Справочник Пользователя для Motorola MC68HC908MR16
Central Processor Unit (CPU)
Arithmetic/Logic Unit (ALU)
MC68HC908MR16/MC68HC908MR32 — Rev. 4.0
Advance Information
MOTOROLA
Central Processor Unit (CPU)
77
N — Negative Flag
The CPU sets the negative flag when an arithmetic operation, logic
operation, or data manipulation produces a negative result, setting
bit 7 of the result.
operation, or data manipulation produces a negative result, setting
bit 7 of the result.
1 = Negative result
0 = Non-negative result
0 = Non-negative result
Z — Zero Flag
The CPU sets the zero flag when an arithmetic operation, logic
operation, or data manipulation produces a result of $00.
operation, or data manipulation produces a result of $00.
1 = Zero result
0 = Non-zero result
0 = Non-zero result
C — Carry/Borrow Flag
The CPU sets the carry/borrow flag when an addition operation
produces a carry out of bit 7 of the accumulator or when a subtraction
operation requires a borrow. Some instructions — such as bit test and
branch, shift, and rotate — also clear or set the carry/borrow flag.
produces a carry out of bit 7 of the accumulator or when a subtraction
operation requires a borrow. Some instructions — such as bit test and
branch, shift, and rotate — also clear or set the carry/borrow flag.
1 = Carry out of bit 7
0 = No carry out of bit 7
0 = No carry out of bit 7
6.5 Arithmetic/Logic Unit (ALU)
The ALU performs the arithmetic and logic operations defined by the
instruction set.
instruction set.
Refer to the CPU08 Reference Manual, Motorola document order
number CPU08RM/AD, for a description of the instructions and
addressing modes and more detail about CPU architecture.
number CPU08RM/AD, for a description of the instructions and
addressing modes and more detail about CPU architecture.
6.6 Low-Power Modes
The WAIT and STOP instructions put the MCU in low power-consumption
standby modes.
standby modes.