TweetFollow Us on Twitter

SADE Debugging
Volume Number:5
Issue Number:9
Column Tag:Programmer's Workshop

SADE™ Debugging

By Joe Pillera, Ann Arbor, MI

Debugging In MPW With SADE™

Joe Pillera is a Scientific Staff Member at Bell Northern Research (BNR) in Ann Arbor, Michigan. Prior to this he was a Systems Analyst at the Ford Motor Company. He earned his B.S. in Computer Science from Eastern Michigan University, and is now a Master’s of Computer Science degree candidate at Wayne State University. His primary area of research is object oriented programming and software engineering.

Introduction

A good debugger is a programmer’s best friend. One of the serious drawbacks to MPW (Macintosh Programmer’s Workshop) software development has always been a lack of a source level debugger (no, I don’t consider MacsBug hexadecimal dumps debugging!). Until now. Introducing SADE™ - the Symbolic Application Debugging Environment. This is Apple’s new source level debugger for MPW 3.0 and beyond.

In this article I plan to cover the following:

• An overview of SADE.

• SADE in action - debugging a sample C program.

• A numerical integrator - pushing the SADE script language to the limit.

• Talking straight - the good, the bad and the ugly.

Note that even though this is not a ‘comparison’ article, I will occasionally mention THINK’s Lightspeed™ debuggers (because of their excellent performance), as a frame of reference in discussing SADE.

Figure 1. The SADE Menu System

What Is SADE, Anyway?

SADE is not an MPW tool, nor is it physically part of the MPW shell. It is simply a stand-alone application that communicates with your target program under Multifinder. As in THINK’s Lightspeed C, this debugger must be operated under Multifinder, to allow interprocess communication. Two or more megs of memory are strongly recommended; however, the manual does indicate you can squeeze by with one meg. The only special requirements to run SADE are:

1. You must be using Multifinder 6.1b7 or later.

2. The (Pascal or C) compiler must be instructed to generate ‘symbol’ files during program compiles.

One of the more interesting design decisions Apple made was to make SADE appear almost identical to the MPW Shell. This has both an advantage and a disadvantage: the advantage is that of instant familiarity to existing MPW programmers; the disadvantage is that this precludes the use of a user-friendly, animated interface (such as the debuggers used in THINK’s Lightspeed C and Lightspeed Pascal).

Please refer to Figure 1 for a closer look at SADE’s functionality.

Wade Through Your Code With SADE

The most fundamental operation in using a debugger is setting a breakpoint in the source code. Because SADE is so sophisticated, there are four ways to do this:

1. Enter the break command from the SADE command interpreter. The syntax (for debugging a C program) is:

 break <function name>.(<line number>)

2. Call the function SysError from within the C code itself. The syntax of this approach is:

 #include <Errors.h>
 . . .
 SysError(<integer from 129..32511>).

3. Press the SADEKey (Command-Option-<period>).

4. Open a source code file (as read-only from SADE), and use the mouse to select a line of code. Then execute ‘Break’ from the SourceCmds menu.

Method number 1 is fine if your functions are small, otherwise counting the individual lines of code could prove cumbersome.

Why does method number 2 work? When using version 6.1b7 and above of Multifinder, MC68000 exceptions are passed to SADE, if present; if SADE isn’t a concurrently executing task, then a system exception occurs.

Personally, I think method number 3 is somewhat satirical; trying to guess which machine instruction you are now (ahem, were) executing can cause brain damage.

Method number 4, of course, appears to be the most user-friendly of them all.

So in practice, it would seem that all methods except number three can be easily used to set break points in your own code. Refer to Figure 2 for an example of starting up SADE and setting breakpoints. For an illustration of SADE stopping at a breakpoint, please refer to Figure 3. The MPW C source listings will also provide more information on how to set breakpoints within your own code.

One interesting thing I noticed is that a SysError() breakpoint will stop after that line of code is executed, whereas setting a normal breakpoint will stop before that line of code.

SADE has complete facilities for keeping track of variable values. You can either perform a Show Value, which shows the contents of the variable of your choice, or you can use the Watch feature. This feature is analogous to THINK’s Lightspeed Pascal’s ‘Observe’ window: every time a variable’s value changes, it is updated in a display window for you. Please refer to Figure 4 for an example from the ‘Test’ program.

And of course, you have complete code stepping facilities: single step lines of code, and even control whether or not you step into procedure calls.

Program Your Bugs Away

All of the aforementioned features can be found in most other debuggers. However, the feature that sets SADE apart from any other debugger I’ve used is its internal programming facility (henceforth, I’ll refer to SADE programs as ‘scripts’, to differentiate these from your C & Pascal programs). You can actually write SADE procedures and functions to automate debugging tasks. And if that’s not enough, how about a slew of predefined procedures (even printf ) and reserved system variables? Furthermore, complete expression evaluation is possible, including pointer manipulation, bit-wise operations, and string manipulation.

The script facility of SADE is so extensive, it strongly resembles Pascal. Not only that, SADE procedures and functions are fully capable of recursion. Unlike Pascal, however, all variables are dynamically typed - based on their use in the program; this would appear to be the result of an interpretative implementation of this language.

To execute a SADE script, enter the script name (followed by any arguments) and press ‘enter’ from the numeric keypad. Thus, script invocation is identical to executing MPW tools. Before a SADE subroutine can be run, the file that contains it must first be loaded into memory; this is done as follows:

 execute ‘<Full HFS Path>:<File Name>’

As an example, I’ve developed a general purpose numerical integration script, which when given any arbitrary function f(x), will find the (approximate) integral bounded between two values ‘a’ and ‘b’. The foundation to my algorithm is the SADE eval function; this function takes a string representing an expression, and then proceeds to parse it in search of an answer. For example:

 define x = 5
 eval(‘x * 2’)

When executed at the SADE command line, this would return ‘10’ as the result.

The technique of integration I use is called Simpson’s Rule, which partitions an interval from ‘a’ to ‘b’ an even number of times (i.e. N=2M partitions). We then approximate the graph of f(x) by M segments of parabolas; the technique is shown below:

In my case, I partition each region between n and n+1 four times, giving delta x the value of 0.25; integration then simply becomes a matter of alternating the coefficients of the intermediate data values.

Unfortunately, it wasn’t that easy - because I wanted to be able to integrate any continuous function I could think of, not just the simple ones. As it turns out, simple mathematical functions (such as x**n) are not known to SADE, so I had to write my own.

How did I do this for polynomials? Using something called a Taylor Expansion, it is possible to calculate x**n (x to the nth power), where either ‘x’ or ‘n’ can be floating point values. Taylor Expansions are open-ended functions, so it is necessary to determine a stopping criteria that is both accurate and efficient. The Taylor Expansion for x**n is shown below:

For example: because both ‘x’ and ‘n’ can be floating point numbers, integrating the square root of ‘x’ is simply a matter of integrating x**(1/2) power.

Just one more problem - ln(x) is not known to SADE either, so here’s the approximation for it:

This approximation, of course, is only valid for x > 0. For an example of a simple polynomial integration, please refer to Figure 5.

However, before you throw away your favorite numerical analysis package, I should warn you that I found SADE to have problems maintaining floating point precision. Take a look at my exponent script: I noticed that using tricks such as intermediate variables for subexpressions made the difference between a correct answer and something way out in left field. SADE’s natural habitat seems to be integers, which would make a lot of sense seeing how it’s a debugging environment. Therefore, even though Simpson’s Rule will (theoretically) work on any continuous function, my SADE script will only work in cases when SADE handles floating point calculations correctly. We should remember, that SADE is a debugging environment, so I don't consider this to be a drawback.

If all these features still aren’t enough, SADE even provides high level calls to prompt the user with dialog boxes, add custom menus, and even generate music! In short, SADE has every power-tool a programmer could ever ask for in a debugger.

Straight Talk About SADE

SADE is by far the most sophisticated and user-extendable debugger I’ve ever used - but I do have one complaint: its user interface. This drawback is caused by SADE’s own complexity: at times it seems to offer you too many features. All of these features in turn dictate a user-interface that’s not as elegant as the Lightspeed debuggers. If SADE were made to be more user-friendly, even at the expense of some of its bells and whistles, Apple would have a world-class debugger in their hands.

The End...

MacsBug, MPW, Multifinder and SADE are trademarks of Apple Computer, Inc. Lightspeed is a registered trademark of Lightspeed, Inc.

The opinions expressed here are solely those of the author, and not of Bell Northern Research Inc., or its employees.

BIBLIOGRAPHY

Apple Computer, Inc. (1989) SADE: Symbolic Application Debugging Environment, Apple Programmer’s and Developer’s Association, Cupertino, California.

Beyer, William H., PhD. (1978) “Series Expansion,” p.387 in Standard Mathematical Tables - 25th Edition, CRC Press Inc., Boca Raton, Florida.

Shenk, Al, PhD. (1979) “Techniques of Integration,” pp. 424-425 in Calculus and Analytic Geometry - 2nd Edition, Scott, Foresman and Company, Glenview, Illinois.

Symantec, Inc. (1989) “Debugging Programs,” pp. 103-110 in THINK’s Lightspeed Pascal User’s Manual, The Symantec Corporation, Cupertino, California.

Symantec, Inc. (1989) “The Debugger,” pp. 129-145 in THINK’s Lightspeed C User’s Manual, The Symantec Corporation, Cupertino, California.

========== The Integrator Script ===========

# ----------------------------------------
# A simple but powerful use of the SADE™
# script langauge to perform numercial
# integration on almost any function.
# ----------------------------------------
# Copyright © Joe Pillera, 1989
# All Rights reserved
# ----------------------------------------

# ----------------------------------------
#            func integrate(a,b) 
# ----------------------------------------
# Integrate a global function ‘f(x)’ from 
# a to b.  
# ----------------------------------------
# INPUTS:
# a -> integer or floating point
# b -> integer or floating point
# ----------------------------------------
func integrate(lower,upper)
  define factor, result, index, x
  index := lower
  factor := 2
  result := 0
  while index <= upper
    x := index
    if (index = lower) or (index = upper) then
      result := result + eval(f)
   else
     result := result + (factor * eval(f))
   end
   index := index + 0.25
   if factor = 2 then
     factor := 4
   else
     factor := 2
    end
  end
  return (1.0/12.0) * result
end

# ----------------------------------------
# func ln(x)  -> Compute natural log of x
# ----------------------------------------
# INPUTS:
# x -> integer or floating point
# ----------------------------------------
func ln(x)
  define result, term, index, frac
  term   := (x - 1.0) / (x + 1.0)
  result := term + (0.3333 * power(term,3))
  index := 5
  while index <= 25 do
    frac := 1.0 / index
    result := result + 
              (frac * power(term,index))
    index := index + 2
  end
  return (2.0 * result)
end

# ----------------------------------------
# func exponent(a,x) -> Compute a ** x 
# ----------------------------------------
# INPUTS:
# a -> integer or floating point
# x -> integer or floating point
# ----------------------------------------
# NOTE: Use power(a,x) if ‘x’ is a integer,
#       because that routine is faster.
# ----------------------------------------
func exponent(a,x)
  define result,iteration,term
  define numerator,denominator
  term   := x * ln(a) 
  result := 1.0 + term
  for iteration := 2 to 15 do
    numerator   := power(term,iteration)
   denominator := fact(iteration)
    result := result + 
              (numerator / denominator)
  end
  return result
end 

# ----------------------------------------
# func power(x,n)  -> Compute x ** n
# ----------------------------------------
# INPUTS:
# x -> integer or floating point
# n -> integer
# ----------------------------------------
# NOTE: Use iteration for speed.
# ----------------------------------------
func power(x,n)
  define index, result
  if n = 0 then
    return 1
  elseif n = 1 then
    return x
  else
    result := x
    for index := 2 to n do
     result := result * x
  end
  return result
end

# ----------------------------------------
# func fact(n)  -> Compute n!
# ----------------------------------------
# INPUTS:
# n -> integer 
# ----------------------------------------
func fact(n)
  if n = 0 then
    return 1
  elseif n = 1 then
    return 1
  else
    return ( n * fact(n-1) )
  end
end

================== Main.C ==================

#include <Errors.h>

int  number;

main()
{    
  /* Set breakpoint #1 here (from SADE) */
  number = 1;
  
  /* Now pass control to func, and let */
  /* it alter the “number” variable.   */
  func();
 
  /* Hard code breakpoint #3 here */
  SysError(129); 
}

================== Func.C ==================

extern int number;

void func()
{
  /* Set breakpoint #2 here (from SADE) */
  number = 10;
}

================== Test.R ==================

#include “SysTypes.r”

resource ‘vers’ (1) {
    0x1,
    0x00,
    release,
    0x0,
    verUS,
    “”,
    “1.0 / MacTutor Magazine”
};

resource ‘vers’ (2) {
    0x1,
    0x00,
    release,
    0x0,
    verUS,
    “”,
    “For Use With MPW SADE™ Only!”
};

=============== Make File =================

Test ƒƒ Test.make test.r
 Rez test.r -append -o Test
func.c.o ƒ Test.make func.c
  C -sym on func.c
main.c.o ƒ Test.make main.c
  C -sym on main.c

SOURCES = test.r func.c main.c
OBJECTS = func.c.o main.c.o

Test ƒƒ Test.make {OBJECTS}
 Link -w -t APPL -c ‘????’ -sym on -mf 
 {OBJECTS} 
 “{CLibraries}”CRuntime.o 
 “{Libraries}”Interface.o 
 “{CLibraries}”StdCLib.o 
 “{CLibraries}”CSANELib.o 
 “{CLibraries}”Math.o 
 “{CLibraries}”CInterface.o 
 -o Test

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Google Earth 7.1.8.3036 - View and contr...
Google Earth gives you a wealth of imagery and geographic information. Explore destinations like Maui and Paris, or browse content from Wikipedia, National Geographic, and more. Google Earth combines... Read more
QuickBooks 16.1.11.1556 R12 - Financial...
QuickBooks helps you manage your business easily and efficiently. Organize your finances all in one place, track money going in and out of your business, and spot areas where you can save. Built for... Read more
Google Earth 7.1.8.3036 - View and contr...
Google Earth gives you a wealth of imagery and geographic information. Explore destinations like Maui and Paris, or browse content from Wikipedia, National Geographic, and more. Google Earth combines... Read more
QuickBooks 16.1.11.1556 R12 - Financial...
QuickBooks helps you manage your business easily and efficiently. Organize your finances all in one place, track money going in and out of your business, and spot areas where you can save. Built for... Read more
FileZilla 3.24.0 - Fast and reliable FTP...
FileZilla (ported from Windows) is a fast and reliable FTP client and server with lots of useful features and an intuitive interface. Version 3.24.0: New The context menu for remote file search... Read more
Bookends 12.7.8 - Reference management a...
Bookends is a full-featured bibliography/reference and information-management system for students and professionals. Bookends uses the cloud to sync reference libraries on all the Macs you use.... Read more
Duplicate Annihilator 5.8.3 - Find and d...
Duplicate Annihilator takes on the time-consuming task of comparing the images in your iPhoto library using effective algorithms to make sure that no duplicate escapes. Duplicate Annihilator detects... Read more
BusyContacts 1.1.6 - Fast, efficient con...
BusyContacts is a contact manager for OS X that makes creating, finding, and managing contacts faster and more efficient. It brings to contact management the same power, flexibility, and sharing... Read more
MarsEdit 3.7.10 - Quick and convenient b...
MarsEdit is a blog editor for OS X that makes editing your blog like writing email, with spell-checking, drafts, multiple windows, and even AppleScript support. It works with with most blog services... Read more
BusyCal 3.1.4 - Powerful calendar app wi...
BusyCal is an award-winning desktop calendar that combines personal productivity features for individuals with powerful calendar sharing capabilities for families and workgroups. Its unique features... Read more

Super Mario Run dashes onto Android in M...
Super Mario Run was one of the biggest mobile launches in 2016 before it was met with a lukewarm response by many. While the game itself plays a treat, it's pretty hard to swallow the steep price for the full game. With that said, Android users... | Read more »
WarFriends Beginner's Guide: How to...
Chillingo's new game, WarFriends, is finally available world wide, and so far it's a refreshing change from common mobile game trends. The game's a mix of tower defense, third person shooter, and collectible card game. There's a lot to unpack here... | Read more »
Super Gridland (Entertainment)
Super Gridland 1.0 Device: iOS Universal Category: Entertainment Price: $1.99, Version: 1.0 (iTunes) Description: Match. Build. Survive. "exquisitely tuned" - Rock Paper Shotgun No in-app purches, and no ads! | Read more »
Red's Kingdom (Games)
Red's Kingdom 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Mad King Mac has kidnapped your father and stolen your golden nut! Solve puzzles and battle goons as you explore and battle your... | Read more »
Turbo League Guide: How to tame the cont...
| Read more »
Fire Emblem: Heroes coming to Google Pla...
Nintendo gave us our first look at Fire Emblem: Heroes, the upcoming mobile Fire Emblem game the company hinted at last year. Revealed at the Fire Emblem Direct event held today, the game will condense the series' tactical RPG combat into bite-... | Read more »
ReSlice (Music)
ReSlice 1.0 Device: iOS Universal Category: Music Price: $9.99, Version: 1.0 (iTunes) Description: Audio Slice Machine Slice your audio samples with ReSlice and create flexible musical atoms which can be triggered by MIDI notes or... | Read more »
Stickman Surfer rides in with the tide t...
Stickson is back and this time he's taken up yet another extreme sport - surfing. Stickman Surfer is out this Thursday on both iOS and Android, so if you've been following the other Stickman adventures, you might be interested in picking this one... | Read more »
Z-Exemplar (Games)
Z-Exemplar 1.4 Device: iOS Universal Category: Games Price: $3.99, Version: 1.4 (iTunes) Description: | Read more »
5 dastardly difficult roguelikes like th...
Edmund McMillen's popular roguelike creation The Binding of Isaac: Rebirth has finally crawled onto mobile devices. It's a grotesque dual-stick shooter that tosses you into an endless, procedurally generated basement as you, the pitiable Isaac,... | Read more »

Price Scanner via MacPrices.net

Twelve South Releases RelaxedLeather Cases fo...
Inspired by the laid-back luxury of burnished leather boots and crafted in rich tones of taupe, herb and marsala, RelaxedLeather cases deliver smart, easy protection for the iPhone 7. Each genuine... Read more
Week’s Best Deal: New 2016 13-inch 2.0GHz Mac...
Amazon has the new 2016 13″ 2.0GHz non-Touch Bar MacBook Pros on sale for a limited time for $225 off MSRP including free shipping: - 13″ 2.0GHz MacBook Pro, Space Gray (MLL42LL/A): $1274.99 $225 off... Read more
Back in stock: Apple refurbished Mac minis fr...
Apple has Certified Refurbished Mac minis available starting at $419. Apple’s one-year warranty is included with each mini, and shipping is free: - 1.4GHz Mac mini: $419 $80 off MSRP - 2.6GHz Mac... Read more
Apple Ranked ‘Most Intimate Brand’
The top ranked ‘”intimate” brands continued to outperform the S&P and Fortune 500 indices in revenue and profit over the past 10 years, according to MBLM’s Brand Intimacy 2017 Report, the largest... Read more
B-Eng introduces SSD Health Check for Mac OS
Fehraltorf, Switzerland based independant Swiss company- B-Eng has announced the release and immediate availability of SSD Health Check 1.0, the company’s new hard drive utility for Mac OS X. As the... Read more
Apple’s Education discount saves up to $300 o...
Purchase a new Mac or iPad using Apple’s Education Store and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free: -... Read more
4-core 3.7GHz Mac Pro on sale for $2290, save...
Guitar Center has the 3.7GHz 4-core Mac Pro (MD253LL/A) on sale for $2289.97 including free shipping or free local store pickup (if available). Their price is a $710 savings over standard MSRP for... Read more
128GB Apple iPad Air 2, refurbished, availabl...
Apple has Certified Refurbished 128GB iPad Air 2s WiFis available for $419 including free shipping. That’s an $80 savings over standard MSRP for this model. A standard Apple one-year warranty is... Read more
13-inch 2.7GHz Retina MacBook Pro on sale for...
B&H Photo has the 2015 13″ 2.7GHz/128GB Retina Apple MacBook Pro on sale for $100 off MSRP. Shipping is free, and B&H charges NY tax only: - 13″ 2.7GHz/128GB Retina MacBook Pro (MF839LL/A): $... Read more
Laptop Market – Flight To Quality? – The ‘Boo...
Preliminary quarterly PC shipments data released by Gartner Inc. last week reveal an interesting disparity between sales performance of major name PC vendors as opposed to that of less well-known... Read more

Jobs Board

*Apple* macOS Systems Integration Administra...
…most exceptional support available in the industry. SCI is seeking an Junior Apple macOS systems integration administrator that will be responsible for providing Read more
*Apple* Retail - Multiple Positions- Deer Pa...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Technician - nfrastructure (United S...
Let’s Work Together Apple Technician This position is based in Portland, ME Life at nfrastructure At nfrastructure, we understand that our success results from our Read more
*Apple* Mobile Master - Best Buy (United Sta...
**467692BR** **Job Title:** Apple Mobile Master **Location Number:** 000602-Columbia MO-Store **Job Description:** **What does a Best Buy Apple Mobile Master Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.