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

src/mod.S

@@ -120,11 +120,10 @@ add_line_numbers:
     beqz s7, .LLineNumbersSkipEmptyCheck
     
     mv t0, s4 # move the current string buf pointer into t0
-    li t1, 1
+    addi t0, t0, 1 # move the str pointer forward one
-    sub t0, t0, t1 # move the str pointer back one
     lb t0, 0(t0)
     # t4 still contains a newline char
-    beq t0, t4, 1f # if the previous byte IS a newline, skip to writing
+    beq t0, t4, 1f # if the next byte IS a newline, skip to writing
     
     .LLineNumbersSkipEmptyCheck: