Chapter 17. H8/300 Dependent Features

111

.h8300sn

Recognize and emit additional instructions for the H8S variant in normal mode, and also make

.int

emit 32 bit numbers rather than the usual (16 bit) for the H8/300 family.

On the H8/300 family (including the H8/300H)

.word

directives generate 16 bit numbers.

17.5. Opcodes

For detailed information on the H8/300 machine instruction set, see [H8/300 Series Programming

Manual]. For information specific to the H8/300H, see [H8/300H Series Programming Manual] (Re 

nesas).

as

implements all the standard H8/300 opcodes. No additional pseudo instructions are needed on this

family.

Four H8/300 instructions (

add

,

cmp

,

mov

,

sub

) are defined with variants using the suffixes

.b

,

.w

,

and

.l

to specify the size of a memory operand.

as

supports these suffixes, but does not require them;

since one of the operands is always a register,

as

can deduce the correct size.

For example, since

r0

refers to a 16 bit register,

mov

r0,@foo

is equivalent to

mov.w

r0,@foo

If you use the size suffixes,

as

issues a warning when the suffix and the register size do not match.