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as86(1)								       as86(1)

NAME
       as86 - Assembler for 8086..80386 processors

SYNOPSIS
       as86  [-0123agjuw]  [-lm[list]]	[-n name]  [-o obj] [-b[bin]] [-s sym]
       [-t textseg] src

       as86_encap prog.s prog.v [prefix_] [as86_options]

DESCRIPTION
       as86 is an assembler for the 8086..80386	 processors,  it's  syntax  is
       closer  to the intel/microsoft form rather than the more normal generic
       form of the unix system assembler.

       The src file can be '-' to assemble the standard input.

       This assembler can be compiled to support the 6809  cpu	and  may  even
       work.

       as86_encap  is  a  shell	 script	 to  call as86 and convert the created
       binary into a C file prog.v to be included in or linked	with  programs
       like  boot  block  installers.	The prefix_ argument is a prefix to be
       added to all variables defined by the source, it defaults to  the  name
       of   the	 source	 file.	The  variables	defined	 include  prefix_start
       prefix_size and prefix_data  to	define	and  contain  the  code,  plus
       integers	 containing the values of all exported labels.	Either or both
       the prog.s and prog.v arguments can be '-' for standard in/out.

OPTIONS
       -0     start with 16-bit code segment, warn for all instructions > 8086

       -1     start with 16-bit code segment,  warn  for  all  instructions  >
	      80186

       -2     start  with  16-bit  code	 segment,  warn for all instructions >
	      80286

       -3     start with 32-bit code segment, don't warn for any instructions.
	      (not even 486 or 586)

       -a     enable  partial  compatibility  with  Minix asld. This swaps the
	      interpretation of round brackets and square brackets as well  as
	      making  alterations  to the code generation and syntax for 16bit
	      jumps and calls. ("jmp @(bx)" is then a valid instruction)

       -g     only put global symbols in object or symbol file

       -j     replace all short jumps with similar 16 or 32 bit jumps, the  16
	      bit  conditional branches are encoded as a short conditional and
	      a long unconditional branch.

       -O     this causes the assembler to add extra  passes  to  try  to  use
	      forward	references   to	 reduce	 the  bytes  needed  for  some
	      instructions.  If the labels move on the last pass the assembler
	      will  keep  adding  passes  until the labels all stabilise (to a
	      maximum of 30 passes) It's probably not a good idea to use  this
	      with  hand  written  assembler use the explicit br bmi bcc style
	      opcodes for 8086 code or the jmp near style for conditional i386
	      instructions and make sure all variables are defined before they
	      are used.

       -l     produce list file, filename may follow

       -m     print macro expansions in listing

       -n     name of module follows (goes in object instead of source name)

       -o     produce object file, filename follows

       -b     produce a raw binary file, filename may follow.  This is a 'raw'
	      binary  file  with  no  header, if there's no -s option the file
	      starts at location 0.

       -s     produce an ASCII symbol file, filename follows.  The  format  of
	      this table is designed to be easy to parse for encapsulation and
	      related activities in relation to binary files created with  the
	      -b  option.  If a binary file doesn't start at location zero the
	      first two items in the table are the start and end addresses  of
	      the binary file.

       -u     assume undefined symbols are imported-with-unspecified segment.

       -w-    allow the assembler to print warning messages.

       -t n   move all text segment data in segment n+3.

AS86 SOURCE
       Special characters

       *      Address of the start of the current line.

       ; !    Either  of  these	 marks the start of a comment. In addition any
	      'unexpected' character at the start of a line is assumed to be a
	      comment (but it's also displayed to the terminal).

       $      Prefix  for  hexadecimal	numbers, the 'C' syntax, eg 0x1234, is
	      also accepted.

       %      Prefix for binary numbers.

       #      Prefix for immediate operands.

       [ ]    Specifies an indirect operand.
	      Unlike MASM the assembler has no type information on labels just
	      a	 segment and offset. This means that the way this operator and
	      the immediate prefix work are like traditional assemblers.

	      Examples:
		   mov	   ax,bx
		   jmp	   bx
	      Direct register addressing, the jump copies BX into PC.

		   mov ax,[bx]
		   jmp [bx]
	      Simple indirect register addressing, the jump moves the contents
	      of the location specified by BX into the PC.

		   mov ax,#1234
	      Immediate value, ax becomes 1234.

		   mov ax,1234
		   mov ax,_hello
		   mov ax,[_hello]
	      Absolute	addressing,  ax	 is  set to contents of location 1234.
	      Note the third option is not strictly consistant but is in place
	      mainly for asld compatibility.

		   mov ax,_table[bx]
		   mov ax,_table[bx+si]
		   mov eax,_table[ebx*4]

		   mov ax,[bx+_table]
		   mov ax,[bx+si+_table]
		   mov eax,[ebx*4+_table]
	      Indexed  addressing,  both  formats are ok, I think the first is
	      more correct but I tend to used the second. :-)

       Conditionals

       IF, ELSE, ELSEIF, ENDIF
	      Numeric condition

       IFC, ELSEIFC
	      String compare (str1,str2)

       FAIL .FAIL
	      Generate user error.

       Segment related

       .TEXT .ROM .DATA .BSS
	      Set current segment. These can be preceded by the keyword .SECT

       LOC    Set numeric segment 0=TEXT, 3=DATA,ROM,BSS, 14=MAX.  The segment
	      order  set  by  the linker is now 0,4,5,6,7,8,9,A,B,C,D,E,1,2,3.
	      Segment 0 and all segments  above	 3  are	 assumed  to  be  text
	      segment.	 Note  the  64k	 size restrictions are not imposed for
	      segments 3-14.

       Label type definition

       EXPORT PUBLIC .DEFINE
	      Export label defined in this object

       ENTRY  Force linker to include the specified label in a.out

       .GLOBL .GLOBAL
	      Define label as external and force import even if it isn't used.

       EXTRN EXTERN IMPORT .EXTERN
	      Import list of externally defined labels
	      NB: It doesn't make sense to use imports for raw binary files.

       .ENTER Mark entry for old binary file (obs)

       Data definition

       DB .DATA1 .BYTE FCB
	      List of 1 byte objects.

       DW .DATA2 .SHORT FDB .WORD
	      List of 2 byte objects.

       DD .DATA4 .LONG
	      List of 4 byte objects.

       .ASCII FCC
	      Ascii string copied to output.

       .ASCIZ Ascii string copied to output with trailing nul byte.

       Space definition

       .BLKB RMB .SPACE
	      Space is counted in bytes.

       .BLKW .ZEROW
	      Space is counted in words. (2 bytes each)

       COMM .COMM LCOMM .LCOMM
	      Common area data definition

       Other useful pseudo operations.

       .ALIGN .EVEN
	      Alignment

       EQU    Define label

       SET    Define re-definable label

       ORG .ORG
	      Set assemble location

       BLOCK  Set assemble location and stack old one

       ENDB   Return to stacked assemble location

       GET INCLUDE
	      Insert new file (no quotes on name)

       USE16 [cpu]
	      Define default operand size as 16 bit, argument is cpu type  the
	      code  is	expected  to  run  on  (86,  186,  286, 386, 486, 586)
	      instructions for cpus later than specified give a warning.

       USE32 [cpu]
	      Define default operand size as 32 bit, argument is cpu type  the
	      code  is	expected  to  run  on  (86,  186,  286, 386, 486, 586)
	      instructions for cpus later than specified give  a  warning.  If
	      the cpu is not mentioned the assembler ensures it is >= 80386.

       END    End of compilation for this file.

       .WARN  Switch warnings

       .LIST  Listings on/off (1,-1)

       .MACLIST
	      Macro listings on/off (1,-1)

       Macros, now working, the general form is like this.

	   MACRO sax
	      mov ax,#?1
	   MEND
	   sax(1)

       Unimplemented/unused.

       IDENT  Define object identity string.

       SETDP  Set DP value on 6809

       MAP    Set binary symbol table map number.

       Registers
	      BP BX DI SI
	      EAX EBP EBX ECX EDI EDX ESI ESP
	      AX CX DX SP
	      AH AL BH BL CH CL DH DL
	      CS DS ES FS GS SS
	      CR0 CR2 CR3 DR0 DR1 DR2 DR3 DR6 DR7
	      TR3 TR4 TR5 TR6 TR7 ST

       Operand type specifiers
	      BYTE DWORD FWORD FAR PTR PWORD QWORD TBYTE WORD NEAR

	      The  'near and 'far' do not allow multi-segment programming, all
	      'far' operations are specified explicitly through the use of the
	      instructions:  jmpi, jmpf, callf, retf, etc. The 'Near' operator
	      can be  used  to	force  the  use	 of  80386  16bit  conditional
	      branches.	 The 'Dword' and 'word' operators can control the size
	      of operands on far jumps and calls.

       General instructions.
	      These are in general the same as the instructions found  in  any
	      8086 assembler, the main exceptions being a few 'Bcc' (BCC, BNE,
	      BGE, etc) instructions which are shorthands for a	 short	branch
	      plus  a  long  jump  and 'BR' which is the longest unconditional
	      jump (16 or 32 bit).

       Long branches
	      BCC BCS BEQ BGE BGT BHI BHIS BLE BLO BLOS BLT BMI	 BNE  BPC  BPL
	      BPS BVC BVS BR

       Intersegment
	      CALLI CALLF JMPI JMPF

       Segment modifier instructions
	      ESEG FSEG GSEG SSEG

       Byte operation instructions
	      ADCB  ADDB  ANDB	CMPB  DECB DIVB IDIVB IMULB INB INCB MOVB MULB
	      NEGB NOTB ORB OUTB RCLB RCRB ROLB RORB SALB SARB SHLB SHRB  SBBB
	      SUBB TESTB XCHGB XORB

       Standard instructions
	      AAA  AAD AAM AAS ADC ADD AND ARPL BOUND BSF BSR BSWAP BT BTC BTR
	      BTS CALL CBW CDQ CLC CLD CLI CLTS CMC CMP CMPS CMPSB CMPSD CMPSW
	      CMPW  CMPXCHG  CSEG CWD CWDE DAA DAS DEC DIV DSEG ENTER HLT IDIV
	      IMUL IN INC INS INSB INSD INSW INT INTO  INVD  INVLPG  INW  IRET
	      IRETD  J JA JAE JB JBE JC JCXE JCXZ JE JECXE JECXZ JG JGE JL JLE
	      JMP JNA JNAE JNB JNBE JNC JNE JNG JNGE JNL JNLE JNO JNP JNS  JNZ
	      JO JP JPE JPO JS JZ LAHF LAR LDS LEA LEAVE LES LFS LGDT LGS LIDT
	      LLDT LMSW LOCK LODB LODS	LODSB  LODSD  LODSW  LODW  LOOP	 LOOPE
	      LOOPNE LOOPNZ LOOPZ LSL LSS LTR MOV MOVS MOVSB MOVSD MOVSW MOVSX
	      MOVW MOVZX MUL NEG NOP NOT OR OUT OUTS OUTSB  OUTSD  OUTSW  OUTW
	      POP POPA POPAD POPF POPFD PUSH PUSHA PUSHAD PUSHF PUSHFD RCL RCR
	      RDMSR REP REPE REPNE REPNZ REPZ RET RETF RETI ROL ROR  SAHF  SAL
	      SAR  SBB	SCAB  SCAS  SCASB SCASD SCASW SCAW SEG SETA SETAE SETB
	      SETBE SETC SETE SETG SETGE SETL SETLE SETNA SETNAE SETNB	SETNBE
	      SETNC  SETNE  SETNG  SETNGE SETNL SETNLE SETNO SETNP SETNS SETNZ
	      SETO SETP SETPE SETPO SETS SETZ SGDT SHL SHLD SHR SHRD SIDT SLDT
	      SMSW  STC	 STD STI STOB STOS STOSB STOSD STOSW STOW STR SUB TEST
	      VERR VERW WAIT WBINVD WRMSR XADD XCHG XLAT XLATB XOR

       Floating point
	      F2XM1 FABS FADD FADDP FBLD FBSTP FCHS FCLEX  FCOM	 FCOMP	FCOMPP
	      FCOS  FDECSTP  FDISI  FDIV  FDIVP	 FDIVR FDIVRP FENI FFREE FIADD
	      FICOM FICOMP FIDIV FIDIVR FILD FIMUL FINCSTP  FINIT  FIST	 FISTP
	      FISUB  FISUBR  FLD FLD1 FLDL2E FLDL2T FLDCW FLDENV FLDLG2 FLDLN2
	      FLDPI FLDZ FMUL FMULP FNCLEX FNDISI  FNENI  FNINIT  FNOP	FNSAVE
	      FNSTCW  FNSTENV  FNSTSW FPATAN FPREM FPREM1 FPTAN FRNDINT FRSTOR
	      FSAVE FSCALE FSETPM FSIN FSINCOS FSQRT  FST  FSTCW  FSTENV  FSTP
	      FSTSW  FSUB  FSUBP  FSUBR FSUBRP FTST FUCOM FUCOMP FUCOMPP FWAIT
	      FXAM FXCH FXTRACT FYL2X FYL2XP1

Using GASP
       The Gnu assembler preprocessor provides some reasonable implementations
       of user biased pseudo opcodes.

       It can be invoked in a form similar to:

       gasp   [-a...]  file.s [file2.s] |
	      as86 [...]  - [-o obj] [-b bin]

       Be  aware  though  that	Gasp  generates an error for .org commands, if
       you're not using alternate syntax you can use  org  instead,  otherwise
       use  block  and endb.  The directive export is translated into .global,
       which forces an import, if you are making a file using -b use public or
       .define instead.

       The GASP list options have no support in as86.

SEE ALSO
       as(1), ld86(1), bcc(1)

BUGS
       The 6809 version does not support -0, -3, -a or -j.

       If  this	 assembler  is	compiled with BCC this is classed as a 'small'
       compiler, so there is a maximum input line length of 256 characters and
       the instruction to cpu checking is not included.

       The  checking  for  instructions that work on specific cpus is probably
       not complete, the distinction between 80186  and	 80286	is  especially
       problematic.

       The  .text  and	.data  pseudo  operators are not useful for raw binary
       files.

       When using the org directive the assembler can  generate	 object	 files
       that may break ld86(1).

				   Mar, 1999			       as86(1)
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