Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet

SAM4S Series [DATASHEET]

Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14

136

UHADD8 Unsigned Halving Add 8.
condis an optional condition code, see 

.

Rdis the destination register.
Rnis the register holding the first operand.
Rmis 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.

Unsigned Halving Add and Subtract with Exchange and Unsigned Halving Subtract and Add with Exchange.
Syntax

op{cond} {Rd}, Rn, Rm

where:
opis one of:
UHASX Add and Subtract with Exchange and Halving.
UHSAX Subtract and Add with Exchange and Halving.
condis an optional condition code, see 

.

Rdis the destination register.
Rn, Rmare registers holding the first and second operands.
Operation
The UHASX instruction: