Keil Software — A51/AX51/A251 Macro Assembler and Utilities |
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Appendix C. Listing File Format
This appendix describes the format of the listing file generated by the assembler.
Assembler Listing File Format
The Ax51 assembler, unless overridden by controls, outputs two files: an object file and a listing file. The object file contains the machine code. The listing file contains a formatted copy of your source code with page headers and, if
requested through controls (SYMBOL or XREF), a symbol table. |
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Sample Ax51 Listing |
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A251 |
MACRO |
ASSEMBLER |
ASAMPLE1 |
25/01/2001 15:02:23 PAGE |
1 |
A251 |
MACRO |
ASSEMBLER |
V1.40 |
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OBJECT MODULE PLACED |
IN ASAMPLE1.OBJ |
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ASSEMBLER INVOKED BY: F:\RK\ZX\ASM\A251.EXE ASAMPLE1.A51 XREF |
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LOC |
OBJ |
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LINE |
SOURCE |
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1$NOMOD51
2$INCLUDE (REG52.INC) +1 3 +1 $SAVE
+1 106 +1 $RESTORE
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108 |
NAME |
SAMPLE |
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109 |
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110 |
EXTRN |
CODE |
(PUT_CRLF, PUTSTRING) |
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111 |
PUBLIC |
TXTBIT |
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112 |
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------ |
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113 |
PROG |
SEGMENT CODE |
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------ |
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114 |
PCONST |
SEGMENT CODE |
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------ |
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115 |
VAR1 |
SEGMENT DATA |
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------ |
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116 |
BITVAR |
SEGMENT BIT |
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------ |
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117 |
STACK |
SEGMENT IDATA |
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118 |
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------ |
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119 |
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RSEG |
STACK |
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000000 |
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120 |
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DS |
10H |
; 16 Bytes Stack |
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121 |
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000000 |
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122 |
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CSEG |
AT |
0 |
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123 |
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USING |
0 |
; Register-Bank 0 |
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124 |
; Execution starts at address 0 on power-up. |
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000000 |
020000 |
F |
125 |
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JMP |
START |
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126 |
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------ |
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127 |
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RSEG |
PROG |
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128 |
; first |
set Stack Pointer |
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000000 |
758100 |
F |
129 |
START: |
MOV |
SP,#STACK-1 |
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130 |
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131 |
; Initialize serial interface |
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132 |
; Using |
TIMER |
1 to Generate Baud Rates |
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133 |
; Oscillator frequency = 11.059 MHz |
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000003 |
758920 |
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134 |
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MOV |
TMOD,#00100000B |
;C/T = 0, Mode = 2 |
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000006 |
758DFD |
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135 |
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MOV |
TH1,#0FDH |
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000009 |
D28E |
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136 |
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SETB |
TR1 |
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00000B |
759852 |
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137 |
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MOV |
SCON,#01010010B |
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138 |
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Keil Software — A51/AX51/A251 Macro Assembler and Utilities |
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Listing File Heading
Every page has a header on the first line. It contains the words Ax51 MACRO ASSEMBLER followed by the title, if specified. If the title is not specified, then the module name is used. It is derived from the NAME directive (if specified), or from the root of the source filename. On the extreme right side of the header, the date (if specified) and the page number are printed.
In addition to the normal header, the first page of listing includes the Ax51 listing file header. This header shows the assembler version number, the file name of the object file, if any, and the entire invocation line.
C
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Appendix C. Listing File Format |
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Source Listing
The main body of the listing file is the formatted source listing. A section of formatted source is shown in the following.
Sample Source Listing
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LOC |
OBJ |
LINE |
SOURCE |
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000006 758DFD |
135 |
MOV TH1,#0FDH |
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The format for each line in the listing file depends on the source line that appears |
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on it. Instruction lines contain 4 fields. The name of each field and its meanings |
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is shown in the list below: |
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LOC shows the location relative or absolute (code address) of the first byte of |
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the instruction. The value is displayed in hexadecimal.
OBJ shows the actual machine code produced by the instruction, displayed in
hexadecimal. If the object that corresponds to the printed line is to be fixed up (it contains external references or is relocatable), an F or E is printed after the OBJ field. The object fields to be fixed up contain zeros.
LINE shows the INCLUDE nesting level, if any, the number of source lines
from the top of the program, and the macro nesting level, if any. All values in this field are displayed in decimal numbers.
SOURCE shows the source line as it appears in the file. This line may be
extended onto the subsequent lines in the listing file.
DB, DW, and DD directives are formatted similarly to instruction lines, except the OBJ field shows the data values placed in memory. All data values are shown. If the expression list is long, then it may take several lines in the listing file to display all of the values placed in memory. The extra lines will only contain the LOC and OBJ fields.
The directives that affect the location counter without initializing memory (e.g. ORG, DBIT, or DS) do not use the OBJ field, but the new value of the location counter is shown in the LOC field.
The SET and EQU directives do not have a LOC or OBJ field. In their place the assembler lists the value that the symbol is set to. If the symbol is defined to equal one of the registers, then REG is placed in this field. The remainder of the directive line is formatted in the same way as the other directives.