Fix calling issues

1 files changed, 138 insertions, 147 deletions

diff --git a/asm/test_py_src.atk16 b/asm/test_py_src.atk16
index 2d8e311..b605dad 100644
--- a/asm/test_py_src.atk16
+++ b/asm/test_py_src.atk16
@@ -2,7 +2,9 @@
 
 @use ext_std:*
 
-@let sp              RH
+@let sp              RH   ; stack pointer (points to empty slot at top of stack)
+@let fp              RG   ; frame pointer (points to base of currently active frame)
+
 @let vector_table    0x10
 @let vt_ISR0         0x10 ; ISR0
 @let vt_ISR1         0x11 ; ISR1
@@ -30,6 +32,7 @@
 @address 0x0
   ldi vt_stack_addr RA
   ldr RA SP
+  mov SP FP
   jpi program_segment
 
 @address vector_table
@@ -77,47 +80,39 @@
   23
 @label text_mem_addr_p
   25
-@label int_1
+@label int_0
   65
-@label int_5
+@label int_6
   26
 
-; <ast.FunctionDef object at 0x1048ce500>
+; <ast.FunctionDef object at 0x104f1f370>
 @label nth_letter
 ; stack frame with offsets
-; return_address_0 3
-; n 4
-; <ast.Return object at 0x1048ce440>
-; <ast.Add object at 0x1045f6ad0>
-; BinOp lhs <ast.BinOp object at 0x1048ce410>
-; <ast.Name object at 0x1048ce3e0> (n)
-  ldi vt_stack_addr RA
-  ldr RA RA
-  ldi 4 RB
-  add RA RB RA
-  ldr RA RA
-  spu RA
-; BinOp rhs <ast.BinOp object at 0x1048ce410>
-; <ast.Constant object at 0x1048ce3b0>
-  ldi int_1 RA
-  ldr RA RA
-  spu RA
-  spo RB
-  spo RA
-  add RA RB RA
-  spu RA
-  ldi vt_stack_addr RA
-  ldr RA RA
-  ldi 3 RB
-  add RA RB RA
-; stack address of return address is stored in reg RA
-  spo RB
-; return value is stored in reg RB
-  mov RA SP
-  ldr RA RA
-  spu RB
+; n 0
+; <ast.Return object at 0x104f1f430>
+; <ast.Add object at 0x104ed2c20>
+; BinOp lhs <ast.BinOp object at 0x1051b52a0>
+; <ast.Call object at 0x1051b5270>
+; Builtin call ord [<ast.Constant object at 0x1051b51e0>]
+; <ast.Constant object at 0x1051b51e0>
+  ldi int_0 RC
+  ldr RC RC ; int_0 = 65
+  spu RC
+; BinOp rhs <ast.BinOp object at 0x1051b52a0>
+; <ast.Name object at 0x1051b51b0> (n)
+  ldi 0 RC
+  add FP RC RC
+  ldr RC RC
+  spu RC
+  spo RD
+  spo RC
+  add RC RD RC
+  spu RC
+; return value is on top of stack
 ; return from function
-  jpr RA
+  subi FP 1 FP
+  ldr FP RB
+  jpr RB
 
 @label main
 ; stack frame with offsets
@@ -125,186 +120,182 @@
 ; text_mem_addr 1
 ; i 2
   addi SP 3 SP
-; <ast.Assign object at 0x1048ce860>
-; assigning graphics_mode_addr at stack segment + 0
+; <ast.Assign object at 0x104f1ffd0>
+; assigning graphics_mode_addr at FP + 0
 ; evaluating value to be assigned
-; <ast.Call object at 0x1048ce800>
-; Builtin call load [<ast.Name object at 0x1048ce770>]
-; <ast.Name object at 0x1048ce770> (GRAPHICS_MODE_ADDR_P)
+; <ast.Call object at 0x104f1fa00>
+; Builtin call load [<ast.Name object at 0x104f1f970>]
+; <ast.Name object at 0x104f1f970> (GRAPHICS_MODE_ADDR_P)
   ldi graphics_mode_addr_p RC
   ldr RC RC
   spu RC
+; (load) dereferencing top of stack
   spo RC
   ldr RC RC
   spu RC
-; assigning value to stack segment + 0
-  ldi vt_stack_addr RA
-  ldr RA RA
+; assigning stack address (FP + 0) := top of stack
+  spo RA
   ldi 0 RB
-  add RA RB RA
-  spo RB
-  str RB RA
-; <ast.Assign object at 0x1048ce740>
-; assigning text_mem_addr at stack segment + 1
+  add RB FP RB
+  str RA RB
+; <ast.Assign object at 0x104f1f940>
+; assigning text_mem_addr at FP + 1
 ; evaluating value to be assigned
-; <ast.Call object at 0x1048ce6e0>
-; Builtin call load [<ast.Name object at 0x1048ce650>]
-; <ast.Name object at 0x1048ce650> (TEXT_MEM_ADDR_P)
+; <ast.Call object at 0x104f1f610>
+; Builtin call load [<ast.Name object at 0x104f1f550>]
+; <ast.Name object at 0x104f1f550> (TEXT_MEM_ADDR_P)
   ldi text_mem_addr_p RC
   ldr RC RC
   spu RC
+; (load) dereferencing top of stack
   spo RC
   ldr RC RC
   spu RC
-; assigning value to stack segment + 1
-  ldi vt_stack_addr RA
-  ldr RA RA
+; assigning stack address (FP + 1) := top of stack
+  spo RA
   ldi 1 RB
-  add RA RB RA
-  spo RB
-  str RB RA
-; <ast.Call object at 0x1048ce5f0>
-; Builtin call store [<ast.Name object at 0x1048ce560>, <ast.Name object at 0x1048ce530>]
-; <ast.Name object at 0x1048ce560> (graphics_mode_addr)
-  ldi vt_stack_addr RA
-  ldr RA RA
-  ldi 0 RB
-  add RA RB RA
+  add RB FP RB
+  str RA RB
+; <ast.Call object at 0x104f1f4f0>
+; Builtin call store [<ast.Name object at 0x104f1f3d0>, <ast.Name object at 0x104f1f3a0>]
+; <ast.Name object at 0x104f1f3d0> (graphics_mode_addr)
+  ldi 0 RA
+  add FP RA RA
   ldr RA RA
   spu RA
-; <ast.Name object at 0x1048ce530> (TEXT_MODE)
+; <ast.Name object at 0x104f1f3a0> (TEXT_MODE)
   ldi text_mode RA
   ldr RA RA
   spu RA
   spo RB
   spo RA
   str RB RA
-; <ast.Assign object at 0x1048ce350>
-; assigning i at stack segment + 2
+  ldi 0 RA
+  spu RA
+; popping free-standing Expr result from stack
+  spo RA
+; <ast.Assign object at 0x1051b5150>
+; assigning i at FP + 2
 ; evaluating value to be assigned
-; <ast.Constant object at 0x1048ce2f0>
+; <ast.Constant object at 0x1051b50f0>
   ldi 0 RC
   spu RC
-; assigning value to stack segment + 2
-  ldi vt_stack_addr RA
-  ldr RA RA
+; assigning stack address (FP + 2) := top of stack
+  spo RA
   ldi 2 RB
-  add RA RB RA
-  spo RB
-  str RB RA
-; <ast.Call object at 0x1048ce290>
-; Builtin call asm [<ast.Constant object at 0x1048ce200>]
-  ldi 0b111111111 RG
-; <ast.While object at 0x1048ce1d0>
-@label while_test_2
-; <ast.Name object at 0x1048ce170> (i)
-  ldi vt_stack_addr RB
-  ldr RB RB
-  ldi 2 RC
-  add RB RC RB
+  add RB FP RB
+  str RA RB
+; <ast.While object at 0x1051b50c0>
+@label while_test_1
+; <ast.Compare object at 0x1051b5090>
+; <ast.Name object at 0x1051b5060> (i)
+  ldi 2 RB
+  add FP RB RB
   ldr RB RB
   spu RB
-; <ast.Constant object at 0x1048ce140>
-  ldi int_5 RB
-  ldr RB RB
+; <ast.Constant object at 0x1051b5030>
+  ldi int_6 RB
+  ldr RB RB ; int_6 = 26
   spu RB
+; Comparing <ast.Name object at 0x1051b5060> <ast.Lt object at 0x104ed2470> <ast.Constant object at 0x1051b5030>
   spo RC
   spo RB
   sub RB RC RB
-  bri carry Compare_true_6
+  bri carry Compare_true_4
   ldi 0 RB
   spu RB
-  jpi Compare_end_7
-@label compare_true_6
+  jpi Compare_end_5
+@label compare_true_4
   ldi 1 RB
   spu RB
-@label compare_end_7
+@label compare_end_5
   spo RA
   addi RA 0 RA
-  bri zero While_else_3
-; <ast.Call object at 0x1048ce0e0>
-; Builtin call store [<ast.BinOp object at 0x1048ce050>, <ast.Call object at 0x1048cdd80>]
-; <ast.Add object at 0x1045f6ad0>
-; BinOp lhs <ast.BinOp object at 0x1048ce050>
-; <ast.Name object at 0x1048ce020> (text_mem_addr)
-  ldi vt_stack_addr RA
-  ldr RA RA
-  ldi 1 RB
-  add RA RB RA
+  bri zero While_else_2
+; <ast.Call object at 0x1051b4fd0>
+; Builtin call store [<ast.BinOp object at 0x1051b4f40>, <ast.Call object at 0x1051b4eb0>]
+; <ast.Add object at 0x104ed2c20>
+; BinOp lhs <ast.BinOp object at 0x1051b4f40>
+; <ast.Name object at 0x1051b4f10> (text_mem_addr)
+  ldi 1 RA
+  add FP RA RA
   ldr RA RA
   spu RA
-; BinOp rhs <ast.BinOp object at 0x1048ce050>
-; <ast.Name object at 0x1048cdff0> (i)
-  ldi vt_stack_addr RA
-  ldr RA RA
-  ldi 2 RB
-  add RA RB RA
+; BinOp rhs <ast.BinOp object at 0x1051b4f40>
+; <ast.Name object at 0x1051b4ee0> (i)
+  ldi 2 RA
+  add FP RA RA
   ldr RA RA
   spu RA
   spo RB
   spo RA
   add RA RB RA
   spu RA
-; <ast.Call object at 0x1048cdd80>
+; <ast.Call object at 0x1051b4eb0>
 ; Call function nth_letter
+  spu FP
   ldi 0 RA
   spu RA
-; <ast.Name object at 0x1048cdd20> (i)
-  ldi vt_stack_addr RA
-  ldr RA RA
-  ldi 2 RB
-  add RA RB RA
+; <ast.Name object at 0x1051b4e50> (i)
+  ldi 2 RA
+  add FP RA RA
   ldr RA RA
   spu RA
+  subi SP 2 FP
 ; set up return address and jump to subroutine
-  subi SP 2 RA
-  lpc RB
-  addi RB 3 RB
-  str RB RA
+  lpc RA
+  addi RA 4 RA
+  str RA FP
+  addi FP 1 FP
   jpi nth_letter
+  spo RA
+  mov FP SP
+  spo FP
+  spu RA
   spo RB
   spo RA
   str RB RA
-; <ast.Assign object at 0x1048ccc70>
-; assigning i at stack segment + 2
+  ldi 0 RA
+  spu RA
+; popping free-standing Expr result from stack
+  spo RA
+; <ast.Assign object at 0x1051b4e20>
+; assigning i at FP + 2
 ; evaluating value to be assigned
-; <ast.Add object at 0x1045f6ad0>
-; BinOp lhs <ast.BinOp object at 0x1048cda50>
-; <ast.Name object at 0x1048cd750> (i)
-  ldi vt_stack_addr RC
-  ldr RC RC
-  ldi 2 RD
-  add RC RD RC
+; <ast.Add object at 0x104ed2c20>
+; BinOp lhs <ast.BinOp object at 0x1051b4dc0>
+; <ast.Name object at 0x1051b4d90> (i)
+  ldi 2 RC
+  add FP RC RC
   ldr RC RC
   spu RC
-; BinOp rhs <ast.BinOp object at 0x1048cda50>
-; <ast.Constant object at 0x1048cd720>
+; BinOp rhs <ast.BinOp object at 0x1051b4dc0>
+; <ast.Constant object at 0x1051b4d60>
   ldi 1 RC
   spu RC
   spo RD
   spo RC
   add RC RD RC
   spu RC
-; assigning value to stack segment + 2
-  ldi vt_stack_addr RA
-  ldr RA RA
+; assigning stack address (FP + 2) := top of stack
+  spo RA
   ldi 2 RB
-  add RA RB RA
-  spo RB
-  str RB RA
-  jpi While_test_2
-@label while_else_3
-@label while_end_4
-; <ast.While object at 0x1048cd0f0>
-@label while_test_8
-; <ast.Constant object at 0x1048cd060>
+  add RB FP RB
+  str RA RB
+  jpi While_test_1
+@label while_else_2
+@label while_end_3
+; <ast.While object at 0x1051b4d30>
+@label while_test_7
+; <ast.Constant object at 0x1051b4d00>
   ldi 1 RB
   spu RB
   spo RA
   addi RA 0 RA
-  bri zero While_else_9
-; <ast.Pass object at 0x1048ccfa0>
-  jpi While_test_8
-@label while_else_9
-@label while_end_10
-  subi SP 3 SP
+  bri zero While_else_8
+; <ast.Pass object at 0x1051b4cd0>
+  jpi While_test_7
+@label while_else_8
+@label while_end_9
+  mov FP SP
+  hlt