ATMEGA324P-B_14 Datasheet, PDF (11/344 Pages) ATMEL Corporation – 8-bit Atmel Microcontroller with 16/32/64Kbytes In-system Programmable Flash

• Bit 5 – H: Half Carry Flag
The half carry flag H indicates a half carry in some arithmetic operations. Half carry Is useful in BCD arithmetic. See the
“Instruction Set Description” for detailed information.
• Bit 4 – S: Sign Bit, S = N ⊕ V
The S-bit is always an exclusive or between the negative flag N and the two’s complement overflow flag V. See the
“Instruction Set Description” for detailed information.
• Bit 3 – V: Two’s Complement Overflow Flag
The two’s complement overflow flag V supports two’s complement arithmetics. See the “Instruction Set Description” for
detailed information.
• Bit 2 – N: Negative Flag
The negative flag N indicates a negative result in an arithmetic or logic operation. See the “Instruction Set Description” for
detailed information.
• Bit 1 – Z: Zero Flag
The zero flag Z indicates a zero result in an arithmetic or logic operation. See the “Instruction Set Description” for detailed
information.
• Bit 0 – C: Carry Flag
The carry flag C indicates a carry in an arithmetic or logic operation. See the “Instruction Set Description” for detailed
information.
7.4 General Purpose Register File
The register file is optimized for the AVR enhanced RISC instruction set. In order to achieve the required performance and
flexibility, the following input/output schemes are supported by the register file:
● One 8-bit output operand and one 8-bit result input
● Two 8-bit output operands and one 8-bit result input
● Two 8-bit output operands and one 16-bit result input
● One 16-bit output operand and one 16-bit result input
Figure 7-2 shows the structure of the 32 general purpose working registers in the CPU.
Figure 7-2. AVR CPU General Purpose Working Registers
General
Purpose
Working
Registers
7
0
R0
R1
R2
…
R13
R14
R15
R16
R17
…
R26
R27
R28
R29
R30
R31
Addr.
0x00
0x01
0x02
0x0D
0x0E
0x0F
0x10
0x11
0x1A
0x1B
0x1C
0x1D
0x1E
0x1F
X-register low byte
X-register high byte
Y-register low byte
Y-register high byte
Z-register low byte
Z-register high byte
ATmega164P-B/ATmega324P-B/ATmega644P-B [DATASHEET]
11
9255E–AVR–08/14