From c4314b35efe14fd0c1c57c8c3577431b380e323e Mon Sep 17 00:00:00 2001
From: Victor Mignot <victor@vmignot.fr>
Date: Tue, 29 Jul 2025 08:39:33 +0200
Subject: use c99 instead of c23

---
 Makefile    |  2 +-
 README.md   |  4 ++--
 src/clock.c | 12 ++++++------
 src/clock.h |  2 +-
 src/main.c  |  1 -
 5 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/Makefile b/Makefile
index 8576e6f..053c357 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 ARCH = arm-none-eabi
 CC = $(ARCH)-gcc
-CFLAGS = -mcpu=cortex-m4 -mthumb -mfloat-abi=hard -std=c23 -g -O0 -ffreestanding -Wpedantic -Wall -Wextra -Werror
+CFLAGS = -mcpu=cortex-m4 -mthumb -mfloat-abi=hard -std=c99 -g -O0 -ffreestanding -Wpedantic -Wall -Wextra -Werror
 LDFLAGS = -Tlink.ld -nostdlib
 
 SRCDIR = src
diff --git a/README.md b/README.md
index 9ee6690..5d98261 100644
--- a/README.md
+++ b/README.md
@@ -10,8 +10,8 @@ As such, it is by no way intended to be daily-driven by anyone.
 
 Moreover, I don't even recommend to flash it on any other hardware than the PineTime dev kit wired to a STLink-V2 interface.
 
-nanji is written in C23.
-However, at the time I write this, GCC does not fully support the C23 standard (and as such, can't rely on all new features).
+nanji is written in C99 for to be buildable with most compilers.
+Moreover, as much as I would like to use C23, its new features are still not all implemented by GCC for the `arm-none-eabi` target.
 
 ## Building and flashing
 
diff --git a/src/clock.c b/src/clock.c
index 5603693..328ad52 100644
--- a/src/clock.c
+++ b/src/clock.c
@@ -44,18 +44,18 @@ enum clock_registers {
 	TRACECONFIG         = 0x55c,
 };
 
-static bool init_hfclk() {
+static int init_hfclk() {
 	/* We just assert that the source clock is running with the CPU internal clock
      * as source */
 	u32 hfclk_status = READ_CLK_REG(HFCLKSTAT);
-	int clk_src = hfclk_status & 0x1;
-	bool clk_running = (hfclk_status >> 16) & 0x1;
+	u32 clk_src = hfclk_status & 0x1;
+	u32 clk_running = (hfclk_status >> 16) & 0x1;
 
 	return (clk_src == HFINT) && clk_running;
 }
 
-static bool init_lfclk() {
-	bool clk_started = false;
+static int init_lfclk() {
+	int clk_started = 0;
 	enum lfclk_src src = LFRC;
 
 	/* LFCLK use the LFRC clock by default, so it should be ready
@@ -74,6 +74,6 @@ static bool init_lfclk() {
 	return src == LFRC;
 }
 
-bool init_clock() {
+int init_clock() {
 	return init_hfclk() && init_lfclk();
 }
diff --git a/src/clock.h b/src/clock.h
index 30cfb44..8c5d1f0 100644
--- a/src/clock.h
+++ b/src/clock.h
@@ -5,6 +5,6 @@
  * Init the nrf52832 CLOCK device and ensure that clock sources are correctly
  * selected.
  */
-bool init_clock();
+int init_clock();
 
 #endif
diff --git a/src/main.c b/src/main.c
index 02c20f8..aab0723 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,6 +1,5 @@
 #include "clock.h"
 
-[[noreturn]]
 void main() {
 	init_clock();
 
-- 
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