122
CHAPTER 5 CPU ARCHITECTURE
5.4 Operand Address Addressing
The following methods are available to specify the register and memory (addressing) which undergo manipulation
during instruction execution.
5.4.1 Implied addressing
[Function]
The register which functions as an accumulator (A and AX) in the general register is automatically (implicitly)
addressed.
Of the
µ
PD78078 and 78078Y Subseries instruction words, the following instructions employ implied addressing.
Instruction
Register to be Specified by Implied Addressing
MULU
A register for multiplicand and AX register for product storage
DIVUW
AX register for dividend and quotient storage
ADJBA/ADJBS
A register for storage of numeric values which become decimal correction targets
ROR4/ROL4
A register for storage of digit data which undergoes digit rotation
[Operand format]
Because implied addressing can be automatically employed with an instruction, no particular operand format is
necessary.
[Description example]
In the case of MULU X
With an 8-bit x 8-bit multiply instruction, the product of A register and X register is stored in AX. In this example,
the A and AX registers are specified by implied addressing.
Summary of Contents for PD78076
Page 2: ...2 MEMO ...
Page 12: ...12 MEMO ...
Page 48: ...48 MEMO ...
Page 64: ...64 MEMO ...
Page 82: ...82 MEMO ...
Page 100: ...100 MEMO ...
Page 130: ...130 MEMO ...
Page 180: ...180 MEMO ...
Page 222: ...222 MEMO ...
Page 248: ...248 MEMO ...
Page 288: ...288 MEMO ...
Page 308: ...308 MEMO ...
Page 364: ...364 MEMO ...
Page 494: ...494 MEMO ...
Page 526: ...526 MEMO ...
Page 544: ...544 MEMO ...
Page 558: ...558 MEMO ...
Page 580: ...580 MEMO ...
Page 596: ...596 MEMO ...
Page 598: ...598 MEMO ...
Page 626: ...626 MEMO ...