先展示8051的：
以下是一个简单的 8051 单片机模拟器的 Python 代码示例，它可以模拟 8051 的基本指令集、中断、IO 端口等功能。
class CPU:
def __init__(self):
self.A = 0x00 # Accumulator
self.PSW = 0x00 # Program status word
self.DPTR = 0x0000 # Data pointer
self.PC = 0x0000 # Program counter
self.IE = False # Interrupt enable flag
self.IP = 0x00 # Interrupt priority
def reset(self):
self.A = 0x00
self.PSW = 0x00
self.DPTR = 0x0000
self.PC = 0x0000
self.IE = False
self.IP = 0x00
def fetch(self, mem):
instr = mem[self.PC]
self.PC += 1
return instr
def decode(self, instr):
op = (instr >> 3) & 0x1F
reg = instr & 0x07
return op, reg
def execute(self, op, reg, mem):
if op == 0x00: # NOP
pass
elif op == 0x01: # AJMP
addr = (self.PC & 0xF800) | (reg << 1)
self.PC = addr
elif op == 0x02: # LJMP
addr_hi = mem[self.PC]
addr_lo = mem[self.PC+1]
self.PC = (addr_hi << 8) | addr_lo
# ... more instructions ...
def interrupt(self, mem, int_num):
self.IE = False
self.IP = int_num
self.PSW = (self.PSW & 0xCF) | ((int_num & 0x03) << 4)
mem[0x03] = self.PC & 0xFF
mem[0x02] = self.PC >> 8
self.PC = int_num * 8 + 3
def run(self, mem):
while True:
instr = self.fetch(mem)
op, reg = self.decode(instr)
self.execute(op, reg, mem)
if self.PC == 0xFFFF:
break
再展示AVR的：
以下是一个简单的 AVR 单片机模拟器的 Python 代码示例，它可以模拟 AVR 的基本指令集、中断、IO 端口等功能。
class CPU:
def __init__(self):
self.R = [0] * 32 # General purpose registers
self.PC = 0x0000 # Program counter
self.SREG = 0x00 # Status register
self.IE = False # Interrupt enable flag
self.INT1 = False # Interrupt 1 flag
self.INT2 = False # Interrupt 2 flag
def reset(self):
self.R = [0] * 32
self.PC = 0x0000
self.SREG = 0x00
self.IE = False
self.INT1 = False
self.INT2 = False
def fetch(self, mem):
instr = mem[self.PC]
self.PC += 1
return instr
def decode(self, instr):
op = (instr >> 26) & 0x3F
rd = (instr >> 21) & 0x1F
rr = (instr >> 16) & 0x1F
k = instr & 0xFFFF
return op, rd, rr, k
def execute(self, op, rd, rr, k, mem):
if op == 0x00: # NOP
pass
elif op == 0x01: # ADD Rd, Rr
res = self.R[rd] + self.R[rr]
self.R[rd] = res & 0xFF
self.SREG = (self.SREG & 0xFD) | ((res >> 8) & 0x02)
if res & 0x100:
self.SREG |= 0x01
if self.R[rd] == 0:
self.SREG |= 0x02
elif op == 0x02: # SUB Rd, Rr
res = self.R[rd] - self.R[rr]
self.R[rd] = res & 0xFF
self.SREG = (self.SREG & 0xFD) | ((res >> 8) & 0x02)
if res & 0x100:
self.SREG |= 0x01
if self.R[rd] == 0:
self.SREG |= 0x02
# ... more instructions ...
def interrupt(self, mem, int_num):
self.IE = False
self.PC = int_num * 4
self.R[31] = self.SREG
self.SREG |= (int_num << 3)
mem[0x005E] = self.PC & 0xFF
mem[0x005F] = self.PC >> 8
def run(self, mem):
while True:
instr = self.fetch(mem)
op, rd, rr, k = self.decode(instr)
self.execute(op, rd, rr, k, mem)
if self.PC == 0xFFFF:
break
if self.IE and self.INT1:
self.interrupt(mem, 1)
if self.IE and self.INT2:
self.interrupt(mem, 2)
class Memory:
def __init__(self):
self.sram = [0] * 1024 # SRAM
self.io = [0] * 32 # IO registers
def read(self, addr):
if addr < 0x0200:
return self.sram[addr]
elif addr < 0x0400:
return self.io[addr - 0x0200]
elif addr < 0x1000:
return self.sram[addr]
else:
raise Exception("Invalid address")
def write(self, addr, value):
if addr < 0x0200:
self.sram[addr] = value
elif addr < 0x0400:
self.io[addr - 0x0200] = value
elif addr < 0x1000:
self.sram[addr] = value
else:
raise Exception("Invalid address")
将 CPU 和内存模拟器组合在一起，可以实现一个简单的 AVR 单片机模拟器。然而，需要注意的是，这只是一个基础的模拟器，不能实现复杂的芯片功能和外设操作。实际上，现有的 AVR 模拟器通常还包含更多的功能，如调试器、仿真外设等。
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