100 lines
2.7 KiB
Groff
100 lines
2.7 KiB
Groff
.\" $Header$
|
|
.TH M68K2_AS 1
|
|
.ad
|
|
.SH NAME
|
|
m68k2_as \- assembler for Motorola 68000
|
|
.SH SYNOPSIS
|
|
/usr/em/lib/m68k2_as [options] argument ...
|
|
.br
|
|
/usr/em/lib/m68k4_as [options] argument ...
|
|
.SH DESCRIPTION
|
|
This assembler is made with the general framework
|
|
described in \fIuni_ass\fP(6).
|
|
.SH SYNTAX
|
|
.IP registers
|
|
The 68000 has the following registers:
|
|
seven data-registers (d1 - d7), seven address-registers (a1 - a6, sp)
|
|
of which sp is the system stack pointer, a program counter (pc),
|
|
a status register (sr), and a condition codes register (ccr) which is actually
|
|
just the low order byte of the status register.
|
|
.IP "addressing modes"
|
|
.nf
|
|
.ta 8 16 24 32 40 48
|
|
syntax meaning (name)
|
|
|
|
reg contents of `reg' is operand, where `reg' is
|
|
one of the registers mentioned above (register direct)
|
|
|
|
(areg) contents of `areg' is address of operand, where
|
|
`areg' is an address-register
|
|
(address register indirect)
|
|
|
|
(areg)+ same as (areg), but after the address is used,
|
|
`areg' is incremented by the operand length
|
|
(postincrement)
|
|
|
|
-(areg) same as (areg), but before the address is used,
|
|
`areg' is decremented by the operand length
|
|
(predecrement)
|
|
|
|
expr(areg)
|
|
expr(pc) `expr' + the contents of the register yields the
|
|
address of the operand (displacement)
|
|
|
|
expr(areg, ireg)
|
|
expr(pc, ireg) `expr' + the contents of the register + the contents
|
|
of `ireg' yields the address of the operand. `ireg' is
|
|
an address- or a data-register.
|
|
`ireg' may be followed by .w or .l indicating whether
|
|
the size of the index is a word or a long
|
|
(displacement with index)
|
|
|
|
expr `expr' is the address of the operand
|
|
(absolute address)
|
|
|
|
#expr `expr' is the operand (immediate)
|
|
.fi
|
|
|
|
Some instructions have as operand a register list. This list consists of
|
|
one or more ranges of registers separated by '/'s. A register range consists
|
|
of either one register (e.g. d3) or two registers separated by a '-'
|
|
(e.g. a2-a4, or d4-d5). The two registers must be in the same set (address-
|
|
or data-registers) and the first must have a lower number than the second.
|
|
.IP instructions
|
|
Some instructions can have a byte, word, or longword operand.
|
|
This may be indicated by prepending the mnemonic with .b, .w, or .l
|
|
respectively. Default is .w.
|
|
.SH "SEE ALSO"
|
|
uni_ass(6),
|
|
ack(1),
|
|
.br
|
|
MC68000 16-bit microprocessor User's manual, Motorola Inc, 1979
|
|
.SH EXAMPLE
|
|
.sp 2
|
|
.nf
|
|
.ta 8 16 24 32 40 48 56 64
|
|
.define .cii
|
|
|
|
.text
|
|
.cii:
|
|
movem.l a0/d0/d1,.savreg
|
|
move.l (sp)+,a0 ! return address
|
|
move (sp)+,d0 ! destination size
|
|
sub (sp)+,d0 ! destination - source size
|
|
bgt 1f
|
|
sub d0,sp ! pop extra bytes
|
|
bra 3f
|
|
1:
|
|
move (sp),d1
|
|
ext.l d1
|
|
swap d1
|
|
asr #1,d0
|
|
2:
|
|
move.w d1,-(sp)
|
|
sub #1,d0
|
|
bgt 2b
|
|
3:
|
|
move.l a0,-(sp)
|
|
movem.l .savreg,a0/d0/d1
|
|
rts
|
|
.fi
|