HP 64700 series User manual

HP 64700 Emulators
Terminal Interface:
Analyzer User’s Guide
Edition 1
64740-90909E1187
Printed in U.S.A. 11/87

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Edition 1 11/87 64740-90909E1187

Using this Manual
Thismanualwillshowyou howto usetheHP 64700 series analyzer
with thefirmware resident TerminalInterface.
Thismanualwill:
•Brieflyintroduce the analyzer and its features.
•Showyou howto use the analyzer in its simplest, power-up condi-
tion. From there, it will progressivelyshowyou howand whyyou
would use additional trace commands.
•Showyou howto use the external analyzer.
•Showyou howto cross-trigger between the emulation analyzer and
the external analyzer.
•Showyou howto specifyanalyzer clocks.
•Show you how to save the analyzer configuration in a command file.
Thismanualwillnot:
•Showyou howto use the analyzer with the PC Interface; thisis
done in the HP 64700 Emulators PC Interface: Analyzer User’s
Guide.
•Showyou howto use the analyzer with the SoftkeyInterface;this is
done in the HP 64700 Emulators Softkey Interface: Analyzer User’s
Guide.
•Describe all analyzer commands options in alphabetical order;this
is done in the HP 64700 Emulators Terminal Interface:User’s Refer-
ence.
•Showyou howto use the external timing analyzer. Timing analysis
is onlyavailable when usinghost computer interfaces such asthe
PC Interface or the SofkeyInterface. Refer to the appropriate host
computer interface Analyzer User’s Guide.
•Show you how to cross-trigger the analyzers of multiple HP 64700
Series emulators over the Coordinated Measurement Bus (CMB);
this is done in the HP 64700 Emulators Terminal Interface: CMB
User’s Guide.

Organization
Chapter 1 Introducing the HP 64700 Series Analyzer. Thischapter liststhe basic
featuresofthe analyzer. The followingchapters showyou howto use
these features.
Chapter 2 GettingStarted. Thischapter showsyou howto use the analyzer from
itssimplest power-up condition to makingsimple sequence specifica-
tions.
Chapter 3 Accessing Full AnalyzerCapability. This chapter shows you how to ac-
cessand use the full power and capabilityof the HP 64700 Series ana-
lyzer (morepowerfulsequencingandtheusecomplexexpressions).
Chapter 4 Usingthe External Analyzer. This chapter showsyou howto usethe
external analyzer aspart ofthe emulation analyzer or asan inde-
pendent state analyzer.
Chapter 5 MakingCoordinatedMeasurements. Thischapter showsyouhowto
use the analyzer trigger condition to break the emulator and howto
cross-trigger between the emulation analyzer and the externalanalyzer.
Chapter 6 Special AnalyzerTopics. Thischapter showsyou howto nameand
qualifyanalyzer clock sources. It showsyou howto useslave clocksto
demultiplexdata on analyzer trace signals. It also shows you howto
save and retrieve analyzer command specifications to and from com-
mandfiles.

Contents
Chapter 1 Introducing the HP 64700 Series Analyzer
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Analyzer Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Simple Measurements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Trace Storage, Prestore,and Count . . . . . . . . . . . . . . . . . . . . . . 1-3
Sequencer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Simple Commands for Common Measurements. . . . . . . . . . . . 1-3
External Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Coordinated Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Other Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Chapter 2 Getting Started
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
The Sample Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Description of the Sample Program . . . . . . . . . . . . . . . . . . . . . . 2-2
Before You Can Use the Analyzer . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Map Memory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Load the Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Contents-1

Run the Program. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
The Default Trace Specification. . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Initializing the Analyzer (tinit) . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Startingthe Trace (t) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Haltingthe Trace (th) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Displaying the Trace Status(ts) . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Displaying the Trace (tl) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Expressions in Trace Commands. . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Tokens. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Trace Labels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
Predefined Trace Labels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
Predefined Equates for Emulation Analyzer Status. . . . . . . . . . 2-13
Expression Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14
Changing the Trace Format (tf). . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14
Specifying a Simple Trigger (tg). . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16
Specifying an Occurrence Count. . . . . . . . . . . . . . . . . . . . . . . . . 2-18
Specifying Storage Qualifiers (tsto) . . . . . . . . . . . . . . . . . . . . . . . . . 2-19
PrestoringStates (tpq) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20
Qualifying Prestore States. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20
TurningOffPrestore. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21
Changingthe Count Qualifier (tcq). . . . . . . . . . . . . . . . . . . . . . . . . 2-22
Using the Sequencer (tsq) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23
Resetting the Sequencer (tsq -r) . . . . . . . . . . . . . . . . . . . . . . . . . 2-24
The Default Sequencer Specification . . . . . . . . . . . . . . . . . . . . . 2-24
Simple Trigger and the Sequencer . . . . . . . . . . . . . . . . . . . . . . . 2-25
Primaryand SecondaryBranch Expressions (tif, telif) . . . . . . . . 2-26
Inserting Sequence Terms (tsq -i) . . . . . . . . . . . . . . . . . . . . . . . . 2-29
DeletingSequence Terms(tsq -d). . . . . . . . . . . . . . . . . . . . . . . . 2-29
Changingthe Trigger Position (tp) . . . . . . . . . . . . . . . . . . . . . . . . . 2-30
Tracing a Program asit Starts Up . . . . . . . . . . . . . . . . . . . . . . . . . . 2-32
Contents-2

Chapter 3 Accessing Full Analyzer Capability
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
"Easy"and "Complex"Configuration Differences . . . . . . . . . . . . . . 3-2
Sequence Terms and the Trigger . . . . . . . . . . . . . . . . . . . . . . . . 3-2
PrimaryBranch Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
SecondaryBranch Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Storage Qualifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
ComplexExpressions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Commands that Change in the "Complex"Configuration. . . . . . . . 3-7
The Sample Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
Before You Can Use the Analyzer . . . . . . . . . . . . . . . . . . . . . . . 3-12
Switching into the "Complex"Configuration (tcf -c). . . . . . . . . . . . 3-12
The Default Sequencer Specification (tsq -r). . . . . . . . . . . . . . . . . . 3-13
Specifying a Simple Trigger (tg). . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
Usingthe Sequencer in the "Complex"Configuration . . . . . . . . . . 3-16
Hints to Make SettingUp the Sequencer Easy . . . . . . . . . . . . . 3-17
Tracing"Windows"ofActivity. . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23
Isolating and Tracing Specific Conditions. . . . . . . . . . . . . . . . . . 3-28
Chapter 4 Using the External Analyzer
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Before You Can Use the ExternalAnalyzer . . . . . . . . . . . . . . . . . . 4-1
Connecting the Analyzer Probe Linesto the Target System . . . 4-2
SpecifyingExternal Trace Signal Threshold Voltages . . . . . . . . 4-8
Defining External Trace Labels. . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
Selecting the External Analyzer Mode . . . . . . . . . . . . . . . . . . . . 4-9
Aligned with Emulation Analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
Independent State Analyzer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
Contents-3

Independent State Analyzer Commands (xt, xtarm,...) . . . . . . . 4-10
Specifying the Independent Analyzer Clock Source. . . . . . . . . . 4-11
Independent Timing Analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
External Analyzer Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
Chapter 5 Making Coordinated Measurements
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Specifying an Arm Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
DrivingSignalsWhen the Trigger is Found . . . . . . . . . . . . . . . . 5-3
Breakingon an Analyzer Trigger. . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
Cross-ArmingBetween Emulation and External Analyzers. . . . . . 5-6
Cross-Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Chapter 6 Special Analyzer Topics
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Displaying Trace Activity(ta). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Specifying the Analyzer Clock Source (tck). . . . . . . . . . . . . . . . . . . 6-2
TracingBackground Execution. . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
Selecting Clock Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
Specifying the Maximum Qualified Clock Speed. . . . . . . . . . . . 6-4
Qualifying Clocks (tck -l, -h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
Contents-4

Using Slave Clocks for Demultiplexing (tsck) . . . . . . . . . . . . . . . . . 6-6
Mixed Clocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
True Demultiplexing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9
Saving Trace Specifications in Command Files. . . . . . . . . . . . . . . . 6-9
Example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9
Contents-5

Illustrations
Figure 1-1. Block Diagram of HP 64700 Series Analyzer . . . . . . . 1-2
Figure 2-1. Pseudo-Code Algorithm of Sample Program . . . . . . . 2-3
Figure 2-2. Sample Program Listing. . . . . . . . . . . . . . . . . . . . . . . . 2-4
Figure 2-3. The Default Sequencer Specification. . . . . . . . . . . . . . 2-24
Figure 2-4. SpecifyingPrimaryand SecondaryBranches . . . . . . . . 2-27
Figure 3-1. "Complex"Configuration Sample Program . . . . . . . . . 3-8
Figure 3-2. "Complex"Configuration Default Sequencer. . . . . . . . 3-14
Figure 3-3. Simple Trigger in "Complex"Configuration . . . . . . . . 3-16
Figure 3-4. Flowchart of Hypothetical Program. . . . . . . . . . . . . . . 3-18
Figure 3-5. Drawingthe Sequencer Diagram . . . . . . . . . . . . . . . . . 3-20
Figure 3-6. Tracinga "Window"of Activity. . . . . . . . . . . . . . . . . . . 3-24
Figure 3-7. Sequencer to Isolate Sample Program Bug . . . . . . . . . 3-31
Figure 4-1. Assemblingthe Analyzer Probe . . . . . . . . . . . . . . . . . . 4-2
Figure 4-2. Attaching Grabbers to Probe Wires. . . . . . . . . . . . . . . 4-3
Figure 4-3. Removing Cover to Emulator Connector . . . . . . . . . . 4-4
Figure 4-4. Connectingthe Probe to the Emulator . . . . . . . . . . . . 4-5
Figure 4-5. Connecting Probe to the Target System. . . . . . . . . . . . 4-7
Figure 5-1. Coordinated Measurements. . . . . . . . . . . . . . . . . . . . . 5-4
Figure 6-1. Qualified Clocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
Figure 6-2. Mixed Clock Demultiplexing . . . . . . . . . . . . . . . . . . . . 6-6
Figure 6-3. Slave Clocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
Figure 6-4. True Demultiplexing. . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Contents-6

1
Introducing the HP 64700 Series Analyzer
Overview Thismanualdescribesthe HP 64700 Series analyzer. Each HP 64700
Seriesemulator containsan internalemulation analyzer. Your emula-
tor mayoptionallycontain an externalanalyzer.
The emulation analyzercapturesemulator buscycle information syn-
chronouslywith the processor’sclock signal. Atraceis a collection of
these captured states. Thetrigger state specifies when the trace meas-
urement istaken. The externalanalyzercaptures activityon signals ex-
ternal to the emulator,typicallyother target system signals.
The analyzer commandsare the same in everyemulator;consequently,
thismanualisshipped with everyHP 64700 Series emulator. A block
diagram ofthe analyzer is shown in figure 1-1.
Analyzer Features This chapter lists basicfeatures ofthe HP 64700 Series analyzer. The
chapterswhich followshowyou howto use thesefeatures.
Simple
Measurements The default condition ofthe analyzer allowsyou to perform a simple
measurement byenteringa single"trace"command. You can enter ad-
Introduction 1-1

Figure 1-1. Block Diagram of HP 64700 Series Analyzer
Introduction 1-2

ditionaltrace commandsto qualifywhen execution shouldbe traced
and which buscycle statesshould bestored.
Trace Storage,
Prestore, and Count The analyzer can store up to 1024 states in trace memory. These states
can be normalstorage statesor prestore states(stateswhich precede
normalstorage states). A count maybe associated with normal storage
states;you can specifythat theanalyzer count in either time or the oc-
currences ofsome state. When counts are specified,only512 states can
be stored.
Sequencer You can use the analyzer to search for a particular sequence ofstates.
The sequencer, which makes this possible, has several levels (also called
sequence terms). Each level of the sequencer can search for two states
at a time. When oneofthese statesisfound, the sequencer branchesto
another sequence term. The termthat isbranched to dependson
which state is found first.
Simple Commands
for Common
Measurements
When the emulator ispoweredup or initialized,the analyzer isset up
in its"easy"configuration. The "easy"configuration hidesmuch ofthe
complexityof the analyzer and makesit easier to use;it allowsyou to
make simple measurementswithout requiringa thorough knowledge
ofthe analyzer. You can accessthe full capabilityofthe analyzer via a
commandto select the "complex"configuration.
External Analysis Your HP 64700 Series emulator mayoptionallycontain an external
analyzer. The externalanalyzer provides16external trace signalsand
two external clock inputs. You can use the externalanalyzer asan ex-
tension to the emulation analyzer,asan independentstate analyzer,or
asan independent timinganalyzer.
Coordinated
Measurements When multiple HP 64700 Series emulators are connected via the Coor-
dinated Measurement Bus(CMB),you can usetheanalyzer to trigger
Introduction 1-3

the analyzers ofother emulators. You can also use the analyzer to trig-
ger instrumentsconnected to theBNC port. Conversely,the analyzer
maybe triggeredbyother emulatorsandinstruments.
Also,ifyour emulator containsan externalanalyzerbeingusedasan in-
dependent analyzer,coordinated measurementsmaytake place be-
tween the emulation analyzer and theexternalanalyzer.
Other Features The list above is onlya basic description of the HP 64700 Series ana-
lyzer features. Thechapters which followshowyou howto use these
features.
Introduction 1-4

2
Getting Started
Introduction Thischapter shows you howto use the emulation analyzer from mak-
ingsimple measurementsto searchingfor a sequence ofstates. It does
notdescribe howto accessor use the full capabilityofthe analyzer (see
the chapteron "AccessingFullAnalyzer Capability").
Thischapter:
•Describes the sample program on which example measurements
are made.
•Describes the default, power-up condition of the analyzer (includ-
ing how to: initialize the analyzer, start the trace measurement,halt
the trace,displaythe trace status, displaythe trace, and change the
format ofthe trace listing).
•Describes expressions allowed in trace commands.
•Shows you howto specifya simple trigger.
•Shows you howto specifya storage qualifier.
•Shows you how trace prestore is used.
•Shows you howto change the count qualifier.
•Shows you howto use the sequencer.
•Shows you how to change the position of the trigger state in the
trace.
Getting Started 2-1

Prerequisites Before readingthe examplesin thischapter you should alreadyknow
howthe emulator operates. You should knowwhat thevariousemula-
tor promptsmean,and you shouldknowhowto use theemulation
commands. Refer to the appropriate TerminalInterface:Emulator
User’s Guide manualto learnabout theemulator;then,return tothis
manual.
The Sample
Program The sample program is used to illustrate analyzer examples. Thesam-
pleprogramiswritten in assemblylanguageso the disassembledtrace
listingswill be more meaningful.
The examples in this chapter have been generated using an 80186 (HP
64764) emulator. The sample program is written in 80186assembly
language.
It isnot important that you knowthe 80186 assemblylanguage; how-
ever,you shouldunderstand what thevarioussectionsoftheprogram
do and associate these taskswith the labelsused in the program.
You are encouraged to rewrite the sample program in the assembly
language appropriateforyour emulator. Then,you can use your ana-
lyzer to perform the examplesshown in thischapter. Ofcourse,the
output ofyour commandswillbedifferentthan those shown here.
Description of the
Sample Program A pseudo-code algorithm ofthe sample programisshown in figure2-1.
Thesample program isnot intended to represent a realroutine. The
programusesfour different callersofthe WRITE_NUMBER subrou-
tine to simulatesituationsin realprogramswhere routinesare called
Getting Started 2-2

from manydifferent places. An example later in this chapter will show
youhowto use theanalyzer to determinewherearoutineiscalledfrom.
An assembler listing of the sample program is shown in figure 2-2. It is
providedso that you can see the addressesassociated with the program
labels. Theprogram area, which containsthe instructionsto be exe-
cuted bythe microprocessor,islocatedat 400H. The RESULTSarea,
to which the random numbersare written,islocatedat 500H. The area
which containsa variable used bythe RAND subroutine and the loca-
tions for the stack is located at 600H.
Before You Can
Use the Analyzer Before you can use the analyzer to performmeasurementson the sam-
pleprogram,you must map memoryand load the sample program.
Initialize the stack pointer.
AGAIN: Save the two previous random numbers.
Call the RAND random number generator subroutine.
Test the two least significant bits of the previous random number.
If 00B then goto CALLER_0.
If 01B then goto CALLER_1.
If 10B then goto CALLER_2.
If 11B then goto CALLER_3.
CALLER_0: Call the WRITE_NUMBER subroutine.
Goto AGAIN (repeat program).
CALLER_1: Call the WRITE_NUMBER subroutine.
Goto AGAIN (repeat program).
CALLER_2: Call the WRITE_NUMBER subroutine.
Goto AGAIN (repeat program).
CALLER_3: Call the WRITE_NUMBER subroutine.
Goto AGAIN (repeat program).
WRITE_NUMBER: Write the random number to a 256 byte data area, using the second
previous random number as an offset into that area.
RETURN from subroutine.
RAND: Pseudo-random number generator which returns a random number
from 0-0FFH.
RETURN from subroutine.
Figure 2-1. Pseudo-Code Algorithm of Sample Program
Getting Started 2-3

FILE: anly.S HEWLETT-PACKARD: 80186 Assembler
LOCATION OBJECT CODE LINE SOURCE LINE
1 "80186"
2 ORG 400H
3 ASSUME DS:ORG,ES:ORG
4
0400 B80000 5 START MOV AX,SEG RAND_SEED
0403 8ED8 6 MOV DS,AX
0405 8ED0 7 MOV SS,AX
0407 B80000 8 MOV AX,SEG RESULTS
040A 8EC0 9 MOV ES,AX
040C BCFE06 10 MOV SP,OFFSET STACK
11 * The next three instructions move the second
12 * previous random number into DI (offset to
13 * RESULTS area).
040F 8AC7 14 AGAIN MOV AL,BH
0411 25FF00 15 AND AX,#0FFH
0414 8BF8 16 MOV DI,AX
17 * Previous random # moved to BH.
0416 8AFB 18 MOV BH,BL
19 * RAND returns random number in AX.
0418 E83300 20 CALL RAND
21 * Current random # moved to BL.
041B 8AD8 22 MOV BL,AL
041D 8AE7 23 MOV AH,BH
24 * The following instructions determine which
25 * caller calls WRITE_NUMBER (depends on last
26 * two bits of the previous random number).
041F D0DC 27 RCR AH,1
0421 7207 28 JC ONE_THREE
0423 D0DC 29 RCR AH,1
0425 7216 30 JC CALLER_2
0427 E90700 31 JMP CALLER_0
042A D0DC 32 ONE_THREE RCR AH,1
042C 7215 33 JC CALLER_3
042E E90600 34 JMP CALLER_1
35 * The WRITE_NUMBER routine is called from four
36 * different places. The program is repeated
37 * after the subroutine return.
0431 E81400 38 CALLER_0 CALL WRITE_NUMBER
0434 EBD9 39 JMP AGAIN
0436 90 40 NOP
0437 E80E00 41 CALLER_1 CALL WRITE_NUMBER
043A EBD3 42 JMP AGAIN
043C 90 43 NOP
043D E80800 44 CALLER_2 CALL WRITE_NUMBER
0440 EBCD 45 JMP AGAIN
0442 90 46 NOP
0443 E80200 47 CALLER_3 CALL WRITE_NUMBER
0446 EBC7 48 JMP AGAIN
Figure 2-2. Sample Program Listing
Getting Started 2-4