COP8SA-DM National Semiconductor, COP8SA-DM Datasheet - Page 145

• Manufacturer Part Number: COP8SA-DM
• Description: MODULE DEBUGGING FOR COP8SA
• Manufacturer: National Semiconductor

Specifications of COP8SA-DM

• Module/board Type: Debugger Module
• For Use With/related Products: Cop 8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *COP8SA-DM

Syntax:
Description:
Operation:
SUBC A,[B]
SUBC A,#
SUBC A,MD
Instruction
a)SUBC A,[B]
b)SUBC A,#
c)SUBC A,MD
The result is placed back in the accumulator, and the Carry flag is either
reset or set, depending on the presence or absence of a borrow from the
result. Similarly, the Half Carry flag is either reset or set, depending on
the presence or absence of a borrow from the low-order nibble.
This instruction is implemented by adding the one's complement of the
subtrahend to the accumulator and then incrementing the result. Con-
sequently, the borrow is the equivalent of the absence of carry and vice
versa. Similarly, the half carry is the equivalent of the absence of half
borrow and vice versa. A previous borrow (absence of previous carry) will
inhibit the incrementation of the result.
A <- A + VALUE + C
C <- ABSENCE OF BYTE BORROW
HC <- ABSENCE OF LOW NIBBLE HALF BORROW
Register Indirect (B Pointer)
Immediate
Memory Direct
a) The contents of the data memory location referenced by the B
b) The immediate value found in the second byte of the instruction
c) The contents of the data memory location referenced by the ad-
Addressing Mode
pointer are subtracted from the contents of the accumulator, and
the result is simultaneously decremented if the Carry flag is
found previously reset.
is subtracted from the contents of the accumulator, and the result
is simultaneously decremented if the Carry flag is found previ-
ously reset.
dress in the second byte of the instruction are subtracted from
the contents of the accumulator, and the result is simultaneously
decremented if the Carry flag is found previously reset.
Instruction
Cycles
COP8SAx7 MICROCONTROLLER
1
2
4
Bytes Hex Op Code
1
2
3
BD/MA/81
91/Imm.#
81
2-107