Chapter 32.

PDP 11 Dependent Features

32.1. Options

The PDP 11 version of

as

has a rich set of machine dependent options.

32.1.1. Code Generation Options

 mpic |  mno pic

Generate position independent (or position dependent) code.

The default is to generate position independent code.

32.1.2. Instruction Set Extension Options

These options enables or disables the use of extensions over the base line instruction set as introduced

by the first PDP 11 CPU: the KA11. Most options come in two variants: a

 mextension

that enables

extension

, and a

 mno extension

that disables

extension

.

The default is to enable all extensions.

 mall |  mall extensions

Enable all instruction set extensions.

 mno extensions

Disable all instruction set extensions.

 mcis |  mno cis

Enable (or disable) the use of the commercial instruction set, which consists of these

instructions:

ADDNI

,

ADDN

,

ADDPI

,

ADDP

,

ASHNI

,

ASHN

,

ASHPI

,

ASHP

,

CMPCI

,

CMPC

,

CMPNI

,

CMPN

,

CMPPI

,

CMPP

,

CVTLNI

,

CVTLN

,

CVTLPI

,

CVTLP

,

CVTNLI

,

CVTNL

,

CVTNPI

,

CVTNP

,

CVTPLI

,

CVTPL

,

CVTPNI

,

CVTPN

,

DIVPI

,

DIVP

,

L2DR

,

L3DR

,

LOCCI

,

LOCC

,

MATCI

,

MATC

,

MOVCI

,

MOVC

,

MOVRCI

,

MOVRC

,

MOVTCI

,

MOVTC

,

MULPI

,

MULP

,

SCANCI

,

SCANC

,

SKPCI

,

SKPC

,

SPANCI

,

SPANC

,

SUBNI

,

SUBN

,

SUBPI

, and

SUBP

.

 mcsm |  mno csm

Enable (or disable) the use of the

CSM

instruction.

 meis |  mno eis

Enable (or disable) the use of the extended instruction set, which consists of these instructions:

ASHC

,

ASH

,

DIV

,

MARK

,

MUL

,

RTT

,

SOB SXT

, and

XOR

.