5.6.1 List File Format

The assembly list files arrange the content into columns, with the general form:

line [address] [data]

Each line of the list file has a line number. These numbers relate only to the list file itself and are not associated with the lines numbers in the assembly source file from which the list was generated.

The address, if present, is the address at which any output will appear in the device. This may be a program or data space address, which is determined by the psect in which the line is part of. Look for the first psect directive above the line in question.

The data, if present, represents what is associated with the specified address. If this is an instruction opcode, then the mnemonic for that instruction is shown. Lines that represent lables or content in data memory typically do not show the data field, as there is no assembler output corresponding to those lines. The data can also be a comment, which begins with a semicolon, ;, or an assembler directive.

The following PIC18 example shows a typical list file. Note the movlw instruction, whose opcode is 0E50 at address 746E in program memory and which appears on line 51135 of the list file; the DS directive which reserves data space memory at address 100.


51131                           PSECT brText,class=CODE,space=0,reloc=2
51132                           ; Clear objects in BANK1
51133                           GLOBAL bank1Data
51134  00746A  EE01  F000           lfsr   0,bank1Data
51135  00746E  0E50                 movlw        80
51136  007470                   clear:
51137  007470  6AEE                 clrf postinc0,c
51138  007472  06E8                 decf wreg
51139  007474  E1FD                 bnz  clear
51140  007476  0012                 return
51141  007452                   PSECT        bank1,class=BANK1,space=1,noexec
51142                           bank1Data:
51143  000100                   input:
51144  000100                      DS      2

Provided that the link stage has successfully concluded, the listing file is updated by the linker so that it contains absolute addresses and symbol values. Thus, you can use the assembler list file to determine the position and exact opcodes of instructions. Tick marks “'” in the assembly listing, next to addresses or opcodes, indicate that the linker did not update the list file, most likely due to a build error, or a assembler option that stopped compilation before the link stage. For example, in the following listing:

85  000A' 027F                      subwf   127,w
86  000B' 1D03                      skipz
87  000C' 2800'                     goto    u15

These marks indicate that addresses are just address offsets into their enclosing psect, and that opcodes have not been fixed up. Any address field in the opcode that has not been fixed up is shown with a value of 0.