Datasheet

148
SAM4S Series [DATASHEET]
11100F–ATARM–29-Jan-14
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.
cond is an optional condition code, see “Conditional Execution” .
Rd is the destination register.
Rn, Rm are 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.