developer's mag
main page
article
part 1
part 2
part 3
part 4
part 5
part 6
part 7
part 8
part 9
5 - Onto the Code!
Now with all the necessary opcodes under our belt, let's look at our assembly version of the Sieve:
void AssemblySieve(unsigned char *array,int limit)
{
asm("
ldc 3 ; init i/r7
mov t,r7
.i_loop ; label format for our jump
The top of our function shows how we place assembly code into a standard function. The function passes a bitflag array pointer, and a limit on the numbers tested. For simplicity, we pass the array already zeroed, and our code simply sets appropriate bits for the composite numbers.
Notice several things:
- Semicolons are used only for comments, and not to end instructions.
- Lowercase is used for all instructions and registers.
- asm(" introduces the assembly code, while "); at the function's end concludes it.
- .i_loop is a label - this will be the destination of our outer loop's branch.
Previous Section
Next Section