Relocating Macro Assembler and Linker pdf

R E _L O C A T

_I

N G M _A C _{R O A S S E} M _{B L E R}

A N D _L

_I

N K E R

for

Z 8 O _{A N D H D 6 4 1 8} O

by

Patrick

O'Connell

Zas,

_Zlink,

Z1ib, Zcon, Zref _are Copyright 1984/85 by Mitek. No

part of

_this

document may be reproduced

in

_{any way}

_or

by any means

without prior written

permission of the

publisher.

Mdress

requests to

Echelon,

_Inc.,

101

_First

_Street,

Los

_Altos,

CA

Copyright 1984/85 Mitek

All

Rights Reserved

WARNING

THIS SOFTWARE AND MANUAL ARE BOTH PROTECTED BY U.S. COPYRIGHT LAW

(TITLE 17 UNITED STATES CODE). UNAUTHORIZED REPRODUCTION AND/OR SALES MAY RESULT _{IN IMPRISONMENTOF UPTOONEYEARAND} FINES OF UP TO _{$10,000 (17} USC _506). COPYRIGHT INFRINGERS MAY ALSO BE SUBJECT TO _{CIVIL LIABILITY.}

LIMITED WARRANTY

THIS PROGRAM AND INSTRUCTION MANUAL ARE SOLD "AS

_IS,"

WITHOUT WARRANTY AS TO THEIR PERFORMANCE, MERCHANTABILITY, OR _{FITNESS FOR}

ANY PARTICULAR PURPOSE. THE _{ENTIRE RISK} AS TO THE RESULTS AND PERFORMANCE OF THIS PROGRAM _IS ASSUMED BY YOU.

HOWEVER, TO THE _ORIGINAL PURCHASER ONLY, ECHELON WARRANTS THE MAGNETC DISKETTE ON WHICH THE PROGRAM _IS RECORDED TO BE FREE FROM DEFECTS _IN MATERIALS AND FAULTY WORKMANSHIP UNDER NORMAL USE FOR A PERIOD OF _THIRTY DAYS FROM THE DATE OF SHIPMENT. _IF DURING THIS THIRTY-DAY PERIOD THE DISKETTE SHOULD BECOME DEFECTIVE, _IT MAY BE RETURNED TO ECHELON FOR A REPLACEMENT WITHOUT CHARGE.

YOUR SOLE AND EXCLUSIVE REMEDY _IN THE EVENT OF A DEFECT _IS EXPRESSLY _LIMITED TO REPLACEMENT OF THE _DISKETTE AS PROVIDED ABOVE. _{IF FAILURE} OF A _DISKETTE HAS RESULTED FROM ACCIDENT OR ABUSE ECHELON SHALL HAVE NO _{RESPONSIBILITY} TO REPLACE THE DISKETTE U7'DER THE TERMS OF THIS _LIMITED WARRANTY.

ANY _IMPLIED WARRANTIES RELATING TO THE _{DISKETTE, INCLUDINGANY}

IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICU-LAR PURPOSE, ARE _LIMITED TO A PERIOD OF THIRTY DAYS FROM DATE OF SHIPMENT. ECHELOP' SHALL NOT BE LIABLE FOR INDIRECT, SPECIAL, OR

CONSEQUENTIAL DAMAGES RESULTING FROM THE USE OF _THIS PRODUCT. SOME STATES DO _{NOT ALLOW THE EXCLUSION OR}

LIMITATION OF

INCIDEN-TIAL OR CONSEQUENTIAL DAMAGES, SO _{THE ABOVE LIMITATIONS MIGHT NOT}

APPLY TO YOU. THIS WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, AND YOU MAY ALSO HAVE OTHER RIGHTS WHICH VARY FROM STATE TO STATE.

Trademarks: Zas,

_Zlink,

_Zlib,

Zcon,

_Zref,

_Mitek;

ZDM, RD

Software;

DSD,

_soft

_Solutions;

_{Z-System, Echelon,}

_Inc.;

_Z80,

Zilog,

Inc.;

HD64180,

_Hitachi;

CP/M, DDT, _{SID, ZSID,}

_Digital

TABLE OF CONTENTS

Chapter 1

_{INTRODUCFION...}

_I

1.1 Overview 1

1.2

_Distribution

_Files

1

1.3

_Installation

1

1.4 Software Updates 2

Chapter 2 ZAS

_{INVCCATION...}

3

2.1 ZAS _Operation 3

2.2 ZAS _Options 3

2.3 Assembly

_Statistics

4

Chapter 3 PROGRAM

_FORMAT...

5

3.1 Label

_Field

5

3.2 Operation

_Field

5

3.3 Operand

_Field

5

3.4 Comment

_Field

6

Chapter 4

_{EXPRESSIONS...}

7

4.1 Numeric Constants 7

4.2

_String

Constants 7

4.3 Character Constants 7

4.4 Labels 8

4.4.1 Label

_{Characteristics}

8

4.4.2 Relocation Bases 8

4.5 Relocation Counter Reference 9

4.6 Registers 9

4.7 Operators 10

4.8 Precedence

_of

Operators 11

4.9 Parentheses Versus Brackets 12

4.10 Expression

_Restrictions

12

Chapter 5

_{PSEUIX)-OPS...}

13

5.1 General Pseudo-ops 13

5.2

_Listing

Control Pseudo-ops 16

5.3 Conditional Assembly Pseudo-ops 16

5.3.1 IF Pseudo-ops Evaluatiorí 16

5.3.2 Conditional Assembly Forms 17

5.4 Linkage Pseudo-ops 19

5.5 Relocation Base Pseudo-ops 20

5.6 Macro Pseudo-ops d?

~4

5.7 Special Function Pseudo-ops 22

Chapter 6 MACRO

_FACILITY...

23

6.1 Repeat Macros 23

6.2 Stored Macros 25

6.3

_Exiting

Macros 25

6.4 Local Symbols 25

6.5 Macro

_Invocation

26

TABLE OF CONTENTS (continued)

Chapter 7 ZAS ERROR

_MESSAGES...

29

7.1 Non-Fatal Errors 29

7.2 Fatal Errors 30

7.2.1 General Fatal

_Error

Messages 30

7.2.2 Macro Fata!

_Error

Messages 30 CHAPTER 8 CROSS-REFERENCE _{GENERATION...} 31

8.1 Overview 31

8.2 ZREF _Operation 3i

8.3 Reserved Symbols 31

CHAPTER 9 CODE

_CONVERTER...

33

9.1 Code _{Converter Operation} 33

9.2 Convertible TDL _Pseudo-ops 33

9.3

_Error

Messages 34

CHAPTER 10

LINKER...

35

10.1 Overview 35

10.2 ZLINK _Operation 35

10.3 ZLINK _Options 35

10.4 Define Next Free Memory _Location 36

10.5 ZLINK

_Error

_Messages 37

CHAPTER 11 LIBRARY

_MANAGER...

39

11.1 Overview 39

11.2 ZLIB Operation 39

11.3 ZLIB Options 39

11.4 ZLIB Messages 39

11.5 ZLIB

_Error

Messages 40

Appendix A: Z80 Mnemonic _Machine

_Instruction

Codes

Appendix B: _{Software Update} Form

Appendix C: _Pseudo-op Summary

CHAPTER 1 INTRODUCTION

1—I OVERVIEW

ZAS (Z80 _and HD64180 _{Relocating Macro Assembler) reads assembly}

language statements from a

disk

file

and produces

either

an

Intel

compatible

HEX

file

or

a

Microsoft

compatible

REL

file.

These

files

can then be loaded

using

Echelon

supplied

MLOAD,

_or

CP/f'1

LOAD, _command

_or

_any

_Microsoft

_{object compatible}

_linker.

A

symbol

_table

_file

(SYM)

_{is optionally}

_produced

_that

_{can be used}

with

Echelon DSD _or

_Digital

_Research SID _and ZSID _debuggers. The _minimum Z

or

CP/M system

configuration in

which

_to

_{use zas}

_is

48k-bytes of

RAM

_with

_one

_{disk drive.}

As _{soon as you receive} ZAS, make _{backup copies!} Then _{go through}

the

_installation

_process using a _copy.

1.2 DISTRIBUTION _FILES

You

_will

_find

_the

_following

_files

_{on your}

_distribution

_disk:

File

Function

ZAS.COM _Assembler

ZLINK.COM

_Linker

ZLIB.COM

_Library

_Manager

ZCON.COf1 8080

_to

Z80 Code _Converter ZREF.COM _{Cross-reference Generator}

TEST.Z80 Test Assembly

_File

INSTZAS.COM

_Installation

_Program

1.3 INSTALLATION The

_installation

program was designed

_to

set assembler output

op-tions.

Type

_in

INSTZAS

_to

_{invoke the}

_installation

_program. The

CHAPTER

_I:

INTRODUCTION

INSTMS<cr>

ZAS

_installation

_options:

l.

Listing to terminal

_-

_off

2.

_{Listing to disk}

_file

_{- off}

3.

_{Listing to printer}

_-

_off

4. Generate

_object

_file

_-

_on 5. Generate symbol

_file

_-

_off

6.

_object

_file

type

_{- rel}

7. _{IF trueness based on}

- least significant

bit

99. Changes _complete

Enter

_option

number

_to

change:

The _{preset values}

_{for different}

_options

_{is indicated to right of}

option.

To _change

_(toggle)

_an

_{option value (i.e., onto}

_{off, rel}

to

hex,

_{or least}

_significant

_bit

_to

_all

_sixteen

_bits),

_simply

enter option

number

_(l

_to

7)

_followed

by

_carriage

_return

<CR>. When

_{desired option}

_{changes have been made,}

_{type in}

99

_to

_end

installation

program and have ZAS.COM

_{automatically}

updated.

1.4 UPDATES

You _can

_{assist in refining}

ZAS _{by recommending enhancements and}

reporting

any software problems on a _copy

of

the Software Update

Form, a sample

of

which

is in

Appendix B. Software updates

will

be _provided

_{at regular intervals}

_for

_{a nominal fee.} You

_will

be

cmvrm

2 ZAS INVOCATION

2.1 ZAS OPERATION

ZAS

_is

_{invoked by}

_typing:

ZAS

_{filename.filetype}

where

_{filename is the}

_name

_{of the}

_source

_fije

_to

be assembled.

If

no

filetype

is specified,

then Z80

is

assumed. Typing ^C

will

cancel ZAS

_operation.

2.2 ZAS OFTIONS

A

_variety

_{of options}

_are

_available

_{to provide control}

_over

the

execution pararneters

_of

ZAS. _{They are used once}

_at

the end

_of

_a command

_line

_{and spaces are not allowed between}

_options:

ZAS _filename

_{$}options

There _are two types

_{of options:}

non-disk reference options arid

disk reference options.

Using

_{the non-disk reference options}

reverses the settings

supplied

by

the

Install

Program and

in-cludes the

C, H, _and L

_options.

C: CRT

_Option.

_{Setting the}

C

option

_will

page

the output of

ZAS,

_at

23

_lines

_{per page.}

_Pressing

_{any key}

_allows

_you

_to

continue

_{to scroll}

through the output _{page by page.} However,

_it

should be _noted

_that

_a ^C

_will

_{abort the assembly.}

H: _Hex

_Option.

When

_this

_{option is set}

it

will

generate

_Intel

compatible hex

files

instead

_{of Microsoft}

compatible REL

_files.

Note: When

_using

HEX

_files,

_{you must have an} ORG

_{statement of}

1OOH _{or higher}

_to

_{prevent an}

_inverted

_address

error

from MLOAD or

LOAD.COM.

L:

_Listing

tcj

_Printer

_Option.

_Setting

_the

L

_option

sends a

formatted

assembly

_listing

_to

Z

or CP,"61 LST: device.

The

_{disk reference options require}

two

_characters.

The

_first

character

_is

the P, O, _or S

option

characters. The _second

charac-ter

indicates

the output disk drive for the specified

option.

The _{second character must} be _{A-P or} Z, _where Z

_(for

zero or

null)

suppresses the output

_altogether.

o:

object

_File

Generation

(filename.REL _{or filename.HEX).} The O

option specifies

the disk for object

_file

output.

Depending _on the H

option,

the

_object

_{file will}

be _a

_Microsoft

_compatible REL

file

or an

Intel

compatible HEX

_file.

P:

_Listing

_to

_a PRN

_File

_{(filenarne.PRN).} The P

option

_will

send

a formatted assembly

_listing

_to

the

_{specified disk.}

S: Symbol

_File

_Generation

(filename.SYMÁ The S

CHAPTER _2: ZAS INVOCATION

2.3 ASSEMBLY _STATISTICS

At the completion

_of

an assembly, ZAS _{provides several}

_statistics

on the program assembled. The output

_is

_as

_follows:

Assembly

_statistics:

nnnn

lines

nnnn

labels

nnnn macros read nnnn macro expansions nnnn

_errors

cFlAprER 3 PRCX;RAMFORMAT

Acceptable _program

_{input consists of}

a _sequence

of

statements

in

the form:

label

operation operand comment

where each

_field

_is

separated _{by one or more spaces and/or} tabs.

All fields

are

optional

and may begin

in

_{any column} except

for

the

_label

_field

which must begin

_in

column _one. The _statement

_is

terminated

by a

carriage return

and a

line

feed

is allowed

but

not necessary. You rnay also

insert

blank

lines into

the _program. The _{statement may be}

_either

_{upper or lower-case except}

_for

_macro

parameters. For macro parameters, the

_actual

and formal parameters must be

_in

_{the saíne case}

_{for substitution}

_to

_{take place.}

3.1 IABEL FIELD

Labels take the form:

label

_or

label:

and are

optional

except for the

SET, EQU, _and MACRO _assembler

directives.

The

_label

_consist-s

_of

_{alphanumeric characters, a} ?, an @,

_or

a $ and the

first

character must not be _numeric.

If

the

label

exceeds 15

_{characters then the label is truncated to the}

right.

Labels _{can be}

_either

_upper-case

_{or lower-case.}

The ":

_"

following

a

label is optional.

Examples

of labels include the

following:

a123 ?a123 @a123

aLL: ?ALL:

_{update_file}

Áll?

INDEX UPDATE$EILE

3.2 OPERATION _FIELD

The _operation

_field

_{contains one}

_of

_the

_{following three:}

_a

mne-monic machine

_instruction

code, a pseudo

operation

code which

directs

the

assembly

_{process, or}

a _macro. The Z80 mnemonic

machine

_instruction

codes

_are

_listed

_in

Appendix A _and

_Hitachi

HD64180

_instruction

codes

_are

_listed

_{in Appendix}

D. _The

assembler pseudo-op codes _are

_{discussed in}

Chapter 5,

_with

a

summary

of the

pseudo-ops

_listed

Appendix C. And

_the

_macro

instructions

are discussed

in

Chapter 6.

3.3 OPERAND _FIELD The _operand

field

may contain numeric constants, character

con-stants,

ASCII

_strings,

_relocation

_{counter references,}

_labels,

register

_{references, operators, or expressions containing}

_any

combination

_of

the

_previously

mentioned items. Expresstons _are

CHAPTER _3: PR(JGRPM FORMAT

3.4 COFHENT _FIEID

A _comment

_field

_is

_{always preceded by a semicolon}

_(;).

_Comments

CHAETER 4 EXPRESSIONS

Before the

pseudo

_operations

and macros can be

described,

_it

is

necessary

to discuss expressions

because

_of

_their

_complexity.

Expressions consist of simple

operands combined

_{into properly}

formed sub-expressions by operators. Blanks and tabs _are ignored between operators and operands

_of

the expression. Each

expres-sion produces a

16-bit

value during the assembly.

If

only 8

bits

are needed,

the least

significant

half of the 16-bit value is

used.

4.1 NUMERIC CONSTANTS

A numeric

_{constant is}

a

16-bit

value in

_one

of several

number

bases. The _base,

_called

_the

_{radix of}

_{the constant,}

_is

_{denoted by} a

trailing

radix indicator.

Any numeric constant which does not

terminate with

a

radix indicator

_{uses the}

default radix

which has

been

_initially

set

_to

decimal. The

_{radix indicators}

_are:

B

_binary

_{constant base} 2

O

octal

constant base 8

Q

octal

constant base 8

D _{decimal constant base} 10

H _{hexadecimal constant base} 16

A _constant

_is

a _sequence

of digits,

followed

by an

optional radix

indicator,

where the

_digits

_are

_{appropriate for}

the

_radix,

_i.e.,

binary constants

must be composed

_of

O _and

I digits

etc.

For hexadecimal constants, the leading

_digit

must be _{a decimal}

_digit

in order to avoid confusing the

hexadecimal

_{constant with}

_an

identifier

(a

_leading

O

will

work).

A _numeric

_constant

_must

produce a

binary

number which _{can be}

contained within

a

16-bit

value.

4.2 ASCII STRINGS

String

constants represent _sequences

_of

ASCII characters, and are represented by enclosing the characters

_within

apostrophe symbols

(').

_All

strings

must be

_fully

_{contained within}

_{the current}

physical line.

The _{apostrophe character}

itself

can be included

within

a

string

by

representing

it

_as a double apostrophe

("),

which becomes a

single

apostrophe when read by the assembler.

4.3 CHARACTER CONSTANTS

Like strings,

character

constants

are composed

of

O, _1,

or

2

ASCII characters,

_delimited

by an apostrophe (') _or

_quotation

(") symbol. One

_difference

_between

_strings

_{and character constants}

pseudo-CHAPTER _4: EXPRESSIONS

ops.

In

all

other

cases, a

character

constant

is

assumed.

Another

_difference

_{is that the value of}

a

character constant is

calculated

and

_{the result}

_{is stored with the}

low

_{byte in the}

first

address and

_{the high byte in the}

second address. For

example,

_in

the character constant:

DW _'AB'

the value of

A

_{is stored in the}

_{second memory}

_location

_and B

_is

stored

_in

the

_first

_memory

_location.

_{In the}

_string:

DB _'AB'

the value of

A

_{is stored in the}

first

memory

location

and B

_is

stored

_in

the _{second memory}

_location.

4.4 T?F'[FT"é

A

_{label is given}

a

valuedeterminedby

the type of statement

it

precedes.

_If

the

_label

precedes a _macro

definition,

the

label is

given

a

_text

value,

which

is the

body

of the

_macro

definition.

If

the label

precedes _an EQU

_or

SET _pseudo

_operation,

_then

_the

label

is given the value of the

operand

_field.

_If

a

label

precedes _any

_{other type of statement,}

_it

_{is given the value of}

the

_{current relocation}

counter.

The

_{value of}

a

label is not allowed to

change

unless the label

precedes a SET pseudo-op.

_In

which _case,

there is

_no

limit

_to

the number

_of

times the

_label's

value may change.

4.4.1

LABEL CHARACTERISTICS

Labels

_fall

into

one

of three categories:

public,

external,

_or

local.

Public labels

are

labels

defined

in

the

current

program module _{and can be}

_{referenced in other}

_program modules

_External

labels

are

labels

which have been defined as

public in

some

other

program module and are being referenced

in

the module

declaring

them

_external.

_If

a

label

has

not

been

declared external

_or

public then

_it

is local

and cannot be

_referenced

_{by any}

_other

program module.

4.4.2

REUJCATION BASES

The

_symbolic

_names

_for

_{independently located}

_{memory areas are}

called relocationbases.

These

_{relocationbases}

may

represent

ROM, _shared COMMON

areas, special

memory areas such as

video

refresh,

memory mapped I/O, etc.

Within

each sub-program, each

of

these

memory areas

is referenced

by a

unique

_name. The

actual

allocation

and mapping

_{of the}

_name

_{to physical}

addresses

_is

deferred

_to

the

_{link edit}

and load _process.

_{All label}

references

within

the assembled _{program are}

_{relative to}

_one

_of

these

reloca-tion

bases. The

_{four relocation}

_{bases and}

_{their typical}

_{uses are}

CHAPTER _4: EXPRESSIONS

Absolute:

Absolute assembles

_{non-relocatable}

code. A _programmer

selects

Absolute

mode _{when a}

_{block of}

_{program code}

_{is to}

_be

loaded each

_{time into specific}

addresses, regardless

_of

what else

is

located

_at

the same

time.

Data

_Relative:

Data

_Relative

assembles code

_for

a

section of

a

program

that

may change and

therefore

must be loaded

into

RAM.

This

_{applies especially to}

_program data _areas. Symbols

_in

Data

Relative

are

relocatable.

Code

_Relative:

Code (program)

_Relative

assembles code

_for

sections

_of

_programs

_that

_will

not be _{changed and}

_therefore

_can

be

_loaded

_into

ROM/PROM. Symbols

_in

Code

_Relative

_are

relocatable.

COMMON: COMMON _{assembles code}

_{that is}

_loaded

_into

_a

_defined

common data _area. This

allows

_program modules

_to

share a block

of

memory and common values.

To _change

_{the relocation}

_{base, use one}

_{of the following}

pseudo-ops

in

a statement

line:

ASEG _Absolute

DSEG _Data

_Relative

CSEG Code

_{Relative--default}

CO.YLYON _CO!)MON

4.5 RELOCATION COUNTER REFERENCE

The

_current

_relocation

_counter

may be

referenced

_as a

16-bit

value

by use

of the

symbol $. The

_{value represented}

by $

is

always the

_relocation

counter value

_at

the

_{start of}

the

_current

statement. For example,

JP $

will

endlessly junp

_to

_itself.

4.6 RE)GISTERS

When ZAS _{encounters a one or two character symbol,}

it

will

look

up

the

symbol

in the corresponding

8

or 16-bit

register

table

(see the next page).

_If

the symbol

_is

found, then the operand

_is

assumed

_to

be a

register

reference.

_Because these

_single

and double character symbols _are reserved words, _{do not use them as}

CHAPTER _4: EXPRESSIONS

8-Bit

Registers

_16-Bit

Registers

(Reserved Words) (Reserved Words)

A BC

B DE

C _HL

D _IX

E _IY

H SP

L AF

M

I

R

4.7 OPERAIKJRS

The operands

_previously

_described

_can be combined

_in

normal

algebraic expression using

any

combination of properly

formed operands, operators, and parenthesized expressions.

_All

arithme-tic

operators (",-,*,/,MOD,SHL,

and SHR) _{produce a}

_16-bit

un-signed

_arithmetic

_result.

The

_relational

_operators (EQ, _{LT, LE,} GT, GE, and NE) _{produce a}

_true

(OFFFFH)

or false

(OOOOH)

16-bit

result.

And _the

_logical

_operators (NOT, AND, OR, _and XOR) _operate

bit-by-bit

on

their

operand(s)

producing

a

16-bit

result

of

16

individual

_bit

operations.

The HIGH _and LOW

_{operators always}

produce a

16-bit

result

with

a

high order byte

which

is

_zero. The NUL _{operator produces a}

_true

_or

_{false result.}

The _operators

_for

_{the operand}

_field

_{are given below.}

_In

_general,

the

_letters

x

andy represent

operands which _are

treated

_as

16-bit

unsigned

_quantities

_in

the _range 0-65535.

Arithmetic

Operators Result

x"y

arithmetic

sum

of

x and y

x-y

arithmetic difference

between x and y x * _y unsigned

multiplication

of

x by y x

/

_y unsigned

division of

x by y

x MOD _y remainder

after division of

x by y x SHL _y

shift left

by y,

with

_zero

right

fill

x SHR _y

shift

right

by

_{y, with}

_zero

left

fill

Relational

Operators Result

x EQ _{y, x=y}

_true

if

x equals _y,

false

otherwise

x LT

_y,

x<y

true

if

x

is less

than _y,

false

otherwise x LE _y, x<=y

true

if

x

is

less _{or equal}

to y,

else

false

x GT

_y,

x>y

_true

_if

x

is greater

than _y,

false

otherwise x GE _{y, x)=y}

_true

if

x

is greater

_{or equal}

to y,

else

false

x NE _{y, x<>y}

_true

CHAPTER _4: EXPRESSIONS

Logical

Operators Result

NOT y

bit-by-bit

logical

inverse

of

y x AND _y

bitwise logical

AND of x and y x OR _y,

x!y

bitwise logical

OR

of

x and y x XOR y

logical exclusive

OR

of

x and y

Special

Operators Result

HIGH _y

_identical

_to

_y SHR 8 _{(high order byte}

_of

_y)

LOW

y

identical

to

y AND OFFH _{(low order} byte

_of

y)

NUL

_line

_true

if

the remainder

_of

the

_{current line is null}

or contains only space and/or tab characters. Be-cause

the

NUL

operator

uses

the rest of

the

current

source

line

as an operand,

it

must be the

last

operator on a

line.

4.8 PRECEDENCE OF OPERATORS

Without parentheses _{or brackets} operators have an order of

appli-cation

as

if

they were parenthesized or bracketed. As described below,

_{the operators}

_listed

_first

have

_highest

precedence, and

the operators

_listed

last

have

_lowest

precedence.

_Operators

listed

on the same

line

have equal

priority

and are applied from

left

to right in

the expression

highest precedence *

_/

MOD _{SHL SHR} + _—

EQ _{LT LE GT} GE _NE

NOT AND

OR _XOR

HIGH LOW

lowest precedence NUL

The _expressions shown _{below are}

_equivalent:

X _{" y} * Z = X _{" [y} * Z]

x OR _y * a SHR b = _x OR {y * la SHR

_bll

Balanced parenthesized _{or bracketed} sub-expressions _{can always} be

used

_{to override the order of}

precedence

_described

above. The

last

expression could be

_{rewritten to force application of}

opera-tors in

a

different

order:

CHAPTER _4: EXPRESSIONS

4.9 parentheses xmtsus brackets

Parentheses and

_brackets

_are

_{not interchangeable.}

_{They serve}

different

purposes. Parentheses are used

in expressions that

have

_indirect

addressing modes. For example,

LD HL, ₍₅₊₁₎

will

load

_{the register}

_pair

HL from

_{the contents of}

_memory

location six

(5"1) _{and seven.}

Brackets _are used

_for

_all

_other

expressions where the addressing

mode

_is

_not

_indirect.

_{Using the above example}

_with

_brackets, LD _HL, 15+1)

will

load the

_{register pair}

HL

_with

_{the immediate value}

_six.

4.10 EXPRESSION RESTRICTIONS

The _operand

_field

_of

_{a statement may}

_{consist of}

_{a ccmplex}

arith-metic expression

_with

the

_{following restrictions:}

(I)

An

_external

may

only

have _an

absolute quantity

added

_or

subtracted from

_it.

The

_result

_will

be

_external.

(2) A

_relocatable

_value may have an absolute

_or

another

relocat-able value (in the

same

relocation

base) added

to or

sub-tracted

from

_it.

The

_result

_will

_relocatable.

(3)

_If

two

_relocatable

values _are subtracted then the

_result

_will

be absolute.

(4)

_In

_all

_{other arithmetic}

and

_logical

operations, both operands must be _absolute. The

_result

_will

be _absolute.

An _expression

_error

_will

be _generated

if

an expression does not

CHAPTER 5 PSEUDO-OPS

5.1 GENERAL PSEUDO-OPS

DB: The _{D.efine Byte pseudo-op}

_is

used

_to

enter _{one or more} one-byte data values

_into

_{the program.} The _{statement form}

_is:

DB _n

_{,n...}

where n

is

_{any expression}

with

a

valid B-bit

value. More than _one

byte _can be _defined

_at

_{a time by separating}

it

from the preceding

value with

a _comma.

All

of the bytes defined in

a

single

DB

statement _are assigned consecutive memory

locations.

The

Zilog

mnemonic DEFB _can be _{used instead}

_of

DB.

DC: _{The D.efine C.haracter pseudo-op}

_{stores the characters in}

a

string in

successive memory

locations

beginning

with

the

current

relocation

counter. The _most

_significant

_bit

_of

_the

_last

charac-ter

_will

be _set

_to

_one. The _form

_for

_the DC _pseudo-op

is:

DC

_'string'

DS: _{The D.efine Space pseudo-op}

reserves

an area

of

memory. The form

_is:

DS _{expression {,expression}}

where the value

_of

the

_first

expression gives the number

_of

bytes

to

be

_reserved.

The

_Zilog

mnemonic DEFS _{can be used}

_{instead of}

DS.

To

_initialize

_{the reserved space, set the}

_optional

_second

expres-sion

_to

the value desired.

_If

the second expression

_{is omitted,}

the reserved

space

is

left

as

is

(uninitialized).

The

reserved

block of

memory

is not automatically

initialized

to

zeros. To

initialize

to

zeros give the second expression the value O.

All

names used

in

the

first

expression must be

_previously

_defined on _pass 1. Otherwise, a U

error

(undefined symbol)

is

generated

during

pass 1, and a P

_error

(phase

error)

will

probably

be

generated

_during

_pass 2 _because

_the

DS _{pseudo-op generated no}

code on pass 1.

DW: _The

_Define

_Word

_directive

_is

_used

_{to enter}

_a

_16-bit

_value

into

the _program. This

_directive

takes the form:

DW

nn

{,nn...}

Where nn

is

any

expression with

a

valid

16-bit value. Multiple

16-bit

values may be defined

with

_one DW _{statement by separating}

the values with

a _comma.

All

16-bit values defined

by the DW

pseudo-op _are stored

_in

standard Z80 _{word format}

_with

_the

_least

significant

byte

_first.

The

_Zilog

mnemonic DEFW _{can be used}

CHAPTER 5: PSETJ1X)-OPS

END: The END _statement

_{is optional.}

_All

_statements

_following

_the END _are ignored. The _form

_is:

END _{lexpressiorú}

The

_optional

_expression

_is

_{the program}

_starting

_address.

If

an

Intel

compatible hex

_file

_is

being generated, then

_{this starting}

address

_will

be _included

_in

_the

_last

_record

_of

_{the hex}

_file.

If

a REL

file

is being generated, then

ZLINK

will

place

a JUMP

instruction

at

1OOH

_to

_the

_{specified starting}

_address.

EQU: The EQUate _statement

_is

_used

_to

name _synonyms

for

particu-lar

numeric values. The _form

_is:

label

EQU _expression

The

_{label mustbe present andcannot label}

_any

_{other statement.}

The _{assembler evaluates the expression and assigns}

_this

_value

_to

the

_label.

The

_{label is usually}

_{a name which describes the value}

of the expression.

Also,

_this

name _{can be used}

throughout the

program as a parameter

_or

operand.

.IN: The.l.N.sert

_(or

MACLIB) pseudo-op

_{allows the}

_programmer

_to

use

the

same

section of

assembler source code

in

a number

of

different

assemblies. The _format

_is:

.IN {d:

_}filenaIne

_or MACLIB

_{K: lfilename}

where d

_{is the optional}

Z

or

CP/M

disk

specifier

(defaulting

to

the

logged

_disk)

and

_filename

_{is the}

_file

_on

_{disk with}

_the

assumed

_filetype

LIB.

This

_directive

causes

the specified

file

to

be

copied into the

assembly

_in

_its

_entirety,

and

_to

be

_{treated exactly}

_as

if it

were

part of

the

_original

_source

_file.

_{All inserted}

_source

_lines

_are

flagged with

a "+" on

the

listing.

Only _one

level of insert

is

allowed, they cannot be _nested.

.LIST: This pseudo-op _resumes a

listing

which has been suppressed

by the .XLIST

directive.

See the next page.

PAGE: The _{page pseudo-op gives}

_control

_{over the output}

_formatting

which

_is

_{sent to the}

PRN

_file

_and/or

_directly

_to

Z

or

CP/M LST:

device. The _form

_for

_the PAGE _statement

_is:

PAGE _{expression}

If

the

PAGE

_{statement is}

_used

_{without the optional}

_expression

then a form feed

is

sent

_to

the output

_file

and/or Z _or CP/M LST:

device. The _{form feed}

_is

_{sent before the statement}

_with

PAGE _has

been

_printed.

Consequently,

_the

PAGE _command

_is

_{often issued}

directly

ahead

_of

major sections

_of

an assembly language _program,

such as a _group

of subroutines,

_to

_cause

the next statement to

appear

at

the top

_of

the

_{following printer}

_page.

CHAPTER _5: PSEUIXJ-OPS

page

size.

In

this

case,

the expression

which

follows the

PAGE pseudo-op determines the number

_of

output

_{lines to}

be

_printed

_on

each page.

_If

the expression

equates

_to

a

value

between 40 and

90, then

_the

_page

_{size is set to the value of the expression.}

When

_this

_{value is}

_reached

_for

_{each page,} a form feed

is

issued

to

cause a _page

eject.

The assembler

initially

assumes a 56

line

page

size

and produces a _page

eject

at the beginning of the

listing.

Usually,

no more

than

one PAGE

statement with the

expression

_{option is}

included

_in

a

particular

_program.

.RADIX: The _{statement form}

_is:

.RADIX _n

where n

is

2, 8, 10,

_or

16.

This

pseudo-op set-s

the radix to

n

for

_all

numbers which

_follow,

unless another .RADIX _statement

_is

encountered, or the radix is overridden

by a

suffix

radix

modi-fier.

_Initially,

the default

radix

is set to

10

_(decima]).

SET: The SET _statement

_is

used

_to

name _synonyms

for particular

numeric values. The _form

_is:

label

SET expression

The

_label

_must be _{present and cannot}

_label

_any

_other

_statement,

except

for

another SET. The _{assembler evaluates the expression}

and assigns

_this

value

_to

the

_label.

The

_{label is usually}

_{a name}

which describes the value

_of

the expression. Also,

_this

name _can

be used

_{throughout the}

_{program as} a

parameter or

operand. The

Zilog

mnemonic DEFL _can be _{used instead}

_of

SET.

.TITLE and .SBTTL: The

_title

and

_subtitle

pseudo-ops

_{take the}

form:

.TITLE

_{'string-constant}

_I'

.SBTTL

_{'string-constant}

_2'

where

_{the string-constants}

_{are an ASCII}

_string,

enclosed

_in

apostrophes,

which do not exceed 64

_characters.

If

a .TITLE

and/or .SBTTL

_is

_{encountered during the assembly, then each page}

of

the

_listing

_{is prefixed with}

the

_title

and,'or

_subtitle

string-constant.

The

_title

_line

_will

be preceded by a

standard

ZAS

header _as

_follows:

MITEK _{Relocating Macro Assembler vers n.n page nnn}

string-constant

_l

string-constant

2

where _n.n

_{is the}

ZAS

_version

_{number, nnn}

_{is the current}

_page

number and

_{string-constant}

1 _and/or 2

_is

_the

_string

_given

_in

_the

corresponding

pseudo-op. ZAS

initially

assumes

that

these

pseudo-ops _are

_{not in effect.}

When

_specified,

_the

title

line,

along

_{with the}

_subtitle

_line

_{are not}

_{included in the line}

_count

CHAPTER _5: PSEUDO-OPS

5.2 LISTING CONTROL PSEUDO-OPS

.LALL: ,L,ist ALL macro

lines,

including

lines

that

do

_not

generate code.

.LIST:

This pseudo-op

resumes a

listing

which

has been suppressed by the .XLIST

_directive.

.LFCOND: The _L,ist .F,alse _{CONDitionals pseudo-op assures the}

list-ing

_{of conditional}

expressions

_that

evaluate

_false.

.PRINT: The

_print

_{on console pseudo-op takes the form:}

.PRINT

_pass,text

This

pseudo-op

_will

_output

_text

_{to the console during}

_the

specified

pass. The pass can be one

of

three values:

O

- print text

during both passes

1

- print text

during pass one

2

- print text

during pass two

.SALÍ): ,S.uppress ALL

_of

_{the macro}

_listing,

_including

_all

_text

_and

object

code produced _{by macros.}

.SFCOND: _{The,S.uppress.F.alse CONDitionals pseudo-op suppresses}

the

_{portion of}

the

_listing

_that

contains

_conditional

expressions

that

evaluate

_false.

.XALL: The _EXclude ALL _{non-code macro}

_lines

_pseudo-op

_will

list

source and

object

code produced by a _macro,

but

_source

lines

which do not generate code are not

listed.

.XLIST:

_This

pseudo-op _suppresses

_all

_list

_output

_until

a .LIST

pseudo-op

_is

encountered.

5.3 CONDITIONAL ASSEMBLY PSEUDO-OPS

The

_next

two

_{sections describe the}

ZAS

_conditional

_assembly

facility.

5.3.1

IF PSEUDO-OP EVALUATION

ZAS _{has two}

_different

_methods

_{for evaluating}

_{the trueness}

_of

_an

IF expression. One _{method bases the trueness on the}

_least

signi-ficant

_bit

of

the IF expression, which

_is

compatible

_{with Digital}

Research's ASM, MAC, _and RMAC

_assemblers.

_{The second} method bases

_{the trueness of the expression}

_on

_the

_full

_16-bit

expres-sion value.

This

method

_{is compatible with the Microsoft}

M80

CHAPTER _5: PSEUIXJ-OPS

The

_default

_evaluation

_is

_set

by

_the

_installation

program

(section

1.3). The

_evaluation

_method may also be

explicitly

set

by the

_following

two pseudo-ops:

.IF1

_-

_will

_cause

_{IF expressions to evaluate to true}

if

the least

_{significant bit}

of the

IF

expression

evaluates

_to

1.

OR

.IF16

_-

_will

_cause IF expressions

_to

evaluate

_{to true}

when

the IF expression evaluates

_to

non-zero.

5.3.2

CONDITIONAL ASSEMBLY FYJRMS

The

_IF,

ELSE, and ENDIF pseudo-ops

define

a _range

of

assembly

language statements which _are

_to

be _{included or excluded during}

the

assembly

_process.

The IF and ENDIF

_{statements alone}

can be used

_to

bound a

_{group of statements}

to

be

conditionally

assembled thus:

IF expression statement #1

stat.ernent- #2

e 0

statement #n ENDIF

Upon _{encountering the IF statement, the assembler evaluates the}

expression

_following

the IF

_(all

operands

_in

the expression must be

_defiríed

ahead

_{of the}

IF

_statement).

Depending _on

_the

condi-tional

assembly

_{option in effect,}

_if

the expression evaluates

_to

a

_{non-zero value or the least}

significant bit

evaluates to

a 1,

then

_statement

#1

_{through statement}

#n _{are assembled.}

If

the

expression evaluates to

a

_zero,

then

the statements

_are

listed

but not assembled.

The ELSE

_statement

_{can be used as an}

_alternative

_to

_{an IF}

statement,

and must occur between

_the

IF and ENDIF

_statements.

The _form

_is:

IF expression statement #1

statement #2

0 0 0

statement #n ELSE

statement

_#n"l

statement #n"2

0 9 0

CHAPTER _5: PSEUIX)-OPS

If

the expression

produces

a

_non-zero

(true)

value,

_then

statements

_I

through nareassembled.

However,

_{statements rj+j}

through m _are skipped

in

the assembly _process. When the

expres-sion

prcxiuces a _zero

value (false),

_statements

1

through

n _are

skipped, while statements

_n"l

through

m _are assembled. As _an

example,

_{the conditional}

assembly shown

_in

_Listing

A

_could

_be

rewritten

as shown

in Listing

B.

Listing

A

TTY EQU 1

CRT EQU 2

DEVICE EQU TTY TTYOUT EQU OFO03H CRTOUT EQU OF1OOH

IF DEVICE EQ TTY

CALL TTYOUT ENDIF

IF DEVICE EQ _CRT

CALL CRTOUT ENDIF

Listinq

B

TTY EQU

l

CRT EQU 2

DEVICE EQU TTY TTYOUT EQU OFO03H CRTOUT EQU OF1OOH

IF DEVICE EQ TTY

CALL TTYOUT ELSE

CALL CRTOUT ENDIF

Properly

balanced

_IF'S,

ELSE'S, and ENDIF's _{can be}

_completely

contained

_within

the boundaries

_{of outer}

encQmpassing

_conditional

assembly _groups. The

_structure

_outlined

below shows

_properly

nested IF, ELSE, and ENDIF _statements:

IF exp#1 group #1 IF exp#2 group#2

ELSE

group#3

ENDIF

group#4

ELSE

group#5 IF exp#3 group#6

ENDIF

group#7

CHAPTER _5: PSEUIXJ-OPS

where _group 1

_through

7 _{are sequences}

_{of statements to}

be

conditionally

assembled, and exp#1 through exp#3 are expressions which

_control

the

_conditional

assembly.

_If

exp#1

_{is true,}

then group#1 and group#4 _are always assembled, _{and group} 5,6, and 7

will

be _{skipped. Further,}

if

exp#l _{and exp#2 are both}

_true,

then group#2

_will

also be _included

_in

_{the assembly, otherwise group#3}

will

be

_included.

_If

exp#1 produced a

false value,

_groups 1, 2,

3, and 4

_will

_be

_skipped,

_{and group} 5 _and 7

will

always be assembled.

_If

under these

_{circumstances,}

exp#3

_{is true}

then group#6

_will

also be _included

_with

5 _and 7, _otherwise

it

will

be

skipped

_in

the assembly.

Conditional

assembly

_of

_this

_sort

_can be nested _up

_{to eight}

levels (i.e., there

can be up

to eight

pending IFS

_or

ELSEs

_with

unresolved

ENDIFS

_at

_any

_point

_{in the assembly), but usually}

becomes

_unreadable

_after

two

_{or three levels of nesting.}

The

nesting level

_restriction

also holds for

pending IFS and ELSEs

during _macro

_evaluation.

Nesting

_{level overflow}

_will

produce an

error

during assembly.

5.4 LINKAGE PSEUDO-OPS

EXTRN: _The EXTeR.N.al _pseudo-op

_identifies

_symbols

_whichare

de-fined in

some

other

_program but _are used

in

the _{current- program.} The _form

_is:

EXTRN _symbol

_{{,syñbol...}}

where symbol

_is

the symbol being declared _as

_external.

_Multiple

symbols may be declared

in

the same statement by separating them

with

commas. Also,

if

a symbol

in

an expression

is suffixed with

one

_or

two #

signs,

then

_the

symbol

_{is treated}

_{as an}

_external.

EXT

_is

a _synonym

for

EXTRN.

NAME: The NAME _{pseudo-op takes the form:} NAME _symbol

where symbol

_is

the

_relocatable

module name. This name

is

used

by the

_linking

loader and

_library

_manager

_{to identify}

the module

for

selective

_{loading or manipulation.}

Only

_the

_first

_six

characters _are

_significant

_in

the module name.

_In

the absence of

the NAME _{pseudo-op, up}

_to

_the

first

six

characters

_of

_{the program}

name _are used.

PUBLIC: The PUBLIC _pseudo-op

_identifies

_{those symbols}

_within

_the

current

program which are

to

be made accessible

to

other _programs as

external

symbols.

_This

_directive

has _no

_effect

_on

_the

assembly _process

_for

the

_current

_program, but merely records the name and

value of the

_identified

symbols _on

_{the object}

_file

_for

later

use by the

linking

loader. A

_public

_{symbol must} be _defined

CHAPTER _5: PSEUDO-OPS

.REQUEST: _{Request a}

_library

_search. The _form

_is:

.REQUEST _filename

_{{,fi1ename...}}

This

pseudo-op sends a

_request

_to

ZLINK

_or

_any

_Microsoft

compatible

loader to

search

_{the filenames}

_{in the}

_list

_for

undefined

_external

symbols. The _filename

_in

_the

list

should not

include

_filetypes

_{or device designation.}

ZLINK assumes

the

default

extension .REL _{and the}

_currently

_logged

_{disk drive.}

5.5 REIÁJCATICN BASE PSEUDO-OPS

ASEG: The _Absolute SEGment pseudo-op _never has operands. ASEG

generates

_{non-relocatable}

code.

ASEG

_{sets the location}

_{counter to}

_an

_absolute

_segment

_(actual

address)

_of

_memory. The ASEG

will

default

to

O, _which

_could

cause the module

to write

over

part of

the oFerating system.

_It

is

recommended

_that

each ASEG _be

_{followed with}

an ORG _statement

set

_at

1OOH

or

higher.

COMMON: COMMON _{statements are non-executable, storage}

_allocating

statements.

COMMON

_{assigns variables,}

_arrays,

_and

_{data to}

_a

storage area

called

COMMON _{storage. This}

_{allows various}

_program

modules

_to

share

_the

_same

_storagearea.

The

_lengthof

aCOMMON

area

is the

number

of bytes required to contain the variables,

arrays, anddata declared in the

COMMON

_block,

_{which ends when}

another

_relocation

base pseudo-op

_is

encountered.

CSEG: _The C.ode _SEGment

_directive

_{never has an operand. Code}

assembled

_in

Code

_Relative

mode _{can be loaded}

_into

ROM/PROM.

CSEG _{resets the}

_location

_counter

_to

_{the code}

_relative

_segment

_of

memory. The

location

will

be

that of the

last

CSEG(defaultto

O), _{unless an} ORG

_is

_done

_after

_the CSEG

_to

_{change the}

_location.

However

_the

ORG

_statement

_does

_{not set}

a

hardabsoluteaddress

under CSEG mode. An ORG _{statement under} CSEG _{causes the}

assem-bler

to

add

_the

number

_{of bytes specified}

by

_{the expression}

argument

_{in the}

ORG

_{statement to the}

_last

CSEG _{address loaded.}

For example,

_if

ORG 25

_{is given,}

25

_bytes

will

be added

_{to the}

current

CSEG

_location.

_Then

_csEgwill

_{be loaded. The}

_clearing

effect of

the ORG _statement

_following

CSEG _(and DSEG) _{can be used}

to

give the module _an

_offset.

Rationale

_for

not

_allowing

ORG

_to

set _{an absolute} address

_for

CSEG

_{is to}

_{keep the} CSEG

_relocatable.

CSEG

_is

_the

_default

mode

_of

_{the assembler. ZWsembly begins}

_with

a CSEG

automatically

executed, and

the location

counter in the

Code

_Relative

mode,

_{pointing to location}

O

inthe

CodeRelative

segment

_of

_memory.

_All

subsequent

_instructions

_will

be assembled

into the

Code

_Relative

segment

_of

memory

until

ASEG, DSEG,

_or

COMMON

_is

_executed. CSEG

_is

_{then entered}

_{to return}

_{the assembler}

to

Code

_Relative

mode,

_at

which

_point

_{the location}

_counter