HelpPC 2.10 Quick Reference Utility Copyright 1991 David Jurgens

                          Macro Assembler Directives

                     Processor Code Generation Directives

       .186    enables assembly of 80186 instructions
       .286    enables assembly of non privileged 80286 instructions
       .286C   same as .286
       .286P   enables assembly of all 80286 instructions
       .287    enabled assembly of 80287 instructions
       .386    enabled assembly of non privileged 80386 instructions
               If used before .MODEL segments are defined as 32bits.
               Causes all segments to default to DWORD alignment.
       .386P   enabled assembly of all 80386 instructions (see .386)
       .387    enabled assembly of 80387 instructions
       .8086   default, enables assembly of 8088/8086 instruction
       .8087   default, enables assembly of 8087 instructions

       These directives must precede the segment they are to effect.
       they cannot occur within a segment.

                           Memory Model Directives

       .CODE  [name]   starts code segment; must follow .MODEL directive
       .CONST          starts a constant data segment with name CONST;
                       must follow .MODEL directive; placed in DGROUP
       .DATA           starts a near data segment for initialized data
                       with name _DATA; must follow .MODEL directive;
                       placed in DGROUP
       .DATA?          starts a near data segment for uninitialized
                       data with name _BSS; must follow .MODEL
                       directive; placed in DGROUP
       .FARDATA [name] not placed in any group
       .FARDATA? [name] not placed in any group
       .MODEL model    defines memory model to be one of the following:
                       SMALL, COMPACT, MEDIUM, LARGE or HUGE;  must be
                       used prior to any other segment directive
       .STACK [size]   indicates start of stack segment named 'STACK'
                       with size indicating number of bytes to reserve,
                       default is 1k; placed in DGROUP

         Segment Definition, Segment Ordering and Linkage Directives

       .ALPHA          orders segments alphabetically
       .SEQ            orders segments sequentially (default)
       ASSUME sreg:name [,sreg:name...]   selects default segment
                       register to be used by the assembler, not the CPU,
                       for addressing all symbols in the segment or group.
                       Name must be associated with a SEGMENT or GROUP
                       or set to "NOTHING" to indicate no segment register
                       is to be associated.
       COMM def [,def...]  defines variables that are both public and
                       external (communal).  Can be used in and include
                       file to identify it to each source file without
                       declaring it in each model as extern.  Actually
                       defines data once.  Communal variables cannot be
                       initialized, and are not guaranteed to be allocated
                       contiguously since these are allocated by the linker.
       DOSSEG          orders segments the same as DOS.  This is Microsoft
                       languages default order; causes paragph alignment
       END [name]      marks end of source module and sets program
                       start address (CS:IP) if 'name' is present
  name ENDP            ends procedure 'name'
  name ENDS            ends a segment or structure
       EXTRN name:type [,name:type...]  defines one or more external symbols
  name GROUP seg[,seg]
  name LABEL [NEAR|FAR|PROC]  defines an entry point;  If PROC is specified,
                       it's value depends on the current MODEL
       NAME pgmName    ignored since MASM 5.0; used to set module name
  name PROC [NEAR|FAR] defines procedure; NEAR/FAR has .MODEL default
       PUBLIC name[,name...]  makes symbol 'name' available to other modules
  name SEGMENT [align][combine][use]['class']
               align   = BYTE  align on byte address (no alignment)
                       = WORD  align on even address
                       = DWORD align on DWORD address
                       = PARA  align on next 16 byte paragraph
                       = PAGE  align on next 256 byte boundary
               combine = PUBLIC  similar named segments are concatenated (CS)
                       = STACK   similar named segments are concatenated (SS)
                       = COMMON  similar named segment are overlapped
                       = MEMORY  similar names segments are concatenated
                       = AT addr segment relative to absolute address
                       = nothing segment is private and loaded independent
               use     = USE16   segments will be 16 bits (if .386)
                       = USE32   segments will be 32 bits (if .386)

                          Data Allocation Directives

       ALIGN n         aligns next variable or instruction on a boundary
                       that is a multiple of "n".  This can speed memory
                       fetches on 16 and 32 bit CPU'S if aligned.  New to
                       MASM 5.0, previous versions used EVEN.  Can result
                       in NOP's added to code.
[name] DB init[,init...]  define byte
[name] DD init[,init...]  define double word (DWORD, 4 bytes)
[name] DF init[,init...]  define far word (FWORD, 386, 6 bytes)
[name] DQ init[,init...]  define quad word (QWORD, 8 bytes)
[name] DT init[,init...]  define temp word (TBYTE, 10 bytes)
[name] DW init[,init...]  define word (WORD, 2 bytes)
 count DUP (init[,init...]) duplicate 'init' 'count' times; DUP can be
                       nested to 17 levels; DUP'ed initial values
                       of (?) don't result in data in the object file
                       but instead increment the next data addr
  name ENDS            end of structure or segment
       EVEN            same as align 2;  Aligns data on even boundary
       ORG expr        sets location counter to 'expr';  If 'expr'
                       is '$' the code is ORG'ed at the current loc.
  name RECORD fld[,fld...]  defines a byte or word variable
                       consisting of bit fields;  fields have the format:
                       fieldname:width[=expr];  the sum of all widths
                       must be <= 0
[name] STRUC <[init[,init]]>  defines beginning of a structure; Values
                       between <> are initializers;  The '<>' symbols
                       are required.

                     Logical and Bit Oriented Directives

 expr1 AND  expr2      returns nonzero if any set bit matches
 expr1 EQ   expr2      returns (-1) for true or (0) for false
 expr1 GE   expr2      returns (-1) for true or (0) for false
 expr1 LE   expr2      returns (-1) for true or (0) for false
 expr1 LT   expr2      returns (-1) for true or (0) for false
       MASK {fldname|record}  returns bit mask for bits in record
 expr1 OR   expr2      returns bitwise OR on expr1 and expr2
       NOT  expr       returns 'expr' with all bits reversed
  expr SHL  count      returns expr shifted left count times
  expr SHR  count      returns expr shifted right count times
       WIDTH {fldname|record}  returns width of field in bit record
 expr1 XOR expr2       returns bitwise XOR on expr1 and expr2

                        Other Operators and Directives

       []              index operator, same as addition
       .MSFLOAT        encode floats in Microsoft Real Format
       .TYPE   expr    returns byte defining mode and scope of expr
  name EQU     expr    assigns expression to name. surround text with <>
       HIGH    expr    returns high byte of 'expr'
       INCLUDE filespec  inserts code from 'filespec' into file
       INCLUDELIB filespec  stores link library info in .OBJ file
       LENGTH  var     returns number of data objects in DUPed 'var'
       LOW     expr    returns low byte of 'expr'
 expr1 MOD     expr2   return remainder of expr1/expr2
       OFFSET  expr    returns offset of expr;   When .MODEL is used
                       the offset of a group relative segment refers
                       to the end of the segment
  type PTR     expr    forces 'expr' to 'type'
       SEG     expr    returns segment of expression
       SHORT           sets type of label to short, less than 128
                       bytes from start of next instruction
       SIZE    var     returns # of bytes allocated by DUP directive
       THIS    type    returns an operand of specified type whose
                       offset and segment values are equal to the
                       current location
       TYPE    expr    returns type of expression

       Program Listing and Documentation Directives

       .CREF           restores listing of cross reference symbols
       .LALL           include macro expansion in listings
       .LFCOND         include false conditional blocks in listings
       .LIST           starts listing of statements
       .SALL           suppress listing of all macro expansions
       .SFCOND         suppress false conditional blocks in listings
       .XALL           start listing of macro expansion
       .XCREF [name[,name...]]  suppress symbols in cross reference
       .XLIST          suppress program listing
       COMMENT delimiter [text]
       PAGE   [[len],wid]      sets page length&width or ejects if no parms
       SUBTTL  text    defines program listing subtitle
       TITLE   text    defines program listing title

       Condition Assembly Directives

       ELSE            else clause for conditional assembly block
       ENDIF           terminates a conditional assembly block
       IFDEF   name    conditional assembly if name is defined

       Macro Definition Directives

       ENDM            terminates a macro block
       EXITM           exit macro expansion immediately
       IRP  parm,<arg[,arg...]> parm in the statements enclosed by the
                       IRP and ENDM will be repeated and replaced with the
                       values of "arg" for each "arg" in the <>.
       IRPC parm,<string>  parm in the statements enclosed by the IRPC
                       and ENDM will be repeated and replaced with the values
                       of each char in the "string" for each character
                       position in the string.  "string" should be enclosed
                       in <> if it contains spaces or other separators.
       LOCAL name[,name...]  defines scope symbol as local to a macro
  name MACRO [parm[,parm...]]  defines a macro and it's parameters
       PURGE name[,name]  purges macros from memory
       REPT    expr    repeats all statements through ENDM statement for
                       'expr' times

       User Message Directives

       .ERR            generates and error
       .ERR1           generates an error on PASS 1
       .ERR2           generates an error on PASS 2
       .ERRB   <arg>   generates an error if 'arg' is blank
       .ERRDEF name    generates an error if 'name' is previously defined
       .ERRDIF[I] <arg1>,<arg2>
       .ERRE   expr    generates and error is 'expr' is false
       %OUT    text    displays 'text' to console

       Predefined Equates (available only if simplified segments are used)

       @curseg         contains the current segment
       @filename       current file name without extension
       @code           contains the current code segment
       @codesize       0 for small & compact, 1 for large, medium & huge
       @datasize       0 for small & medium, 1 for compact & large, 2=huge
       @const          contains segment of define by .CONST
       @data           contains segment of define by .DATA
       @data?          contains segment of define by .DATA?
       @fardata        contains segment of define by .FARDATA
       @fardata?       contains segment of define by .FARDATA?
       @stack          contains segment of define by .STACK

       Most of these are only available if the simplified segment system
       is used.  @curseg and @filename are available regardless.

       Radix Specifiers

       .RADIX expr     sets radix [2..16] for numbers (dec. default)
       B               binary data specifier
       Q               octal data specifier
       O               octal data specifier
       D               decimal data specifier
       H               hexadecimal data specifier

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