sylveos

commit 30e4911af3d7a3913c1043b8441dbdefcf3cd30a
parent f4fb47a6ec50ad18e6043a8cf55a65404b2718bb
Author: Sylvia Ivory <git@sivory.net>
Date:   Tue, 13 Jan 2026 18:12:42 -0800

Use proper error handling

Diffstat:
M
Justfile
 | 
2
+-
M
src/gpio.zig
 | 
46
+++++++++++++++++++++++++---------------------
M
src/labs/2-gpio.zig
 | 
72
++++++++++++++++++++++++++++++++++++------------------------------------

3 files changed, 62 insertions(+), 58 deletions(-)
diff --git a/Justfile b/Justfile
@@ -6,4 +6,4 @@ lab name:
     rm src/*.runner.zig
 
 list name="SylveOS": build
-    arm-none-eabi-objdump -m armv6 -d zig-out/bin/{{ name }}
+    arm-none-eabi-objdump -m armv6 -d zig-out/bin/{{ name }}.elf
diff --git a/src/gpio.zig b/src/gpio.zig
@@ -23,8 +23,12 @@ const FunctionSelect = enum(u3) {
     alt_fn_5 = 0b010,
 };
 
-fn fn_sel(pin: u8, sel: FunctionSelect) void {
-    if (pin > 53) @panic("pin out of range (0...53)");
+const GpioError = error{
+    PinOutOfRange,
+};
+
+fn fn_sel(pin: u8, sel: FunctionSelect) GpioError!void {
+    if (pin > 53) return GpioError.PinOutOfRange;
 
     const index = @divFloor(pin, 10);
     const address: *volatile u32 = &GPFSEL0[index];
@@ -37,8 +41,8 @@ fn fn_sel(pin: u8, sel: FunctionSelect) void {
     address.* = state;
 }
 
-fn addr_get(pin: u8, address: [*]volatile u32) *volatile u32 {
-    if (pin > 53) @panic("pin out of range (0...53)");
+fn addr_get(pin: u8, address: [*]volatile u32) GpioError!*volatile u32 {
+    if (pin > 53) return GpioError.PinOutOfRange;
 
     return &address[@divFloor(pin, 32)];
 }
@@ -53,33 +57,33 @@ fn addr_bitset(pin: u8, address: *volatile u32) void {
 }
 
 // Turn on
-fn output_set(pin: u8) void {
-    addr_bitset(pin, addr_get(pin, GPSET0));
+fn output_set(pin: u8) GpioError!void {
+    addr_bitset(pin, try addr_get(pin, GPSET0));
 }
 
 // Turn off
-fn output_clear(pin: u8) void {
-    addr_bitset(pin, addr_get(pin, GPCLR0));
+fn output_clear(pin: u8) GpioError!void {
+    addr_bitset(pin, try addr_get(pin, GPCLR0));
 }
 
-pub fn set_output(pin: u8) void {
-    fn_sel(pin, .output);
+pub fn set_output(pin: u8) GpioError!void {
+    try fn_sel(pin, .output);
 }
 
-pub fn set_input(pin: u8) void {
-    fn_sel(pin, .input);
+pub fn set_input(pin: u8) GpioError!void {
+    try fn_sel(pin, .input);
 }
 
-pub fn set_on(pin: u8) void {
-    output_set(pin);
+pub fn set_on(pin: u8) GpioError!void {
+    try output_set(pin);
 }
 
-pub fn set_off(pin: u8) void {
-    output_clear(pin);
+pub fn set_off(pin: u8) GpioError!void {
+    try output_clear(pin);
 }
 
-pub fn read(pin: u8) bool {
-    const address = addr_get(pin, GPLEV0);
+pub fn read(pin: u8) GpioError!bool {
+    const address = try addr_get(pin, GPLEV0);
 
     const offset: u5 = @truncate(pin % 32);
     const mask = (@as(u32, 1) << offset);
@@ -87,10 +91,10 @@ pub fn read(pin: u8) bool {
     return (address.* & mask) == mask;
 }
 
-pub fn write(pin: u8, state: bool) void {
+pub fn write(pin: u8, state: bool) GpioError!void {
     if (state) {
-        set_on(pin);
+        try set_on(pin);
     } else {
-        set_off(pin);
+        try set_off(pin);
     }
 }
diff --git a/src/labs/2-gpio.zig b/src/labs/2-gpio.zig
@@ -5,74 +5,74 @@ const led0 = 20;
 const led1 = 21;
 const act = 47;
 
-pub fn blink_1() void {
-    gpio.set_output(led0);
+pub fn blink_1() !void {
+    try gpio.set_output(led0);
     for (0..10) |_| {
-        gpio.set_on(led0);
+        try gpio.set_on(led0);
         util.delay_cycles(1000000);
-        gpio.set_off(led0);
+        try gpio.set_off(led0);
         util.delay_cycles(1000000);
     }
-    gpio.set_on(led0);
+    try gpio.set_on(led0);
 }
 
-pub fn blink_2() void {
-    gpio.set_output(led0);
-    gpio.set_output(led1);
+pub fn blink_2() !void {
+    try gpio.set_output(led0);
+    try gpio.set_output(led1);
 
     for (0..10) |_| {
-        gpio.set_on(led0);
-        gpio.set_off(led1);
+        try gpio.set_on(led0);
+        try gpio.set_off(led1);
         util.delay_cycles(3000000);
-        gpio.set_off(led0);
-        gpio.set_on(led1);
+        try gpio.set_off(led0);
+        try gpio.set_on(led1);
         util.delay_cycles(3000000);
     }
 }
 
-pub fn loopback() void {
+pub fn loopback() !void {
     const input = 9;
     const output = 10;
 
-    gpio.set_output(led0);
-    gpio.set_input(input);
-    gpio.set_output(led1);
-    gpio.set_output(output);
+    try gpio.set_output(led0);
+    try gpio.set_input(input);
+    try gpio.set_output(led1);
+    try gpio.set_output(output);
 
     var v = false;
     for (0..20) |_| {
-        gpio.write(led0, v);
-        gpio.write(output, v);
-        gpio.write(led1, gpio.read(input));
+        try gpio.write(led0, v);
+        try gpio.write(output, v);
+        try gpio.write(led1, try gpio.read(input));
         util.delay_cycles(1500000);
         v = !v;
     }
 }
 
-pub fn act_blink() void {
-    gpio.set_output(act);
+pub fn act_blink() !void {
+    try gpio.set_output(act);
     for (0..10) |_| {
-        gpio.set_on(act);
+        try gpio.set_on(act);
         util.delay_cycles(1000000);
-        gpio.set_off(act);
+        try gpio.set_off(act);
         util.delay_cycles(1000000);
     }
-    gpio.set_on(act);
+    try gpio.set_on(act);
 }
 
-pub fn all() void {
-    gpio.set_output(led0);
-    gpio.set_output(led1);
-    gpio.set_output(act);
+pub fn all() !void {
+    try gpio.set_output(led0);
+    try gpio.set_output(led1);
+    try gpio.set_output(act);
     for (0..10) |_| {
-        gpio.set_on(led0);
-        gpio.set_on(led1);
-        gpio.set_on(act);
+        try gpio.set_on(led0);
+        try gpio.set_on(led1);
+        try gpio.set_on(act);
         util.delay_cycles(1000000);
-        gpio.set_off(led0);
-        gpio.set_off(led1);
-        gpio.set_off(act);
+        try gpio.set_off(led0);
+        try gpio.set_off(led1);
+        try gpio.set_off(act);
         util.delay_cycles(1000000);
     }
-    gpio.set_on(act);
+    try gpio.set_on(act);
 }