31 lines
1.6 KiB
Lua
31 lines
1.6 KiB
Lua
vmz = {
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pc = 0,
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acc = 0,
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mem = { [0]=0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0 },
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b2oa = function(byte) return math.floor(byte / 32), byte % 32 end,
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boot = function(self) self.pc, self.acc = 0, 0 for pc=0,31 do self.mem[pc]=0 end return self end,
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load = function(self, bytes) for pc = 0, 31 do self.mem[pc]=bytes[pc] or 0 end return self end,
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clam = function(n) if n<0 then n=n+256 elseif n>255 then n=n-256 end return n end,
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opfn = {[0]=
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function(self,addr) self.pc=self.pc+1 return true end, -- NOP
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function(self,addr) self.acc=self.mem[addr] self.pc=self.pc+1 return true end, -- LDA
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function(self,addr) self.mem[addr]=self.acc self.pc=self.pc+1 return true end, -- STA
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function(self,addr) self.acc=self.clam(self.acc+self.mem[addr]) self.pc=self.pc+1 return true end, -- ADD
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function(self,addr) self.acc=self.clam(self.acc-self.mem[addr]) self.pc=self.pc+1 return true end, -- SUB
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function(self,addr) if (self.acc==0) then self.pc=addr else self.pc=self.pc+1 end return true end, -- BRZ
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function(self,addr) self.pc=addr return true end, -- JMP
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function(self,addr) self.pc=self.pc+1 return false end, -- STP
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},
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step = function(self)
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local oper, addr = self.b2oa(self.mem[self.pc])
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return self.opfn[oper](self,addr)
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end,
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exec = function(self)
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while self.pc < 32 and self:step() do end
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return self
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end,
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}
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-- object code derived from js sim code
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print("2 + 2 = " .. vmz:boot():load({[0]=35,100,224,2,2}):exec().acc)
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print("7 x 8 = " .. vmz:boot():load({[0]=44,106,76,43,141,75,168,192,44,224,8,7,0,1}):exec().acc)
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