Atmel SAM4S-XPLD Atmel ATSAM4S-XPLD ATSAM4S-XPLD Hoja De Datos

 123

SAM4S [DATASHEET]

11100E–ATARM–24-Jul-13

Unsigned Halving Add 16 and Unsigned Halving Add 8

Syntax

op{cond}{Rd,} Rn, Rm

where:

op

is any of:

UHADD16 Unsigned Halving Add 16.

UHADD8 Unsigned Halving Add 8.

cond

Rd

is the destination register.

Rn

is the register holding the first operand.

Rm

is the register holding the second operand.

Operation

Use these instructions to add 16- and 8-bit data and then to halve the result before writing the result to the destination
register:

The UHADD16 instruction:

1.

Adds each halfword from the first operand to the corresponding halfword of the second operand.

2.

Shuffles the halfword result by one bit to the right, halving the data.

3.

Writes the unsigned results to the corresponding halfword in the destination register.

The UHADD8 instruction:

1.

Adds each byte of the first operand to the corresponding byte of the second operand.

2.

Shuffles the byte result by one bit to the right, halving the data.

3.

Writes the unsigned results in the corresponding byte in the destination register.

Restrictions

Do not use SP and do not use PC

Condition Flags

These instructions do not change the flags.

Examples

UHADD16 R7, R3      ; Adds halfwords in R7 to corresponding halfword of R3 

                    ; and writes halved result to corresponding halfword 

                    ; in R7

UHADD8  R4, R0, R5  ; Adds bytes of R0 to corresponding byte in R5 and 

                    ; writes halved result to corresponding byte in R4.