def test_can_calculate_factorial():
vm = quaff.VirtualMachine()
vm.run(
[
# n:
quaff.inst_const(6), # [6]
# n!:
quaff.inst_const(1), # [T1, 6]
quaff.inst_swap(1), # [6, T1]
quaff.inst_dup(), # [6, 6, T1]
quaff.inst_const(0), # [0, 6, 6, T1]
quaff.inst_cmp(), # [1, 6, T1]
quaff.inst_jle(7), # [6, T1]
quaff.inst_dup(), # [6, 6, T1]
quaff.inst_swap(2), # [T1, 6, 6]
quaff.inst_mul(), # [T6, 6]
quaff.inst_swap(1), # [6, T6]
quaff.inst_const(-1), # [-1, 6, T6]
quaff.inst_add(), # [5, T6]
quaff.inst_jmp(-11),
quaff.inst_pop(),
]
)
assert_stack_elements(vm, [720])
def test_const_then_swap_2():
vm = quaff.VirtualMachine()
vm.run([quaff.inst_const(42), quaff.inst_const(7), quaff.inst_const(64), quaff.inst_swap(2)])
assert_stack_elements(vm, [42, 7, 64])