.so macro
.he 'AS68''AS68'
.pr PROGRAM AS
as68 - assembler for the Motorola 68000
.us USAGE
as68 [-i] [-p] [-u] [-a] [-N] sourcefile
.fn FUNCTION
\&'as68' is the REGULUS 68000 assembler.
It is used to assemble a program for the Motorola 68000.
The syntax accepted is identical to the Motorola 68000 cross assembler as
described in Motorola Manual M68KXASM(D3) with the exceptions and
additions described below.
The source file must be present as the first argument.
The assembler always produces a relocatable object file whose name
is the same as the source file primary name with a ".o" extension --
ie. if the source file name is "test.s" then the object file name is
"test.o"; if the source file name is "pgm1" then the object file
name is "pgm1.o".
.sp
The -i option is used to initialize the assembler in the case that
the file '/lib/as68symb' does not exist or becomes corrupted.  It
also requires the use of the initialization file /lib/as68init.
The command would be of the form : 'as68 -i /lib/as68init'.
.sp
If the -p flag is specified, the assembler produces a hexidecimal
side-by-side listing on the standard output
(you may want to redirect this to a file).
Error messages are also produced on the standard output file whether or not
the -p flag is specified.
.sp
If the -u flag is specified, all undefined symbols in the assembly
are treated as global.
.sp
If the -a flag is specified, all address constants are generated
as 16-bit numbers.
Default is 32-bit numbers for all externals.
.sp
If the -N flag is specified, pass 1.5 of the assembler is not executed.
This pass changes all long relative branches to short relative branches
where possible.
.sp
Error messages begin with an &,
indicate the source line on which the error occurred
and are meant to be self-explanatory.
The error messages preceded by a single '&' are generated during the
first pass of the assembler and those preceded by a pair '&&' are
generated during the second pass of the assembler.
.sp
The assembler accepts both upper and lower case characters.
Labels and variables are case sensitive ('LOOP' is different
from 'Loop'), but mnemonics and directives can be in either upper
or lower case.
.sp
Macros are implemented using the C preprocessor which is part of the
cc68 command (see C68(cmnd)).
Conditional assembly is also implemented using the
preprocessor.
Use the command "cc -P pgm.s" to expand macros using the C preprocessor.
The expanded file is left on pgm.i.
.sp
.fl FILES
/lib/as68symb
.br
/tmp/a6????A (???? is the process id number)
.br
/lib/as68init
.sa SEE ALSO
as68 (misc), lo68 (cmnd), c68 (cmnd)
.ex EXTRAS
The following enhancements have been added to aid the assembly language
programmer by making the assembly language more regular:
.sp
move, add, sub mnemonics will actually generate moveq, addq, and suba
instructions where possible.
If a move instruction rather than a moveq instruction is desired (affecting
only lower byte or word of D register), the size attribute must be
explicitly coded ie. move.b or move.w.
The assembler will change any
move or move.l to moveq if possible.
.sp
clr.x An is allowed and will actually generate a suba.x An,An instruction.
.sp
add, sub, cmp with an A register source/destination are allowed and
generate adda, suba, cmpa.
.sp
add, and, cmp, eor, or, sub are allowed with immediate first operands
and actually generate addi, andi, cmpi, eori, ori, subi instructions
if the second operand is not register direct.
.sp
All branch instructions generate short relative branches where
possible, including forward references.
.sp
Any shift instruction with no shift count specified assumes a shift count
of one; ie. "asl r1" is equivalent to "asl #1,r1".
.sp
jsr instructions are changed to bsr instructions if the resulting
bsr is shorter than the jsr.
.sp
The mnemonics 'inc' and 'dec' are also recognized and are functionally
equivilent to "addq 1" or "subq 1".
.sp
Several additional mnemonics have been added to the condition code
instructions which map to the standard set (bt -> bra, bhs
-> bhis, bnz -> bne, bze -> beq, dbhs -> dbhi,
dblo -> dbcs, dbnz -> dbne, dbze -> dbeq, shs
-> scc, slo -> scc, snz -> sne, sze -> seq).
.bg BUGS
\&.set is currently implemented as a .equ.
.sp
There are several directives which are recognized but ignored:
mask2, idnt, ttl, opt, and page.
.sp
PC relative addressing mode is currently not supported.
