Release Notes for MPASM™ Assembler v5.06
27 October 2006

Table of Contents

Important MPLINK Linker and MPLAB IDE Compatibility Note

Due to a change in COFF file format, MPASM Assembler v5.00 and later will not be compatible with versions of MPLINK Linker prior to v4.00 or versions of the MPLAB IDE prior to v7.21.

MPASM Assembler v5.00 and later will have backward compatibility to earlier versions at the source level only. Any existing object files or libraries compiled with earlier versions of the tools will not link using new versions of the tools. They will need to be recompiled from source.

If the user attempts to use this release with object files or libraries compiled with earlier versions of MPLAB C18 Compiler, MPLINK Linker, and MPASM Assembler, the error message that will be received will be similar to:

Error - Coff file format for 'C:\mcc18\lib/c018i.o' is out of date.

If the user attempts to use an old version of MPLINK Linker to link object files or libraries compiled with this release, the error message that will be received will be similar to:

Error - Coff file format for 'C:\mcc18\lib/c018i.o' does not appear to be a valid COFF file.

Command Line Device Options Supported

10F200       10F202       10F204       10F206
10F220       10F222

12C508       12C508A      12C509       12C509A
12C671       12C672
12CE518      12CE519      12CE673      12CE674
12CR509A
12F508       12F509       12F510       12F609*
12F615       12F629       12F635       12F675
12F683

14000

16C432       16C433       16C505       16C52
16C54        16C54A       16C54B       16C54C
16C55        16C554       16C557       16C558
16C55A       16C56        16C56A       16C57
16C57C       16C58A       16C58B
16C5X
16C61        16C62        16C620       16C620A
16C621       16C621A      16C622       16C622A
16C62A       16C62B       16C63        16C63A
16C64        16C642       16C64A       16C65
16C65A       16C65B       16C66        16C662
16C67        16C71        16C710       16C711
16C712       16C715       16C716       16C717
16C72        16C72A       16C73        16C73A
16C73B       16C74        16C745       16C747
16C74A       16C74B       16C76        16C765
16C77        16C770       16C771       16C773
16C774       16C781       16C782       16C84
16C923       16C924       16C925       16C926
16CE623      16CE624      16CE625
16CR54       16CR54A      16CR54B      16CR54C
16CR56A      16CR57A      16CR57B      16CR57C
16CR58A      16CR58B      16CR62       16CR620A
16CR63       16CR64       16CR65       16CR72
16CR83       16CR84
16CXX
16F505       16F506       16F54        16F57
16F59        16F610       16F616       16F627
16F627A      16F628       16F628A      16F630
16F631       16F636       16F639       16F648A
16F676       16F677       16F684       16F685
16F687       16F688       16F689       16F690
16F716       16F72        16F73        16F737
16F74        16F76        16F767       16F77
16F777       16F785       16F818       16F819
16F83        16F84        16F84A       16F87
16F870       16F871       16F872       16F873
16F873A      16F874       16F874A      16F876
16F876A      16F877       16F877A      16F88
16F883       16F884       16F886       16F887
16F913       16F914       16F916       16F917
16F946

16HV540      16HV616      16HV785

17C42        17C42A       17C43        17C44
17C752       17C756       17C756A      17C762
17C766
17CR42       17CR43
17CXX

18C242       18C252       18C442       18C452
18C601       18C658       18C801       18C858

18F1220      18F1230      18F1231      18F1320
18F1330      18F1331      18F2220      18F2221
18F2320      18F2321      18F2331      18F2410
18F242       18F2420      18F2423      18F2431
18F2439      18F2450      18F2455      18F248
18F2480      18F24J10     18F24K20*    18F2510
18F2515      18F252       18F2520      18F2523
18F2525      18F2539      18F2550      18F258
18F2580      18F2585      18F25J10     18F25K20
18F2610      18F2620      18F2680      18F2682
18F2685      18F4220      18F4221      18F4320
18F4321      18F4331      18F4410      18F442
18F4420      18F4423      18F4431      18F4439
18F4450      18F4455      18F448       18F4480
18F44J10     18F44K20*    18F4510      18F4515
18F452       18F4520      18F4523      18F4525
18F4539      18F4550      18F458       18F4580
18F4585      18F45J10     18F45K20     18F4610
18F4620      18F4680      18F4682      18F4685
18F6310      18F6390      18F63J11     18F63J90
18F6410      18F6490      18F64J11     18F64J15
18F64J90     18F6520      18F6525      18F6527
18F6585      18F65J10     18F65J11     18F65J15
18F65J50     18F65J90     18F6620      18F6621
18F6622      18F6627      18F6680      18F66J10
18F66J11     18F66J15     18F66J16     18F66J50
18F66J55     18F66J60     18F66J65     18F6720
18F6722      18F67J10     18F67J11     18F67J50
18F67J60     18F8310      18F8390      18F83J11
18F83J90     18F8410      18F8490      18F84J11
18F84J15     18F84J90     18F8520      18F8525
18F8527      18F8585      18F85J10     18F85J11
18F85J15     18F85J50     18F85J90     18F8620
18F8621      18F8622      18F8627      18F8680
18F86J10     18F86J11     18F86J15     18F86J16
18F86J50     18F86J55     18F86J60     18F86J65
18F8720      18F8722      18F87J10     18F87J11
18F87J50     18F87J60     18F96J60     18F96J65
18F97J60

EEPROM16     EEPROM8

RF509AF      RF509AG      RF675F       RF675H
RF675K

*Note: Early adopter part support added since last release

THE PARTS CORRESPONDING TO THESE OPTIONS MAY NOT ALL BE COMMERCIALLY AVAILABLE.

These can be chosen through the introductory screen, on the command line, or in source file.

NOTES:

Operating System Support List for v5.06

MPASMWIN.EXE is the 32-bit Windows version of MPASM Assembler which is distributed with MPLAB IDE and MPLAB C18. It is supported by the following platforms:

Windows 98, Windows NT, Windows ME, Windows 2000, Windows XP

MPASM.EXE is the command-line version of MPASM Assembler which is distributed with MPLAB C18 only. It is supported by the following platforms:

Windows 98, Windows NT, Windows ME, Windows 2000, Windows XP

NOTE: MPASM.EXE does not support device file names greater than an 8.3 format (e.g. p18f87J15.INC). Use MPASMWIN.EXE instead.

Repairs and Enhancements Made Since v5.00

Known Problems

The following is a list of known problems. For a list of limitations, please see MPASM Assembler Help, Troubleshooting, Assembler Limitations.

(1008)
There are no warnings when overflow or underflow occurs during expression evaluation.

(16921 / 23355)
MPASM Assembler generates a COD file which cannot handle line number information for program memory addresses greater than 64K. This adversely affects debugging.
The workaround is to generate a .O file, link with MPLINK Linker, and debug in MPLAB IDE v6.0 or greater.
Here is an example of what might happen. Suppose the source is 
        ORG 0xF00000
        DB 0xAB ; eedata
        ORG 0x0
        MOVLW 3
        MOVLW 4
The disassembly window in MPLAB IDE may appear this way: 
        Disassembly               Source
                                  ORG 0xF00000
        000000 0E03 MOVLW 3       DB 0xAB
                                  ORG 0x0
                                  MOVLW 3
        000000 0E04 MOVLW 4       MOVLW 4
The source line for address 0xF00000 has been associated with the code at address 0x0.

(17236)
Using a symbol other than one introduced by the DEFINE directive as the operand of an IFDEF or IFNDEF directive causes the IFDEF/IFNDEF to possibly be evaluated incorrectly.

(18510)
A file register operand which is greater than the absolute max ram address does not generate a message of any kind.
For example, 
        LIST P=18F452
        MOVWF 0x1000
        END
will assemble without warning.

(18811)
MPASMWIN generates incorrect code for 'goto' targeting a local label.
A 'goto' targeting a local label is generating an instruction where the file register field is set to 0 instead of the local label's value.
The workaround is to use the "$ + n" expression as the target of the 'goto'.

(19703)
The Japanese directory delimiter character on Windows XP-J and Windows ME-J is not accepted by MPASM.
The workaround is to invoke MPASM on the command line with a source file path which does not contain any directory delimiters.

(19788)
MPASM.EXE has problems accepting a file name which contains a space just before the '.' character of the extension. For example, 
        MPASM.EXE /Q "TEST .ASM"
will cause a 'file not found' error, but for MPASMWIN.EXE, this is acceptable.

(20776)
The return value of the MPASMWIN.EXE process (returned by 'spawnvp') does not get stored in the DOS environment variable ERRORLEVEL.

(20986)
When assembling with the '/o' option, a duplicate address label declaration causes no error, warning, or message. For example, the program fragment 
        U1 IDATA
        X  DB 1
        U2 IDATA
        X  DB 2
            CODE
           MOVWF X
assembles quietly, but the definition of X which is used in the MOVWF instruction is not well defined.

(21677)
When using MPASM.EXE without the '/q' option, and an output file is specified to be in a nonexistent directory, then the output file is not generated, but no error message is emitted.
When the '/q' option is used, the message "Couldn't open file..." is emitted. This can be confusing.

(21798)
The length of the command line argument string to mpasm.exe is limited to about 120 characters. Anything beyond that is truncated.

(21988)
MPASM cannot handle a source file with UNIX-style line endings. Please convert line endings to the DOS (CR/LF) format.

(22227)
Error messages are not emitted to standard out.

(22387)
MPASM cannot assemble files in Unicode format.

(22541)
A warning is not emitted if the operand for the PUSHL instruction is less than -128, only if it is less than -255. A warning should be emitted if the operand is less than -128, since the operand is 8 bits wide.

(22660)
When assembling with '/o' and the operand of a DT directive is relocatable but more than 8 bits wide, the linker will fill both bytes of the directive with 16 bits of the operand (instead of truncating the operand to 8 bits for a RETLW instruction): 
        UDATA 0x124
        X RES 1
        CODE 0x100
        DT X
will generate 0x0124 at address 0x100 instead of 0x3424 (RETLW 0x24).

(23071)
The LIST n=nnn directive does not properly format the listing file.

(23490)
As MPASM rescans macro expressions, it searches the substituted arguments for parameters. E.g., 
        #define F(X,Y) X + Y
        Y EQU 2
        movlw F(Y,1)
will yield movlw 2 instead of movlw 3. After Y is substituted in place of X, it is replaced itself by the second argument upon rescanning.

(23747)
MAXROM is defined incorrectly for 17C43.
The following source code: 
        LIST p=17c43
        ORG 0xFFE
        NOP
        ....
        ORG 0xFFFE
        NOP
        ....
        END
Should cause the assembler to emit warning[220] when the code crosses 0x1000. Instead the assembler emits a warning when the code crosses 0x10000.
Also note that "__maxrom 0xFFF" causes the assembler to emit the following error:

Error[126] MAXROM.ASM 3 : Argument out of range (must be greater than or equal to 65535)

As a workaround: 
        LIST p=17c43
        __maxrom 0xFFFF
        __badrom 0x1000 - 0xFFFF
        ORG 0xFFE
        NOP
        ....
        END
Causes the assembler to emit "Invalid ROM location," warning[228], when the code crosses 0x1000.

(24275)
After a file is compiled, the debug information does not seem to be loaded.

(24560)
No error or warning is produced for the following code: 
        bsf   ,1
        END
This assembles as if "bsf 0,1" was given.

(24794)
MPASM generates invalid PIC18 relocation for $+<odd offset>. The following code, containing an invalid goto destination address, assembles without error when generating an object file (18f452): 
                      code 0
                      bra start

        startscn      code 0x100
        start         nop
                      goto $-1
                      bra $

                      end
causing a link-time error:

Error - file 'C:\test\mpasm\gotoneg1.o', section 'startscn', Symbol '_startscn_0102' is not word-aligned.
It can not be used as the target of a call or goto instruction.

However, the assembler generates a warning when assembling equivalent code in absolute mode: 
                      org 0
                      bra start

                      org 0x100
        start         nop
                      goto $-1
                      bra $

                      end

Warning[226] C:\TEST\MPASM\GOTONEG1.ASM 8 : Destination address must be word aligned

(25130)
Incorrect error message given for RES directive.
The following code: 
        list p=18f452
        F CODE
        ORG 1
        foo res 2
        end
produces this message:

Error[158] C:\MPASM\SOURCE\TRES.ASM 4 : Cannot use RES directive with odd number of bytes

RES has a value of 2 which is even. The ORG 1 is causing an odd boundary which is what the error message should describe.

(25131)
The following code does not produce the expected raw data in the coff file nor does it give the user a warning that no memory has been reserved. 
        list p=18f452
        Z CODE
        baz res 1
        end
(26223)
MPASM does not correctly handle Windows CLI and DOS command line string limitations and error diagnostics can be ambiguous or absent.

(26588)
The Processor Type list in the MPASM.EXE GUI (DOS executable) doesn't display all of the processors. Many 16xxx and all 18xxx processors are not shown.
The workaround is to use the MPASMWIN.EXE GUI.

(27088)
MPASM may generate an invalid COFF file when passing an undefined constant as a macro parameter.
For example: 
        RM          MACRO Name,Size
                    LOCAL i    =0
        Name        RES   0
                    GLOBAL Name
                    WHILE i <Size
        Name#v(i)     RES 1
                      i +=1
                    ENDW
                    ENDM
        myuscn      UDATA
                    RM hello,myconstsz ; Should cause an assembly error
        myconstsz  equ  2
                    CODE
                    lfsr  0,hello0
                    END
Assembly of this code causes only a warning, but MPLINK gives an error message "reloc[0] has an invalid r_symndx." while trying to link the COFF file.
MPASM should give an error.
To avoid this problem, the code should define 'myconstsz' before calling the macro, as shown: 
        myconstsz  equ 2
        RM hello, myconstsz
(27165)
MPASM does not give an error when ENDIF is missing; it gives only a warning.
With a macro like: 
        IF (CONST)
        ; no ENDIF
MPASM assembles it and gives no error, only a warning.

(27914)
The assembler gives an error when the FILL macro is used with Address - $. For example, the following code: 
        #include <p16f877a.inc>

        cfill code 0x7f
        fill (clrf PCLATH), H'4FF'-$
        end
causes the assembler to give this error: 
        Operand contains unresolvable labels or is too complex
(28228)
Running the assembler on a file with a '.' in the name, other than the '.' separating the file extension from the base name, for example foo.bar.asm, results in a DOS error: 
        File not found.
Any resulting intermediate or output files will not include the portion of the file name after the first '.' For example, the file name above may cause files named foo.ERR, foo.COD, or foo.LST to be created.

Using MPASM Assembler

Create your source code with any text editor. The file should contain ASCII text only. Assemble your code with the command line:

        mpasm <file>[.asm]
A version of MPASM Assembler is also available for Windows. To invoke this assembler, execute: 
        mpasmwin
from within Windows. You will then be given a Windows interface window. Help on using the interface is provided on-line. MPASMWIN.EXE can also be invoked with parameters or through drag-and-drop. In these cases, the interface screen is not displayed and assembly begins immediately.

Correct any syntax problems, referring to the MPASM Assembler, MPLINK Object Linker, MPLIB Object Librarian User's Guide(DS33014) for syntax help. MPASM assembles with INHX32 as the default hex output, and generates a listing file, error file, and .COD file.

Serial EEPROM Support:

Two "processor" selections are provided to generate byte data - EEPROM8 and EEPROM16. Both generate data in terms of bytes, but EEPROM8 considers a "word" to be 8 bits wide, while EEPROM16 considers a "word" to be 16 bits wide. The "program counter" is always incremented in terms of bytes.

The default size for memory products is 128 bytes. This can be overridden by using the LIST M=<max address> directive. Note that <max address> is always evaluated as a decimal number. The header file MEMORY.INC is provided to define the maximum address for available memory devices. The format of the defined symbols is _<device>; for example, to set the maximum memory size for a 24LCS21, use the directive LIST M=_24LCS21.

The following data generation directives are supported for memory products:

        DW           FILL        ORG
The behavior of other data generation directives is not guaranteed. All other directives are unchanged.

An example of generating a file for programming a memory device is as follows:

;*************************************************
; Generate data for a 8-bit wide memory device.

        LIST    P=EEPROM8, R=DECIMAL
        INCLUDE "MEMORY.INC"
        LIST    M=_24LCS21

#DEFINE MAX_VALUE       255

        ORG     0

;-------------------------------------------------
; Create a packed-byte, null terminated string.

        DW      "Hello World", 0

;-------------------------------------------------
; Create data representing a line.  The X position
; is implied from the position of the data in the
; device.  The Y values are stored in the device.

; First, define an equation for the line.

#DEFINE Line( X )       Slope * X + Y_Intercept

; Now define the values needed for the equation.

Slope                   EQU     10
Y_Intercept             EQU     5

; Declare and initialize the X and Y values.

        VARIABLE        X = 0, Y = Line( X )

; Generate values until the maximum Y value is
; reached or the device is filled up.

        WHILE (Y <= MAX_VALUE) && ($ <= _24LCS21)
           DW   Y
X = X + 1
Y = Line( X )
        ENDW

;-------------------------------------------------
; Perform some checking based on the line data
; generated above.

; If the device filled up before the end of the
; line was reached, generate an error. Otherwise,
; if the device is almost out of room, generate a
; message.

        IF (Y < MAX_VALUE)
           ERROR        "Device is full."
        ELSE
           IF (($+10) > _24LCS21)
              MESSG     "Device is nearly full."
           ENDIF
        ENDIF

;-------------------------------------------------
; Fill the rest of the device with zeroes.

        FILL    0, _24LCS21 - $ + 1

        END
CLRW COMMAND:

The CLRW encoding was changed on all 14-bit core devices from 0x0100 to 0x0103 (v1.40 and later). This will not affect the expected operation of the instruction, but it will change the value for the instruction in the hex file and therefore the checksum.

WARNING MESSAGE:

The text for Message #302 was modified to explain more clearly that bank indication bits are stripped when assembling instructions that access file registers. The appropriate bank must be selected by the appropriate bank selection bits. For example, 14-bit core devices contain the lower seven bits of the file register address in the opcode, with two bank selection bits in the STATUS register. The message was changed from:

        Argument out of range. Least significant bits used.
to:
        Register in operand not in bank 0. Ensure that bank bits are correct.
END DIRECTIVE:

Take care to not use the END directive in a macro. If the END directive is encountered in a macro, it can cause the assembler to loop indefinitely. Macros should be terminated with the ENDM directive.

Customer Support


Microchip provides online support via our home page at:
http://www.microchip.com

Technical support is available through the web site at:
http://support.microchip.com

A forum for discussion of Microchip products and tools is available at:
http://forum.microchip.com