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Correct bug in the object file output code leading to stack corruption
It turns out leaving a pointer to a stack allocated temporary in a
persistent data structure is not conducive to correct program operation.
Undo the export check setup in the object file output sequence so a
pointer to stack allocated memory is not left hanging when the function
returns. This seems to correct at least one mysterious crash bug, and
possibly others.
Thanks to Boisy Pitre for reporting the crash bug that led to this
discovery, as well as a previous crash bug that likely has the same
root cause.
Additional thanks to Ciaran Anscomb whose debugger wielding wizardry
revealed the exact location of this particular bit of unbrilliance.
author | William Astle <lost@l-w.ca> |
---|---|
date | Sat, 03 Aug 2024 14:30:06 -0600 |
parents | fc072f6cde09 |
children |
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >Cycle Counts</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE="LW Tool Chain" HREF="index.html"><LINK REL="UP" TITLE="LWASM" HREF="c62.html"><LINK REL="PREVIOUS" TITLE="Convenience Instructions" HREF="x827.html"><LINK REL="NEXT" TITLE="LWLINK" HREF="c838.html"></HEAD ><BODY CLASS="SECTION" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >LW Tool Chain</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="x827.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Chapter 3. LWASM</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="c838.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECTION" ><H1 CLASS="SECTION" ><A NAME="AEN832" >3.12. Cycle Counts</A ></H1 ><P > The following options for displaying cycle counts in listings are provided. These options are enabled from pragmas on the command line or in the assembly files themselves. For compatibility with other assemblers you can use the "OPT" keyword in addition to "PRAGMA."</P ><PRE CLASS="PROGRAMLISTING" >opt c - enable cycle counts: [8] opt cd - enable detailed cycle counts breaking down addressing modes: [5+3] opt ct - show a running subtotal of cycles opt cc - clear the running subtotal</PRE ><P > The assembler supports both 6809 as well as native-mode 6309 cycle counts. In 6309 mode the counts are displayed in parenthesis instead of brackets. In addition, some operations have a variable cycle count. In this case a "+?" is displayed to alert the reader. Sample output is shown below.</P ><PRE CLASS="PROGRAMLISTING" >266f 7d25e2 (window.asm):00313 [7] 7 move tst putflg 2672 2602 (window.asm):00314 [5] 12 bne a@ 2674 1e13 (window.asm):00315 [8] 20 exg x,u 2676 0dd6 (window.asm):00316 [6] 26 a@ tst is6309 2678 2618 (window.asm):00317 [5] 31 bne exit@ (window.asm):00318 opt 6309 267a 10860085 (window.asm):00319 (4) 35 b@ ldw #133 267e 113813 (window.asm):00320 (6+?) 41 tfm x+,u+ 2681 30881b (window.asm):00321 (4+1) 46 leax 27,x 2684 33c81b (window.asm):00322 (4+1) 51 leau 27,u 2687 4a (window.asm):00323 (1) 52 deca 2688 26f0 (window.asm):00324 (5) 57 bne b@</PRE ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="x827.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="c838.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Convenience Instructions</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="c62.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >LWLINK</TD ></TR ></TABLE ></DIV ></BODY ></HTML >