.TH AS6502 1 11/5/84 
.SH NAME
as6502 \- assembler for MOS Technology 650X microprocessors
.SH SYNOPSIS
.B as6502
[ option ] file ...
.SH DESCRIPTION
.I As6502
assembles the named files and produces
a listing on the standard output.
Available options are:
.TP 4
.B \-i
ignore .nlst pseudo ops in the source file.
.TP
.B \-l
produce only an error listing on the standard output.
.TP
.B \-n
print address in normal <high byte><low byte> format,
rather than split <low byte>:<high byte> format.
.TP
.B \-o
generate the ASCII object file
.B "6502.out."
The per-line format of that file is:
.br
    ;<address low byte><address high byte><data>...
.TP
.B \-s
print symbol table at the end of the assembly listing.
.TP
Symbol conventions:
.br
.tr ~|
Up to 19 alphanumeric (a-z ~ A-Z ~ 0-9 ~ . ~ _) characters,
.tr ~~
with initial character non-numeric.
.sp
Asterisk (*) is symbolic name of the location counter.
.TP
Op code mnemonics (upper and/or lower case):
.br
ADC   BIT   BVS   CPX   INC   LDX   PHP   RTI   SEI  TAY
.br
AND   BMI   CLC   CPY   INX   LDY   PLA   RTS   STA  TSX
.br
ASL   BNE   CLD   DEC   INY   LSR   PLP   SBC   STX  TXA
.br
BCC   BPL   CLI   DEX   JMP   NOP   ROL   SEC   STY  TXS
.br
BCS   BRK   CLV   DEY   JSR   ORA   ROR   SED   TAX  TYA
.br
BEQ   BVC   CMP   EOR   LDA   PHA
.TP
Pseudo op mnemonics:
.br
=      equate label to operand value.
.br
*=     equate location counter to operand value.
.br
 .WORD  assign 16 bit operand value to next 2 locations.
.br
 .DBYT  assign 16 bit value to next 2 locations, reverse.
.br
 .BYTE  assign 8 bit operand value to next location.
.br
 .NLST  turn listing mode off.
.br
 .LIST  turn listing mode on.
.TP
Constant types:
.br
%       binary number prefix.
.br
@ or 0  octal number prefix.
.br
$       hexadecimal number prefix.
.br
 '       ASCII character prefix.
.br
 "       ASCII character string prefix and suffix.
.br
default (leading digit 1 through 9)  decimal number.
.TP
Operand field operators:
.br
+     addition               ^     logical exclusive OR
.br
-     subtraction            ~     logical 1's complement
.br
/     integer division       $     logical AND
.br
.tr ||
*     multiplication         |     logical OR
.br
%     modulo                 <     low byte
.br
                             >     high byte
.SH FILES
.PD 0
.TP
/BIN/as6502   the assembler
.TP
6502.out      object (with -o option)
.SH "SEE ALSO"
.TP
J. H. Van Ornum, "as6502 User Notes"
.SH DIAGNOSTICS
.in 0
File handling diagnostics:
.in 15
.ti 5
Invalid argument count - as6502 invoked without a source file or
with too many source files.
.ti 5
Open error for file <name> - as6502 cannot open source file.
.ti 5
Create error (6502.out) - as6502 cannot create object file.
.ti 5
Close error - as6502 cannot close the source file.
.ti 5
Close error (6502.out) - as6502 cannot close object file.
.in 0
Assembly error diagnostics:
.in 15
.ti 5
Symbol table full - symbol table overflowed allotted space.
Number of symbols is a function of symbol sizes.
.ti 5
Label multiply defined - symbol defined more than once.
.ti 5
Sync error - the pass 2 value of symbol in the label field is different
than the pass 1 value.
.ti 5
Invalid operation code - op code mnemonic is invalid.
.ti 5
Operand field missing - the op code mnemonic requires an operand, and none was
found.
.ti 5
Invalid operand field - operand field contains an operator which is not
recognized by as6502.
.ti 5
Invalid branch address - branch instruction to a location which is out of range.
.ti 5
Invalid addressing mode - tried to use an addressing mode which is not
available to the operation code.
.ti 5
Operand field size error - operand is larger than hex FF.
.ti 5
Undefined symbol in operand field - a symbol in the operand field never
appeared in the label field.
.SH BUGS