Merge pull request #2899 from o1-labs/dw/sub-tests

o1vm/riscv32im: add tests for sub

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

@@ -0,0 +1,25 @@
+.section .text
+.globl _start
+
+_start:
+
+    # Test 1: Simple subtraction
+    li t0, 1000           # t0 = 1000
+    li t1, 500            # t1 = 500
+    sub t2, t0, t1        # t2 = t0 - t1 (Expected: t2 = 500)
+
+    # Test 2: Subtracting from zero
+    li t3, 0              # t3 = 0
+    li t4, 100            # t4 = 100
+    sub t5, t3, t4        # t5 = t3 - t4 (Expected: t5 = -100)
+
+    # 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/resources/programs/riscv32im/src/sub_2.S

@@ -0,0 +1,25 @@
+.section .text
+.globl _start
+
+_start:
+
+    # Test 3: Subtracting a larger value (result negative)
+    li t0, 300            # t0 = 300
+    li t1, 500            # t1 = 500
+    sub t2, t0, t1        # t2 = t0 - t1 (Expected: t2 = -200)
+
+    # Test 4: Subtracting negative values (result positive)
+    li t3, 100            # t3 = 100
+    li t4, -50            # t4 = -50
+    sub t5, t3, t4        # t5 = t3 - t4 (Expected: t5 = 150)
+
+    # 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/resources/programs/riscv32im/src/sub_3.S

@@ -0,0 +1,22 @@
+.section .text
+.globl _start
+
+_start:
+    # Test 5: Result of subtracting from a register (using same value)
+    li t0, 1234           # t0 = 1234
+    sub t1, t0, t0        # t1 = t0 - t0 (Expected: t1 = 0)
+
+    # Test 6: Handling overflow (large subtraction result)
+    li t2, 2147483647     # t2 = 2147483647 (max positive signed 32-bit)
+    li t3, -1             # t3 = -1
+    sub t4, t2, t3        # t4 = t2 - t3 (Expected: t0 = 2147483648, wraparound to -2147483648)
+    # 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

@@ -251,3 +251,54 @@ fn test_addi_boundary_immediate() {
     assert_eq!(witness.registers[T1], 2147);
     assert_eq!(witness.registers[T3], (-1048_i32) as u32);
 }
+
+#[test]
+fn test_sub() {
+    let curr_dir = std::env::current_dir().unwrap();
+    let path = curr_dir.join(std::path::PathBuf::from(
+        "resources/programs/riscv32im/bin/sub",
+    ));
+    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[T2], 500);
+    assert_eq!(witness.registers[T5], (-100_i32) as u32);
+}
+
+#[test]
+fn test_sub_2() {
+    let curr_dir = std::env::current_dir().unwrap();
+    let path = curr_dir.join(std::path::PathBuf::from(
+        "resources/programs/riscv32im/bin/sub_2",
+    ));
+    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[T2], -200_i32 as u32);
+    assert_eq!(witness.registers[T5], 150);
+}
+
+#[test]
+fn test_sub_3() {
+    let curr_dir = std::env::current_dir().unwrap();
+    let path = curr_dir.join(std::path::PathBuf::from(
+        "resources/programs/riscv32im/bin/sub_3",
+    ));
+    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], 0);
+    assert_eq!(witness.registers[T4], -2147483648_i32 as u32);
+}