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Addressing Modes
3-12 RISC 16-Bit CPU
3.3.3 Symbolic Mode
The symbolic mode is described in Table 3−6.
Table 3−6.Symbolic Mode Description
Assembler Code Content of ROM
MOV EDE,TONI MOV X(PC),Y(PC)
X = EDE − PC
Y = TONI − PC
Length: Two or three words
Operation: Move the contents of the source address EDE (contents of
PC + X) to the destination address TONI (contents of PC + Y).
The words after the instruction contain the differences
between the PC and the source or destination addresses.
The assembler computes and inserts offsets X and Y
automatically. With symbolic mode, the program counter (PC)
is incremented automatically so that program execution
continues with the next instruction.
Comment: Valid for source and destination
Example: MOV EDE,TONI ;Source address EDE = 0F016h
;Dest. address TONI=01114h
011FEh
Address
Space
0F102h
04090h PC
0FF16h
0FF14h
0FF12h
0xxxxh
0A123h
0F018h
0F016h
0F014h
0xxxxh
0xxxxh
05555h
01116h
01114h
01112h
0xxxxh
0FF14h
+0F102h
0F016h
0FF16h
+011FEh
01114h
Register
Before:
011FEh
Address
Space
0F102h
04090h
PC
0FF16h
0FF14h
0FF12h
0xxxxh
0A123h
0F018h
0F016h
0F014h
0xxxxh
0xxxxh
0A123h
01116h
01114h
01112h
0xxxxh
Register
After:
0xxxxh