Chapter 17.

H8/300 Dependent Features

17.1. Options

as

has no additional command line options for the Renesas (formerly Hitachi) H8/300 family.

17.2. Syntax

17.2.1. Special Characters

;

is the line comment character.

$

can be used instead of a newline to separate statements. Therefore you may not use

$

in symbol

names on the H8/300.

17.2.2. Register Names

You can use predefined symbols of the form

rnh

and

rnl

to refer to the H8/300 registers as sixteen

8 bit general purpose registers.

n

is a digit from

0

to

7

); for instance, both

r0h

and

r7l

are valid

register names.

You can also use the eight predefined symbols

rn

to refer to the H8/300 registers as 16 bit registers

(you must use this form for addressing).

On the H8/300H, you can also use the eight predefined symbols

ern

(

er0

. . .

er7

) to refer to the

32 bit general purpose registers.

The two control registers are called

pc

(program counter; a 16 bit register, except on the H8/300H

where it is 24 bits) and

ccr

(condition code register; an 8 bit register).

r7

is used as the stack pointer,

and can also be called

sp

.

17.2.3. Addressing Modes

as understands the following addressing modes for the H8/300:

rn

Register direct

@rn

Register indirect

@(d, rn)

@(d:16, rn)

@(d:24, rn)

Register indirect: 16 bit or 24 bit displacement

d

from register

n

. (24 bit displacements are only

meaningful on the H8/300H.)