From e82a429d5eb6ae9dd51178a1007e5dd8569916cb Mon Sep 17 00:00:00 2001
From: n loewen <n@nloewen.com>
Date: Thu, 20 Mar 2025 10:12:25 +0000
Subject: [PATCH] Start work on pi pico version of CPU simulator

---
 src/pi-pico/cpu-pi-pico.py | 298 +++++++++++++++++++++++++++++++++++++
 1 file changed, 298 insertions(+)
 create mode 100644 src/pi-pico/cpu-pi-pico.py

diff --git a/src/pi-pico/cpu-pi-pico.py b/src/pi-pico/cpu-pi-pico.py
new file mode 100644
index 0000000..0fef346
--- /dev/null
+++ b/src/pi-pico/cpu-pi-pico.py
@@ -0,0 +1,298 @@
+# TO USE KEYPAD TO MANIPULATE DATA:
+#
+# A button: run/halt
+# B button: when halted, toggles address/data entry
+# Right button: when halted, single-steps
+#
+# Address entry: press the two digits for the address. It is entered immediately (there's no "enter" key)
+# Data entry: likewise. After you press the second digit, it will automatically go to the next address.
+
+
+import time
+import board
+import keypad
+import digitalio
+from tm1637_display import TM1637Display
+
+
+class TwoDigitHexInput:
+    def __init__(self):
+        self.digits = [0x0, 0x0]
+        self.currentDigit = 0
+        self.value = 0
+       
+    def input(self, d):
+        self.digits[self.currentDigit] = d
+        self.value = (self.digits[0] * 16) + self.digits[1]
+        print("INPUT", self.digits)
+        self.currentDigit = 0 if self.currentDigit else 1
+        
+    def clear(self):
+        self.__init__()
+        print(self.digits)
+        
+
+class CPU:
+    def __init__(self):
+        self.running = False
+        self.IP = 254
+        self.acc = 0
+        self.flags = { 'C': False, 'Z': False, 'N': False, 'Eq': False }
+        self.instruction = { 'opcode': False, 'operand': False }
+        self.memory = False
+
+
+    def load_memory(self, bytes):
+        self.memory = bytes + bytearray(256 - len(bytes))
+        print(type(self.memory))
+        print('mem 254', self.memory[254])
+        # print(self.memory)
+
+    def start(self):
+        self.running = True
+
+    def step(self):
+        if self.IP >= 256:
+            self.IP = 0
+        print("IP:", self.IP)
+        self.instruction['opcode'] = self.memory[self.IP]
+        self.IP = self.IP+1
+        self.instruction['operand'] = self.memory[self.IP]
+        self.IP = self.IP+1
+        self.nums2mnems[self.instruction['opcode']](self, self.instruction['operand'])
+
+        print("instr:", self.instruction['opcode'], self.instruction['operand'])
+        print("mnem:", self.nums2mnems[self.instruction['opcode']])
+        print("acc:", self.acc)
+        print("running:", self.running)
+        print()
+        # self.print_screen()
+        print("byte 26 (keyboard):", self.memory[26])
+        print()
+
+    def hlt(self, operand):
+        self.running = False
+
+    def nop(self, operand):
+        pass
+
+    def lda_lit(self, operand):
+        self.acc = operand
+
+    def lda_mem(self, operand):
+        self.acc = memory[operand]
+
+    def sta_lit(self, operand):
+        memory[operand] = self.acc
+
+    def sta_mem(self, operand):
+        memory[memory[operand]] = self.acc
+
+    def add_lit(self, operand):
+        self.acc = self.acc + operand
+        if self.acc > 255:
+            self.acc = self.acc % 256
+            self.flags['C'] = True
+        else:
+            self.flags['C'] = False
+        self.flags['Z'] = True if self.acc == 0 else False
+        self.flags['Eq'] = True if self.acc == operand else False
+        self.flags['N'] = True if self.acc > 127 else False
+
+    def add_mem(self, operand):
+        self.acc = self.acc + self.memory[operand]
+        if self.acc > 255:
+            self.acc = self.acc % 256
+            self.flags['C'] = True
+        else:
+            self.flags['C'] = False
+        self.flags['Z'] = True if self.acc == 0 else False
+        self.flags['Eq'] = True if self.acc == operand else False
+        self.flags['N'] = True if self.acc > 127 else False
+
+    def sub_lit(self, operand):
+        self.acc = self.acc - operand
+        if self.acc < 0:
+            self.acc = self.acc % 256
+            self.flags['C'] = True
+        else:
+            self.flags['C'] = False
+        self.flags['Z'] = True if self.acc == 0 else False
+        self.flags['Eq'] = True if self.acc == operand else False
+        self.flags['N'] = True if self.acc > 127 else False
+
+    def sub_mem(self, operand):
+        self.acc = self.acc - self.memory[operand]
+        if self.acc > 255:
+            self.acc = self.acc % 256
+            self.flags['C'] = True
+        else:
+            self.flags['C'] = False
+        self.flags['Z'] = True if self.acc == 0 else False
+        self.flags['Eq'] = True if self.acc == operand else False
+        self.flags['N'] = True if self.acc > 127 else False
+
+    def jmp_lit(self, operand):
+        self.IP = operand
+
+    def jmp_mem(self, operand):
+        self.IP = memory[operand]
+
+    def ske(self, operand):
+        if self.flags['Eq']:
+            self.IP += 2
+
+    def skz(self, operand):
+        if self.flags['Z']:
+            self.IP += 2
+
+    def skn(self, operand):
+        if self.flags['N']:
+            self.IP += 2
+
+    def skc(self, operand):
+        if self.flags['C']:
+            self.IP += 2
+
+    def cst(self, operand):
+        self.flags['C'] = True
+
+    def ccl(self, operand):
+        self.flags['C'] = False
+
+    nums2mnems = {
+        0: hlt,
+        1: nop,
+        2: lda_lit,
+        3: sta_lit,
+        4: add_lit,
+        5: sub_lit,
+        6: jmp_lit,
+        7: ske,
+        8: skz,
+        9: skn,
+        10: skc,
+        11: cst,
+        12: ccl,
+        16: hlt,
+        17: nop,
+        18: lda_mem,
+        19: sta_mem,
+        20: add_mem,
+        21: sub_mem,
+        22: jmp_mem,
+        23: ske,
+        24: skz,
+        25: skn,
+        26: skc,
+        27: cst,
+        28: ccl,
+    }
+
+
+### PI PICO SPECIFIC STUFF ###
+
+# to list board features: print(dir(board))
+
+display_1 = TM1637Display(board.GP0, board.GP1, length=4)
+display_2 = TM1637Display(board.GP2, board.GP3, length=4)
+
+keymatrix = keypad.KeyMatrix(
+    row_pins = (board.GP5, board.GP6, board.GP7, board.GP8),
+    column_pins = (board.GP9, board.GP10, board.GP11, board.GP12, board.GP13) )
+
+keymap = {
+    15:"0", 16:"1", 17:"2", 18:"3", 19:"runhalt",
+    10:"4", 11:"5", 12:"6", 13:"7", 14:"step",
+    5:"8", 6:"9", 7:"A", 8:"B", 9:"addrdata",
+    0:"C", 1:"D", 2:"E", 3:"F", 4:"NA" }
+
+numericKeys = [ "0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F" ]
+
+def toHex(n):
+    return "%0.2X" % n
+
+class Monitor:
+    def __init__(self, cpu):
+        self.cpu = cpu
+        self.monitorMode = 'addressEntry' # or dataEntry
+        self.monitorAddressInput = TwoDigitHexInput()
+        self.monitorDataInput = TwoDigitHexInput()
+
+    def handleKeys(self):
+        keypad_event = keymatrix.events.get()
+        keyPressed = True if (keypad_event and keypad_event.released ) else False
+        key = keymap[keypad_event.key_number] if keyPressed else False
+        numericKeyPressed = True if (keyPressed and (key in numericKeys)) else False
+
+        if self.cpu.running:
+          if key == "runhalt":
+              print("HALT PRESSED")
+              self.cpu.running = False
+              time.sleep(0.5) # lazy debounce
+              # km.events.clear() # don't track keypresses from during the run
+
+          if numericKeyPressed:
+            self.cpu.memory[26] = int(key, 16)
+
+        elif not self.cpu.running:
+            if key == "runhalt":
+                self.cpu.running = True
+                print("\nSTARTING")
+                time.sleep(0.5) # lazy debounce
+
+            if key == "addrdata":
+                self.monitorMode = 'addressEntry' if self.monitorMode != 'addressEntry' else 'dataEntry'
+                print("\nENTERING", self.monitorMode, "MODE")
+                self.monitorDataInput.currentDigit = 0
+                self.monitorAddressInput.currentDigit = 0
+                time.sleep(0.5) # lazy debounce
+
+            if key == "step":
+                print("\nSINGLE STEP FROM MONITOR ADDR")
+                # self.IP = self.monitorAddressInput.value
+                self.cpu.step()
+                time.sleep(0.5) # lazy debounce
+
+            if numericKeyPressed:
+                if self.monitorMode == 'addressEntry':
+                    self.monitorAddressInput.input(int(key, 16))
+                    self.cpu.IP = self.monitorAddressInput.value
+                    print("MA", self.cpu.IP)
+
+                else:
+                    self.monitorDataInput.input(int(key, 16))
+                    self.cpu.memory[self.cpu.IP] = self.monitorDataInput.value
+                    print("MD", self.monitorDataInput.value)
+                    if self.monitorDataInput.currentDigit == 0: # that was the second keypress, so go to the next addresss
+                        self.cpu.IP = (self.cpu.IP + 1) % 256
+                        print("ADVANCING")
+                print("Acc", self.cpu.acc, "IP", self.cpu.IP, "Data", self.cpu.memory[self.cpu.IP], "\n")
+            
+
+
+    def run(self):
+        self.cpu.start()
+        t = time.time()
+        while (time.time() - t) < 120:
+            self.handleKeys()
+            display_1.print(toHex(self.monitorAddressInput.value) + toHex(self.monitorDataInput.value))
+            display_2.print(toHex(self.cpu.IP) + toHex(self.cpu.acc))
+            if self.cpu.running:
+                self.cpu.step()
+                time.sleep(0.5)
+        print("timeout")
+        print(self.cpu.memory)
+
+
+cpu = CPU()
+monitor = Monitor(cpu)
+
+#prog = '04 FF 04 01 14 01 00 00 01 01 01 01 01 01'
+prog = '00'
+program_bytes = bytearray.fromhex(prog.replace(" ", ""))
+# Add jmp at addr 254:
+program_with_jump = program_bytes + bytearray(254 - len(program_bytes)) + bytearray.fromhex('0600')
+cpu.load_memory(program_with_jump)
+
+monitor.run()
\ No newline at end of file