1987-03-02 11:28:52 +00:00
|
|
|
.\" $Header$
|
1987-03-11 14:54:29 +00:00
|
|
|
.TH Z80_AS 6ACK
|
1987-03-02 11:28:52 +00:00
|
|
|
.ad
|
|
|
|
|
.SH NAME
|
|
|
|
|
z80_as \- assembler for Zilog z80
|
|
|
|
|
.SH SYNOPSIS
|
|
|
|
|
~em/lib/z80/as [options] argument ...
|
|
|
|
|
.SH DESCRIPTION
|
|
|
|
|
This assembler is made with the general framework
|
|
|
|
|
described in \fIuni_ass\fP(6). It is an assembler generating relocatable
|
|
|
|
|
object code in \fIack.out\fP(5) format.
|
|
|
|
|
.SH SYNTAX
|
|
|
|
|
.IP registers
|
|
|
|
|
The z80 has six general-purpose 8-bit registers: b, c, d, e, h, l;
|
|
|
|
|
an 8-bit accumulator: a; an 8-bit flag register: f; an 8-bit interrupt
|
|
|
|
|
vector: i; an 8-bit memory refresh register: r; two 16-bit index registers:
|
|
|
|
|
ix, iy; a 16-bit stack pointer: sp; and a 16-bit program counter: pc.
|
|
|
|
|
The general-purpose registers can be paired to form three registers pairs of
|
|
|
|
|
16 bits each: bc, de, hl.
|
|
|
|
|
An alternate set of registers is provided that duplicates the accumulator,
|
|
|
|
|
the flag register, and the general-purpose registers. The "exx"-instruction
|
|
|
|
|
exchanges the contents of the two sets of general-purpose registers; the
|
|
|
|
|
contents of the accumulator and flag register can be exchanged with the contents
|
|
|
|
|
of their alternates by the "ex af, af2"-instruction.
|
|
|
|
|
.IP "addressing modes"
|
|
|
|
|
.nf
|
|
|
|
|
.ta 8n 16n 24n 32n 40n 48n
|
|
|
|
|
syntax meaning
|
|
|
|
|
|
|
|
|
|
expr dependent on the instruction, the
|
|
|
|
|
value of \fIexpr\fP can be immediate
|
|
|
|
|
data or the address of the operand.
|
|
|
|
|
There is no special notation for
|
|
|
|
|
immediate data.
|
|
|
|
|
|
|
|
|
|
(ireg + expr)
|
|
|
|
|
(ireg - expr) the contents of ireg (which must be
|
|
|
|
|
one of the index-registers) + or -
|
|
|
|
|
the - one byte - value of \fIexpr\fP
|
|
|
|
|
yield the address of the operand.
|
|
|
|
|
|
|
|
|
|
(expr) the value of \fIexpr\fP is the address of
|
|
|
|
|
the operand.
|
|
|
|
|
|
|
|
|
|
reg the contents of \fIreg\fP - one of the above-
|
|
|
|
|
mentioned registers - is the operand.
|
|
|
|
|
|
|
|
|
|
(reg) the contents of \fIreg\fP - one of the 16-bit
|
|
|
|
|
registers except pc - is the address of
|
|
|
|
|
the operand.
|
|
|
|
|
|
|
|
|
|
nz, z, nc, c,
|
|
|
|
|
po, pe, p, m the letters indicate a condition-code:
|
|
|
|
|
nonzero, zero, carry, no carry,
|
|
|
|
|
parity odd, parity even, sign positive,
|
|
|
|
|
sign negative respectively. Used by conditional
|
|
|
|
|
jump, call, and return instructions.
|
|
|
|
|
|
|
|
|
|
.fi
|
|
|
|
|
.IP instructions
|
|
|
|
|
The jr-instruction will automatically be replaced by a jp-instruction if the
|
|
|
|
|
target is too remote.
|
|
|
|
|
.SH "SEE ALSO"
|
|
|
|
|
uni_ass(6),
|
|
|
|
|
ack(1),
|
|
|
|
|
ack.out(5),
|
|
|
|
|
.br
|
|
|
|
|
Z80 Users Manual, Joseph J. Carr, Reston Publishing Company, 1980
|
