English Amiga Board - View Single Post - Blitter fill, writing clearing instead of setting?

a/b · 20 December 2019, 15:22

Code:

/*if (topLeft) {
                    reverse = FALSE;
                    fci = FALSE;
                } else {
                    reverse = TRUE;
                    fci = TRUE;
                }*/
fci = reverse = !topleft;

/*                if (topRight) {
                    reverse = FALSE;
                    fci = TRUE;
                } else {
                    reverse = TRUE;
                    fci = FALSE;
                }*/
reverse = !(fci = topright);

/*            if (bottomRight) {
                reverse = TRUE;
                fci = TRUE;
            } else {
                reverse = FALSE;
                fci = FALSE;
            }*/
fci = reverse = bottomRight;

etc...

Yeah, it's the same code, but 8*6 lines shorter. It's 'easier' to map directly to Scc in asm (I'm sure the produced code is the same, but it's about the idea/hint to give to compiler how to optimize w/o using branches).
And I don't find it any harder to understand, but that's subjective.

20 December 2019, 15:22	#17
a/b Registered User Join Date: Jun 2016 Location: europe Posts: 1,048	Code: /if (topLeft) { reverse = FALSE; fci = FALSE; } else { reverse = TRUE; fci = TRUE; }/ fci = reverse = !topleft; /* if (topRight) { reverse = FALSE; fci = TRUE; } else { reverse = TRUE; fci = FALSE; }/ reverse = !(fci = topright); / if (bottomRight) { reverse = TRUE; fci = TRUE; } else { reverse = FALSE; fci = FALSE; }/ fci = reverse = bottomRight; etc... Yeah, it's the same code, but 86 lines shorter. It's 'easier' to map directly to Scc in asm (I'm sure the produced code is the same, but it's about the idea/hint to give to compiler how to optimize w/o using branches). And I don't find it any harder to understand, but that's subjective.