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CHAPTER 5 ADDRESSING
5.2.7 Short direct addressing
[Function]
This type of addressing directly addresses memory subject to manipulation in a fixed space with the 8-bit immediate
data in the instruction word. This kind of addressing can be used with most instructions, and allows various kinds
of data to be manipulated using a small number of bytes and small number of clocks.
With short direct addressing, the applicable address range varies according to the LOCATION instruction in the
same way as the internal data area location addresses. When a LOCATION 0 instruction is executed, internal
RAM from 0FD20H to 0FEFFH and special function registers (SFRs) from 0FF00H to 0FF1FH can be accessed.
When a LOCATION 0FH instruction is executed, internal RAM from 0FFD20H to 0FFEFFH and SFRs from
0FFF00H to 0FFF1FH can be accessed.
Ports frequently accessed in the program, timer/counter unit compare registers and capture registers are mapped
onto the SFR area on which short direct addressing is used. These special function registers can be manipulated
using a small number of bytes and small number of clocks.
[Operand Format]
Performed when an instruction with one of the operand formats shown below is executed.
Identifier
Description Format
saddr
Label or immediate data 0FD20H to 0FF1FH
saddr1
Label or immediate data 0FE00H to 0FEFFH
saddr2
Label or immediate data 0FD20H to 0FDFFH and 0FF00H to 0FF1FH
saddrp
Label or immediate data 0FD20H to 0FF1EH
saddrp1
Label or immediate data 0FE00H to 0FEFEH
saddrp2
Label or immediate data 0FD20H to 0FDFFH and 0FF00H to 0FF1EH
(If 0FDFFH is specified, the high-order byte is 0FE00H)
saddrg
saddrg1
saddrg2
Label or immediate data 0FD20H to 0FEFDH
Label or immediate data 0FE00H to 0FEFDH (during 24-bit manipulation)
Label or immediate data 0FD20H to 0FDFFH (during 24-bit manipulation)
Remark
The addresses in this table are those that apply when the LOCATION 0 instruction is executed.
When the LOCATION 0FH instruction is executed, F0000H should be added to the values shown.
The
μ
PD784915 Subseries is fixed to the LOCATION 0 instruction.