From ad6059adc7039a54d1db75da783068654906a679 Mon Sep 17 00:00:00 2001
From: Alex Ong <the.onga@gmail.com>
Date: Wed, 24 Jan 2018 14:15:56 +1100
Subject: [PATCH] core: Saved 60~ bytes (and possible performance) by storing
 col_mask when iterating through columns (#522)

---
 tmk_core/common/keyboard.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/tmk_core/common/keyboard.c b/tmk_core/common/keyboard.c
index 864db2b2..929b862a 100644
--- a/tmk_core/common/keyboard.c
+++ b/tmk_core/common/keyboard.c
@@ -126,17 +126,18 @@ void keyboard_task(void)
             matrix_ghost[r] = matrix_row;
 #endif
             if (debug_matrix) matrix_print();
-            for (uint8_t c = 0; c < MATRIX_COLS; c++) {
-                if (matrix_change & ((matrix_row_t)1<<c)) {
+            matrix_row_t col_mask = 1;
+            for (uint8_t c = 0; c < MATRIX_COLS; c++, col_mask <<= 1) {
+                if (matrix_change & col_mask) {
                     keyevent_t e = (keyevent_t){
                         .key = (keypos_t){ .row = r, .col = c },
-                        .pressed = (matrix_row & ((matrix_row_t)1<<c)),
+                        .pressed = (matrix_row & col_mask),
                         .time = (timer_read() | 1) /* time should not be 0 */
                     };
                     action_exec(e);
                     hook_matrix_change(e);
                     // record a processed key
-                    matrix_prev[r] ^= ((matrix_row_t)1<<c);
+                    matrix_prev[r] ^= col_mask;
 
                     // This can miss stroke when scan matrix takes long like Topre
                     // process a key per task call
-- 
2.45.2