12.26 __smlsdx intrinsic
This intrinsic inserts an
SMLSDX instruction into the instruction stream generated by the compiler.
you to exchange the halfwords in the second operand, then perform
two 16-bit signed multiplications. The difference of the products
is added to a 32-bit accumulate operand. The Q bit is set if the
addition overflows. Overflow cannot occur during the multiplications
or the subtraction.
unsigned int __smlsdx(unsigned int
, unsigned int
holds the first halfword operands for each multiplication
holds the second halfword operands for each multiplication
holds the accumulate value.
__smlsd intrinsic returns the difference
of the product of each multiplication, added to the accumulate value.
unsigned int dual_multiply_diff_prods(unsigned int val1, unsigned int val2, unsigned int val3)
unsigned int res;
res = __smlsd(val1,val2,val3); /* p1 = val1[15:0] × val2[31:16]
p2 = val1[31:16] × val2[15:0]
res[31:0] = p1 - p2 + val3[31:0]