tick: optional SP debugging

2 files changed, 13 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index c082c6f..1f3dcc7 100644
--- a/Makefile
+++ b/Makefile
@@ -8,7 +8,7 @@ CFLAGS_OPT=-Os \
 	-fwhole-program
 CFLAGS_WARN=-std=gnu99 -Wall -Wextra -Wno-unused -pedantic
 CFLAGS_LD=-Wl,-T,avr4-signature.x 
-CFLAGS=${CFLAGS_WARN} ${CFLAGS_OPT} ${CFLAGS_LD}
+CFLAGS_=${CFLAGS_WARN} ${CFLAGS_OPT} ${CFLAGS_LD} ${CFLAGS}
 MCU_door=48
 MCU_lightctrl=88
 AVRDUDE=avrdude
@@ -32,4 +32,4 @@ endif
 %.flash: %.elf Makefile
 	avr-objcopy -j .text -j .data -O ihex $< $@
 %.elf: %.c *.c *.x Makefile
-	avr-gcc -mmcu=atmega$(MCU_$(basename $@)) ${CFLAGS} -o $@ $<
+	avr-gcc -mmcu=atmega$(MCU_$(basename $@)) ${CFLAGS_} -o $@ $<
diff --git a/tick.c b/tick.c
index 87dcbc6..76ebcc0 100644
--- a/tick.c
+++ b/tick.c
@@ -13,6 +13,7 @@ ISR(TIMER1_COMPA_vect)
 static void uart_puttick(void)
 {
 	uint16_t frac = TCNT1;
+
 	_uart_putch('@');
 	uart_puthex(systick.u8[3]);
 	uart_puthex(systick.u8[2]);
@@ -20,6 +21,16 @@ static void uart_puttick(void)
 	uart_puthex(systick.u8[0]);
 	_uart_putch('.');
 	uart_puthex16(frac);
+#if DEBUG_SP
+	_uart_putch('~');
+	uint8_t spl, sph;
+	asm ("\n\
+		in %[spl], 0x3d\n\
+		in %[sph], 0x3e\n\
+	" : [spl] "=r" (spl), [sph] "=r" (sph));
+	uart_puthex(sph);
+	uart_puthex(spl);
+#endif
 	_uart_putch(' ');
 }