
Chapter 2
111
Load Page Select bits when jump or call
110
101
100
Page7
1C00
1FFF
Page6
1BFF
1800
Page5
Page4
1000
13FF
17FF
1400
Page3
Page2
Page1
Page0
C00
FFF
800
BFF
400
7FF
000
3FF
011
010
001
000
Program ROM
A7~A0
A9~A8
A12~A10
RET
RETL
RETI
RETS
CALL
8-level stack
(13-bit address)
PC
2.4.3 Address Mode
Direct and Indirect Address modes are provided for accessing data memory.
In Direct Address mode, the data memory address is specified in the operand
and cannot be changed during run time. The following example illustrates the
direct-addressing mode of data access:
Example:
Direct-addressing mode of data memory access
MOV A, 0x05
; move content of R5 to ACC
MOV 0x10, A
; move content of ACC to R10
BS 0x12, 0
; set bit 0 of R12 to “1”
INC 0x15
; increase R15 by 1
JBS 0x03, 3
; if bit 3 of R3 is “1”, skip
JZ 0x11
; R11=R11+1, if R11=0, skip
In Indirect Address mode, the data memory accessed by the instruction is not
fixed. The data location to be accessed can be modified by the program during
run time. This feature is useful for performing data tables in the data memory.
The R0 register is the Indirect Address access window and R4 contains the real
address. When a program writes the address value N in R4, all the instructions
that access R0 will operate on the location N of the data memory. The
following example will further illustrates the Indirect Address operation:
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Architecture
EM60000 Series User’s Manual
Содержание EM60000 series
Страница 8: ...Contents viii Contents EM60000 Series User s Manual ...
Страница 24: ...Chapter 2 16 Architecture EM60000 Series User s Manual ...
Страница 54: ...Chapter 4 46 Special Function Control EM60000Series User s Manual ...
Страница 80: ...Chapter 5 72 Instruction Set EM60000Series User s Manual ...