module forth
-RS = Array{Int, 1}()
-DS = Array{Int, 1}()
-
-IP = 0
-W = 0
-X = 0
-jmp = nothing
-
-primitives = Array{Expr,1}()
-memory = Array{Int64,1}()
-headers = Array{Tuple{AbstractString, Int64},1}()
-
-function addPrim(name::AbstractString, expr::Expr)
- push!(primitives, expr)
- push!(memory, -length(primitives))
- push!(headers, (name, length(memory)))
+# VM mem size
+size_mem = 640*1024
+
+# Buffer sizes
+size_BIVar = 16 #
+size_RS = 1024 # Return stack size
+size_PS = 1024 # Parameter stack size
+size_TIB = 4096 # Terminal input buffer size
+
+# The mem array constitutes the memory of the VM. It has the following geography:
+#
+# mem = +-----------------------+
+# | Built-in Variables |
+# +-----------------------+
+# | Return Stack |
+# +-----------------------+
+# | Parameter Stack |
+# +-----------------------+
+# | Terminal Input Buffer |
+# +-----------------------+
+# | Dictionary |
+# +-----------------------+
+#
+# Note that all words (user-defined, primitive, variables, etc) are included in
+# the dictionary.
+#
+# Simple linear addressing is used with one exception: references to primitive code
+# blocks, which are represented as anonymous functions, appear the negative index
+# into the primitives array which contains only these functions.
+
+mem = Array{Int64,1}(size_mem)
+primitives = Array{Function,1}()
+
+# Built-in variables
+
+nextVarAddr = 1
+RSP0 = nextVarAddr; nextVarAddr += 1
+PSP0 = nextVarAddr; nextVarAddr += 1
+HERE = nextVarAddr; nextVarAddr += 1
+LATEST = nextVarAddr; nextVarAddr += 1
+
+mem[RSP0] = size_BIVar # bottom of RS
+mem[PSP0] = mem[RSP0] + size_RS # bottom of PS
+TIB = mem[PSP0] + size_PS # address of terminal input buffer
+mem[HERE] = TIB + size_TIB # location of bottom of dictionary
+mem[LATEST] = 0 # no previous definition
+
+# VM registers
+type Reg
+ RSP::Int64 # Return stack pointer
+ PSP::Int64 # Parameter/data stack pointer
+ IP::Int64 # Instruction pointer
+ W::Int64 # Working register
+ X::Int64 # Extra register
+end
+reg = Reg(mem[RSP0], mem[PSP0], 0, 0, 0)
+
+# Stack manipulation functions
+
+function pushRS(val::Int64)
+ mem[reg.RSP+=1] = val
+end
+
+function popRS()
+ val = mem[reg.RSP]
+ reg.RSP -= 1
+ return val
+end
+
+function pushPS(val::Int64)
+ mem[reg.PSP += 1] = val
+end
+
+function popPS()
+ val = mem[reg.PSP]
+ reg.PSP -= 1
+ return val
+end
+
+# Primitive creation and calling functions
+
+function createHeader(name::AbstractString, flags::Int64)
+ mem[mem[HERE]] = mem[LATEST]
+ mem[LATEST] = mem[HERE]
+ mem[HERE] += 1
+
+ mem[mem[HERE]] = length(name) + flags; mem[HERE] += 1
+ mem[mem[HERE]:(mem[HERE]+length(name)-1)] = [Int(c) for c in name]; mem[HERE] += length(name)
+end
+
+function defPrim(name::AbstractString, f::Function; flags::Int64=0)
+ createHeader(name, flags)
+
+ push!(primitives, f)
+ mem[mem[HERE]] = -length(primitives)
+ mem[HERE] += 1
+
+ return -length(primitives)
+end
+
+callPrim(addr::Int64) = primitives[-addr]()
+
+function defExistingVar(name::AbstractString, varAddr::Int64; flags::Int64=0)
+ defPrim(name, eval(:(() -> begin
+ pushPS($(varAddr))
+ return NEXT
+ end)))
+end
+
+function defConst(name::AbstractString, val::Int64; flags::Int64=0)
+ defPrim(name, eval(:(() -> begin
+ pushPS($(val))
+ return NEXT
+ end)))
+end
+
+function defNewVar(name::AbstractString, initial::Int64; flags::Int64=0)
+ createHeader(name, flags)
- return expr
-end
-
-NEXT = addPrim("next", :(begin
- W = memory[IP]
- IP += 1
- X = memory[W]
- jmp = primitives[-X]
-end))
-
-DOCOL = addPrim("docol", :(begin
- push!(RS, IP)
- IP = W + 1
- jmp = NEXT
-end))
-
-EXIT = addPrim("exit", :(begin
- IP = pop!(RS)
- jmp = NEXT
-end))
-
-# VM loop
-#jmp = NEXT
-#while true
-# eval(jmp)
+ varAddr = mem[HERE] + 1
+ push!(primitives, eval(:(() -> begin
+ pushPS($(varAddr))
+ return NEXT
+ end)))
+ mem[mem[HERE]] = -length(primitives); mem[HERE] += 1
+
+ mem[mem[HERE]] = initial; mem[HERE] += 1
+
+ return varAddr
+end
+
+# Threading Primitives
+
+NEXT = defPrim("NEXT", () -> begin
+ reg.W = mem[reg.IP]
+ reg.IP += 1
+ X = mem[reg.W]
+ return X
+end)
+
+DOCOL = defPrim("DOCOL", () -> begin
+ pushRS(reg.IP)
+ reg.IP = reg.W + 1
+ return NEXT
+end)
+
+EXIT = defPrim("EXIT", () -> begin
+ reg.IP = popRS()
+ return NEXT
+end)
+
+
+# Basic forth primitives
+
+DROP = defPrim("DROP", () -> begin
+ popPS()
+ return NEXT
+end)
+
+SWAP = defPrim("SWAP", () -> begin
+ mem[reg.PSP], mem[reg.PSP-1] = mem[reg.PSP-1], mem[reg.PSP]
+ return NEXT
+end)
+
+DUP = defPrim("DUP", () -> begin
+ pushPS(mem[reg.PSP])
+ return NEXT
+end)
+
+LIT = defPrim("LIT", () -> begin
+ pushPS(mem[reg.IP])
+ reg.IP += 1
+ return NEXT
+end)
+
+# Memory primitives
+
+STORE = defPrim("!", () -> begin
+ addr = popPS()
+ dat = popPS()
+ mem[addr] = dat
+ return NEXT
+end)
+
+FETCH = defPrim("@", () -> begin
+ addr = popPS()
+ pushPS(mem[addr])
+ return NEXT
+end)
+
+ADDSTORE = defPrim("+!", () -> begin
+ addr = popPS()
+ toAdd = popPS()
+ mem[addr] += toAdd
+ return NEXT
+end)
+
+SUBSTORE = defPrim("-!", () -> begin
+ addr = popPS()
+ toSub = popPS()
+ mem[addr] -= toSub
+ return NEXT
+end)
+
+
+# Built-in variables
+
+defExistingVar("HERE", HERE)
+defExistingVar("LATEST", LATEST)
+defExistingVar("PSP0", PSP0)
+defExistingVar("RSP0", RSP0)
+defNewVar("STATE", 0)
+defNewVar("BASE", 10)
+
+# Constants
+
+defConst("VERSION", 1)
+defConst("DOCOL", DOCOL)
+
+# Return Stack
+
+TOR = defPrim(">R", () -> begin
+ pushRS(popPS())
+ return NEXT
+end)
+
+FROMR = defPrim("R>", () -> begin
+ pushPS(popRS())
+ return NEXT
+end)
+
+RSPFETCH = defPrim("RSP@", () -> begin
+ pushPS(RSP)
+ return NEXT
+end)
+
+RSPSTORE = defPrim("RSP!", () -> begin
+ RSP = popPS()
+ return NEXT
+end)
+
+RDROP = defPrim("RDROP", () -> begin
+ popRS()
+ return NEXT
+end)
+
+# Parameter Stack
+
+PSPFETCH = defPrim("PSP@", () -> begin
+ pushPS(PSP)
+ return NEXT
+end)
+
+PSPSTORE = defPrim("PSP!", () -> begin
+ PSP = popPS()
+ return NEXT
+end)
+
+# I/O
+
+defConst("TIB", TIB)
+NUMTIB = defNewVar("#TIB", 0)
+TOIN = defNewVar(">IN", TIB)
+
+#KEY = defPrim("KEY", (reg) -> begin
+# if toin >= numtib
+#
+# end
+#
+# return NEXT
+#end)
+#
+#EMIT = defPrim("EMIT", (reg) -> begin
+#
+# return NEXT
+#end)
+#
+#WORD = defPrim("WORD", (reg) -> begin
+#
+# return NEXT
+#end)
+#
+#NUMBER = defPrim("NUMBER", (reg) -> begin
+#
+# return NEXT
+#end)
+#
+#### VM loop ####
+#function runVM(reg::Reg)
+# jmp = NEXT
+# while (jmp = callPrim(reg, jmp)) != 0 end
#end
+# Debugging tools
+
+function coredump(startAddr::Int64; count::Int64 = 16, cellsPerLine::Int64 = 8)
+ chars = Array{Char,1}(cellsPerLine)
+
+ for i in 0:(count-1)
+ addr = startAddr + i
+ if i%cellsPerLine == 0
+ print("$addr:")
+ end
+
+ print("\t$(mem[addr]) ")
+
+ if (mem[addr]>=32 && mem[addr]<176)
+ chars[i%cellsPerLine + 1] = Char(mem[addr])
+ else
+ chars[i%cellsPerLine + 1] = '.'
+ end
+
+ if i%cellsPerLine == cellsPerLine-1
+ println(string("\t", ASCIIString(chars)))
+ end
+ end
+end
+
+function dumpPS()
+ count = reg.PSP - mem[PSP0]
+
+ if count > 0
+ print("<$count>")
+ for i in (mem[PSP0]+1):reg.PSP
+ print(" $(mem[i])")
+ end
+ println()
+ else
+ println("Parameter stack empty")
+ end
+end
+
end
The Lambda Lab / projects / forth.jl.git / blobdiff