Introduction

This chapter describes the Watcom Assembler. It takes as input an assembler source file (a file with extension .a) and produces, as output, an object file.

The Watcom Assembler command-line syntax is as follows:

wasm [options] asm_file [options] [@env_var]

The square brackets [ ] denote items that are optional.

asm_file

is the filename specification of the assembler source file to be assembled. A default filename extension of .a is assumed when no extension is specified.

options

is a list of valid Watcom Assembler options, each preceded by a dash (-). Options may be specified in any order.

The options supported by the Watcom Assembler are as follows:

{0,1,2,3,4,5}{p}{r,s}

0

same as .8086

1

same as .186

2{p}

same as .286 or .286p

3{p}

same as .386 or .386p (also defines __386__, and changes the default USE attribute of segments from USE16 to USE32)

4{p}

same as .486 or .486p (also defines __386__, and changes the default USE attribute of segments from USE16 to USE32)

5{p}

same as .586 or .586p (also defines __386__, and changes the default USE attribute of segments from USE16 to USE32)

p

protect mode

r

defines __REGISTER__

s

defines __STACK__

For example,

    -2       -3p     -4pr     -5p
      

bt=os

defines __os__, and checks the os_INCLUDE environment variable for include files

c

don't output OMF COMENT records that allow wdisasm to figure out when data bytes have been placed in a code segment

dname[=text]

define text macro

d1

line number debugging support

e

stop reading assembler source file at the END directive. Normally, anything following the END directive causes an error.

enumber

set error limit number

fe=file_name

set error file name

fo=file_name

set object file name

fi=file_name

force file_name to be included

fpc

same as .no87

fpi

inline 80x87 instructions with emulation

fpi87

inline 80x87 instructions

fp0

same as .8087

fp2

same as .287 or .287p

fp3

same as .387 or .387p

fp5

same as .587 or .587p

i=directory

add directory to list of include directories

j or s

force signed types to be used for signed values

m{t,s,m,c,l,h,f}

memory model: (Tiny, Small, Medium, Compact, Large, Huge, Flat)

-mt

Same as .model tiny

-ms

Same as .model small

-mm

Same as .model medium

-mc

Same as .model compact

-ml

Same as .model large

-mh

Same as .model huge

-mf

Same as .model flat

Each of the model directives also defines __model__ (for example, .model small defines __SMALL__). They also affect whether something like foo proc is considered a far or near procedure.

nd=name

set data segment name

nm=name

set module name

nt=name

set name of text segment

o

allow C form of octal constants

zq or q

operate quietly

? or h

print a help message

wnumber

set the warning level number

we

treat all warnings as errors