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From: "Pierre Muller" <muller@ics.u-strasbg.fr>
To: "'Mark Kettenis'" <mark.kettenis@xs4all.nl>
Cc: <pedro@codesourcery.com>, <drow@false.org>, <gdb-patches@sourceware.org>
References: <004f01c8ac58$06a1ddb0$13e59910$@u-strasbg.fr> <000c01c8c246$de300f50$9a902df0$@u-strasbg.fr> <200805301157.m4UBvOL5009408@brahms.sibelius.xs4all.nl> <001901c8c256$06f8be00$14ea3a00$@u-strasbg.fr>
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Subject: RE: [PING2] : [RFC/RFA] PING: skip __main
Date: Fri, 30 May 2008 18:45:00 -0000
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+  target_read_memory (pc, &op, 1);
+  if (op == 0xe8)
+    {
+      gdb_byte buf[4];
+
+      if (target_read_memory (pc + 1, buf, sizeof buf) == 0)
+       {
+         CORE_ADDR call_dest = pc + 5 + extract_unsigned_integer (buf, 4);
  Just one small question about this line:
I fear that this line is incorrect,
shouldn't we use extract_signed_integer here?

  The address is relative to pc+5 meaning that
if main is at a higher address than __main,
buf will contain a negative 4byte integer.

  This will usually not matter (if overflows are allowed), 
unless CORE_ADDR is 8-byte long, 
which would then give a value above 0xffffffff.

  This can happen for cross configured gdb, but also if gdb is configured
with --enable-64bit-bfd.

  I don't even know if these result would be always correct
(assuming for instance that main is below __main, but that
__main resides above 0x80000000 boundary for example).

  Maybe the only correct way is to force the operation to be performed
with 4-byte integers and take the result, even if overflow
occurred.


Pierre Muller
Pascal language support maintainer for GDB