Finish calli/callr/return, add test code

4 files changed, 136 insertions, 0 deletions

diff --git a/test/e2e/call_stack/lib.atk16 b/test/e2e/call_stack/lib.atk16
new file mode 100644
index 0000000..39672e0
--- /dev/null
+++ b/test/e2e/call_stack/lib.atk16
@@ -0,0 +1,42 @@
+@label mul
+  ; multiply a signed/unsigned (a) and an unsigned number (b)
+  ; parameters RA = a
+  ;            RB = b
+  ; return     RG = a * b
+
+  stack_stash RA RB
+  ; initialize return value in RG to 0
+  ldi 0 RG
+@label mul_loop
+  ; if b == 0, we are done
+  subi RB 0 RB
+  bri zero mul_done
+  ; RG += RA
+  add RA RG RG
+  dec RB
+  jpi mul_loop
+@label mul_done
+  stack_restore RA RB
+  return
+
+; Recursive impl of the factorial
+; Calling convention is that arguments are in registers RA..RG (max 7 arguments since RH = SP)
+; and the return value is in RG (note: overwriting arg in RG)
+
+@label fact
+  ; parameters RA = n
+  ; return     RG = factorial(n)
+  subi RA 0 RA
+  bri zero fact_basecase
+@label fact_reccase
+  stack_stash RA RB
+  mov RA RB             ; RB := n
+  subi RA 1 RA          ; RA := n - 1
+  calli fact            ; RG := fact(n - 1)
+  mov RG RA             ; RA := fact(n - 1)
+  calli mul             ; RG := n * fact(n - 1)
+  stack_restore RA RB
+  return
+@label fact_basecase
+  ldi 1 RG
+  return
diff --git a/test/e2e/call_stack/run_fact.atk16 b/test/e2e/call_stack/run_fact.atk16
new file mode 100644
index 0000000..06ad59c
--- /dev/null
+++ b/test/e2e/call_stack/run_fact.atk16
@@ -0,0 +1,11 @@
+; bootstrap code (must be called to setup mandatory data)
+; will jump to label main
+@include ../bootstrap
+@include lib
+
+@let INPUT %INPUT% ; value replaced by test driver code
+
+@label main
+  ldi INPUT RA
+  calli fact
+  hlt
diff --git a/test/e2e/call_stack/run_mul.atk16 b/test/e2e/call_stack/run_mul.atk16
new file mode 100644
index 0000000..feaabe7
--- /dev/null
+++ b/test/e2e/call_stack/run_mul.atk16
@@ -0,0 +1,18 @@
+; bootstrap code (must be called to setup mandatory data)
+; will jump to label main
+@include ../bootstrap
+@include lib
+
+; values replaced by test driver code
+@label INPUT_A
+  %INPUT_A%
+@label INPUT_B
+  %INPUT_B%
+
+@label main
+  ldi INPUT_A RA
+  ldr RA RA
+  ldi INPUT_B RB
+  ldr RB RB
+  calli mul
+  hlt
diff --git a/test/e2e/call_stack/test_call_stack.py b/test/e2e/call_stack/test_call_stack.py
new file mode 100644
index 0000000..3895f5c
--- /dev/null
+++ b/test/e2e/call_stack/test_call_stack.py
@@ -0,0 +1,65 @@
+import time
+from atk16_asm import assemble
+from atk16_emu import Machine
+from test.utils import pad_bytearray
+
+def run_mul(a: int, b: int) -> int:
+  filename = "test/e2e/call_stack/run_mul.atk16"
+  with open(filename, "r") as f:
+    source = f.read()
+
+  source = source.replace("%INPUT_A%", str(a))
+  source = source.replace("%INPUT_B%", str(b))
+
+  obj = assemble(source, filename)
+  rom_image = pad_bytearray(obj.program)
+
+  machine = Machine()
+  machine.load_rom_image(rom_image)
+  machine.reset()
+  machine.run_until_halted()
+
+  return machine.rg.value
+
+def test_mul_1():
+  expected = 30
+  received = run_mul(5, 6)
+
+  assert expected == received
+
+def test_mul_2():
+  a = -100
+  b = 200
+  expected = a * b
+  received = run_mul(a, b)
+
+  assert expected == received
+
+def run_fact(n: int) -> int:
+  filename = "test/e2e/call_stack/run_fact.atk16"
+  with open(filename, "r") as f:
+    source = f.read()
+
+  source = source.replace("%INPUT%", str(n))
+  obj = assemble(source, filename)
+  rom_image = pad_bytearray(obj.program)
+
+  machine = Machine()
+  machine.load_rom_image(rom_image)
+  machine.reset()
+  machine.run_until_halted()
+
+  return machine.rg.value
+
+def test_fact_0():
+  expected = 1
+  received = run_fact(0)
+
+  assert expected == received
+
+def test_fact_6():
+  expected = 720
+  received = run_fact(6)
+
+  assert expected == received
+