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1.1 root 1: Microsoft Macro Assembler Package
2: Version 5.00
3:
4: If you purchased the Macro Assembler package as an update to a
5: previous version, you did not receive a registration card.
6: This is not a mistake. The update is only available to
7: registered owners, who do not need to reregister.
8:
9: Text files on the Macro Assembler disks are tabbed to save
10: disk space. If your printer does not automatically handle
11: tabs during printing, you must use a print program that
12: expands tabs. For example, use the DOS PRINT program to print
13: this and other document or source files on the disk.
14:
15: ==( MASM.EXE )==
16:
17: New Feature
18:
19: The /LA option has been added to specify a complete listing
20: of all symbols, macros, and false conditionals. It is
21: equivalent to using the .LIST, .LFCOND, .LALL, and .CREF
22: directives throughout the source file. The option overrides
23: any conflicting directives in the source file.
24:
25: Clarification
26:
27: The PTR operator can be used to specify the size of a
28: register indirect operand for a CALL or JMP instruction.
29: However, the size cannot be specified with NEAR or FAR. Use
30: WORD or DWORD instead. (In 80386 32-bit segments, use DWORD
31: or FWORD.) Examples are shown below:
32:
33: ; 8086, 80826, or 80386 16-bit mode
34:
35: jmp WORD PTR [bx] ; Legal near jump
36: call NEAR PTR [bx] ; Illegal near call
37: call DWORD PTR [bx] ; Legal far call
38: jmp FAR PTR [bx] ; Illegal far jump
39:
40: ; 80386 32-bit mode only
41:
42: jmp DWORD PTR [bx] ; Legal near jump
43: call NEAR PTR [bx] ; Illegal near call
44: call FWORD PTR [bx] ; Legal far call
45: jmp FAR PTR [bx] ; Illegal far jump
46:
47: This limitation only applies to register indirect operands.
48: NEAR or FAR can be applied to operands associated with
49: labels. Examples are shown below:
50:
51: jmp NEAR PTR pointer[bx] ; Legal
52: call FAR PTR location ; Legal
53:
54: Correction
55:
56: When evaluating expressions, MASM does 16-bit arithmetic
57: except when the 80386 processor is enabled. If the .386 or
58: .386P directive has been given, MASM does 32-bit arithmetic.
59: This behavior is consistent with earlier versions of MASM,
60: which always did 16-bit arithmetic. The notes in Sections
61: 9.2.1, 9.2.1.5, and 9.2.2 of the Programmer's Guide are
62: incorrect. MASM extends constant operands to 17 bits (33 bits
63: with .386) before calculations, but then truncates the result
64: to 16 bits (32 bits with .386). The EQ and NE operators work
65: on 16-bit operands (32-bit with .386), but the LT, LE, GT, and
66: GE operators work on 17-bit (33-bit with .386) operands.
67:
68: Clarification
69:
70: The @FARDATA predefined equate mentioned in Section 5.1.5 does
71: not exist. References to this equate and examples of it in
72: several parts of the Programmer's Guide are incorrect. In
73: particular, the description of declaring external symbols in
74: Section 8.2 is incomplete and the example is incorrect. You
75: cannot access the segment of an external far data variable
76: with the @FARDATA equate or with the segment name FAR_DATA.
77: Instead you must use the SEG operator as shown below:
78:
79: .FARDATA
80: EXTRN fvar:WORD ; FAR variable in far data
81: .CODE
82: start: ASSUME es:SEG fvar ; Tell the assembler
83: mov ax,SEG fvar ; Tell the processor
84: mov es,ax
85:
86: This is the same limitation described for communal variables
87: in Section 8.4. The reason is that under the DOS segment
88: conventions, multiple far data segments share the same name
89: (FAR_DATA) and have private combine type. Segments with the
90: same name can only be distinguished indirectly using the SEG
91: operator.
92:
93: Clarification
94:
95: New CS assume statements are automatically given each time you
96: use the .CODE directive, as shown below:
97:
98: .CODE TASK1 ; Does ASSUME CS:TASK1_TEXT
99: .
100: .
101: .
102: .CODE TASK2 ; Does ASSUME CS:TASK2_TEXT
103: .
104: .
105: .
106:
107: Clarification
108:
109: The .286P and .386P processor directives enable instructions
110: that are normally used in systems programming. However,
111: some of these instructions do not necessarily require that
112: the processor be in privileged or protected mode.
113:
114: Correction
115:
116: Public absolute symbols must be declared during pass 1. This
117: means that aliases for absolute symbols or other forward
118: references to them will cause errors. For example, the
119: following code generates an error:
120:
121: PUBLIC lines
122: lines EQU rows
123: rows EQU 25
124:
125: This behavior is different than in previous versions of MASM
126: and contrary to the note in Section 8.1.
127:
128: Behavior Change
129:
130: Some errors and questionable practices that were ignored by
131: earlier versions are now flagged as errors. As a result,
132: existing source code may produce errors or warnings.
133: The following are examples:
134:
135: - Labels defined only during pass 1 will cause errors if
136: used in expressions.
137: - A CS assume that changes from pass 1 to pass 2 causes
138: an error.
139: - Constants are now checked for type overflow.
140: - Reserved words used as labels produce warnings.
141: - The OFFSET operator used with a constant produces a
142: warning.
143:
144: Correction
145:
146: The assembler documentation indicates in several places that
147: CX will be 0 following a SCAS or CMPS instruction if no match
148: is found. This is misleading since CX may also be zero after
149: a search or compare in which the last string element matches.
150:
151: Testing the zero flag is more reliable. After a REPNE
152: comparison or scan, the zero flag will be cleared if no match
153: was found. After a REPE comparison or scan, the zero flag
154: will be set if no nonmatch was found. This correction affects
155: the following references:
156:
157: Assembler Reference
158:
159: CMPS instruction, last paragraph
160:
161: SCAS instruction, last paragraph
162:
163: Programmer's Guide
164:
165: Section 18.3, last paragraph of description; in example,
166: change "JCXZ notfound" to "JNZ notfound"
167:
168: Section 18.4, last paragraph of description; in example,
169: change "JCXZ allmatch" to "JZ allmatch"
170:
171: Other Corrections
172:
173: Section Description
174:
175: 5.2.2 The segment align, combine, use, and class types
176: can be given in ANY order.
177:
178: 13.3 Pushing a value DECREASES the value of SP. Popping
179: INCREASES the value.
180:
181: 16.3 When two 16-bit numbers are multiplied with MUL or
182: IMUL, the LEAST-signicant bits of the product will
183: be in AX and the MOST-significant bits in DX.
184:
185: 16.4 To divide a 32-bit number by a 16-bit number with
186: DIV or IDIV, put the LEAST-signicant bits in AX
187: and the MOST-significant bits in DX.
188:
189: 16.5 In several cases, the registers and values
190: described in text do not match those used in the
191: examples. The examples are correct.
192:
193: ==( MASM.EXE, LINK.EXE, and LIB.EXE )==
194:
195: Clarification
196:
197: The description of STACK combine type in Section 5.2.2.3
198: does not explain how multiple initialized stack segments are
199: combined. The total size of the stack is the total size of
200: all stack definitions. LINK puts initialized data for each
201: defined stack segment at the end of the stack. Data initialized
202: in the last segment linked overrides data initialized in
203: previoussegments. This behavior is usually not relevant, since
204: most programs only define one stack of uninitialized data.
205: Stack data cannot be initialized with simplified segment
206: directives.
207:
208: New Feature
209:
210: The /NOE[XTDICTIONARY] option has been added to the linker. It
211: Tells the linker not to use the extended dictionary in
212: searching libraries. Use this option if you redefine a
213: standard-library routine (such as _setargv or _nullcheck) in a
214: program module, or if you get linker error L2044 during
215: linking. This option may slow linking on some programs.
216:
217: The "extended dictionary" is a block of data telling the linker
218: about interlibrary dependencies; that is, for each module in
219: the library, the extended dictionary tells the linker which
220: other modules in the same library are also required. Although
221: the linker can process libraries faster with this information,
222: it has trouble in processing if you redefine symbols (such as
223: the names of standard-library routines) that otherwise would
224: have been defined in one of the modules described in the
225: extended dictionary.
226:
227: One new LINK error message and two LIB messages have been
228: added to support this option. The linker message is shown
229: below:
230:
231: L2044 <name> : symbol multiply defined, use /NOE
232:
233: The message indicates that the linker found what it interprets
234: as a public-symbol redefinition, probably because you have
235: redefined a symbol that is defined in a library. Relink with
236: the /NOE option. If error L2025 results for the same symbol,
237: then you have a genuine symbol-redefinition error.
238:
239: The following LIB messages are new:
240:
241: U4157 insufficient memory, extended dictionary not created
242: U4158 internal error, extended dictionary not created
243:
244: This indicates that LIB could not create an extended
245: dictionary. The library is still valid, but the linker will
246: not be able to take advantage of the extended dictionary to
247: speed linking.
248:
249: New Feature
250:
251: LIB has a new option, /N[OIGNORECASE]. It tells LIB to ignore
252: case when comparing symbols in the extended and regular
253: dictionaries. The default is to ignore case.
254:
255: New Message
256:
257: The following new LINK message warns about a practice that is
258: legal in real mode, but illegal in protected mode:
259:
260: warning L4003: intersegment self-relative fixup at <position>
261:
262: In assembly-language, the warning only occurs if the DOSSEG
263: directive or /DOSSEG linker option is used. It indicates a
264: 16-bit jump to an address in another segment. For example,
265: the following code produces the error:
266:
267: _TEXT SEGMENT
268: EXTRN doit:NEAR
269: jmp _TEXT2:doit
270: .
271: .
272: .
273: _TEXT ENDS
274:
275: _TEXT2 SEGMENT
276: PUBLIC doit
277: doit PROC NEAR
278: .
279: .
280: .
281: doit ENDP
282: _TEXT2 ENDS
283:
284: The warning usually indicates a fatal error in high-level-
285: language programs. It can occur when the /NT option is used
286: to compile a small-model C program.
287:
288: New Messages
289:
290: The following LINK messages are related to quick libraries.
291: See you QuickBASIC or QuickC documentation for details:
292:
293: L2043 Quick Library support module missing
294: L1003 /QUICKLIB, /EXEPACK incompatible
295: L1115 /QUICKLIB, overlays incompatible
296:
297: New Message
298:
299: The following new LIB message warns that a module specified to
300: be replaced does not exist in the library:
301:
302: U4155 <modulename> : module not in library
303:
304: LIB adds the module anyway.
305:
306: ==( CodeView Debugger )==
307:
308: New Feature
309:
310: The /R option has been added to enable the CodeView debugger
311: to use the debug registers (DR0, DR1, DR2, and DR3) of the
312: 80386 processor. The option is ignored if you do not have an
313: 80386 processor.
314:
315: The display does not change to indicate that the debug
316: registers are in use, but debugger operations with
317: tracepoint or trace memory statements (but not with
318: watchpoint statements) will be much faster. Any of the
319: following conditions will prevent the debugger from using
320: debug registers:
321:
322: 1) /E is used.
323: 2) More than four tracepoints are set.
324: 3) A tracepoint watches more than four bytes of memory.
325: 4) A watchpoint is set.
326:
327: Clarification
328:
329: The Pascal expression evaluator described in the CodeView
330: and Utilities manual is not implemented in this version of
331: the CodeView debugger. It will be implemented in the
332: debugger supplied with the next version of Pascal, which
333: will also produce executable files with CodeView symbolic
334: information. Current versions of Pascal do not work with the
335: CodeView debugger.
336:
337: Corrections
338:
339: Section 4.2 of the CodeView and Utilities manual should mention
340: that FORTRAN relational operators do not work with string
341: variables or constants.
342:
343: Use the /Zi option, not /D as indicated in Sections 1.2.2 and
344: 1.2.6, when using BC to compile BASIC programs for the
345: CodeView debugger.
346:
347: Warning
348:
349: Some versions of the GENOA EGA short card are incompatible
350: with CodeView when used with a mouse. You can work around this
351: problem by turning off the mouse with /M.
352:
353: ==( CREF.EXE )==
354:
355: New Feature
356:
357: Cross-reference listing files created with CREF now have an
358: additional symbol. A line number followed by + indicates
359: that a symbol is modified at the given line. For example:
360:
361: TST . . . . . . . . . . . . . . 134# 237 544+
362:
363: The symbol TST is defined at line 134, used at line 237, and
364: modified at line 544.
365:
366: ==( MAKE.EXE )==
367:
368: Warning
369:
370: MAKE considers a backslash immediately followed by a carriage
371: return-line feed to be a continuation character. When it finds
372: this combination in a description file, MAKE concatenates the
373: line immediately following to the current line.
374:
375: If you define a macro that ends in a backslash, make sure that
376: you put a space after the terminating backslash. For example:
377:
378: BINPATH=C:\SRC\BIN\<space><new-line>
379: LIBPATH=C:\SRC\LIB\<space><new-line>
380:
381: New Feature
382:
383: The new /X option has the following syntax:
384:
385: /X <filename>
386:
387: This option redirects errors output by MAKE, or by any
388: programs that MAKE runs, to the given file. If the <filename>
389: argument is a dash (-), MAKE redirects error output to STDOUT.
390: You may send both error output and standard output to the same
391: file by combining the "/X -" form of this option with DOS
392: redirection, as in the following example:
393:
394: MAKE /X - project.mak >make.log
395:
396: DO NOT specify the same file name for /X as the file name
397: following the redirection symbol (>).
398:
399: ==( ERROUT.EXE )==
400:
401: Correction
402:
403: The ERROUT utility does not accept batch files. To redirect
404: standard-error output from a batch file, you must enter a
405: command of the following form:
406:
407: ERROUT COMMAND /c <batchfile>
408:
409: If no /f option is given, ERROUT redirects standard-error
410: output to the standard-output device.
411:
412: ==( Exit Codes )==
413:
414: Exit codes returned by LINK, LIB, and MAKE have changed:
415:
416: Code Meaning
417:
418: 0 No error.
419:
420: 2 Program error. Something was wrong with the
421: commands or files input to the utility.
422:
423: 4 System error, such as a file error or user
424: interrupt.
425:
426:
427: ==( Mixed-Languages Programming Guide )==
428:
429: Correction
430:
431: C recognizes up to 31 characters of symbol names, not eight
432: as stated in Section 1.2.
433:
434: Clarification
435:
436: The example programs for BASIC in Chapter 6 will not work
437: with QuickBASIC Versions 2.0 or 3.0. They will work if you
438: rewrite the function as a subprogram, and omit the DECLARE
439: statement. Functions and DECLARE statements are supported
440: in QuickBASIC 4.0 and in future versions of Microsoft BASIC
441: compilers.
442:
443: Clarification
444:
445: Section 6.6 of the Mixed Languages Programming Guide gives
446: instructions for setting up a call to a high-level language
447: from assembly language. Before you execute a call to a BASIC,
448: Pascal, or FORTRAN routine, declare an additional parameter if
449: the return value is noninteger. This additional parameter must
450: contain the offset address of the return value, for which you
451: must allocate room within the stack segment (normally DGROUP,
452: the same as the default data segment).
453:
454: ==( Macro Files )==
455:
456: New Feature
457:
458: Macro files have been added to the Macro Assembler package.
459: The following files are provided:
460:
461: MIXED.INC For defining assembler procedures
462: that can be called from high-level
463: languages
464:
465: MIXED.DOC Documentation for the macros in
466: MIXED.INC.
467:
468: DOS.INC For calling common DOS interrupts
469:
470: BIOS.INC For calling common BIOS interrupts
471: used on IBM and IBM-compatible computers
472:
473: MACRO.DOC Description, syntax, and reference
474: for using the macros in DOS.INC and
475: BIOS.INC.
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