From 7600c04cd9a2936e29a159a9f8c910dd1c3e66a4 Mon Sep 17 00:00:00 2001
From: juank <juank@fktech.net>
Date: Tue, 26 May 2020 06:02:01 -0300
Subject: [PATCH 01/13] [Feature Request] Swap buttons on PS2 Mouse/Trackball

---
 tmk_core/protocol/ps2_mouse.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tmk_core/protocol/ps2_mouse.c b/tmk_core/protocol/ps2_mouse.c
index a0e52bc7c3a5..183146900be3 100644
--- a/tmk_core/protocol/ps2_mouse.c
+++ b/tmk_core/protocol/ps2_mouse.c
@@ -150,6 +150,13 @@ static inline void ps2_mouse_convert_report_to_hid(report_mouse_t *mouse_report)
     // remove sign and overflow flags
     mouse_report->buttons &= PS2_MOUSE_BTN_MASK;
 
+#ifdef PS2_MOUSE_INVERT_BUTTONS
+    int buttons = mouse_report->buttons;
+    buttons |= ((mouse_report->buttons >> PS2_MOUSE_BTN_LEFT) & 1U) << 1;
+    buttons |= (mouse_report->buttons >> PS2_MOUSE_BTN_RIGHT) & 1U;
+    mouse_report->buttons = buttons;
+#endif
+
 #ifdef PS2_MOUSE_INVERT_X
     mouse_report->x = -mouse_report->x;
 #endif

From de9d50ac79916431febd4db9b31fd37fd1d79cf4 Mon Sep 17 00:00:00 2001
From: juank <juank@fktech.net>
Date: Tue, 26 May 2020 06:12:10 -0300
Subject: [PATCH 02/13] [Feature Request] Swap buttons on PS2 Mouse/Trackball

---
 docs/feature_ps2_mouse.md | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/docs/feature_ps2_mouse.md b/docs/feature_ps2_mouse.md
index c1bd8bff50a8..b28adb997e9a 100644
--- a/docs/feature_ps2_mouse.md
+++ b/docs/feature_ps2_mouse.md
@@ -246,6 +246,16 @@ Fine control over the scrolling is supported with the following defines:
 #define PS2_MOUSE_SCROLL_DIVISOR_V 2
 ```
 
+### Invert Mouse buttons
+
+To invert the left & right buttonsyou can put:
+
+```c
+#define PS2_MOUSE_INVERT_BUTTONS
+```
+
+into config.h.
+
 ### Invert Mouse and Scroll Axes :id=invert-mouse-and-scroll-axes
 
 To invert the X and Y axes you can put:

From beff95ac2a0817554cf9cff4699e2062828a6933 Mon Sep 17 00:00:00 2001
From: juank <juank@fktech.net>
Date: Tue, 26 May 2020 06:16:40 -0300
Subject: [PATCH 03/13] Added id: to the doc

---
 docs/feature_ps2_mouse.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/feature_ps2_mouse.md b/docs/feature_ps2_mouse.md
index b28adb997e9a..587ca6e0b3ac 100644
--- a/docs/feature_ps2_mouse.md
+++ b/docs/feature_ps2_mouse.md
@@ -246,7 +246,7 @@ Fine control over the scrolling is supported with the following defines:
 #define PS2_MOUSE_SCROLL_DIVISOR_V 2
 ```
 
-### Invert Mouse buttons
+### Invert Mouse buttons :id=invert-buttons
 
 To invert the left & right buttonsyou can put:
 

From 2fa53fdb2feb311fbcab779b80e2ac6c8c4210d3 Mon Sep 17 00:00:00 2001
From: juank <juank@fktech.net>
Date: Tue, 26 May 2020 06:18:27 -0300
Subject: [PATCH 04/13] Missing space

---
 docs/feature_ps2_mouse.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/feature_ps2_mouse.md b/docs/feature_ps2_mouse.md
index 587ca6e0b3ac..c17a327019a6 100644
--- a/docs/feature_ps2_mouse.md
+++ b/docs/feature_ps2_mouse.md
@@ -248,7 +248,7 @@ Fine control over the scrolling is supported with the following defines:
 
 ### Invert Mouse buttons :id=invert-buttons
 
-To invert the left & right buttonsyou can put:
+To invert the left & right buttons you can put:
 
 ```c
 #define PS2_MOUSE_INVERT_BUTTONS

From 351b635b20e291f75be5df165e77efc62337d315 Mon Sep 17 00:00:00 2001
From: juank <juank@fktech.net>
Date: Wed, 27 May 2020 01:16:45 -0300
Subject: [PATCH 05/13] Solve comment
 https://github.com/qmk/qmk_firmware/pull/9205#discussion_r430783182

---
 tmk_core/protocol/ps2_mouse.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/tmk_core/protocol/ps2_mouse.c b/tmk_core/protocol/ps2_mouse.c
index 183146900be3..d08422772e63 100644
--- a/tmk_core/protocol/ps2_mouse.c
+++ b/tmk_core/protocol/ps2_mouse.c
@@ -151,10 +151,7 @@ static inline void ps2_mouse_convert_report_to_hid(report_mouse_t *mouse_report)
     mouse_report->buttons &= PS2_MOUSE_BTN_MASK;
 
 #ifdef PS2_MOUSE_INVERT_BUTTONS
-    int buttons = mouse_report->buttons;
-    buttons |= ((mouse_report->buttons >> PS2_MOUSE_BTN_LEFT) & 1U) << 1;
-    buttons |= (mouse_report->buttons >> PS2_MOUSE_BTN_RIGHT) & 1U;
-    mouse_report->buttons = buttons;
+    mouse_report->buttons = (mouse_report->buttons >> PS2_MOUSE_BTN_LEFT & 1U) << PS2_MOUSE_BTN_RIGHT | (mouse_report->buttons >> PS2_MOUSE_BTN_RIGHT & 1U) << PS2_MOUSE_BTN_LEFT | (mouse_report->buttons >> PS2_MOUSE_BTN_MIDDLE & 1U) << PS2_MOUSE_BTN_MIDDLE;
 #endif
 
 #ifdef PS2_MOUSE_INVERT_X

From 7811e9f2bedf281266c489da688fca773eb4e1cd Mon Sep 17 00:00:00 2001
From: juank <juank@fktech.net>
Date: Wed, 27 May 2020 20:10:42 -0300
Subject: [PATCH 06/13] Solve comments
 https://github.com/qmk/qmk_firmware/pull/9205#discussion_r430783182 &
 https://github.com/qmk/qmk_firmware/pull/9205#discussion_r430783884

---
 tmk_core/protocol/ps2_mouse.c | 18 +++++++++++++++---
 tmk_core/protocol/ps2_mouse.h | 11 +++++++++++
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/tmk_core/protocol/ps2_mouse.c b/tmk_core/protocol/ps2_mouse.c
index d08422772e63..37e6beba2104 100644
--- a/tmk_core/protocol/ps2_mouse.c
+++ b/tmk_core/protocol/ps2_mouse.c
@@ -147,11 +147,23 @@ static inline void ps2_mouse_convert_report_to_hid(report_mouse_t *mouse_report)
     mouse_report->x = X_IS_NEG ? ((!X_IS_OVF && -127 <= mouse_report->x && mouse_report->x <= -1) ? mouse_report->x : -127) : ((!X_IS_OVF && 0 <= mouse_report->x && mouse_report->x <= 127) ? mouse_report->x : 127);
     mouse_report->y = Y_IS_NEG ? ((!Y_IS_OVF && -127 <= mouse_report->y && mouse_report->y <= -1) ? mouse_report->y : -127) : ((!Y_IS_OVF && 0 <= mouse_report->y && mouse_report->y <= 127) ? mouse_report->y : 127);
 
+#ifdef PS2_MOUSE_INVERT_BUTTONS
+    mouse_report->buttons = ( \
+        // Change right to left
+        BIT_SET_BY(mouse_report->buttons, PS2_MOUSE_BTN_LEFT, PS2_MOUSE_BTN_RIGHT) | \
+        // Change left to right
+        BIT_SET_BY(mouse_report->buttons, PS2_MOUSE_BTN_RIGHT,PS2_MOUSE_BTN_LEFT) | \
+        // Leave the rest untouched
+        BITMASK_CLEAR(mouse_report->buttons, (
+            // Calculate mask for the rest
+            BIT_VALUE(PS2_MOUSE_BTN_MASK, PS2_MOUSE_BTN_LEFT) | \
+            BIT_VALUE(PS2_MOUSE_BTN_MASK, PS2_MOUSE_BTN_RIGHT)
+        ))
+    // remove sign and overflow flags
+    ) & PS2_MOUSE_BTN_MASK;
+#else
     // remove sign and overflow flags
     mouse_report->buttons &= PS2_MOUSE_BTN_MASK;
-
-#ifdef PS2_MOUSE_INVERT_BUTTONS
-    mouse_report->buttons = (mouse_report->buttons >> PS2_MOUSE_BTN_LEFT & 1U) << PS2_MOUSE_BTN_RIGHT | (mouse_report->buttons >> PS2_MOUSE_BTN_RIGHT & 1U) << PS2_MOUSE_BTN_LEFT | (mouse_report->buttons >> PS2_MOUSE_BTN_MIDDLE & 1U) << PS2_MOUSE_BTN_MIDDLE;
 #endif
 
 #ifdef PS2_MOUSE_INVERT_X
diff --git a/tmk_core/protocol/ps2_mouse.h b/tmk_core/protocol/ps2_mouse.h
index 30053ef18703..532974f6af9a 100644
--- a/tmk_core/protocol/ps2_mouse.h
+++ b/tmk_core/protocol/ps2_mouse.h
@@ -21,6 +21,17 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <stdbool.h>
 #include "debug.h"
 
+/*
+ * Binary manipulation macros
+ */
+
+/* a=target variable, b=bit number to act upon 0-n, c=bit number to act upon 0-n */
+#define BIT_SET_BY(a, b, c) ((a >> b & 1U) << c)
+#define BIT_GET(a, b) (a >> b & 1U)
+#define BIT_VALUE(a, b) ((a >> b & 1U) << b)
+/* x=target variable, y=mask */
+#define BITMASK_CLEAR(x,y) ((x) & (~(y)))
+
 #define PS2_MOUSE_SEND(command, message)                                                \
     do {                                                                                \
         __attribute__((unused)) uint8_t rcv = ps2_host_send(command);                   \

From 3999300505bb4417352c03db24d707dfe1f28514 Mon Sep 17 00:00:00 2001
From: juank <juank@fktech.net>
Date: Wed, 27 May 2020 23:08:08 -0300
Subject: [PATCH 07/13] Format code more according to
 https://docs.qmk.fm/#/coding_conventions_c

---
 tmk_core/protocol/ps2_mouse.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/tmk_core/protocol/ps2_mouse.c b/tmk_core/protocol/ps2_mouse.c
index 37e6beba2104..1a00a131b08f 100644
--- a/tmk_core/protocol/ps2_mouse.c
+++ b/tmk_core/protocol/ps2_mouse.c
@@ -148,21 +148,17 @@ static inline void ps2_mouse_convert_report_to_hid(report_mouse_t *mouse_report)
     mouse_report->y = Y_IS_NEG ? ((!Y_IS_OVF && -127 <= mouse_report->y && mouse_report->y <= -1) ? mouse_report->y : -127) : ((!Y_IS_OVF && 0 <= mouse_report->y && mouse_report->y <= 127) ? mouse_report->y : 127);
 
 #ifdef PS2_MOUSE_INVERT_BUTTONS
-    mouse_report->buttons = ( \
-        // Change right to left
-        BIT_SET_BY(mouse_report->buttons, PS2_MOUSE_BTN_LEFT, PS2_MOUSE_BTN_RIGHT) | \
-        // Change left to right
-        BIT_SET_BY(mouse_report->buttons, PS2_MOUSE_BTN_RIGHT,PS2_MOUSE_BTN_LEFT) | \
-        // Leave the rest untouched
-        BITMASK_CLEAR(mouse_report->buttons, (
-            // Calculate mask for the rest
-            BIT_VALUE(PS2_MOUSE_BTN_MASK, PS2_MOUSE_BTN_LEFT) | \
-            BIT_VALUE(PS2_MOUSE_BTN_MASK, PS2_MOUSE_BTN_RIGHT)
-        ))
-    // remove sign and overflow flags
+    mouse_report->buttons = (
+        /* Change right to left */
+        BIT_SET_BY(mouse_report->buttons, PS2_MOUSE_BTN_LEFT, PS2_MOUSE_BTN_RIGHT) |
+        /* Change left to right */
+        BIT_SET_BY(mouse_report->buttons, PS2_MOUSE_BTN_RIGHT, PS2_MOUSE_BTN_LEFT) |
+        /* Leave the rest */
+        BITMASK_CLEAR(mouse_report->buttons, (BIT_VALUE(PS2_MOUSE_BTN_MASK, PS2_MOUSE_BTN_LEFT) | BIT_VALUE(PS2_MOUSE_BTN_MASK, PS2_MOUSE_BTN_RIGHT)))
+    /* Remove sign and overflow flags */
     ) & PS2_MOUSE_BTN_MASK;
 #else
-    // remove sign and overflow flags
+    /* remove sign and overflow flags */
     mouse_report->buttons &= PS2_MOUSE_BTN_MASK;
 #endif
 

From 222cc2fa81ea1c59f4cc26486f4a62eca8a39b74 Mon Sep 17 00:00:00 2001
From: juank <juank@fktech.net>
Date: Thu, 28 May 2020 16:19:51 -0300
Subject: [PATCH 08/13] change logic to LUT

---
 tmk_core/protocol/ps2_mouse.c | 13 +++---------
 tmk_core/protocol/ps2_mouse.h | 37 +++++++++++++++++------------------
 2 files changed, 21 insertions(+), 29 deletions(-)

diff --git a/tmk_core/protocol/ps2_mouse.c b/tmk_core/protocol/ps2_mouse.c
index 1a00a131b08f..b5699b3a3435 100644
--- a/tmk_core/protocol/ps2_mouse.c
+++ b/tmk_core/protocol/ps2_mouse.c
@@ -148,17 +148,10 @@ static inline void ps2_mouse_convert_report_to_hid(report_mouse_t *mouse_report)
     mouse_report->y = Y_IS_NEG ? ((!Y_IS_OVF && -127 <= mouse_report->y && mouse_report->y <= -1) ? mouse_report->y : -127) : ((!Y_IS_OVF && 0 <= mouse_report->y && mouse_report->y <= 127) ? mouse_report->y : 127);
 
 #ifdef PS2_MOUSE_INVERT_BUTTONS
-    mouse_report->buttons = (
-        /* Change right to left */
-        BIT_SET_BY(mouse_report->buttons, PS2_MOUSE_BTN_LEFT, PS2_MOUSE_BTN_RIGHT) |
-        /* Change left to right */
-        BIT_SET_BY(mouse_report->buttons, PS2_MOUSE_BTN_RIGHT, PS2_MOUSE_BTN_LEFT) |
-        /* Leave the rest */
-        BITMASK_CLEAR(mouse_report->buttons, (BIT_VALUE(PS2_MOUSE_BTN_MASK, PS2_MOUSE_BTN_LEFT) | BIT_VALUE(PS2_MOUSE_BTN_MASK, PS2_MOUSE_BTN_RIGHT)))
-    /* Remove sign and overflow flags */
-    ) & PS2_MOUSE_BTN_MASK;
+    // remove sign and overflow flags and apply buttons LUT
+    mouse_report->buttons = btns_lut[mouse_report->buttons & PS2_MOUSE_BTN_MASK];
 #else
-    /* remove sign and overflow flags */
+    // remove sign and overflow flags
     mouse_report->buttons &= PS2_MOUSE_BTN_MASK;
 #endif
 
diff --git a/tmk_core/protocol/ps2_mouse.h b/tmk_core/protocol/ps2_mouse.h
index 532974f6af9a..909d8d1dc12e 100644
--- a/tmk_core/protocol/ps2_mouse.h
+++ b/tmk_core/protocol/ps2_mouse.h
@@ -21,17 +21,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <stdbool.h>
 #include "debug.h"
 
-/*
- * Binary manipulation macros
- */
-
-/* a=target variable, b=bit number to act upon 0-n, c=bit number to act upon 0-n */
-#define BIT_SET_BY(a, b, c) ((a >> b & 1U) << c)
-#define BIT_GET(a, b) (a >> b & 1U)
-#define BIT_VALUE(a, b) ((a >> b & 1U) << b)
-/* x=target variable, y=mask */
-#define BITMASK_CLEAR(x,y) ((x) & (~(y)))
-
 #define PS2_MOUSE_SEND(command, message)                                                \
     do {                                                                                \
         __attribute__((unused)) uint8_t rcv = ps2_host_send(command);                   \
@@ -86,14 +75,24 @@ __attribute__((unused)) static enum ps2_mouse_mode_e {
  *    1|[                    X movement(0-255)                         ]
  *    2|[                    Y movement(0-255)                         ]
  */
-#define PS2_MOUSE_BTN_MASK 0x07
-#define PS2_MOUSE_BTN_LEFT 0
-#define PS2_MOUSE_BTN_RIGHT 1
-#define PS2_MOUSE_BTN_MIDDLE 2
-#define PS2_MOUSE_X_SIGN 4
-#define PS2_MOUSE_Y_SIGN 5
-#define PS2_MOUSE_X_OVFLW 6
-#define PS2_MOUSE_Y_OVFLW 7
+#define PS2_MOUSE_BTN_MASK 0x07 // 0b0000111
+#define PS2_MOUSE_BTN_LEFT 0    // 0b0000001
+#define PS2_MOUSE_BTN_RIGHT 1   // 0b0000010
+#define PS2_MOUSE_BTN_MIDDLE 2  // 0b0000100
+#define PS2_MOUSE_X_SIGN 4      // 0b0001000
+#define PS2_MOUSE_Y_SIGN 5      // 0b0010000
+#define PS2_MOUSE_X_OVFLW 6     // 0b0100000
+#define PS2_MOUSE_Y_OVFLW 7     // 0b1000000
+
+#ifdef PS2_MOUSE_INVERT_BUTTONS
+/*
+ * LUT for change mouse buttons
+ *
+ * table index is the mouse_report->buttons state from PS2 (after &= PS2_MOUSE_BTN_MASK)
+ * the value replace the mouse_report->buttons before to send to the USB interface
+ */
+static const __attribute__((unused)) uint8_t btns_lut[8] = {0b000, 0b010, 0b001, 0b011, 0b100, 0b101, 0b110, 0b111};
+#endif
 
 /* mouse button to start scrolling; set 0 to disable scroll */
 #ifndef PS2_MOUSE_SCROLL_BTN_MASK

From d0ed90aff9f6630d872786f9654b93405dbff916 Mon Sep 17 00:00:00 2001
From: juank <juank@fktech.net>
Date: Thu, 28 May 2020 21:03:17 -0300
Subject: [PATCH 09/13] WIP: Clean up

---
 tmk_core/protocol/ps2_mouse.c | 10 ++++++++++
 tmk_core/protocol/ps2_mouse.h | 26 ++++++++------------------
 2 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/tmk_core/protocol/ps2_mouse.c b/tmk_core/protocol/ps2_mouse.c
index b5699b3a3435..459158460dd7 100644
--- a/tmk_core/protocol/ps2_mouse.c
+++ b/tmk_core/protocol/ps2_mouse.c
@@ -36,6 +36,16 @@ static inline void ps2_mouse_clear_report(report_mouse_t *mouse_report);
 static inline void ps2_mouse_enable_scrolling(void);
 static inline void ps2_mouse_scroll_button_task(report_mouse_t *mouse_report);
 
+#ifdef PS2_MOUSE_INVERT_BUTTONS
+/*
+ * LUT for change mouse buttons
+ *
+ * table index is the mouse_report->buttons state from PS2 (after &= PS2_MOUSE_BTN_MASK)
+ * the value replace the mouse_report->buttons before to send to the USB interface
+ */
+static const uint8_t btns_lut[8] = {0b000, 0b010, 0b001, 0b011, 0b100, 0b101, 0b110, 0b111};
+#endif
+
 /* ============================= IMPLEMENTATION ============================ */
 
 /* supports only 3 button mouse at this time */
diff --git a/tmk_core/protocol/ps2_mouse.h b/tmk_core/protocol/ps2_mouse.h
index 909d8d1dc12e..30053ef18703 100644
--- a/tmk_core/protocol/ps2_mouse.h
+++ b/tmk_core/protocol/ps2_mouse.h
@@ -75,24 +75,14 @@ __attribute__((unused)) static enum ps2_mouse_mode_e {
  *    1|[                    X movement(0-255)                         ]
  *    2|[                    Y movement(0-255)                         ]
  */
-#define PS2_MOUSE_BTN_MASK 0x07 // 0b0000111
-#define PS2_MOUSE_BTN_LEFT 0    // 0b0000001
-#define PS2_MOUSE_BTN_RIGHT 1   // 0b0000010
-#define PS2_MOUSE_BTN_MIDDLE 2  // 0b0000100
-#define PS2_MOUSE_X_SIGN 4      // 0b0001000
-#define PS2_MOUSE_Y_SIGN 5      // 0b0010000
-#define PS2_MOUSE_X_OVFLW 6     // 0b0100000
-#define PS2_MOUSE_Y_OVFLW 7     // 0b1000000
-
-#ifdef PS2_MOUSE_INVERT_BUTTONS
-/*
- * LUT for change mouse buttons
- *
- * table index is the mouse_report->buttons state from PS2 (after &= PS2_MOUSE_BTN_MASK)
- * the value replace the mouse_report->buttons before to send to the USB interface
- */
-static const __attribute__((unused)) uint8_t btns_lut[8] = {0b000, 0b010, 0b001, 0b011, 0b100, 0b101, 0b110, 0b111};
-#endif
+#define PS2_MOUSE_BTN_MASK 0x07
+#define PS2_MOUSE_BTN_LEFT 0
+#define PS2_MOUSE_BTN_RIGHT 1
+#define PS2_MOUSE_BTN_MIDDLE 2
+#define PS2_MOUSE_X_SIGN 4
+#define PS2_MOUSE_Y_SIGN 5
+#define PS2_MOUSE_X_OVFLW 6
+#define PS2_MOUSE_Y_OVFLW 7
 
 /* mouse button to start scrolling; set 0 to disable scroll */
 #ifndef PS2_MOUSE_SCROLL_BTN_MASK

From 94c625e2811269eb63035ee4b483a91383cf0d68 Mon Sep 17 00:00:00 2001
From: juank <juank@fktech.net>
Date: Fri, 29 May 2020 03:06:49 -0300
Subject: [PATCH 10/13] WIP: Solution with xor operators to mask the change

---
 tmk_core/protocol/ps2_mouse.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/tmk_core/protocol/ps2_mouse.c b/tmk_core/protocol/ps2_mouse.c
index 459158460dd7..62ee1cb4a650 100644
--- a/tmk_core/protocol/ps2_mouse.c
+++ b/tmk_core/protocol/ps2_mouse.c
@@ -36,14 +36,6 @@ static inline void ps2_mouse_clear_report(report_mouse_t *mouse_report);
 static inline void ps2_mouse_enable_scrolling(void);
 static inline void ps2_mouse_scroll_button_task(report_mouse_t *mouse_report);
 
-#ifdef PS2_MOUSE_INVERT_BUTTONS
-/*
- * LUT for change mouse buttons
- *
- * table index is the mouse_report->buttons state from PS2 (after &= PS2_MOUSE_BTN_MASK)
- * the value replace the mouse_report->buttons before to send to the USB interface
- */
-static const uint8_t btns_lut[8] = {0b000, 0b010, 0b001, 0b011, 0b100, 0b101, 0b110, 0b111};
 #endif
 
 /* ============================= IMPLEMENTATION ============================ */
@@ -158,8 +150,9 @@ static inline void ps2_mouse_convert_report_to_hid(report_mouse_t *mouse_report)
     mouse_report->y = Y_IS_NEG ? ((!Y_IS_OVF && -127 <= mouse_report->y && mouse_report->y <= -1) ? mouse_report->y : -127) : ((!Y_IS_OVF && 0 <= mouse_report->y && mouse_report->y <= 127) ? mouse_report->y : 127);
 
 #ifdef PS2_MOUSE_INVERT_BUTTONS
-    // remove sign and overflow flags and apply buttons LUT
-    mouse_report->buttons = btns_lut[mouse_report->buttons & PS2_MOUSE_BTN_MASK];
+    // swap left & rigth buttons & remove sign and overflow flags
+    uint8_t btns_change      = ((mouse_report->buttons >> PS2_MOUSE_BTN_LEFT) ^ (mouse_report->buttons >> PS2_MOUSE_BTN_RIGHT)) & 1;
+    mouse_report->buttons = ((btns_change << PS2_MOUSE_BTN_LEFT) | (btns_change << PS2_MOUSE_BTN_RIGHT)) & PS2_MOUSE_BTN_MASK;
 #else
     // remove sign and overflow flags
     mouse_report->buttons &= PS2_MOUSE_BTN_MASK;

From b649448ab33a47bb7a3bd6fe536dfbaff51dad95 Mon Sep 17 00:00:00 2001
From: juank <juank@fktech.net>
Date: Fri, 29 May 2020 04:47:35 -0300
Subject: [PATCH 11/13] delete #endif & added the missed xor operator (ahhh)

---
 tmk_core/protocol/ps2_mouse.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/tmk_core/protocol/ps2_mouse.c b/tmk_core/protocol/ps2_mouse.c
index 62ee1cb4a650..59ea8cbce0cf 100644
--- a/tmk_core/protocol/ps2_mouse.c
+++ b/tmk_core/protocol/ps2_mouse.c
@@ -36,8 +36,6 @@ static inline void ps2_mouse_clear_report(report_mouse_t *mouse_report);
 static inline void ps2_mouse_enable_scrolling(void);
 static inline void ps2_mouse_scroll_button_task(report_mouse_t *mouse_report);
 
-#endif
-
 /* ============================= IMPLEMENTATION ============================ */
 
 /* supports only 3 button mouse at this time */
@@ -149,13 +147,13 @@ static inline void ps2_mouse_convert_report_to_hid(report_mouse_t *mouse_report)
     mouse_report->x = X_IS_NEG ? ((!X_IS_OVF && -127 <= mouse_report->x && mouse_report->x <= -1) ? mouse_report->x : -127) : ((!X_IS_OVF && 0 <= mouse_report->x && mouse_report->x <= 127) ? mouse_report->x : 127);
     mouse_report->y = Y_IS_NEG ? ((!Y_IS_OVF && -127 <= mouse_report->y && mouse_report->y <= -1) ? mouse_report->y : -127) : ((!Y_IS_OVF && 0 <= mouse_report->y && mouse_report->y <= 127) ? mouse_report->y : 127);
 
-#ifdef PS2_MOUSE_INVERT_BUTTONS
-    // swap left & rigth buttons & remove sign and overflow flags
-    uint8_t btns_change      = ((mouse_report->buttons >> PS2_MOUSE_BTN_LEFT) ^ (mouse_report->buttons >> PS2_MOUSE_BTN_RIGHT)) & 1;
-    mouse_report->buttons = ((btns_change << PS2_MOUSE_BTN_LEFT) | (btns_change << PS2_MOUSE_BTN_RIGHT)) & PS2_MOUSE_BTN_MASK;
-#else
     // remove sign and overflow flags
     mouse_report->buttons &= PS2_MOUSE_BTN_MASK;
+
+#ifdef PS2_MOUSE_INVERT_BUTTONS
+    // swap left & rigth buttons & remove sign and overflow flags
+    uint8_t btns_change = ((mouse_report->buttons >> PS2_MOUSE_BTN_LEFT) ^ (mouse_report->buttons >> PS2_MOUSE_BTN_RIGHT)) & 1;
+    mouse_report->buttons ^= ((btns_change << PS2_MOUSE_BTN_LEFT) | (btns_change << PS2_MOUSE_BTN_RIGHT));
 #endif
 
 #ifdef PS2_MOUSE_INVERT_X

From 0351a32f5072ff52fc081ed3eba79219757c6901 Mon Sep 17 00:00:00 2001
From: juank <juank@fktech.net>
Date: Sat, 30 May 2020 09:33:19 -0300
Subject: [PATCH 12/13] Variable (mouse_report->buttons): avoid setting twice
 https://github.com/qmk/qmk_firmware/pull/9205#discussion_r430783884

---
 tmk_core/protocol/ps2_mouse.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/tmk_core/protocol/ps2_mouse.c b/tmk_core/protocol/ps2_mouse.c
index 59ea8cbce0cf..15d72691c21d 100644
--- a/tmk_core/protocol/ps2_mouse.c
+++ b/tmk_core/protocol/ps2_mouse.c
@@ -147,13 +147,13 @@ static inline void ps2_mouse_convert_report_to_hid(report_mouse_t *mouse_report)
     mouse_report->x = X_IS_NEG ? ((!X_IS_OVF && -127 <= mouse_report->x && mouse_report->x <= -1) ? mouse_report->x : -127) : ((!X_IS_OVF && 0 <= mouse_report->x && mouse_report->x <= 127) ? mouse_report->x : 127);
     mouse_report->y = Y_IS_NEG ? ((!Y_IS_OVF && -127 <= mouse_report->y && mouse_report->y <= -1) ? mouse_report->y : -127) : ((!Y_IS_OVF && 0 <= mouse_report->y && mouse_report->y <= 127) ? mouse_report->y : 127);
 
-    // remove sign and overflow flags
-    mouse_report->buttons &= PS2_MOUSE_BTN_MASK;
-
 #ifdef PS2_MOUSE_INVERT_BUTTONS
     // swap left & rigth buttons & remove sign and overflow flags
-    uint8_t btns_change = ((mouse_report->buttons >> PS2_MOUSE_BTN_LEFT) ^ (mouse_report->buttons >> PS2_MOUSE_BTN_RIGHT)) & 1;
-    mouse_report->buttons ^= ((btns_change << PS2_MOUSE_BTN_LEFT) | (btns_change << PS2_MOUSE_BTN_RIGHT));
+    uint8_t btns_change   = ((mouse_report->buttons >> PS2_MOUSE_BTN_LEFT) ^ (mouse_report->buttons >> PS2_MOUSE_BTN_RIGHT)) & 1;
+    mouse_report->buttons = (mouse_report->buttons ^ ((btns_change << PS2_MOUSE_BTN_LEFT) | (btns_change << PS2_MOUSE_BTN_RIGHT))) & PS2_MOUSE_BTN_MASK;
+#else
+    // remove sign and overflow flags
+    mouse_report->buttons &= PS2_MOUSE_BTN_MASK;
 #endif
 
 #ifdef PS2_MOUSE_INVERT_X

From c4e7a819c31de5b5c687029c39a74781cac7a28a Mon Sep 17 00:00:00 2001
From: Juan Pablo Kutianski <jkutianski@gmail.com>
Date: Thu, 5 Aug 2021 15:09:11 -0700
Subject: [PATCH 13/13] Update tmk_core/protocol/ps2_mouse.c

Co-authored-by: Nick Brassel <nick@tzarc.org>
---
 tmk_core/protocol/ps2_mouse.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tmk_core/protocol/ps2_mouse.c b/tmk_core/protocol/ps2_mouse.c
index 15d72691c21d..a47f3f6e3358 100644
--- a/tmk_core/protocol/ps2_mouse.c
+++ b/tmk_core/protocol/ps2_mouse.c
@@ -148,9 +148,10 @@ static inline void ps2_mouse_convert_report_to_hid(report_mouse_t *mouse_report)
     mouse_report->y = Y_IS_NEG ? ((!Y_IS_OVF && -127 <= mouse_report->y && mouse_report->y <= -1) ? mouse_report->y : -127) : ((!Y_IS_OVF && 0 <= mouse_report->y && mouse_report->y <= 127) ? mouse_report->y : 127);
 
 #ifdef PS2_MOUSE_INVERT_BUTTONS
-    // swap left & rigth buttons & remove sign and overflow flags
-    uint8_t btns_change   = ((mouse_report->buttons >> PS2_MOUSE_BTN_LEFT) ^ (mouse_report->buttons >> PS2_MOUSE_BTN_RIGHT)) & 1;
-    mouse_report->buttons = (mouse_report->buttons ^ ((btns_change << PS2_MOUSE_BTN_LEFT) | (btns_change << PS2_MOUSE_BTN_RIGHT))) & PS2_MOUSE_BTN_MASK;
+    // swap left & right buttons
+    uint8_t needs_left = mouse_report->buttons & PS2_MOUSE_BTN_RIGHT;
+    uint8_t needs_right = mouse_report->buttons & PS2_MOUSE_BTN_LEFT;
+    mouse_report->buttons = (mouse_report->buttons & ~(PS2_MOUSE_BTN_MASK)) | (needs_left ? PS2_MOUSE_BTN_LEFT : 0) | (needs_right ? PS2_MOUSE_BTN_RIGHT : 0);
 #else
     // remove sign and overflow flags
     mouse_report->buttons &= PS2_MOUSE_BTN_MASK;