shithub: mc

Info  •  Files  •  Log  •  Branches

Clean up the blitting code.

    First, simplifies the generation code. Second, tries to use
    the largest 'mov's available.

--- a/6/isel.c

+++ b/6/isel.c

@@ -374,7 +374,8 @@

 static void blit(Isel *s, Loc *to, Loc *from, size_t dstoff, size_t srcoff, size_t sz)

 {

-    size_t i;

+    size_t i, m, modesz;

+    Mode modes[] = {ModeQ, ModeL, ModeW, ModeB, ModeNone};

     Loc *sp, *dp; /* pointers to src, dst */

     Loc *tmp, *src, *dst; /* source memory, dst memory */

@@ -381,23 +382,18 @@

     sp = inr(s, from);

     dp = inr(s, to);

-    /* Slightly funny loop condition: We might have trailing bytes

-     * that we can't blit word-wise. */

-    tmp = locreg(ModeQ);

-    for (i = 0; i < sz/Ptrsz; i++) {

-        src = locmem(i*Ptrsz + srcoff, sp, NULL, ModeQ);

-        dst = locmem(i*Ptrsz + dstoff, dp, NULL, ModeQ);

-        g(s, Imov, src, tmp, NULL);

-        g(s, Imov, tmp, dst, NULL);

-    }

-    /* now, the trailing bytes */

-    tmp = locreg(ModeB);

-    i *= Ptrsz; /* we counted in Ptrsz chunks; now we need a byte offset */

-    for (; i < sz; i++) {

-        src = locmem(i + srcoff, sp, NULL, ModeB);

-        dst = locmem(i + dstoff, dp, NULL, ModeB);

-        g(s, Imov, src, tmp, NULL);

-        g(s, Imov, tmp, dst, NULL);

+    modesz = 8;

+    i = 0;

+    for (m = 0; modes[m] != ModeNone; m++) {

+        tmp = locreg(modes[m]);

+        while (i + modesz <= sz) {

+            src = locmem(i + srcoff, sp, NULL, modes[m]);

+            dst = locmem(i + dstoff, dp, NULL, modes[m]);

+            g(s, Imov, src, tmp, NULL);

+            g(s, Imov, tmp, dst, NULL);

+            i += modesz;

+        }

+        modesz /= 2;

     }

 }