Fix another jump issue in assembler, improve monitor

2 files changed, 12 insertions, 9 deletions

diff --git a/atk16_asm/asm_eval.py b/atk16_asm/asm_eval.py
index 09c3a75..f9a4e3d 100644
--- a/atk16_asm/asm_eval.py
+++ b/atk16_asm/asm_eval.py
@@ -27,10 +27,6 @@ constants: dict[str, str] = {
 
 Symbols = dict[str, int]
 
-def check_size(bits: int, val: int) -> None:
-  if val >= 2 ** bits:
-    raise Exception(f"Value does not fit in {bits} bits: 0x{val:>04x}")
-
 def eval_symbol(symbols: Symbols, c: str) -> str:
   if c in symbols:
     return str(symbols[c])
@@ -42,6 +38,9 @@ def eval_symbol(symbols: Symbols, c: str) -> str:
 
 def eval_expr(symbols: Symbols, expr: str, bits: int = 16) -> int:
   expr = eval_symbol(symbols, expr)
-  ret = eval(expr, symbols.copy()) # eval as Python expr
-  check_size(bits, ret)
-  return ret
+  val = eval(expr, symbols.copy()) # eval as Python expr
+
+  if val >= 2 ** bits:
+    raise Exception(f"When evaluating expression \"{expr}\":\nValue does not fit in {bits} bits: 0x{val:>04x}")
+
+  return val
diff --git a/atk16_asm/asm_ops.py b/atk16_asm/asm_ops.py
index 3198d4c..65cf0da 100644
--- a/atk16_asm/asm_ops.py
+++ b/atk16_asm/asm_ops.py
@@ -124,7 +124,7 @@ def expand_jpr(addr_reg: str) -> ExpandResult:
 @register_primitive
 def make_jpi(meta: Meta, symbols: Symbols, imm: int | str) -> int:
   """JPI 0110 XXXI IIII IIII"""
-  imm_e = eval_expr(symbols, str(imm), bits=9)
+  imm_e = eval_expr(symbols, str(imm), bits=16)
   imm_e = imm_e - meta.address - 1
 
   if imm_e < -(2 ** 8) or imm_e >= 2 ** 8:
@@ -157,8 +157,12 @@ def expand_brr(flag_s: str, addr_reg: str) -> ExpandResult:
 def make_bri(meta: Meta, symbols: Symbols, flag_s: str, imm: int | str) -> int:
   """BRI 1000 XFFI IIII IIII"""
   flag_s_e = eval_expr(symbols, flag_s, bits=2)
-  imm_e = eval_expr(symbols, str(imm), bits=9)
+  imm_e = eval_expr(symbols, str(imm), bits=16)
   imm_e = imm_e - meta.address - 1
+
+  if imm_e < -(2 ** 8) or imm_e >= 2 ** 8:
+    raise Exception(f"jpi imm value is not representable in 9 bits: {imm_e}")
+
   imm_e = imm_e & (0b111111111)
   word = (0b1000 << 12) + \
               (flag_s_e << 9) + \