Button IO

Makefile

@@ -4,8 +4,8 @@ build:
 	cargo build --release
 
 extract: build
-	riscv32-elf-objcopy -O binary --only-section=.text target/riscv32i-unknown-none-elf/release/lw-riscv text.bin
-	riscv32-elf-objcopy -O binary --only-section=.rodata target/riscv32i-unknown-none-elf/release/lw-riscv rodata.bin
+	riscv32-elf-objcopy -O binary --only-section=.text target/riscv32i-unknown-none-elf/release/lw-riscv ~/text.bin
+	riscv32-elf-objcopy -O binary --only-section=.rodata target/riscv32i-unknown-none-elf/release/lw-riscv ~/rodata.bin
 
 size: extract
 	cargo size --release -- -A

src/main.rs

@@ -6,20 +6,39 @@ use riscv_rt::entry;
 
 #[panic_handler]
 fn panic_handler(_info: &PanicInfo) -> ! {
+    unsafe {
+        OUTPUT.write_volatile(0xDEADC0DE);
+    }
     loop {}
 }
 
-#[used]
-static TEXT: &str = "lmao YEET";
+const OUTPUT: *mut u32 = 0x2000_0000 as *mut u32;
+const BTNS: *mut u8 = 0x2000_0008 as *mut u8;
 
 #[entry]
 fn main() -> ! {
-    let output = 0x2000_0000 as *mut u32;
-    let mut n: u32 = 6814;
+    let mut value: u32 = 1;
+    let mut btnA_prev = false;
+    let mut btnB_prev = false;
     loop {
+        let btns_value;
+        unsafe {
+            btns_value = BTNS.read_volatile();
+        }
+        let btnA = (btns_value & 0b00000001) > 0;
+        let btnB = (btns_value & 0b00000010) > 0;
+        if btnA && !btnA_prev {
+            value >>= 1;
+        } else if btnB && !btnB_prev {
+            value <<= 1;
+        }
+        if value == 0 {
+            panic!();
+        }
         unsafe {
-            output.write_volatile(n);
+            OUTPUT.write_volatile(value);
         }
-        n += 1;
+        btnA_prev = btnA;
+        btnB_prev = btnB;
     }
 }