diff --git a/src/cpu.c b/src/cpu.c
index 8146d37..797984b 100644
--- a/src/cpu.c
+++ b/src/cpu.c
@@ -924,9 +924,8 @@ static void vm_skipparam(vm_t *vm, uint32_t size, uint8_t prtype, uint8_t offset
     VM_PRELUDE_2(_size);                                  \
     _type a = _vm_source(vm, instr.source, instr.offset); \
     _type b = _vm_source(vm, instr.target, instr.offset); \
-    _type x;                                              \
-    vm->flag_carry = CHECKED_SUB(b, a, &x);               \
-    vm->flag_zero = x == 0;                               \
+    vm->flag_carry = a > b;                               \
+    vm->flag_zero = a == b;                               \
     break;                                                \
 }