12.30 __smuadx intrinsic
This intrinsic inserts an
SMUADX instruction into the instruction stream generated by the compiler.
you to exchange the halfwords of the second operand, perform two
16-bit signed integer multiplications, and add the products together.
Exchanging the halfwords of the second operand produces top × bottom
and bottom × top multiplication. The Q flag is set if the addition overflows.
The multiplications cannot overflow.
unsigned int __smuadx(unsigned int
holds the first halfword operands for each multiplication
holds the second halfword operands for each multiplication.
__smuadx intrinsic returns the products
of the two 16-bit signed multiplications.
unsigned int exchange_dual_multiply_prods(unsigned int val1, unsigned int val2)
unsigned int res;
res = __smuadx(val1,val2); /* val2[31:16][15:0] = val2[15:0][31:16]
p1 = val1[15:0] × val2[15:0]
p2 = val1[31:16] × val2[31:16]
res[31:0] = p1 + p2