1984-07-12 15:18:13 +00:00
|
|
|
.\" $Header$
|
1984-07-12 14:51:48 +00:00
|
|
|
.TH 6500_AS 1
|
|
|
|
|
.ad
|
|
|
|
|
.SH NAME
|
|
|
|
|
6500_as \- assembler for Mostek 6500
|
|
|
|
|
.SH SYNOPSIS
|
|
|
|
|
/usr/em/lib/6500_as [options] argument ...
|
|
|
|
|
.SH DESCRIPTION
|
|
|
|
|
This assembler is made with the general framework
|
|
|
|
|
described in \fIuni_ass\fP(6).
|
|
|
|
|
.SH "SEGMENTS and TYPES"
|
|
|
|
|
An additional segment, the \fIzeropage\fP, can be started by the
|
|
|
|
|
\&\fI.zero\fP pseudo-instruction.
|
|
|
|
|
Some adressing-modes require an address between 0 and 255.
|
|
|
|
|
Such an address must be defined with the means of the \fI.zero\fP
|
|
|
|
|
pseudo-instruction.
|
|
|
|
|
A plain number between 0 and 255 is not allowed.
|
|
|
|
|
The assembler will complain that it must be a zero page expression.
|
|
|
|
|
.IP example
|
|
|
|
|
\&.zero
|
|
|
|
|
.br
|
|
|
|
|
answer: .space 1
|
|
|
|
|
.br
|
|
|
|
|
\&.text
|
|
|
|
|
.br
|
|
|
|
|
and (answer, x)
|
|
|
|
|
.SH SYNTAX
|
|
|
|
|
.IP expressions
|
|
|
|
|
An two-byte expression followed by the pseudo-operator \fI.h\fP (\fI.l\fP)
|
|
|
|
|
has the value of the higher (lower) byte of the expression.
|
|
|
|
|
\&\fI.h\fP and \fI.l\fP bind stronger than all other operators.
|
|
|
|
|
E.g. -1.h parses as -[1.h] which has value 0.
|
|
|
|
|
You have to write [-1].h to get 0xFF.
|
|
|
|
|
.IP "addressing modes"
|
|
|
|
|
.nf
|
|
|
|
|
.ta 8 16 24 32 40 48
|
|
|
|
|
syntax meaning (name)
|
|
|
|
|
|
|
|
|
|
#expr 8-bit value (immediate)
|
|
|
|
|
|
|
|
|
|
expr address (direct)
|
|
|
|
|
|
|
|
|
|
expr, x expr + contents of x
|
|
|
|
|
or or
|
|
|
|
|
expr, y expr + contents of y
|
|
|
|
|
yields address (indexed)
|
|
|
|
|
|
|
|
|
|
(expr) address of address (only with JMP) (indirect)
|
|
|
|
|
|
|
|
|
|
In the next two addressing modes `expr' has to be
|
|
|
|
|
a zeropage expression.
|
|
|
|
|
|
|
|
|
|
(expr, x) expr + contents of x
|
|
|
|
|
yields address (pre-indexed indirect)
|
|
|
|
|
|
|
|
|
|
(expr), y contents of expr + contents of y
|
|
|
|
|
yields address (post-indexed indirect)
|
|
|
|
|
.fi
|
|
|
|
|
.IP instructions
|
|
|
|
|
There are two mnemonics that do not map onto one machine-instruction:
|
|
|
|
|
`add' and `sub'. `Add mode' maps onto `clc; adc mode'.
|
|
|
|
|
`Sub mode' maps onto `sec; sbc mode'.
|
|
|
|
|
.SH "SEE ALSO"
|
|
|
|
|
uni_ass(6),
|
|
|
|
|
ack(1)
|
