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.
Note
The compiler might optimize your code when it detects opportunity to do so, using
equivalent instructions from the same family to produce fewer instructions.
Syntax
int __qsub(int val1, int
val2)
Where:
val1
is the minuend of the saturating subtraction operation
val2
is the subtrahend of the saturating subtraction operation.
Return value
The __qsub intrinsic returns the saturating subtraction of
val1 and
val2.
Errors
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.
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