190

Chapter 32. PDP 11 Dependent Features

 m11/21

Same as

 mt11

.

 m11/23 |  m11/24

Same as

 mf11

.

 m11/34

Same as

 mkd11e

.

 m11/34a

Ame as

 mkd11e  mfpp

.

 m11/35 |  m11/40

Same as

 mkd11a

.

 m11/44

Same as

 mkd11z

.

 m11/45 |  m11/50 |  m11/55 |  m11/70

Same as

 mkb11

.

 m11/53 |  m11/73 |  m11/83 |  m11/84 |  m11/93 |  m11/94

Same as

 mj11

.

 m11/60

Same as

 mkd11k

.

32.2. Assembler Directives

The PDP 11 version of

as

has a few machine dependent assembler directives.

.bss

Switch to the

bss

section.

.even

Align the location counter to an even number.

32.3. PDP 11 Assembly Language Syntax

as

supports both DEC syntax and BSD syntax. The only difference is that in DEC syntax, a

#

character

is used to denote an immediate constants, while in BSD syntax the character for this purpose is

$

.

eneral purpose registers are named

r0

through

r7

. Mnemonic alternatives for

r6

and

r7

are

sp

and

pc

, respectively.

Floating point registers are named

ac0

through

ac3

, or alternatively

fr0

through

fr3

.