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

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SAM4S Series [DATASHEET]

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

SMUADX Signed Dual Multiply Add Reversed.
SMUSD Signed Dual Multiply Subtract.
SMUSDX Signed Dual Multiply Subtract Reversed.
If X is present, the multiplications are bottom × top and top × bottom.

If the X is omitted, the multiplications are bottom × bottom and top × top.
condis an optional condition code, see 

.

Rdis the destination register.
Rn, Rmare registers holding the first and second operands.
Operation
The SMUAD instruction interprets the values from the first and second operands as two signed halfwords in each 

operand. This instruction: 



Optionally rotates the halfwords of the second operand.



Performs two signed 16 × 16-bit multiplications.



Adds the two multiplication results together.



Writes the result of the addition to the destination register.

The SMUSD instruction interprets the values from the first and second operands as two’s complement signed 

integers. This instruction:



Optionally rotates the halfwords of the second operand.



Performs two signed 16 × 16-bit multiplications.



Subtracts the result of the top halfword multiplication from the result of the bottom halfword multiplication.



Writes the result of the subtraction to the destination register.

Restrictions
In these instructions:



Do not use SP and do not use PC.

Condition Flags
Sets the Q flag if the addition overflows. The multiplications cannot overflow.