You can use predefined symbols of the form r
nh
and
r
nl
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 r
n 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
er
n (
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
.