This intrinsic inserts a
QSUB instruction or an equivalent code sequence into the instruction stream generated by the compiler. It enables you to obtain the saturating subtraction of two integers from within your C or C++ code.
The compiler might optimize your code when it detects opportunity to do so, using equivalent instructions from the same family to produce fewer instructions.
is the minuend of the saturating subtraction operation
is the subtrahend of the saturating subtraction operation.
__qsub intrinsic returns the saturating subtraction of
The compiler does not recognize the
__qsub intrinsic when compiling for a
target that does not support the
QSUB instruction. The compiler generates
either a warning or an error in this case, depending on the source language:
- In C code:
Warning: #223-D: function "__qsub" declared implicitly.
- In C++ code:
Error: #20: identifier "__qsub" is undefined.