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Chapter 39. Z8000 Dependent Features

39.2.3. Addressing Modes

as understands the following addressing modes for the Z8000:

rln

rhn

rn

rrn

rqn

Register direct: 8bit, 16bit, 32bit, and 64bit registers.

@rn

@rrn

Indirect register: @rr

n

in segmented mode, @r

n

in unsegmented mode.

addr

Direct: the 16 bit or 24 bit address (depending on whether the assembler is in segmented or

unsegmented mode) of the operand is in the instruction.

address(rn)

Indexed: the 16 or 24 bit address is added to the 16 bit register to produce the final address in

memory of the operand.

rn(#imm)

rrn(#imm)

Base Address: the 16 or 24 bit register is added to the 16 bit sign extended immediate displace 

ment to produce the final address in memory of the operand.

rn(rm)

rrn(rm)

Base Index: the 16 or 24 bit register r

n

or rr

n

is added to the sign extended 16 bit index register

r

m

to produce the final address in memory of the operand.

#xx

Immediate data

xx

.

39.3. Assembler Directives for the Z8000

The Z8000 port of as includes additional assembler directives, for compatibility with other Z8000

assemblers. These do not begin with

.

(unlike the ordinary as directives).

segm

.z8001

Generate code for the segmented Z8001.

unsegm