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Compiler-specific Features
4.7.97 __uqsub16 intrinsic
This intrinsic inserts a UQSUB16 instruction into the instruction stream generated by the
compiler. It enables you to perform two unsigned 16-bit integer subtractions, saturating
the results to the 16-bit unsigned integer range 0 ≤ x ≤ 2 16 - 1.
unsigned int __uqsub16(unsigned int val1, unsigned int val2)
Where:
val1
val2
holds the first halfword operands for each subtraction
holds the second halfword operands for each subtraction.
The __uqsub16 intrinsic returns:
• the subtraction of the low halfword in the second operand from the low halfword
in the first operand, in the low halfword of the return value
• the subtraction of the high halfword in the second operand from the high halfword
in the first operand, in the high halfword of the return value.
The results are saturated to the 16-bit unsigned integer range 0 ≤ x ≤ 2 16 - 1.
Example:
unsigned int subtract_halfwords(unsigned int val1, unsigned int val2)
{
unsigned int res;
}
res = __uqsub16(val1,val2); /* res[15:0] = val1[15:0] - val2[15:0]
res[31:16] = val1[31:16] - val2[31:16]
*/
return res;
See also
• ARMv6 SIMD intrinsics on page 4-109
• Instruction summary on page 4-2 in the Assembler Guide
• Parallel add and subtract on page 4-99 in the Assembler Guide.
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