 /*
  * Page allocated flag: 0 for a free page; 1 when allocated. If
  * the page is free then the following slots are invalid - well
-- 
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