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
User Commands 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)
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User Commands as86(1)
-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
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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
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User Commands as86(1)
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.
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.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
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User Commands as86(1)
.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
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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.
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User Commands as86(1)
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.
ATTRIBUTES
See attributes(5) for descriptions of the following
attributes:
+---------------+------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+------------------+
|Availability | developer/bcc |
+---------------+------------------+
|Stability | Uncommitted |
+---------------+------------------+
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).
NOTES
This software was built from source available at
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User Commands as86(1)
https://java.net/projects/solaris-userland. The original
community source was downloaded from
http://homepage.ntlworld.com/robert.debath/dev86/Dev86src-0.16.17.tar.gz
Further information about this software can be found on the
open source community website at
http://homepage.ntlworld.com/robert.debath/dev86/.
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