PIC24FJ128GA MICROCHIP [Microchip Technology], PIC24FJ128GA Datasheet - Page 25

• Manufacturer Part Number: PIC24FJ128GA
• Description: General Purpose, 16-Bit Flash Microcontrollers
• Manufacturer: MICROCHIP [Microchip Technology]

REGISTER 2-2:
2.3
The PIC24 ALU is 16 bits wide and is capable of addi-
tion, subtraction, bit shifts and logic operations. Unless
otherwise mentioned, arithmetic operations are 2’s
complement in nature. Depending on the operation, the
ALU may affect the values of the Carry (C), Zero (Z),
Negative (N), Overflow (OV) and Digit Carry (DC)
Status bits in the SR register. The C and DC Status bits
operate as Borrow and Digit Borrow bits, respectively,
for subtraction operations.
The ALU can perform 8-bit or 16-bit operations,
depending on the mode of the instruction that is used.
Data for the ALU operation can come from the W
register array, or data memory, depending on the
addressing mode of the instruction. Likewise, output
data from the ALU can be written to the W register array
or a data memory location.
© 2006 Microchip Technology Inc.
Upper Byte:
bit 15
bit 15-4
bit 3
bit 2
bit 1-0
U-0
—
Arithmetic Logic Unit (ALU)
Unimplemented: Read as ‘0’
IPL3: CPU Interrupt Priority Level Status bit
1 = CPU interrupt priority level is greater than 7
0 = CPU interrupt priority level is 7 or less
PSV: Program Space Visibility in Data Space Enable bit
1 = Program space visible in data space
0 = Program space not visible in data space
Unimplemented: Read as ‘0’
Legend:
R = Readable bit
-n = Value at POR
Note:
U-0
—
Lower Byte:
bit 7
User interrupts are disabled when IPL3 = 1.
CORCON: CORE CONTROL REGISTER
U-0
—
U-0
—
U-0
—
U-0
—
W = Writable bit
‘1’ = Bit is set
U-0
—
Preliminary
U-0
—
PIC24FJ128GA FAMILY
U-0
—
The PIC24 CPU incorporates hardware support for
both multiplication and division. This includes a dedi-
cated hardware multiplier and support hardware for
16-bit divisor division.
2.3.1
The ALU contains a high-speed 17-bit x 17-bit
multiplier. It supports unsigned, signed or mixed sign
operation in several multiplication modes:
1.
2.
3.
4.
5.
6.
7.
U-0
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
—
16-bit x 16-bit signed
16-bit x 16-bit unsigned
16-bit signed x 5-bit (literal) unsigned
16-bit unsigned x 16-bit unsigned
16-bit unsigned x 5-bit (literal) unsigned
16-bit unsigned x 16-bit signed
8-bit unsigned x 8-bit unsigned
R/C-0
IPL3
MULTIPLIER
U-0
—
R/W-0
PSV
U-0
—
x = Bit is unknown
bit 8
U-0
—
DS39747C-page 23
U-0
—
bit 0