RealView Compilation Tools - ARM Information Center

Compiler-specific Features
4.7.60 __shadd16 intrinsic
This intrinsic inserts a SHADD16 instruction into the instruction stream generated by the
compiler. It enables you to perform two signed 16-bit integer additions, halving the
results.
unsigned int __shadd16(unsigned int val1, unsigned int val2)
Where:
val1
val2
holds the first two 16-bit summands
holds the second two 16-bit summands.
The __shadd16 intrinsic returns:
• the halved addition of the low halfwords from each operand, in the low halfword
of the return value
• the halved addition of the high halfwords from each operand, in the high halfword
of the return value.
Example:
unsigned int add_and_halve(unsigned int val1, unsigned int val2)
{
unsigned int res;
}
res = __shadd16(val1,val2); /* res[15:0] = (val1[15:0] + val2[15:0])