1165 lines
43 KiB
Haskell
1165 lines
43 KiB
Haskell
module VirtualMachineSpec where
|
|
|
|
import Test.Hspec
|
|
import qualified Data.Sequence as S
|
|
|
|
|
|
import VirtualMachine.VM (VM(..), empty)
|
|
import Runner (run, exec)
|
|
|
|
done :: [Int] -> Int -> Int -> Either String VM
|
|
done stack pc fp = return $ empty { _stack = S.fromList stack, _pc = pc, _fp = fp, _halt = True }
|
|
|
|
fibb :: Int -> Int
|
|
fibb 0 = 1
|
|
fibb 1 = 1
|
|
fibb n = fibb (n-1) + fibb (n-2)
|
|
|
|
spec :: Spec
|
|
spec = do
|
|
describe "nop" $ do
|
|
it "does do nothing" $ do
|
|
let input = " nop \n\
|
|
\ halt "
|
|
let expected = done [] 1 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "halt" $ do
|
|
it "shutdowns the VM" $ do
|
|
let input = "halt"
|
|
let expected = done [] 0 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "throws an error if halt instruction is not encountered and program exits" $ do
|
|
let input = " nop \n\
|
|
\ nop "
|
|
let expected = Left "PC (=2) exceeds program size (=2)"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "push" $ do
|
|
it "supports push" $ do
|
|
let input = " push 1 \n\
|
|
\ halt "
|
|
let expected = done [1] 2 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "supports pushing in the correct order" $ do
|
|
let input = " push 1 \n\
|
|
\ push 2 \n\
|
|
\ push 3 \n\
|
|
\ push 4 \n\
|
|
\ halt "
|
|
let expected = done [4, 3, 2, 1] 8 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "pop" $ do
|
|
it "supports pop" $ do
|
|
let input = " push 1 \n\
|
|
\ pop \n\
|
|
\ halt "
|
|
let expected = done [] 3 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "supports poping in correct order" $ do
|
|
let input = " push 1 \n\
|
|
\ push 2 \n\
|
|
\ push 3 \n\
|
|
\ push 4 \n\
|
|
\ pop \n\
|
|
\ pop \n\
|
|
\ halt "
|
|
let expected = done [2, 1] 10 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if empty stack" $ do
|
|
let input = " pop \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 1 elements, got 0"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "dup" $ do
|
|
it "duplicates the top stack value" $ do
|
|
let input = " push 1 \n\
|
|
\ push 2 \n\
|
|
\ push 3 \n\
|
|
\ dup \n\
|
|
\ halt "
|
|
let expected = done [3, 3, 2, 1] 7 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if empty stack" $ do
|
|
let input = " dup \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 1 elements, got 0"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "swap" $ do
|
|
it "swaps the top 2 stack values" $ do
|
|
let input = " push 1 \n\
|
|
\ push 2 \n\
|
|
\ push 3 \n\
|
|
\ push 4 \n\
|
|
\ push 5 \n\
|
|
\ swap \n\
|
|
\ halt "
|
|
let expected = done [4, 5, 3, 2, 1] 11 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if empty stack" $ do
|
|
let input = " swap \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 2 elements, got 0"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if stack is not big enough" $ do
|
|
let input = " push 5 \n\
|
|
\ swap \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 2 elements, got 1"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "add" $ do
|
|
it "sums the top 2 stack values" $ do
|
|
let input = " push 7 \n\
|
|
\ push 4 \n\
|
|
\ add \n\
|
|
\ halt "
|
|
let expected = done [7+4] 5 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "can be composed" $ do
|
|
let input = " push 4 \n\
|
|
\ push 7 \n\
|
|
\ push 10 \n\
|
|
\ push 3 \n\
|
|
\ add \n\
|
|
\ add \n\
|
|
\ add \n\
|
|
\ halt "
|
|
let expected = done [4+(7+(10+3))] 11 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if empty stack" $ do
|
|
let input = " add \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 2 elements, got 0"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if stack is not big enough" $ do
|
|
let input = " push 5\n\
|
|
\ add \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 2 elements, got 1"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "sub" $ do
|
|
it "substracts the top 2 stack values" $ do
|
|
let input = " push 7 \n\
|
|
\ push 4 \n\
|
|
\ sub \n\
|
|
\ halt "
|
|
let expected = done [7-4] 5 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "can be composed" $ do
|
|
let input = " push 4 \n\
|
|
\ push 7 \n\
|
|
\ push 10 \n\
|
|
\ push 3 \n\
|
|
\ sub \n\
|
|
\ sub \n\
|
|
\ sub \n\
|
|
\ halt "
|
|
let expected = done [4-(7-(10-3))] 11 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if empty stack" $ do
|
|
let input = " sub \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 2 elements, got 0"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if stack is not big enough" $ do
|
|
let input = " push 5 \n\
|
|
\ sub \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 2 elements, got 1"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "mul" $ do
|
|
it "multiplies the top 2 stack values" $ do
|
|
let input = " push 7 \n\
|
|
\ push 4 \n\
|
|
\ mul \n\
|
|
\ halt "
|
|
let expected = done [7*4] 5 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "can be composed" $ do
|
|
let input = " push 4 \n\
|
|
\ push 7 \n\
|
|
\ push 10 \n\
|
|
\ push 3 \n\
|
|
\ mul \n\
|
|
\ mul \n\
|
|
\ mul \n\
|
|
\ halt "
|
|
let expected = done [4*(7*(10*3))] 11 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if empty stack" $ do
|
|
let input = " mul \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 2 elements, got 0"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if stack is not big enough" $ do
|
|
let input = " push 5 \n\
|
|
\ mul \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 2 elements, got 1"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "div" $ do
|
|
it "divides the top 2 stack values" $ do
|
|
let input = " push 7 \n\
|
|
\ push 4 \n\
|
|
\ div \n\
|
|
\ halt "
|
|
let expected = done [7 `div` 4] 5 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "can be composed" $ do
|
|
let input = " push 4 \n\
|
|
\ push 7 \n\
|
|
\ push 10 \n\
|
|
\ push 3 \n\
|
|
\ div \n\
|
|
\ div \n\
|
|
\ div \n\
|
|
\ halt "
|
|
let expected = done [4 `div` (7 `div` (10 `div` 3))] 11 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if empty stack" $ do
|
|
let input = " div \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 2 elements, got 0"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if stack is not big enough" $ do
|
|
let input = " push 5 \n\
|
|
\ div \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 2 elements, got 1"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "neg" $ do
|
|
it "negates the top stack value" $ do
|
|
let input = " push 4 \n\
|
|
\ neg \n\
|
|
\ halt "
|
|
let expected = done [-4] 3 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "the od number of 'neg' instructions should negate the value" $ do
|
|
let input = " push 4 \n\
|
|
\ neg \n\
|
|
\ neg \n\
|
|
\ neg \n\
|
|
\ neg \n\
|
|
\ neg \n\
|
|
\ neg \n\
|
|
\ halt "
|
|
let expected = done [4] 8 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "the even number of 'neg' instructions should not change the value" $ do
|
|
let input = " push 4 \n\
|
|
\ neg \n\
|
|
\ neg \n\
|
|
\ neg \n\
|
|
\ neg \n\
|
|
\ neg \n\
|
|
\ halt "
|
|
let expected = done [-4] 7 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if empty stack" $ do
|
|
let input = " neg \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 1 elements, got 0"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "not" $ do
|
|
it "negates the 'true' value" $ do
|
|
let input = " push 1 \n\
|
|
\ not \n\
|
|
\ halt "
|
|
let expected = done [0] 3 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "negates the 'false' value" $ do
|
|
let input = " push 0 \n\
|
|
\ not \n\
|
|
\ halt "
|
|
let expected = done [1] 3 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "negates any non-zero value to false" $ do
|
|
let input = " push 129 \n\
|
|
\ not \n\
|
|
\ halt "
|
|
let expected = done [0] 3 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "the od number of 'neg' instructions should negate the logic value" $ do
|
|
let input = " push 1 \n\
|
|
\ not \n\
|
|
\ not \n\
|
|
\ not \n\
|
|
\ not \n\
|
|
\ not \n\
|
|
\ not \n\
|
|
\ halt "
|
|
let expected = done [1] 8 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "the even number of 'neg' instructions should not change the value" $ do
|
|
let input = " push 1 \n\
|
|
\ not \n\
|
|
\ not \n\
|
|
\ not \n\
|
|
\ not \n\
|
|
\ not \n\
|
|
\ halt "
|
|
let expected = done [0] 7 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if empty stack" $ do
|
|
let input = " not \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 1 elements, got 0"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "jmp" $ do
|
|
it "changes the program counter register" $ do
|
|
let input = " nop \n\
|
|
\ jmp 4 \n\
|
|
\ halt \n\
|
|
\ nop \n\
|
|
\ nop \n\
|
|
\ jmp 3 "
|
|
let expected = done [] 3 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "skips instructions after jump" $ do
|
|
let input = " nop \n\
|
|
\ jmp 11 \n\
|
|
\ push 1 \n\
|
|
\ push 2 \n\
|
|
\ push 3 \n\
|
|
\ push 4 \n\
|
|
\ halt "
|
|
let expected = done [] 11 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "supports jumping by labels" $ do
|
|
let input = " nop \n\
|
|
\ jmp &end \n\
|
|
\ stop: \n\
|
|
\ halt \n\
|
|
\ push 1 \n\
|
|
\ push 2 \n\
|
|
\ push 3 \n\
|
|
\ push 4 \n\
|
|
\ end: jmp &stop "
|
|
let expected = done [] 3 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "je" $ do
|
|
it "jumps if top stack value == 0" $ do
|
|
let input = " push 0 \n\
|
|
\ je &jumped \n\
|
|
\ pop \n\
|
|
\ push 0 \n\
|
|
\ halt \n\
|
|
\ jumped: \n\
|
|
\ pop \n\
|
|
\ push 1 \n\
|
|
\ halt "
|
|
let expected = done [1] 11 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "proceeds if top stack value != 0" $ do
|
|
let input = " push 1 \n\
|
|
\ je &jumped \n\
|
|
\ pop \n\
|
|
\ push 0 \n\
|
|
\ halt \n\
|
|
\ jumped: \n\
|
|
\ pop \n\
|
|
\ push 1 \n\
|
|
\ halt "
|
|
let expected = done [0] 7 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if empty stack" $ do
|
|
let input = " je 0 \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 1 elements, got 0"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "jne" $ do
|
|
it "jumps if top stack value != 0" $ do
|
|
let input = " push 4 \n\
|
|
\ jne &jumped \n\
|
|
\ pop \n\
|
|
\ push 0 \n\
|
|
\ halt \n\
|
|
\ jumped: \n\
|
|
\ pop \n\
|
|
\ push 1 \n\
|
|
\ halt "
|
|
let expected = done [1] 11 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "proceeds if top stack value == 0" $ do
|
|
let input = " push 0 \n\
|
|
\ jne &jumped \n\
|
|
\ pop \n\
|
|
\ push 0 \n\
|
|
\ halt \n\
|
|
\ jumped: \n\
|
|
\ pop \n\
|
|
\ push 1 \n\
|
|
\ halt "
|
|
let expected = done [0] 7 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if empty stack" $ do
|
|
let input = " jne 0 \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 1 elements, got 0"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "jg" $ do
|
|
it "jumps if top stack value > 0" $ do
|
|
let input = " push 1 \n\
|
|
\ jg &jumped \n\
|
|
\ pop \n\
|
|
\ push 0 \n\
|
|
\ halt \n\
|
|
\ jumped: \n\
|
|
\ pop \n\
|
|
\ push 1 \n\
|
|
\ halt "
|
|
let expected = done [1] 11 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "proceeds if top stack value == 0" $ do
|
|
let input = " push 0 \n\
|
|
\ jg &jumped \n\
|
|
\ pop \n\
|
|
\ push 0 \n\
|
|
\ halt \n\
|
|
\ jumped: \n\
|
|
\ pop \n\
|
|
\ push 1 \n\
|
|
\ halt "
|
|
let expected = done [0] 7 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "proceeds if top stack value < 0" $ do
|
|
let input = " push 1 \n\
|
|
\ neg \n\
|
|
\ jg &jumped \n\
|
|
\ pop \n\
|
|
\ push 0 \n\
|
|
\ halt \n\
|
|
\ jumped: \n\
|
|
\ pop \n\
|
|
\ push 1 \n\
|
|
\ halt "
|
|
let expected = done [0] 8 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if empty stack" $ do
|
|
let input = " jg 0 \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 1 elements, got 0"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "jl" $ do
|
|
it "proceeds if top stack value > 0" $ do
|
|
let input = " push 1 \n\
|
|
\ jl &jumped \n\
|
|
\ pop \n\
|
|
\ push 0 \n\
|
|
\ halt \n\
|
|
\ jumped: \n\
|
|
\ pop \n\
|
|
\ push 1 \n\
|
|
\ halt "
|
|
let expected = done [0] 7 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "proceeds if top stack value == 0" $ do
|
|
let input = " push 0 \n\
|
|
\ jl &jumped \n\
|
|
\ pop \n\
|
|
\ push 0 \n\
|
|
\ halt \n\
|
|
\ jumped: \n\
|
|
\ pop \n\
|
|
\ push 1 \n\
|
|
\ halt "
|
|
let expected = done [0] 7 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "jumps if top stack value < 0" $ do
|
|
let input = " push 1 \n\
|
|
\ neg \n\
|
|
\ jl &jumped \n\
|
|
\ pop \n\
|
|
\ push 0 \n\
|
|
\ halt \n\
|
|
\ jumped: \n\
|
|
\ pop \n\
|
|
\ push 1 \n\
|
|
\ halt "
|
|
let expected = done [1] 12 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if empty stack" $ do
|
|
let input = " jl 0 \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 1 elements, got 0"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "jge" $ do
|
|
it "jumps if top stack value > 0" $ do
|
|
let input = " push 1 \n\
|
|
\ jge &jumped \n\
|
|
\ pop \n\
|
|
\ push 0 \n\
|
|
\ halt \n\
|
|
\ jumped: \n\
|
|
\ pop \n\
|
|
\ push 1 \n\
|
|
\ halt "
|
|
let expected = done [1] 11 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "jumps if top stack value == 0" $ do
|
|
let input = " push 0 \n\
|
|
\ jge &jumped \n\
|
|
\ pop \n\
|
|
\ push 0 \n\
|
|
\ halt \n\
|
|
\ jumped: \n\
|
|
\ pop \n\
|
|
\ push 1 \n\
|
|
\ halt "
|
|
let expected = done [1] 11 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "proceeds if top stack value < 0" $ do
|
|
let input = " push 1 \n\
|
|
\ neg \n\
|
|
\ jge &jumped \n\
|
|
\ pop \n\
|
|
\ push 0 \n\
|
|
\ halt \n\
|
|
\ jumped: \n\
|
|
\ pop \n\
|
|
\ push 1 \n\
|
|
\ halt "
|
|
let expected = done [0] 8 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if empty stack" $ do
|
|
let input = " jge 0 \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 1 elements, got 0"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "jle" $ do
|
|
it "proceeds if top stack value > 0" $ do
|
|
let input = " push 1 \n\
|
|
\ jle &jumped \n\
|
|
\ pop \n\
|
|
\ push 0 \n\
|
|
\ halt \n\
|
|
\ jumped: \n\
|
|
\ pop \n\
|
|
\ push 1 \n\
|
|
\ halt "
|
|
let expected = done [0] 7 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "jumps if top stack value == 0" $ do
|
|
let input = " push 0 \n\
|
|
\ jle &jumped \n\
|
|
\ pop \n\
|
|
\ push 0 \n\
|
|
\ halt \n\
|
|
\ jumped: \n\
|
|
\ pop \n\
|
|
\ push 1 \n\
|
|
\ halt "
|
|
let expected = done [1] 11 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "jumps if top stack value < 0" $ do
|
|
let input = " push 1 \n\
|
|
\ neg \n\
|
|
\ jle &jumped \n\
|
|
\ pop \n\
|
|
\ push 0 \n\
|
|
\ halt \n\
|
|
\ jumped: \n\
|
|
\ pop \n\
|
|
\ push 1 \n\
|
|
\ halt "
|
|
let expected = done [1] 12 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if empty stack" $ do
|
|
let input = " jle 0 \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 1 elements, got 0"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "call" $ do
|
|
it "pushes return address and previous frame pointer to the stack" $ do
|
|
let input = " nop \n\
|
|
\ nop \n\
|
|
\ call &fun \n\
|
|
\ nop \n\
|
|
\ halt \n\
|
|
\ fun: halt "
|
|
-- ┌────┬─ fp points to the beginning of active stack frame
|
|
-- stack indexes: 1 0 │
|
|
-- │ │
|
|
let expected = done [4, -1] 6 0
|
|
-- ├───┤
|
|
-- │ │
|
|
-- │ └─ previous fp
|
|
-- └───── return address (points to the next instruction after call)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "pushes stack frames in correct order for multiple calls" $ do
|
|
let input = " nop \n\
|
|
\ call &f \n\
|
|
\ halt \n\
|
|
\ f: nop \n\
|
|
\ push 1 \n\
|
|
\ nop \n\
|
|
\ call &g \n\
|
|
\ halt \n\
|
|
\ g: nop \n\
|
|
\ call &h \n\
|
|
\ h: halt "
|
|
-- ┌──────────────────────┬─ fp points to the beginning of active stack frame
|
|
-- stack indexes: 6 5 4 3 2 1 0 │
|
|
-- │ │
|
|
let expected = done [14, 3, 10, 0, 1, 3, -1] 14 5
|
|
-- ├──┤ ├──┤ │ ├───┤
|
|
-- │ │ │ │ │ │ │
|
|
-- │ │ │ │ │ └───┴─ call &f
|
|
-- │ │ │ │ └──────── push 1
|
|
-- │ │ └──┴─────────── call &g
|
|
-- └──┴────────────────── call &h
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "ret" $ do
|
|
it "unwinds the stack frame and jumps to the caller" $ do
|
|
let input = " nop \n\
|
|
\ call &f \n\
|
|
\ halt \n\
|
|
\ f: nop \n\
|
|
\ ret "
|
|
let expected = done [] 3 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "leaves the top stack value as a 'return' value from the function" $ do
|
|
let input = " nop \n\
|
|
\ call &f \n\
|
|
\ halt \n\
|
|
\ f: nop \n\
|
|
\ push 4 \n\
|
|
\ ret "
|
|
-- ┌──── this is the top stack value at the time 'ret' instruction being invoked
|
|
let expected = done [4] 3 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "unwinds the stack frames in the correct order for multiple calls" $ do
|
|
let input = " nop \n\
|
|
\ call &f \n\
|
|
\ halt \n\
|
|
\ f: nop \n\
|
|
\ call &g \n\
|
|
\ push 2 \n\
|
|
\ mul \n\
|
|
\ ret \n\
|
|
\ g: nop \n\
|
|
\ call &h \n\
|
|
\ push 4 \n\
|
|
\ add \n\
|
|
\ ret \n\
|
|
\ h: push 6 \n\
|
|
\ ret "
|
|
-- ┌───── h: _ -> 6 │ = 6
|
|
-- │ g: _ -> h + 4 │ = 10 = 6 + 4
|
|
-- │ f: _ -> h * 2 │ = 20 = 10 * 2
|
|
let expected = done [20] 3 (-1)
|
|
-- └───── fp = -1 means the root program: there are no stack frames on the stack
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if there is no previous fp on the stack (stack is empty)" $ do
|
|
let vm = empty { _stack = S.fromList [], _fp = 0 }
|
|
let input = " ret \n\
|
|
\ halt "
|
|
let expected = Left "Cannot determine previous frame pointer (fp)"
|
|
actual <- exec vm input
|
|
actual `shouldBe` expected
|
|
it "raises error if there is no return address on the stack (stack size is 1)" $ do
|
|
let vm = empty { _stack = S.fromList [-1], _fp = 0 }
|
|
let input = " ret \n\
|
|
\ halt "
|
|
let expected = Left "Cannot determine return address"
|
|
actual <- exec vm input
|
|
actual `shouldBe` expected
|
|
|
|
describe "lda" $ do
|
|
it "lifts the function argument to the stack top" $ do
|
|
let input = " push 14 \n\
|
|
\ call &f \n\
|
|
\ nop \n\
|
|
\ f: lda 0 \n\
|
|
\ halt "
|
|
let expected = done [14, 4, -1, 14] 7 1
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "lifts multiple function arguments to the stack top" $ do
|
|
let input = " push 14 \n\
|
|
\ push 11 \n\
|
|
\ push 4 \n\
|
|
\ call &f \n\
|
|
\ nop \n\
|
|
\ f: lda 2 \n\
|
|
\ lda 1 \n\
|
|
\ lda 0 \n\
|
|
\ halt "
|
|
let expected = done [4, 11, 14, 8, -1, 4, 11, 14] 15 3
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "can be combined with 'call' and 'ret' to define a function" $ do
|
|
let input = " push 14 \n\
|
|
\ push 11 \n\
|
|
\ call &sum \n\
|
|
\ halt \n\
|
|
\ sum: lda 1 \n\
|
|
\ lda 0 \n\
|
|
\ add \n\
|
|
\ ret "
|
|
let expected = done [25, 11, 14] 6 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if stack is empty" $ do
|
|
let input = " lda 0 \n\
|
|
\ halt "
|
|
let expected = Left "Index 0 out of stack bounds"
|
|
let vm = empty { _stack = S.fromList [], _fp = 0 }
|
|
actual <- exec vm input
|
|
actual `shouldBe` expected
|
|
it "raises error if stack contains only previous fp" $ do
|
|
let vm = empty { _stack = S.fromList [-1], _fp = 0 }
|
|
let input = " lda 0 \n\
|
|
\ halt "
|
|
let expected = Left "Index 0 out of stack bounds"
|
|
actual <- exec vm input
|
|
actual `shouldBe` expected
|
|
it "raises error if stack contains only previous fp and return address" $ do
|
|
let vm = empty { _stack = S.fromList [2, -1], _fp = 0 }
|
|
let input = " lda 0 \n\
|
|
\ halt "
|
|
let expected = Left "Index 0 out of stack bounds"
|
|
actual <- exec vm input
|
|
actual `shouldBe` expected
|
|
it "loads the first (0) argument if stack contains only previous fp, return address and single argument" $ do
|
|
let vm = empty { _stack = S.fromList [2, -1, 3], _fp = 1 }
|
|
let input = " lda 0 \n\
|
|
\ halt "
|
|
let expected = done [3, 2, -1, 3] 2 1
|
|
actual <- exec vm input
|
|
actual `shouldBe` expected
|
|
it "raises error when accessint second (1) argument if stack contains only previous fp, return address and single argument" $ do
|
|
let vm = empty { _stack = S.fromList [2, -1, 3], _fp = 1 }
|
|
let input = " lda 1 \n\
|
|
\ halt "
|
|
let expected = Left "Index 1 out of stack bounds"
|
|
actual <- exec vm input
|
|
actual `shouldBe` expected
|
|
it "loads the 11th argument if it exists" $ do
|
|
-- ┌─────────────────────────────────────────────────┬── fp points the beginning of active stack frame
|
|
-- │ │
|
|
-- stack indexes: 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 │
|
|
-- │ │
|
|
let vm = empty { _stack = S.fromList [ 2, -1, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 ], _fp = 12 }
|
|
-- │ │
|
|
-- argument indexes (lda): └─ 0 1 2 3 4 5 6 7 8 9 10 11
|
|
-- └───── lda 11 results in pushing 0 on to the top of the stack
|
|
let input = " lda 11 \n\
|
|
\ halt "
|
|
let expected = done [0, 2, -1, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0] 2 12
|
|
actual <- exec vm input
|
|
actual `shouldBe` expected
|
|
|
|
describe "clr" $ do
|
|
it "wipes 4 values before the top of the stack" $ do
|
|
let input = " push 1 \n\
|
|
\ push 2 \n\
|
|
\ push 3 \n\
|
|
\ push 4 \n\
|
|
\ push 5 \n\
|
|
\ clr 4 \n\
|
|
\ halt "
|
|
let expected = done [5] 12 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "can be combined with 'call' and 'ret' to define a function and perform a clean by caller" $ do
|
|
let input = " push 14 \n\
|
|
\ push 11 \n\
|
|
\ call &sum \n\
|
|
\ clr 2 \n\
|
|
\ halt \n\
|
|
\ sum: lda 1 \n\
|
|
\ lda 0 \n\
|
|
\ add \n\
|
|
\ ret "
|
|
let expected = done [25] 8 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "roll" $ do
|
|
it "supports stack with 5 elements" $ do
|
|
let input = " push 4 \n\
|
|
\ push 5 \n\
|
|
\ push 6 \n\
|
|
\ push 7 \n\
|
|
\ push 8 \n\
|
|
\ roll \n\
|
|
\ halt "
|
|
let expected = done [7, 6, 5, 4, 8] 11 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "supports stack with 4 elements" $ do
|
|
let input = " push 4 \n\
|
|
\ push 5 \n\
|
|
\ push 6 \n\
|
|
\ push 7 \n\
|
|
\ roll \n\
|
|
\ halt "
|
|
let expected = done [6, 5, 4, 7] 9 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "supports stack with 3 elements" $ do
|
|
let input = " push 4 \n\
|
|
\ push 5 \n\
|
|
\ push 6 \n\
|
|
\ roll \n\
|
|
\ halt "
|
|
let expected = done [5, 4, 6] 7 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "supports stack with 2 elements" $ do
|
|
let input = " push 4 \n\
|
|
\ push 5 \n\
|
|
\ roll \n\
|
|
\ halt "
|
|
let expected = done [4, 5] 5 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "supports singleton stack" $ do
|
|
let input = " push 4 \n\
|
|
\ roll \n\
|
|
\ halt "
|
|
let expected = done [4] 3 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "supports empty stack" $ do
|
|
let input = " roll \n\
|
|
\ halt "
|
|
let expected = done [] 1 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "can be composed" $ do
|
|
let input = " push 4 \n\
|
|
\ push 5 \n\
|
|
\ push 6 \n\
|
|
\ push 7 \n\
|
|
\ push 8 \n\
|
|
\ roll \n\
|
|
\ roll \n\
|
|
\ roll \n\
|
|
\ halt "
|
|
let expected = done [5, 4, 8, 7, 6] 13 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "does not change the stack order when rolling number equals the stack size" $ do
|
|
let input = " push 4 \n\
|
|
\ push 5 \n\
|
|
\ push 6 \n\
|
|
\ push 7 \n\
|
|
\ push 8 \n\
|
|
\ roll \n\
|
|
\ roll \n\
|
|
\ roll \n\
|
|
\ roll \n\
|
|
\ roll \n\
|
|
\ halt "
|
|
let expected = done [8, 7, 6, 5, 4] 15 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "works in the context of current frame" $ do
|
|
let input = " push 1 \n\
|
|
\ push 2 \n\
|
|
\ push 3 \n\
|
|
\ call &foo \n\
|
|
\ foo: push 10 \n\
|
|
\ push 20 \n\
|
|
\ push 30 \n\
|
|
\ call &bar \n\
|
|
\ bar: push 70 \n\
|
|
\ push 80 \n\
|
|
\ push 90 \n\
|
|
\ roll \n\
|
|
\ halt "
|
|
let expected = done [80, 70, 90, 16, 3, 30, 20, 10, 8, -1, 3, 2, 1] 23 8
|
|
-- ├────────┤ ├────────┤ ├─────┤
|
|
-- │ │ │ │ └─────┴── there are no 'roll' instructions under the root so the data is in the correct order
|
|
-- │ │ └────────┴────────────────── as above - no 'roll' instruction under the 'foo' function
|
|
-- └────────┴───────────────────────────────────── the 'roll' instruction is called under the 'bar' function, so the numbers are rolled
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "over" $ do
|
|
it "pushes the second value from the top" $ do
|
|
let input = " push 1 \n\
|
|
\ push 2 \n\
|
|
\ over \n\
|
|
\ halt "
|
|
let expected = done [1, 2, 1] 5 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "can be used multiple times" $ do
|
|
let input = " push 1 \n\
|
|
\ push 2 \n\
|
|
\ over \n\
|
|
\ over \n\
|
|
\ over \n\
|
|
\ halt "
|
|
let expected = done [1, 2, 1, 2, 1] 7 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if empty stack" $ do
|
|
let input = " over \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 2 elements, got 0"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if stack is not big enough" $ do
|
|
let input = " push 5 \n\
|
|
\ over \n\
|
|
\ halt "
|
|
let expected = Left "Attempt to pop from empty stack: tried to pop 2 elements, got 1"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "ldl" $ do
|
|
it "lifts stack value to the top" $ do
|
|
let input = " call &fun \n\
|
|
\ fun: push 1 \n\
|
|
\ push 2 \n\
|
|
\ push 3 \n\
|
|
\ push 4 \n\
|
|
\ push 5 \n\
|
|
\ ldl 0 \n\
|
|
\ halt "
|
|
let expected = done [1, 5, 4, 3, 2, 1, 2, -1] 14 0
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if not called in the function context (fp == -1)" $ do
|
|
let input = " push 1 \n\
|
|
\ push 2 \n\
|
|
\ push 3 \n\
|
|
\ ldl 0 \n\
|
|
\ halt "
|
|
let expected = Left "No active stack frame to load local variable"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "ldl" $ do
|
|
it "updates local variable value" $ do
|
|
let input = " call &fun \n\
|
|
\ fun: push 1 \n\
|
|
\ push 2 \n\
|
|
\ push 3 \n\
|
|
\ push 4 \n\
|
|
\ push 5 \n\
|
|
\ stl 0 \n\
|
|
\ halt "
|
|
let expected = done [4, 3, 2, 5, 2, -1] 14 0
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
it "raises error if not called in the function context (fp == -1)" $ do
|
|
let input = " push 1 \n\
|
|
\ push 2 \n\
|
|
\ push 3 \n\
|
|
\ stl 0 \n\
|
|
\ halt "
|
|
let expected = Left "No active stack frame to store local variable"
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
describe "examples" $ do
|
|
it "example #1" $ do
|
|
let input = " main: push 2 \n\
|
|
\ push 3 \n\
|
|
\ call &prd \n\
|
|
\ clr 2 \n\
|
|
\ push 5 \n\
|
|
\ call &sum \n\
|
|
\ clr 2 \n\
|
|
\ halt \n\
|
|
\ \n\
|
|
\ sum: lda 0 \n\
|
|
\ lda 1 \n\
|
|
\ add \n\
|
|
\ ret \n\
|
|
\ \n\
|
|
\ prd: lda 0 \n\
|
|
\ lda 1 \n\
|
|
\ mul \n\
|
|
\ ret "
|
|
let expected = done [2*3+5] 14 (-01)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
it "example #2" $ do
|
|
let input = " main: push 100 \n\
|
|
\ loop: push 1 \n\
|
|
\ sub \n\
|
|
\ jne &loop \n\
|
|
\ halt "
|
|
let expected = done [0] 7 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
it "example #3: power - loop variant" $ do
|
|
let input = " push 3 \n\
|
|
\ push 6 \n\
|
|
\ call &pow \n\
|
|
\ clr 2 \n\
|
|
\ halt \n\
|
|
\ pow: lda 1 \n\
|
|
\ lda 0 \n\
|
|
\ push 1 \n\
|
|
\ loop: ldl 1 \n\
|
|
\ je &done \n\
|
|
\ pop \n\
|
|
\ ldl 2 \n\
|
|
\ ldl 0 \n\
|
|
\ mul \n\
|
|
\ stl 2 \n\
|
|
\ ldl 1 \n\
|
|
\ push 1 \n\
|
|
\ sub \n\
|
|
\ stl 1 \n\
|
|
\ jmp &loop \n\
|
|
\ done: ldl 2 \n\
|
|
\ ret "
|
|
let expected = done [3 ^ (6 :: Int)] 8 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
it "example #4: power - recursive variant" $ do
|
|
let input = " push 4 \n\
|
|
\ push 7 \n\
|
|
\ call &pow \n\
|
|
\ clr 2 \n\
|
|
\ halt \n\
|
|
\ pow: lda 1 \n\
|
|
\ lda 0 \n\
|
|
\ ldl 1 \n\
|
|
\ je &edge \n\
|
|
\ pop \n\
|
|
\ ldl 0 \n\
|
|
\ ldl 1 \n\
|
|
\ push 1 \n\
|
|
\ sub \n\
|
|
\ call &pow \n\
|
|
\ clr 1 \n\
|
|
\ mul \n\
|
|
\ ret \n\
|
|
\ edge: pop \n\
|
|
\ push 1 \n\
|
|
\ ret "
|
|
let expected = done [4 ^ (7 :: Int)] 8 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected
|
|
|
|
it "example #5: 11-th element of Fibonacci sequence - recursive variant" $ do
|
|
let input = " push 11 \n\
|
|
\ call &fibb \n\
|
|
\ clr 1 \n\
|
|
\ halt \n\
|
|
\ fibb: lda 0 \n\
|
|
\ ldl 0 \n\
|
|
\ je &done0 \n\
|
|
\ pop \n\
|
|
\ ldl 0 \n\
|
|
\ push 1 \n\
|
|
\ sub \n\
|
|
\ je &done1 \n\
|
|
\ dup \n\
|
|
\ push 1 \n\
|
|
\ sub \n\
|
|
\ call &fibb \n\
|
|
\ clr 1 \n\
|
|
\ over \n\
|
|
\ call &fibb \n\
|
|
\ clr 1 \n\
|
|
\ add \n\
|
|
\ ret \n\
|
|
\ done1: pop \n\
|
|
\ push 1 \n\
|
|
\ ret \n\
|
|
\ done0: pop \n\
|
|
\ push 1 \n\
|
|
\ ret "
|
|
let expected = done [fibb 11] 6 (-1)
|
|
actual <- run input
|
|
actual `shouldBe` expected |