Optimize DECALN screen alignment fill with row memory replication

1 files changed, 7 insertions, 1 deletions

diff --git a/src/core.c b/src/core.c
index 01218cc..f9d547d 100644
--- a/src/core.c
+++ b/src/core.c
@@ -475,10 +475,16 @@ void term_sc_deccara(struct term *t, const struct csi *csi)
 void term_sc_decaln(struct term *t)
 {
     struct cell fill = { .c = 'E', .fg = TERM_COLOR_FG, .bg = TERM_COLOR_BG };
+    struct cell *row0 = NULL;
     for (int y = 0; y < t->rows; y++) {
         int p = phys_row(t, y);
         struct cell *row = row_cells(t, p);
-        for (int x = 0; x < t->cols; x++) row[x] = fill;
+        if (row0) {
+            memcpy(row, row0, (size_t)t->cols * sizeof(struct cell));
+        } else {
+            for (int x = 0; x < t->cols; x++) row[x] = fill;
+            row0 = row;
+        }
         struct srow *srow = &t->scr.slot[p];
         srow->len = (uint16_t)t->cols;
         srow->flags = RF_TAIL_PADDED;