Fix MaybeRelocatable subtraction to unlock if_reloc_equal (keep-s…

…tarknet-strange#491) * Unlock if_reloc_equal by fixing mayberelocatable sub * add unit test
StringNick · Mar 22, 2024 · a61b1c2 · a61b1c2
1 parent 126eb86
commit a61b1c2
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Showing 2 changed files with 20 additions and 4 deletions.
diff --git a/src/integration_tests.zig b/src/integration_tests.zig
@@ -103,9 +103,7 @@ pub fn main() void {
         .{ .pathname = "cairo_programs/if_and_prime.json", .layout = "all_cairo" },
         .{ .pathname = "cairo_programs/if_in_function.json", .layout = "all_cairo" },
         .{ .pathname = "cairo_programs/if_list.json", .layout = "all_cairo" },
-
-        // TODO: panic: integer overflow
-        // .{ .pathname = "cairo_programs/if_reloc_equal.json", .layout = "all_cairo" },
+        .{ .pathname = "cairo_programs/if_reloc_equal.json", .layout = "all_cairo" },
         // TODO: panic index out of bounds
         // .{ .pathname = "cairo_programs/integration_with_alloc_locals.json", .layout = "all_cairo" },
         // TODO: panic index outt of bound

diff --git a/src/vm/memory/relocatable.zig b/src/vm/memory/relocatable.zig
@@ -551,7 +551,12 @@ pub const MaybeRelocatable = union(enum) {
                 // If `other` is also `relocatable`, call `sub` method on `self_value`
                 .relocatable => |r| blk: {
                     if (self_value.segment_index == r.segment_index) {
-                        break :blk MaybeRelocatable.fromInt(u64, self_value.offset - r.offset);
+                        const res: i128 = @as(i128, self_value.offset) - @as(i128, r.offset);
+
+                        break :blk if (res < 0)
+                            MaybeRelocatable.fromFelt(Felt252.fromInt(u128, @intCast(-res)).neg())
+                        else
+                            MaybeRelocatable.fromFelt(Felt252.fromInt(u128, @intCast(res)));
                     }
 
                     break :blk CairoVMError.TypeMismatchNotRelocatable;
@@ -1492,3 +1497,16 @@ test "MaybeRelocatable.mul: should return Felt multiplication operation if both
         (try result2.intoFelt()).toInteger(),
     );
 }
+
+test "MaybeRelocatable.sub: wiht negative relocatable subtraction" {
+    const a = MaybeRelocatable.fromSegment(4, 0);
+    const b = MaybeRelocatable.fromSegment(4, 5);
+
+    try expectEqual(
+        MaybeRelocatable.fromInt(
+            u256,
+            3618502788666131213697322783095070105623107215331596699973092056135872020476,
+        ),
+        try a.sub(b),
+    );
+}