From b3d7d19579866771677d5a0f1f515934ed479faa Mon Sep 17 00:00:00 2001
From: Erick Ahmed <engineering@erickahmed.com>
Date: Wed, 31 Dec 2025 22:43:33 +0100
Subject: [PATCH] Tail jump from ISR to stop_blink

- Saves 7 clock cycles per call vs. previous implementation
---
 src/clockinator.S | 3 +--
 src/led.inc       | 2 +-
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/clockinator.S b/src/clockinator.S
index 7dd31d5..e7a1309 100644
--- a/src/clockinator.S
+++ b/src/clockinator.S
@@ -22,8 +22,7 @@
 ; useful for the tap tempo stuff
 
 isr_stop_blink:
-    rcall       stop_blink              ; Turn off PB0 when TCNT0=OCF0A
-    reti                                ; Exit interrupt
+    rjmp       stop_blink              ; Turn off PB0 when TCNT0=OCF0A
 
 main:
     ; To compile on AtTiny25/45 comment out the SPH part
diff --git a/src/led.inc b/src/led.inc
index 421ecbd..766523e 100644
--- a/src/led.inc
+++ b/src/led.inc
@@ -24,4 +24,4 @@ stop_blink:
     ldi     r16,        (1 << OCF0A)
     out     TIFR,       r16                             ; Clear timer0 interrupt flag register
 
-    ret
+    reti