PIC24HJ12GP201 Datasheet, PDF (18/234 Pages) Microchip Technology – High-Performance, 16-Bit Microcontrollers

PIC24HJ12GP201/202
2.4 Arithmetic Logic Unit (ALU)
The PIC24HJ12GP201/202 ALU is 16 bits wide and is
capable of addition, 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 reg-
ister array, or data memory, depending on the address-
ing mode of the instruction. Likewise, output data from
the ALU can be written to the W register array or a data
memory location.
Refer to the “dsPIC30F/33F Programmer’s Reference
Manual” (DS70157) for information on the SR bits
affected by each instruction.
The PIC24HJ12GP201/202 CPU incorporates hard-
ware support for both multiplication and division. This
includes a dedicated hardware multiplier and support
hardware for 16-bit divisor division.
2.4.1 MULTIPLIER
Using the high-speed 17-bit x 17-bit multiplier, the ALU
supports unsigned, signed or mixed-sign operation in
several multiplication modes:
1. 16-bit x 16-bit signed
2. 16-bit x 16-bit unsigned
3. 16-bit signed x 5-bit (literal) unsigned
4. 16-bit unsigned x 16-bit unsigned
5. 16-bit unsigned x 5-bit (literal) unsigned
6. 16-bit unsigned x 16-bit signed
7. 8-bit unsigned x 8-bit unsigned
2.4.2 DIVIDER
The divide block supports 32-bit/16-bit and 16-bit/16-bit
signed and unsigned integer divide operations with the
following data sizes:
1. 32-bit signed/16-bit signed divide
2. 32-bit unsigned/16-bit unsigned divide
3. 16-bit signed/16-bit signed divide
4. 16-bit unsigned/16-bit unsigned divide
The quotient for all divide instructions ends up in W0
and the remainder in W1. Sixteen-bit signed and
unsigned DIV instructions can specify any W register
for both the 16-bit divisor (Wn) and any W register
(aligned) pair (W(m + 1):Wm) for the 32-bit dividend.
The divide algorithm takes one cycle per bit of divisor,
so both 32-bit/16-bit and 16-bit/16-bit instructions take
the same number of cycles to execute.
2.4.3 MULTI-BIT DATA SHIFTER
The multi-bit data shifter is capable of performing up to
16-bit arithmetic or logic right shifts, or up to 16-bit left
shifts in a single cycle. The source can be either a
working register or a memory location.
The shifter requires a signed binary value to determine
both the magnitude (number of bits) and direction of the
shift operation. A positive value shifts the operand right.
A negative value shifts the operand left. A value of ‘0’
does not modify the operand.
DS70282B-page 16
Preliminary
© 2007 Microchip Technology Inc.