Finish number-nonblank

src/cat.S

@@ -42,6 +42,26 @@ cat_file:
     mv s2, a0
     li s1, 1
 
+    la t1, number_nonblank
+    lb t1, 0(t1)
+    beqz t1, .LNoNonblankNumbers
+
+    mv a1, s2 # load mod buf size to a1
+
+    beqz s1, 1f
+    la a0, mod_buf_0 # load mod_buf_0 as read buf
+    la a2, mod_buf_1 # load mod_buf_1 as write buf
+    j 2f
+    1:
+    la a0, mod_buf_1 # load mod_buf_1 as read buf
+    la a2, mod_buf_0 # load mod_buf_0 as write buf
+    2:
+
+    call add_line_numbers
+    xori s1, s1, 1 # flip the mod buf to write to
+    mv s2, a1 # update the current byte count
+    .LNoNonblankNumbers:
+    
     la t1, number
     lb t1, 0(t1)
     beqz t1, .LNoNumbers