From: Taylor R Campbell <campbell@mumble.net>
Date: Mon, 21 Jan 2019 19:06:20 +0000 (+0000)
Subject: Tweak read/write_compiled_closure_target for clarity and assertions.
X-Git-Tag: mit-scheme-pucked-10.1.20~11^2~66^2~45
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=b5d2c80cca087321a65984636b6867d367e0e255;p=mit-scheme.git

Tweak read/write_compiled_closure_target for clarity and assertions.
---

diff --git a/src/microcode/cmpintmd/aarch64.c b/src/microcode/cmpintmd/aarch64.c
index 59dcacdec..94dedc127 100644
--- a/src/microcode/cmpintmd/aarch64.c
+++ b/src/microcode/cmpintmd/aarch64.c
@@ -130,9 +130,12 @@ read_compiled_closure_target (insn_t * start, reloc_ref_t * ref)
   /* If we're relocating, find where base was in the oldspace.  */
   if (ref)
     base += (ref->old_addr - ref->new_addr);
-  assert (((((int64_t *) addr)[-1]) % (sizeof (insn_t))) == 0);
-  assert (((((int64_t *) addr)[-1]) % (sizeof (SCHEME_OBJECT))) == 0);
-  return ((insn_t *) (((char *) base) + (((int64_t *) addr)[-1])));
+  char * from_pc = ((char *) base);
+  int64_t offset = (((int64_t *) addr)[-1]);
+  assert ((offset % (sizeof (insn_t))) == 0);
+  assert ((offset % (sizeof (SCHEME_OBJECT))) == 0);
+  char * to_pc = (from_pc + offset);
+  return ((insn_t *) to_pc);
 }
 
 /* write_compiled_closure_target(target, start)
@@ -148,7 +151,10 @@ write_compiled_closure_target (insn_t * target, insn_t * start)
   insn_t * addr = (start + CC_ENTRY_PADDING_SIZE + CC_ENTRY_HEADER_SIZE);
   char * from_pc = ((char *) (tospace_to_newspace (addr)));
   char * to_pc = ((char *) target);
-  (((int64_t *) addr)[-1]) = ((int64_t) (to_pc - from_pc));
+  int64_t offset = (to_pc - from_pc);
+  assert ((offset % (sizeof (insn_t))) == 0);
+  assert ((offset % (sizeof (SCHEME_OBJECT))) == 0);
+  (((int64_t *) addr)[-1]) = offset;
 }
 
 unsigned long