12.31 __smusd intrinsic

This intrinsic inserts an SMUSD instruction into the instruction stream generated by the compiler.

It enables you to perform two 16-bit signed multiplications, taking the difference of the products by subtracting the high halfword product from the low halfword product.

Syntax

unsigned int __smusd(unsigned int val1, unsigned int val2)
Where:
val1
holds the first halfword operands for each multiplication
val2
holds the second halfword operands for each multiplication.

Return value

The __smusd intrinsic returns the difference of the products of the two 16-bit signed multiplications.

Example

unsigned int dual_multiply_prods(unsigned int val1, unsigned int val2)
{
    unsigned int res;
    res = __smuad(val1,val2); /* p1 = val1[15:0] × val2[15:0]
                                 p2 = val1[31:16] × val2[31:16]
                                 res[31:0] = p1 - p2
                               */
    return res;
}
Related reference
9.144 ARMv6 SIMD intrinsics
Related information
SMUSD
ARM and Thumb instruction summary
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