From 849ed5a6a03b14defa94a50b66169abac89b9c08 Mon Sep 17 00:00:00 2001
From: Jeremiah <jeremiah.barrar@gmail.com>
Date: Sat, 13 May 2017 08:51:20 -0700
Subject: anti-ghost improvement for older keyboards with empty spots in matrix

---
 tmk_core/common/keyboard.c | 36 ++++++++++++++++++++++++++++++------
 tmk_core/common/keyboard.h |  2 +-
 2 files changed, 31 insertions(+), 7 deletions(-)

(limited to 'tmk_core')

diff --git a/tmk_core/common/keyboard.c b/tmk_core/common/keyboard.c
index eac1f1dd81..93a066e574 100644
--- a/tmk_core/common/keyboard.c
+++ b/tmk_core/common/keyboard.c
@@ -64,20 +64,41 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 
 #ifdef MATRIX_HAS_GHOST
+static uint16_t matrix_ghost_check[MATRIX_ROWS];
 static bool has_ghost_in_row(uint8_t row)
 {
-    matrix_row_t matrix_row = matrix_get_row(row);
-    // No ghost exists when less than 2 keys are down on the row
-    if (((matrix_row - 1) & matrix_row) == 0)
+    matrix_row_t matrix_row = (matrix_get_row(row) & matrix_ghost_check[row]);
+    /* No ghost exists when less than 2 keys are down on the row.
+    If there are "active" blanks in the matrix, the key can't be pressed by the user,
+    there is no doubt as to which keys are really being pressed.
+    The ghosts will be ignored, they are KC_NO.   */
+    if (((matrix_row - 1) & matrix_row) == 0){
         return false;
-
-    // Ghost occurs when the row shares column line with other row
+    }
+    // Ghost occurs when the row shares column line with other row, blanks in the matrix don't matter
+    // If there are more than two real keys pressed and they match another row's real keys, the row will be ignored.
     for (uint8_t i=0; i < MATRIX_ROWS; i++) {
-        if (i != row && (matrix_get_row(i) & matrix_row))
+        if (i != row && __builtin_popcount((matrix_get_row(i) & matrix_ghost_check[i]) & matrix_row) > 1){
             return true;
+        }
     }
     return false;
+    return false;
 }
+
+extern const uint8_t keymaps[][MATRIX_ROWS][MATRIX_COLS];
+// bit map of true keys and empty spots in matrix, each row is reversed
+void make_ghost_check_array(){
+    for (int row = 0; row < MATRIX_ROWS; row++) {
+        for (int col = 0; col < MATRIX_COLS; col++) {
+            if (keymaps[0][row][col] & 0xFF)
+                matrix_ghost_check[row] |= 1<<col;
+            else
+                matrix_ghost_check[row] |= 0<<col;
+        }
+    }
+}
+
 #endif
 
 __attribute__ ((weak))
@@ -117,6 +138,9 @@ void keyboard_init(void) {
 #if defined(NKRO_ENABLE) && defined(FORCE_NKRO)
     keymap_config.nkro = 1;
 #endif
+#ifdef MATRIX_HAS_GHOST
+    make_ghost_check_array();
+#endif
 }
 
 /*
diff --git a/tmk_core/common/keyboard.h b/tmk_core/common/keyboard.h
index 7738251b64..fe2a8fe812 100644
--- a/tmk_core/common/keyboard.h
+++ b/tmk_core/common/keyboard.h
@@ -57,7 +57,7 @@ static inline bool IS_RELEASED(keyevent_t event) { return (!IS_NOEVENT(event) &&
     .time = (timer_read() | 1)                          \
 }
 
-
+void make_ghost_check_array(void);
 /* it runs once at early stage of startup before keyboard_init. */
 void keyboard_setup(void);
 /* it runs once after initializing host side protocol, debug and MCU peripherals. */
-- 
cgit v1.2.3


From b9895771edb4cca2bb17f5872a0e6ee068c91500 Mon Sep 17 00:00:00 2001
From: Jeremiah <jeremiah.barrar@gmail.com>
Date: Sat, 13 May 2017 13:19:28 -0700
Subject: improvements

---
 tmk_core/common/keyboard.c | 39 ++++++++++++++++-----------------------
 tmk_core/common/keyboard.h |  1 -
 2 files changed, 16 insertions(+), 24 deletions(-)

(limited to 'tmk_core')

diff --git a/tmk_core/common/keyboard.c b/tmk_core/common/keyboard.c
index 93a066e574..116914e1ae 100644
--- a/tmk_core/common/keyboard.c
+++ b/tmk_core/common/keyboard.c
@@ -62,12 +62,21 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #endif
 
 
-
 #ifdef MATRIX_HAS_GHOST
-static uint16_t matrix_ghost_check[MATRIX_ROWS];
+extern const uint16_t keymaps[][MATRIX_ROWS][MATRIX_COLS];
+// bit map of true keys and empty spots in matrix, each row is reversed
+static uint16_t get_row_ghost_check(uint16_t row){
+    for (int col = 0; col < MATRIX_COLS; col++) {
+        if (keymaps[0][row][col])
+            row &= 1<<col;
+        else
+            row &= 0<<col;
+    }
+    return row;
+}
 static bool has_ghost_in_row(uint8_t row)
 {
-    matrix_row_t matrix_row = (matrix_get_row(row) & matrix_ghost_check[row]);
+    matrix_row_t matrix_row = (get_row_ghost_check(matrix_get_row(row)));
     /* No ghost exists when less than 2 keys are down on the row.
     If there are "active" blanks in the matrix, the key can't be pressed by the user,
     there is no doubt as to which keys are really being pressed.
@@ -76,29 +85,16 @@ static bool has_ghost_in_row(uint8_t row)
         return false;
     }
     // Ghost occurs when the row shares column line with other row, blanks in the matrix don't matter
-    // If there are more than two real keys pressed and they match another row's real keys, the row will be ignored.
+    // If there are two or more real keys pressed and they match another row's real keys, the row will be ignored.
     for (uint8_t i=0; i < MATRIX_ROWS; i++) {
-        if (i != row && __builtin_popcount((matrix_get_row(i) & matrix_ghost_check[i]) & matrix_row) > 1){
+        if (i != row && __builtin_popcount(
+        get_row_ghost_check(matrix_get_row(i)) & matrix_row
+        ) > 1){
             return true;
         }
     }
     return false;
-    return false;
 }
-
-extern const uint8_t keymaps[][MATRIX_ROWS][MATRIX_COLS];
-// bit map of true keys and empty spots in matrix, each row is reversed
-void make_ghost_check_array(){
-    for (int row = 0; row < MATRIX_ROWS; row++) {
-        for (int col = 0; col < MATRIX_COLS; col++) {
-            if (keymaps[0][row][col] & 0xFF)
-                matrix_ghost_check[row] |= 1<<col;
-            else
-                matrix_ghost_check[row] |= 0<<col;
-        }
-    }
-}
-
 #endif
 
 __attribute__ ((weak))
@@ -138,9 +134,6 @@ void keyboard_init(void) {
 #if defined(NKRO_ENABLE) && defined(FORCE_NKRO)
     keymap_config.nkro = 1;
 #endif
-#ifdef MATRIX_HAS_GHOST
-    make_ghost_check_array();
-#endif
 }
 
 /*
diff --git a/tmk_core/common/keyboard.h b/tmk_core/common/keyboard.h
index fe2a8fe812..f17003c2ff 100644
--- a/tmk_core/common/keyboard.h
+++ b/tmk_core/common/keyboard.h
@@ -57,7 +57,6 @@ static inline bool IS_RELEASED(keyevent_t event) { return (!IS_NOEVENT(event) &&
     .time = (timer_read() | 1)                          \
 }
 
-void make_ghost_check_array(void);
 /* it runs once at early stage of startup before keyboard_init. */
 void keyboard_setup(void);
 /* it runs once after initializing host side protocol, debug and MCU peripherals. */
-- 
cgit v1.2.3


From 99877cdff3f891127e806a9bde7105e6250f3737 Mon Sep 17 00:00:00 2001
From: Jeremiah <barrar@users.noreply.github.com>
Date: Sat, 13 May 2017 16:57:23 -0700
Subject: a bit smaller

---
 tmk_core/common/keyboard.c | 53 ++++++++++++++++++++++++++++++----------------
 1 file changed, 35 insertions(+), 18 deletions(-)

(limited to 'tmk_core')

diff --git a/tmk_core/common/keyboard.c b/tmk_core/common/keyboard.c
index 116914e1ae..d1794c8878 100644
--- a/tmk_core/common/keyboard.c
+++ b/tmk_core/common/keyboard.c
@@ -63,40 +63,54 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 
 #ifdef MATRIX_HAS_GHOST
-extern const uint16_t keymaps[][MATRIX_ROWS][MATRIX_COLS];
-// bit map of true keys and empty spots in matrix, each row is reversed
-static uint16_t get_row_ghost_check(uint16_t row){
+static uint16_t matrix_ghost_check[MATRIX_ROWS];
+
+static inline bool countones(uint16_t data)
+{
+    int count = 0;
     for (int col = 0; col < MATRIX_COLS; col++) {
-        if (keymaps[0][row][col])
-            row &= 1<<col;
-        else
-            row &= 0<<col;
+        if (data & (1<<col))
+            count++;
+    }
+    if (count > 1){
+        return true;
     }
-    return row;
+    return false;
 }
-static bool has_ghost_in_row(uint8_t row)
+static inline bool has_ghost_in_row(uint8_t row, uint16_t rowdata)
 {
-    matrix_row_t matrix_row = (get_row_ghost_check(matrix_get_row(row)));
+    rowdata &= matrix_ghost_check[row];
+    if (((rowdata - 1) & rowdata) == 0){
+        return false;
+    }
     /* No ghost exists when less than 2 keys are down on the row.
     If there are "active" blanks in the matrix, the key can't be pressed by the user,
     there is no doubt as to which keys are really being pressed.
     The ghosts will be ignored, they are KC_NO.   */
-    if (((matrix_row - 1) & matrix_row) == 0){
-        return false;
-    }
     // Ghost occurs when the row shares column line with other row, blanks in the matrix don't matter
-    // If there are two or more real keys pressed and they match another row's real keys, the row will be ignored.
+    // If there are more than two real keys pressed and they match another row's real keys, the row will be ignored.
     for (uint8_t i=0; i < MATRIX_ROWS; i++) {
-        if (i != row && __builtin_popcount(
-        get_row_ghost_check(matrix_get_row(i)) & matrix_row
-        ) > 1){
+        if (i != row && countones((matrix_get_row(i) & matrix_ghost_check[i]) & rowdata)){
             return true;
         }
     }
     return false;
 }
+
+extern const uint16_t keymaps[][MATRIX_ROWS][MATRIX_COLS];
+// bit map of true keys and empty spots in matrix, each row is reversed
+static inline void make_ghost_check_array(void){
+    for (int row = 0; row < MATRIX_ROWS; row++) {
+        for (int col = 0; col < MATRIX_COLS; col++) {
+            if (pgm_read_byte(&keymaps[0][row][col]) != 0)
+                matrix_ghost_check[row] |= 1<<col;
+        }
+    }
+}
+
 #endif
 
+
 __attribute__ ((weak))
 void matrix_setup(void) {
 }
@@ -134,6 +148,9 @@ void keyboard_init(void) {
 #if defined(NKRO_ENABLE) && defined(FORCE_NKRO)
     keymap_config.nkro = 1;
 #endif
+#ifdef MATRIX_HAS_GHOST
+    make_ghost_check_array();
+#endif
 }
 
 /*
@@ -156,7 +173,7 @@ void keyboard_task(void)
         matrix_change = matrix_row ^ matrix_prev[r];
         if (matrix_change) {
 #ifdef MATRIX_HAS_GHOST
-            if (has_ghost_in_row(r)) {
+            if (has_ghost_in_row(r, matrix_row)) {
                 /* Keep track of whether ghosted status has changed for
                  * debugging. But don't update matrix_prev until un-ghosted, or
                  * the last key would be lost.
-- 
cgit v1.2.3


From acd3e97b83aac14961d1892b0b8333963f499505 Mon Sep 17 00:00:00 2001
From: Jeremiah <barrar@users.noreply.github.com>
Date: Sat, 13 May 2017 17:01:27 -0700
Subject: a bit smaller

---
 tmk_core/common/keyboard.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

(limited to 'tmk_core')

diff --git a/tmk_core/common/keyboard.c b/tmk_core/common/keyboard.c
index d1794c8878..0116053fbe 100644
--- a/tmk_core/common/keyboard.c
+++ b/tmk_core/common/keyboard.c
@@ -161,7 +161,7 @@ void keyboard_task(void)
 {
     static matrix_row_t matrix_prev[MATRIX_ROWS];
 #ifdef MATRIX_HAS_GHOST
-    static matrix_row_t matrix_ghost[MATRIX_ROWS];
+  //  static matrix_row_t matrix_ghost[MATRIX_ROWS];
 #endif
     static uint8_t led_status = 0;
     matrix_row_t matrix_row = 0;
@@ -178,13 +178,13 @@ void keyboard_task(void)
                  * debugging. But don't update matrix_prev until un-ghosted, or
                  * the last key would be lost.
                  */
-                if (debug_matrix && matrix_ghost[r] != matrix_row) {
-                    matrix_print();
-                }
-                matrix_ghost[r] = matrix_row;
+                //if (debug_matrix && matrix_ghost[r] != matrix_row) {
+                //    matrix_print();
+                //}
+                //matrix_ghost[r] = matrix_row;
                 continue;
             }
-            matrix_ghost[r] = matrix_row;
+            //matrix_ghost[r] = matrix_row;
 #endif
             if (debug_matrix) matrix_print();
             for (uint8_t c = 0; c < MATRIX_COLS; c++) {
-- 
cgit v1.2.3


From 7b7e285a984a5bf1f7f38f1b5846811dfcb3a185 Mon Sep 17 00:00:00 2001
From: Jeremiah <barrar@users.noreply.github.com>
Date: Sat, 13 May 2017 17:22:38 -0700
Subject: should be using matrix_row_t

---
 tmk_core/common/keyboard.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

(limited to 'tmk_core')

diff --git a/tmk_core/common/keyboard.c b/tmk_core/common/keyboard.c
index 0116053fbe..24cc28892c 100644
--- a/tmk_core/common/keyboard.c
+++ b/tmk_core/common/keyboard.c
@@ -63,9 +63,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 
 #ifdef MATRIX_HAS_GHOST
-static uint16_t matrix_ghost_check[MATRIX_ROWS];
+static matrix_row_t matrix_ghost_check[MATRIX_ROWS];
 
-static inline bool countones(uint16_t data)
+static inline bool countones(matrix_row_t data)
 {
     int count = 0;
     for (int col = 0; col < MATRIX_COLS; col++) {
@@ -77,7 +77,7 @@ static inline bool countones(uint16_t data)
     }
     return false;
 }
-static inline bool has_ghost_in_row(uint8_t row, uint16_t rowdata)
+static inline bool has_ghost_in_row(uint8_t row, matrix_row_t rowdata)
 {
     rowdata &= matrix_ghost_check[row];
     if (((rowdata - 1) & rowdata) == 0){
-- 
cgit v1.2.3


From 37f6f92765513cd66c92178f48785d492eb06b89 Mon Sep 17 00:00:00 2001
From: Jeremiah <barrar@users.noreply.github.com>
Date: Sat, 13 May 2017 18:24:43 -0700
Subject: faster and less bits

---
 tmk_core/common/keyboard.c | 33 +++++++++++++++------------------
 1 file changed, 15 insertions(+), 18 deletions(-)

(limited to 'tmk_core')

diff --git a/tmk_core/common/keyboard.c b/tmk_core/common/keyboard.c
index 24cc28892c..d8b5dc4031 100644
--- a/tmk_core/common/keyboard.c
+++ b/tmk_core/common/keyboard.c
@@ -63,14 +63,25 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 
 #ifdef MATRIX_HAS_GHOST
-static matrix_row_t matrix_ghost_check[MATRIX_ROWS];
+extern const uint16_t keymaps[][MATRIX_ROWS][MATRIX_COLS];
+static matrix_row_t get_real_keys(uint8_t row, matrix_row_t rowdata){
+    matrix_row_t out = 0;
+    for (int col = 0; col < MATRIX_COLS; col++) {
+        if (pgm_read_byte(&keymaps[0][row][col]) && ((rowdata & (1<<col)))){
+            out |= 1<<col;
+        }
+    }
+    return out;
+}
+
 
 static inline bool countones(matrix_row_t data)
 {
     int count = 0;
     for (int col = 0; col < MATRIX_COLS; col++) {
-        if (data & (1<<col))
+        if (data & (1<<col)){
             count++;
+        }
     }
     if (count > 1){
         return true;
@@ -79,7 +90,7 @@ static inline bool countones(matrix_row_t data)
 }
 static inline bool has_ghost_in_row(uint8_t row, matrix_row_t rowdata)
 {
-    rowdata &= matrix_ghost_check[row];
+    rowdata = get_real_keys(row, rowdata);
     if (((rowdata - 1) & rowdata) == 0){
         return false;
     }
@@ -90,24 +101,13 @@ static inline bool has_ghost_in_row(uint8_t row, matrix_row_t rowdata)
     // Ghost occurs when the row shares column line with other row, blanks in the matrix don't matter
     // If there are more than two real keys pressed and they match another row's real keys, the row will be ignored.
     for (uint8_t i=0; i < MATRIX_ROWS; i++) {
-        if (i != row && countones((matrix_get_row(i) & matrix_ghost_check[i]) & rowdata)){
+        if (i != row && countones(get_real_keys(i, matrix_get_row(i)) & rowdata)){
             return true;
         }
     }
     return false;
 }
 
-extern const uint16_t keymaps[][MATRIX_ROWS][MATRIX_COLS];
-// bit map of true keys and empty spots in matrix, each row is reversed
-static inline void make_ghost_check_array(void){
-    for (int row = 0; row < MATRIX_ROWS; row++) {
-        for (int col = 0; col < MATRIX_COLS; col++) {
-            if (pgm_read_byte(&keymaps[0][row][col]) != 0)
-                matrix_ghost_check[row] |= 1<<col;
-        }
-    }
-}
-
 #endif
 
 
@@ -148,9 +148,6 @@ void keyboard_init(void) {
 #if defined(NKRO_ENABLE) && defined(FORCE_NKRO)
     keymap_config.nkro = 1;
 #endif
-#ifdef MATRIX_HAS_GHOST
-    make_ghost_check_array();
-#endif
 }
 
 /*
-- 
cgit v1.2.3


From 63d9698d5c7a088b2eb8220a9a44c8adbca86326 Mon Sep 17 00:00:00 2001
From: Jeremiah <barrar@users.noreply.github.com>
Date: Sat, 13 May 2017 19:07:05 -0700
Subject: faster and less bits... again

---
 tmk_core/common/keyboard.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

(limited to 'tmk_core')

diff --git a/tmk_core/common/keyboard.c b/tmk_core/common/keyboard.c
index d8b5dc4031..fa17ffca25 100644
--- a/tmk_core/common/keyboard.c
+++ b/tmk_core/common/keyboard.c
@@ -74,20 +74,19 @@ static matrix_row_t get_real_keys(uint8_t row, matrix_row_t rowdata){
     return out;
 }
 
-
-static inline bool countones(matrix_row_t data)
+static inline bool countones(matrix_row_t row)
 {
     int count = 0;
-    for (int col = 0; col < MATRIX_COLS; col++) {
-        if (data & (1<<col)){
-            count++;
-        }
+    while (row > 0){
+        count += 1;
+        row &= row-1;
     }
     if (count > 1){
         return true;
     }
     return false;
 }
+
 static inline bool has_ghost_in_row(uint8_t row, matrix_row_t rowdata)
 {
     rowdata = get_real_keys(row, rowdata);
-- 
cgit v1.2.3


From b9b2244b8275066d1226fba0fb75747a194f0553 Mon Sep 17 00:00:00 2001
From: Jeremiah <barrar@users.noreply.github.com>
Date: Sun, 14 May 2017 08:01:01 -0700
Subject: faster, less bits :)

---
 tmk_core/common/keyboard.c | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

(limited to 'tmk_core')

diff --git a/tmk_core/common/keyboard.c b/tmk_core/common/keyboard.c
index fa17ffca25..20b867285e 100644
--- a/tmk_core/common/keyboard.c
+++ b/tmk_core/common/keyboard.c
@@ -76,15 +76,8 @@ static matrix_row_t get_real_keys(uint8_t row, matrix_row_t rowdata){
 
 static inline bool countones(matrix_row_t row)
 {
-    int count = 0;
-    while (row > 0){
-        count += 1;
-        row &= row-1;
-    }
-    if (count > 1){
-        return true;
-    }
-    return false;
+    row &= row-1;
+    return row;
 }
 
 static inline bool has_ghost_in_row(uint8_t row, matrix_row_t rowdata)
-- 
cgit v1.2.3


From 84395e8a0427bcb51c4ef4ff24c7901d1fbb0764 Mon Sep 17 00:00:00 2001
From: Jeremiah <barrar@users.noreply.github.com>
Date: Sun, 14 May 2017 09:36:50 -0700
Subject: whoops

---
 tmk_core/common/keyboard.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'tmk_core')

diff --git a/tmk_core/common/keyboard.c b/tmk_core/common/keyboard.c
index 20b867285e..a3fe559f35 100644
--- a/tmk_core/common/keyboard.c
+++ b/tmk_core/common/keyboard.c
@@ -67,7 +67,7 @@ extern const uint16_t keymaps[][MATRIX_ROWS][MATRIX_COLS];
 static matrix_row_t get_real_keys(uint8_t row, matrix_row_t rowdata){
     matrix_row_t out = 0;
     for (int col = 0; col < MATRIX_COLS; col++) {
-        if (pgm_read_byte(&keymaps[0][row][col]) && ((rowdata & (1<<col)))){
+        if (pgm_read_byte(&keymaps[0][row][col]) && (rowdata & (1<<col))){
             out |= 1<<col;
         }
     }
@@ -83,7 +83,7 @@ static inline bool countones(matrix_row_t row)
 static inline bool has_ghost_in_row(uint8_t row, matrix_row_t rowdata)
 {
     rowdata = get_real_keys(row, rowdata);
-    if (((rowdata - 1) & rowdata) == 0){
+    if ((countones(rowdata)) == 0){
         return false;
     }
     /* No ghost exists when less than 2 keys are down on the row.
-- 
cgit v1.2.3


From 25c6ca750fc74376a2bea7612c0e05401d3ecf5e Mon Sep 17 00:00:00 2001
From: Jeremiah <barrar@users.noreply.github.com>
Date: Sun, 14 May 2017 15:36:44 -0700
Subject: added comments and made function name clearer

---
 tmk_core/common/keyboard.c | 31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

(limited to 'tmk_core')

diff --git a/tmk_core/common/keyboard.c b/tmk_core/common/keyboard.c
index a3fe559f35..97a8f1cd8c 100644
--- a/tmk_core/common/keyboard.c
+++ b/tmk_core/common/keyboard.c
@@ -61,39 +61,45 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #   include "visualizer/visualizer.h"
 #endif
 
-
 #ifdef MATRIX_HAS_GHOST
 extern const uint16_t keymaps[][MATRIX_ROWS][MATRIX_COLS];
 static matrix_row_t get_real_keys(uint8_t row, matrix_row_t rowdata){
     matrix_row_t out = 0;
-    for (int col = 0; col < MATRIX_COLS; col++) {
+    for (uint8_t col = 0; col < MATRIX_COLS; col++) {
+        //read each key in the row data and check if the keymap defines it as a real key
         if (pgm_read_byte(&keymaps[0][row][col]) && (rowdata & (1<<col))){
+            //this creates new row data, if a key is defined in the keymap, it will be set here
             out |= 1<<col;
         }
     }
     return out;
 }
 
-static inline bool countones(matrix_row_t row)
+static inline bool popcount_more_than_one(matrix_row_t rowdata)
 {
-    row &= row-1;
-    return row;
+    rowdata &= rowdata-1; //if there are less than two bits (keys) set, rowdata will become zero
+    return rowdata;
 }
 
 static inline bool has_ghost_in_row(uint8_t row, matrix_row_t rowdata)
 {
-    rowdata = get_real_keys(row, rowdata);
-    if ((countones(rowdata)) == 0){
-        return false;
-    }
     /* No ghost exists when less than 2 keys are down on the row.
     If there are "active" blanks in the matrix, the key can't be pressed by the user,
     there is no doubt as to which keys are really being pressed.
     The ghosts will be ignored, they are KC_NO.   */
-    // Ghost occurs when the row shares column line with other row, blanks in the matrix don't matter
-    // If there are more than two real keys pressed and they match another row's real keys, the row will be ignored.
+    rowdata = get_real_keys(row, rowdata);
+    if ((popcount_more_than_one(rowdata)) == 0){
+        return false;
+    }
+    /* Ghost occurs when the row shares a column line with other row,
+    and two columns are read on each row. Blanks in the matrix don't matter,
+    so they are filtered out.
+    If there are two or more real keys pressed and they match columns with
+    at least two of another row's real keys, the row will be ignored. Keep in mind,
+    we are checking one row at a time, not all of them at once.
+    */
     for (uint8_t i=0; i < MATRIX_ROWS; i++) {
-        if (i != row && countones(get_real_keys(i, matrix_get_row(i)) & rowdata)){
+        if (i != row && popcount_more_than_one(get_real_keys(i, matrix_get_row(i)) & rowdata)){
             return true;
         }
     }
@@ -102,7 +108,6 @@ static inline bool has_ghost_in_row(uint8_t row, matrix_row_t rowdata)
 
 #endif
 
-
 __attribute__ ((weak))
 void matrix_setup(void) {
 }
-- 
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