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
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
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
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.
.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
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
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 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 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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