From 0fc5da3483e15b8d119a753e04b1663580d4d490 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juhani=20Krekel=C3=A4?= <juhani@krekelä.fi>
Date: Sat, 27 Aug 2022 19:25:42 +0300
Subject: [PATCH] Support changed store encoding and load immediate in
 thingamajig_disasm.py

---
 thingamajig_disasm.py | 56 +++++++++++++++++++++++++------------------
 1 file changed, 33 insertions(+), 23 deletions(-)

diff --git a/thingamajig_disasm.py b/thingamajig_disasm.py
index e764d68..b057390 100644
--- a/thingamajig_disasm.py
+++ b/thingamajig_disasm.py
@@ -1,32 +1,32 @@
 #!/usr/bin/env python
 from collections import namedtuple
 
-Opcode = namedtuple('Opcode', ('mnemonic', 'rx', 'ry', 'addr'))
+Opcode = namedtuple('Opcode', ('mnemonic', 'rx', 'ry', 'addr', 'immediate'))
 
 opcodes = [
-	Opcode('halt', rx=False, ry=False, addr=False),
-	Opcode('ret', rx=False, ry=False, addr=False),
+	Opcode('halt', rx=False, ry=False, addr=False, immediate=False),
+	Opcode('ret', rx=False, ry=False, addr=False, immediate=False),
 
-	Opcode('shl', rx=True, ry=False, addr=False),
-	Opcode('shr', rx=True, ry=False, addr=False),
-	Opcode('rol', rx=True, ry=False, addr=False),
-	Opcode('ror', rx=True, ry=False, addr=False),
+	Opcode('shl', rx=True, ry=False, addr=False, immediate=False),
+	Opcode('shr', rx=True, ry=False, addr=False, immediate=False),
+	Opcode('rol', rx=True, ry=False, addr=False, immediate=False),
+	Opcode('ror', rx=True, ry=False, addr=False, immediate=False),
 
-	Opcode('nand', rx=True, ry=True, addr=False),
-	Opcode('and', rx=True, ry=True, addr=False),
-	Opcode('or', rx=True, ry=True, addr=False),
-	Opcode('xor', rx=True, ry=True, addr=False),
+	Opcode('nand', rx=True, ry=True, addr=False, immediate=False),
+	Opcode('and', rx=True, ry=True, addr=False, immediate=False),
+	Opcode('or', rx=True, ry=True, addr=False, immediate=False),
+	Opcode('xor', rx=True, ry=True, addr=False, immediate=False),
 
-	Opcode('load', rx=True, ry=False, addr=True),
-	Opcode('store', rx=True, ry=False, addr=True),
+	Opcode('load', rx=True, ry=False, addr=True, immediate=True),
+	Opcode('store', rx=False, ry=True, addr=True, immediate=False),
 
-	Opcode('breq', rx=True, ry=True, addr=True),
-	Opcode('brneq', rx=True, ry=True, addr=True),
-	Opcode('cleq', rx=True, ry=True, addr=True),
-	Opcode('clneq', rx=True, ry=True, addr=True),
+	Opcode('breq', rx=True, ry=True, addr=True, immediate=False),
+	Opcode('brneq', rx=True, ry=True, addr=True, immediate=False),
+	Opcode('cleq', rx=True, ry=True, addr=True, immediate=False),
+	Opcode('clneq', rx=True, ry=True, addr=True, immediate=False),
 ]
 
-Instruction = namedtuple('Instruction', ['opcode', 'rx', 'ry', 'addr'])
+Instruction = namedtuple('Instruction', ['opcode', 'rx', 'ry', 'addr', 'immediate'])
 Data = namedtuple('Data', ['byte'])
 
 Statement = namedtuple('Statement', ['addr', 'raw', 'contents'])
@@ -42,24 +42,32 @@ def segment(binary, origin):
 		rx = (byte >> 2) & 3
 		ry = byte & 3
 
+		immediate = opcodes[opcode].immediate and ry == 3
+
 		valid = True
 		if not opcodes[opcode].rx and rx != 0: valid = False
-		if not opcodes[opcode].ry and ry != 0: valid = False
-		if opcodes[opcode].addr and ip + 2 >= len(binary): valid = False
+		if not opcodes[opcode].ry and not immediate and ry != 0: valid = False
+		if opcodes[opcode].addr and not immediate and ip + 2 >= len(binary): valid = False
+		if immediate and ip + 1 >= len(binary): valid = False
 
 		if not valid:
 			raw = binary[ip:ip + 1]
 			statements.append(Statement(ip, raw, Data(byte)))
 			ip += 1
+		elif immediate:
+			raw = binary[ip:ip + 2]
+			instruction = Instruction(opcode, rx, ry, None, binary[ip + 1])
+			statements.append(Statement(ip, raw, instruction))
+			ip += 2
 		elif opcodes[opcode].addr:
 			raw = binary[ip:ip + 3]
 			addr = (binary[ip + 1] << 8) + binary[ip + 2]
-			instruction = Instruction(opcode, rx, ry, addr)
+			instruction = Instruction(opcode, rx, ry, addr, None)
 			statements.append(Statement(ip, raw, instruction))
 			ip += 3
 		else:
 			raw = binary[ip:ip + 1]
-			instruction = Instruction(opcode, rx, ry, None)
+			instruction = Instruction(opcode, rx, ry, None, None)
 			statements.append(Statement(ip, raw, instruction))
 			ip += 1
 
@@ -76,7 +84,9 @@ def disasm(binary, origin = 0):
 				fields.append(f'r{contents.rx}')
 			if opcodes[contents.opcode].ry:
 				fields.append(f'r{contents.ry}')
-			if opcodes[contents.opcode].addr:
+			if contents.immediate is not None:
+				fields.append(f'#0x{contents.immediate:02x}')
+			elif opcodes[contents.opcode].addr:
 				fields.append(f'0x{contents.addr:04x}')
 
 			if mnemonic == 'store':