diff --git a/output.c b/output.c
index b48713e..171c083 100644
--- a/output.c
+++ b/output.c
@@ -9,11 +9,29 @@ printw(FILE *fp, unsigned char *s, int slen)
     int c;
 
     c = '\n';
-    while (slen--) {
-        fputc((c = *s++), fp);
-        ++col;
-        if (!(col %= WRAPCOL))
-            fputc((c = '\n'), fp);
+    if (col) {
+        if (slen >= WRAPCOL-col) {
+            fwrite(s, sizeof(*s), WRAPCOL-col, fp);
+            s += WRAPCOL-col;
+            slen -= WRAPCOL-col;
+            col = 0;
+            fputc('\n', fp);
+        } else {
+            fwrite(s, sizeof(*s), slen, fp);
+            s += slen;
+            col += slen;
+            slen -= slen;
+            c = *(s+slen-1);
+        }
+    }
+    for (; slen >= WRAPCOL; slen -= WRAPCOL, s += WRAPCOL) {
+        fwrite(s, sizeof(*s), WRAPCOL, fp);
+        fputc('\n', fp);
+    }
+    if (slen > 0) {
+        fwrite(s, sizeof(*s), slen, fp);
+        col += slen;
+        c = *(s+slen-1);
     }
 
     return c;