RealView Compilation Tools - ARM Information Center

Compiler-specific Features
4.7.89 __uhasx intrinsic
This intrinsic inserts a UHASX instruction into the instruction stream generated by the
compiler. It enables you to exchange the halfwords of the second operand, add the high
halfwords and subtract the low halfwords, halving the results.
unsigned int __uhasx(unsigned int val1, unsigned int val2)
Where:
val1
val2
holds the first operand for the subtraction in the low halfword, and the
first operand for the addition in the high halfword
holds the second operand for the subtraction in the high halfword, and the
second operand for the addition in the low halfword.
The __uhasx intrinsic returns:
• the halved subtraction of the high halfword in the second operand from the low
halfword in the first operand
• the halved addition of the high halfword in the first operand and the low halfword
in the second operand.
Example:
unsigned int exchange_add_subtract(unsigned int val1, unsigned int val2)
{
unsigned int res;
}
res = __uhasx(val1,val2); /* res[15:0] = (val1[15:0] - val2[31:16])