o1vm/riscv32im: test for addi with overflow

o1vm/resources/programs/riscv32im/src/addi_overflow.S

@@ -0,0 +1,23 @@
+.section .text
+.globl _start
+
+_start:
+    li t0, 2147483647    # t0 = 2147483647 (Max 32-bit signed int)
+    addi t1, t0, 1       # t1 = t0 + 1 (Expected: overflow to -2147483648)
+
+    li t2, -2147483648   # t2 = -2147483648 (Min 32-bit signed int)
+    addi t3, t2, -1      # t3 = t2 + (-1) (Expected: overflow to 2147483647)
+
+    li t4, 123456789     # t4 = 123456789
+    addi t5, t4, 0       # t5 = t4 + 0 (Expected: t4 = 123456789)
+
+    # Custom exit syscall
+    li a0, 0
+    li a1, 0
+    li a2, 0
+    li a3, 0
+    li a4, 0
+    li a5, 0
+    li a6, 0
+    li a7, 42
+    ecall

o1vm/tests/test_riscv_elf.rs

@@ -213,3 +213,21 @@ fn test_add_sub_swap() {
     assert_eq!(witness.registers[T0], 10);
     assert_eq!(witness.registers[T1], 5);
 }
+
+#[test]
+fn test_addi_overflow() {
+    let curr_dir = std::env::current_dir().unwrap();
+    let path = curr_dir.join(std::path::PathBuf::from(
+        "resources/programs/riscv32im/bin/addi_overflow",
+    ));
+    let state = o1vm::elf_loader::parse_riscv32(&path).unwrap();
+    let mut witness = Env::<Fp>::create(PAGE_SIZE.try_into().unwrap(), state);
+
+    while !witness.halt {
+        witness.step();
+    }
+
+    assert_eq!(witness.registers[T1], (-2147483648_i32) as u32);
+    assert_eq!(witness.registers[T3], 2147483647);
+    assert_eq!(witness.registers[T5], 123456789);
+}