1as86(1) General Commands Manual as86(1)
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6 as86 - Assembler for 8086..80386 processors
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9 as86 [-0123agjuw] [-lm[list]] [-n name] [-o obj] [-b[bin]] [-s sym]
10 [-t textseg] src
11 as86_encap prog.s prog.v [prefix_] [as86_options]
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16 as86 is an assembler for the 8086..80386 processors, it's syntax is
17 closer to the intel/microsoft form rather than the more normal generic
18 form of the unix system assembler.
19 The src file can be '-' to assemble the standard input.
21 This assembler can be compiled to support the 6809 cpu and may even
23 work.
24 as86_encap is a shell script to call as86 and convert the created
26 binary into a C file prog.v to be included in or linked with programs
27 like boot block installers. The prefix_ argument is a prefix to be
28 added to all variables defined by the source, it defaults to the name
29 of the source file. The variables defined include prefix_start
30 prefix_size and prefix_data to define and contain the code, plus
31 integers containing the values of all exported labels. Either or both
32 the prog.s and prog.v arguments can be '-' for standard in/out.
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37 -0 start with 16-bit code segment, warn for all instructions > 8086
38 -1 start with 16-bit code segment, warn for all instructions >
40 80186
41 -2 start with 16-bit code segment, warn for all instructions >
43 80286
44 -3 start with 32-bit code segment, don't warn for any instructions.
46 (not even 486 or 586)
47 -a enable partial compatibility with Minix asld. This swaps the
49 interpretation of round brackets and square brackets as well as
50 making alterations to the code generation and syntax for 16bit
51 jumps and calls. ("jmp @(bx)" is then a valid instruction)
52 -g only put global symbols in object or symbol file
54 -j replace all short jumps with similar 16 or 32 bit jumps, the 16
56 bit conditional branches are encoded as a short conditional and
57 a long unconditional branch.
58 -O this causes the assembler to add extra passes to try to use
60 forward references to reduce the bytes needed for some
61 instructions. If the labels move on the last pass the assembler
62 will keep adding passes until the labels all stabilise (to a
63 maximum of 30 passes) It's probably not a good idea to use this
64 with hand written assembler use the explicit br bmi bcc style
65 opcodes for 8086 code or the jmp near style for conditional i386
66 instructions and make sure all variables are defined before they
67 are used.
68 -l produce list file, filename may follow
70 -m print macro expansions in listing
72 -n name of module follows (goes in object instead of source name)
74 -o produce object file, filename follows
76 -b produce a raw binary file, filename may follow. This is a 'raw'
78 binary file with no header, if there's no -s option the file
79 starts at location 0.
80 -s produce an ASCII symbol file, filename follows. The format of
82 this table is designed to be easy to parse for encapsulation and
83 related activities in relation to binary files created with the
84 -b option. If a binary file doesn't start at location zero the
85 first two items in the table are the start and end addresses of
86 the binary file.
87 -u assume undefined symbols are imported-with-unspecified segment.
89 -w- allow the assembler to print warning messages.
91 -t n move all text segment data in segment n+3.
93
95 Special characters
96 * Address of the start of the current line.
98 ; ! Either of these marks the start of a comment. In addition any
100 'unexpected' character at the start of a line is assumed to be a
101 comment (but it's also displayed to the terminal).
102 $ Prefix for hexadecimal numbers, the 'C' syntax, eg 0x1234, is
104 also accepted.
105 % Prefix for binary numbers.
107 # Prefix for immediate operands.
109 [ ] Specifies an indirect operand.
111 Unlike MASM the assembler has no type information on labels just
112 a segment and offset. This means that the way this operator and
113 the immediate prefix work are like traditional assemblers.
114 Examples:
116 mov ax,bx
117 jmp bx
118 Direct register addressing, the jump copies BX into PC.
119 mov ax,[bx]
121 jmp [bx]
122 Simple indirect register addressing, the jump moves the contents
123 of the location specified by BX into the PC.
124 mov ax,#1234
126 Immediate value, ax becomes 1234.
127 mov ax,1234
129 mov ax,_hello
130 mov ax,[_hello]
131 Absolute addressing, ax is set to contents of location 1234.
132 Note the third option is not strictly consistant but is in place
133 mainly for asld compatibility.
134 mov ax,_table[bx]
137 mov ax,_table[bx+si]
138 mov eax,_table[ebx*4]
139 mov ax,[bx+_table]
141 mov ax,[bx+si+_table]
142 mov eax,[ebx*4+_table]
143 Indexed addressing, both formats are ok, I think the first is
144 more correct but I tend to used the second. :-)
145 Conditionals
147 IF, ELSE, ELSEIF, ENDIF
149 Numeric condition
150 IFC, ELSEIFC
152 String compare (str1,str2)
153 FAIL .FAIL
155 Generate user error.
156 Segment related
158 .TEXT .ROM .DATA .BSS
160 Set current segment. These can be preceded by the keyword .SECT
161 LOC Set numeric segment 0=TEXT, 3=DATA,ROM,BSS, 14=MAX. The segment
163 order set by the linker is now 0,4,5,6,7,8,9,A,B,C,D,E,1,2,3.
164 Segment 0 and all segments above 3 are assumed to be text
165 segment. Note the 64k size restrictions are not imposed for
166 segments 3-14.
167 Label type definition
169 EXPORT PUBLIC .DEFINE
171 Export label defined in this object
172 ENTRY Force linker to include the specified label in a.out
174 .GLOBL .GLOBAL
176 Define label as external and force import even if it isn't used.
177 EXTRN EXTERN IMPORT .EXTERN
179 Import list of externally defined labels
180 NB: It doesn't make sense to use imports for raw binary files.
181 .ENTER Mark entry for old binary file (obs)
183 Data definition
185 DB .DATA1 .BYTE FCB
187 List of 1 byte objects.
188 DW .DATA2 .SHORT FDB .WORD
190 List of 2 byte objects.
191 DD .DATA4 .LONG
193 List of 4 byte objects.
194 .ASCII FCC
196 Ascii string copied to output.
197 .ASCIZ Ascii string copied to output with trailing nul byte.
199 Space definition
201 .BLKB RMB .SPACE
203 Space is counted in bytes.
204 .BLKW .ZEROW
206 Space is counted in words. (2 bytes each)
207 COMM .COMM LCOMM .LCOMM
209 Common area data definition
210 Other useful pseudo operations.
212 .ALIGN .EVEN
214 Alignment
215 EQU Define label
217 SET Define re-definable label
219 ORG .ORG
221 Set assemble location
222 BLOCK Set assemble location and stack old one
224 ENDB Return to stacked assemble location
226 GET INCLUDE
228 Insert new file (no quotes on name)
229 USE16 [cpu]
231 Define default operand size as 16 bit, argument is cpu type the
232 code is expected to run on (86, 186, 286, 386, 486, 586)
233 instructions for cpus later than specified give a warning.
234 USE32 [cpu]
236 Define default operand size as 32 bit, argument is cpu type the
237 code is expected to run on (86, 186, 286, 386, 486, 586)
238 instructions for cpus later than specified give a warning. If
239 the cpu is not mentioned the assembler ensures it is >= 80386.
240 END End of compilation for this file.
242 .WARN Switch warnings
244 .LIST Listings on/off (1,-1)
246 .MACLIST
248 Macro listings on/off (1,-1)
249 Macros, now working, the general form is like this.
251 MACRO sax
253 mov ax,#?1
254 MEND
255 sax(1)
256 Unimplemented/unused.
259 IDENT Define object identity string.
261 SETDP Set DP value on 6809
263 MAP Set binary symbol table map number.
265 Registers
267 BP BX DI SI
268 EAX EBP EBX ECX EDI EDX ESI ESP
269 AX CX DX SP
270 AH AL BH BL CH CL DH DL
271 CS DS ES FS GS SS
272 CR0 CR2 CR3 DR0 DR1 DR2 DR3 DR6 DR7
273 TR3 TR4 TR5 TR6 TR7 ST
274 Operand type specifiers
276 BYTE DWORD FWORD FAR PTR PWORD QWORD TBYTE WORD NEAR
277 The 'near and 'far' do not allow multi-segment programming, all
279 'far' operations are specified explicitly through the use of the
280 instructions: jmpi, jmpf, callf, retf, etc. The 'Near' operator
281 can be used to force the use of 80386 16bit conditional
282 branches. The 'Dword' and 'word' operators can control the size
283 of operands on far jumps and calls.
284 General instructions.
286 These are in general the same as the instructions found in any
287 8086 assembler, the main exceptions being a few 'Bcc' (BCC, BNE,
288 BGE, etc) instructions which are shorthands for a short branch
289 plus a long jump and 'BR' which is the longest unconditional
290 jump (16 or 32 bit).
291 Long branches
293 BCC BCS BEQ BGE BGT BHI BHIS BLE BLO BLOS BLT BMI BNE BPC BPL
294 BPS BVC BVS BR
295 Intersegment
297 CALLI CALLF JMPI JMPF
298 Segment modifier instructions
300 ESEG FSEG GSEG SSEG
301 Byte operation instructions
303 ADCB ADDB ANDB CMPB DECB DIVB IDIVB IMULB INB INCB MOVB MULB
304 NEGB NOTB ORB OUTB RCLB RCRB ROLB RORB SALB SARB SHLB SHRB SBBB
305 SUBB TESTB XCHGB XORB
306 Standard instructions
308 AAA AAD AAM AAS ADC ADD AND ARPL BOUND BSF BSR BSWAP BT BTC BTR
309 BTS CALL CBW CDQ CLC CLD CLI CLTS CMC CMP CMPS CMPSB CMPSD CMPSW
310 CMPW CMPXCHG CSEG CWD CWDE DAA DAS DEC DIV DSEG ENTER HLT IDIV
311 IMUL IN INC INS INSB INSD INSW INT INTO INVD INVLPG INW IRET
312 IRETD J JA JAE JB JBE JC JCXE JCXZ JE JECXE JECXZ JG JGE JL JLE
313 JMP JNA JNAE JNB JNBE JNC JNE JNG JNGE JNL JNLE JNO JNP JNS JNZ
314 JO JP JPE JPO JS JZ LAHF LAR LDS LEA LEAVE LES LFS LGDT LGS LIDT
315 LLDT LMSW LOCK LODB LODS LODSB LODSD LODSW LODW LOOP LOOPE
316 LOOPNE LOOPNZ LOOPZ LSL LSS LTR MOV MOVS MOVSB MOVSD MOVSW MOVSX
317 MOVW MOVZX MUL NEG NOP NOT OR OUT OUTS OUTSB OUTSD OUTSW OUTW
318 POP POPA POPAD POPF POPFD PUSH PUSHA PUSHAD PUSHF PUSHFD RCL RCR
319 RDMSR REP REPE REPNE REPNZ REPZ RET RETF RETI ROL ROR SAHF SAL
320 SAR SBB SCAB SCAS SCASB SCASD SCASW SCAW SEG SETA SETAE SETB
321 SETBE SETC SETE SETG SETGE SETL SETLE SETNA SETNAE SETNB SETNBE
322 SETNC SETNE SETNG SETNGE SETNL SETNLE SETNO SETNP SETNS SETNZ
323 SETO SETP SETPE SETPO SETS SETZ SGDT SHL SHLD SHR SHRD SIDT SLDT
324 SMSW STC STD STI STOB STOS STOSB STOSD STOSW STOW STR SUB TEST
325 VERR VERW WAIT WBINVD WRMSR XADD XCHG XLAT XLATB XOR
326 Floating point
328 F2XM1 FABS FADD FADDP FBLD FBSTP FCHS FCLEX FCOM FCOMP FCOMPP
329 FCOS FDECSTP FDISI FDIV FDIVP FDIVR FDIVRP FENI FFREE FIADD
330 FICOM FICOMP FIDIV FIDIVR FILD FIMUL FINCSTP FINIT FIST FISTP
331 FISUB FISUBR FLD FLD1 FLDL2E FLDL2T FLDCW FLDENV FLDLG2 FLDLN2
332 FLDPI FLDZ FMUL FMULP FNCLEX FNDISI FNENI FNINIT FNOP FNSAVE
333 FNSTCW FNSTENV FNSTSW FPATAN FPREM FPREM1 FPTAN FRNDINT FRSTOR
334 FSAVE FSCALE FSETPM FSIN FSINCOS FSQRT FST FSTCW FSTENV FSTP
335 FSTSW FSUB FSUBP FSUBR FSUBRP FTST FUCOM FUCOMP FUCOMPP FWAIT
336 FXAM FXCH FXTRACT FYL2X FYL2XP1
337
339 The Gnu assembler preprocessor provides some reasonable implementations
340 of user biased pseudo opcodes.
341 It can be invoked in a form similar to:
343 gasp [-a...] file.s [file2.s] |
345 as86 [...] - [-o obj] [-b bin]
346 Be aware though that Gasp generates an error for .org commands, if
348 you're not using alternate syntax you can use org instead, otherwise
349 use block and endb. The directive export is translated into .global,
350 which forces an import, if you are making a file using -b use public or
351 .define instead.
352 The GASP list options have no support in as86.
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356 as(1), ld86(1), bcc(1)
357
359 The 6809 version does not support -0, -3, -a or -j.
360 If this assembler is compiled with BCC this is classed as a 'small'
362 compiler, so there is a maximum input line length of 256 characters and
363 the instruction to cpu checking is not included.
364 The checking for instructions that work on specific cpus is probably
366 not complete, the distinction between 80186 and 80286 is especially
367 problematic.
368 The .text and .data pseudo operators are not useful for raw binary
370 files.
371 When using the org directive the assembler can generate object files
373 that may break ld86(1).
374 Mar, 1999 as86(1)