Description
Create an assembly language source code file containing four functions. If the functions were
written in C, they would look like the following. (Functions Square and SquareRoot are provided in the main program.)
int32_t Add(int32_t a, int32_t b)
{
return a + b ;
}
int32_t Less1(int32_t a)
{
return a – 1 ;
}
int32_t Square2x(int32_t x)
{
return Square(x + x) ;
}
int32_t Last(int32_t x)
{
return x + SquareRoot(x) ;
}
Test your functions using the main program downloaded from here. If you code works correctly,
the display should look like the image on the right. Press the blue pushbutton to cycle through all
the test cases to verify that everything is correct. Color is used to indicate the status of a function:
IMPORTANT – The .thumb_func directive:
The “.thumb_func” assembler directive specifies that the next label is the entry point of a function that contains instructions from the Thumb
subset of the ARM processor and causes the binary representation of instructions that branch to
that label to be generated somewhat differently.
Thus in a source code file that contains more than
one function, it is imperative that you place a
.thumb_func directive immediately before the
entry point label of every function.
Gray Function never called.
Yellow Function given in main program.
Orange Function never returns.
Green Function returning correct value.
Red Function returning incorrect value.
