Doing my head in!

[forth.jl.git] / src / forth.jl

diff --git a/src/forth.jl b/src/forth.jl
index e720c7f..aac4c2a 100644 (file)
--- a/src/forth.jl
+++ b/src/forth.jl
@@ -1,23 +1,238 @@
-module FORTH
+module forth
 
-function input(prompt::AbstractString="")
-    print(prompt)
-    strip(readline)
+RS = Array{Int64, 1}(1024)
+RSP = 0
+
+PS = Array{Int64, 1}(1024)
+PSP =0
+
+IP = 0
+W = 0
+X = 0
+
+jmp = 0
+
+primitives = Array{Expr,1}()
+memory = Array{Int64,1}(64*1024)
+LATEST = 0
+HERE = 1
+
+# Intperpreter state
+
+STATE = 0
+
+# Current radix
+
+BASE = 10
+
+# Stack manipulation functions
+
+function pushRS(val::Int64)
+    global RSP
+    RS[RSP += 1] = val
+end
+
+function popRS()
+    global RSP
+    val = RS[RSP]
+    RSP -= 1
+    return val
 end
 
-dictCore = Set{AbstractString}([
-    "bye"
-])
+function pushPS(val::Int64)
+    global PSP
+    PS[PSP += 1] = val
+end
 
-function coreEval(word::AbstractString)
-    if word == "bye"
+function popPS()
+    global PSP
+    val = PS[PSP]
+    PSP -= 1
+    return val
 end
 
-function repl()
+# Primitive creation and calling functions
 
-    while true
-        line = input()
+function defPrim(name::AbstractString, expr::Expr)
+    global HERE, LATEST
+
+    memory[HERE] = LATEST
+    LATEST = HERE
+    HERE += 1
+
+    memory[HERE] = length(name); HERE += 1
+    memory[HERE:(HERE+length(name)-1)] = [Int(c) for c in name]; HERE += length(name)
+
+    push!(primitives, expr)
+    memory[HERE] = -length(primitives)
+    HERE += 1
+
+    return -length(primitives)
+end
+
+defVar(name::AbstractString, var::Symbol) = defPrim(name, quote
+    pushPS($var)
+    jmp = NEXT
+end)
+
+defConst(name::AbstractString, val::Int64) = defPrim(name, quote
+    pushPS($val)
+    jmp = Next
+end)
+
+callPrim(addr::Int64) = eval(primitives[-addr])
+
+# Threading Primitives
+
+NEXT = defPrim("NEXT", quote
+    W = memory[IP]
+    IP += 1
+    X = memory[W]
+    jmp = X
+end)
+
+DOCOL = defPrim("DOCOL", quote
+    pushRS(IP)
+    IP = W + 1
+    jmp = NEXT
+end)
+
+EXIT = defPrim("EXIT", quote
+    IP = popRS()
+    jmp = NEXT
+end)
+
+
+# Basic forth primitives
+
+DROP = defPrim("DROP", quote
+    popPS()
+    jmp = NEXT
+end)
+
+SWAP = defPrim("SWAP", quote
+    PS[PSP], PS[PSP-1] = PS[PSP-1], PS[PS]
+    jmp = NEXT
+end)
+
+DUP = defPrim("DUP", quote
+    pushPS(PS[PSP])
+    jmp = NEXT
+end)
 
+LIT = defPrim("LIT", quote
+    pushPS(memory[IP])
+    IP += 1
+    jmp = NEXT
+end)
+
+# Memory primitives
+
+STORE = defPrim("!", quote
+    addr = popPS()
+    dat = popPS()
+    memory[addr] = dat
+    jmp = NEXT
+end)
+
+FETCH = defPrim("@", quote
+    addr = popPS()
+    pushPS(memory[addr])
+    jmp = NEXT
+end)
+
+ADDSTORE = defPrim("+!", quote
+    addr = popPS()
+    toAdd = popPS()
+    memory[addr] += toAdd
+    jmp = NEXT
+end)
+
+SUBSTORE = defPrim("-!", quote
+    addr = popPS()
+    toSub = popPS()
+    memory[addr] -= toSub
+    jmp = NEXT
+end)
+
+
+# Built-in variables
+
+defVar("STATE", :STATE)
+defVar("HERE", :HERE)
+defVar("LATEST", :LATEST)
+defVAR("BASE", :BASE)
+
+# Constants
+
+defConst("VERSION", 1)
+defConst("DOCOL", DOCOL)
+
+# Return Stack
+
+TOR = defPrim(">R", quote
+    pushRS(popPS())
+    jmp = NEXT
+end)
+
+FROMR = defPrim("R>", quote
+    pushPS(popRS())
+end)
+
+RSPFETCH = defPrim("RSP@", quote
+    pushPS(RSP)
+    jmp = NEXT
+end)
+
+RSPSTORE = defPrim("RSP!", quote
+    RSP = popPS()
+    jmp = NEXT
+end)
+
+RDROP = defPrim("RDROP", quote
+    popRS()
+    jmp = NEXT
+end)
+
+# Parameter Stack
+
+PSPFETCH = defPrim("PSP@", quote
+    pushPS(PSP)
+    jmp = NEXT
+end)
+
+PSPSTORE = defPrim("PSP!", quote
+    PSP = popPS()
+    jmp = NEXT
+end)
+
+# I/O
+
+KEY = defPrim("KEY", quote
+
+    jmp = NEXT
+end)
+
+EMIT = defPrim("EMIT", quote
+
+    jmp = NEXT
+end)
+
+WORD = defPrim("WORD", quote
+
+    jmp = NEXT
+end)
+
+NUMBER = defPrim("NUMBER", quote
+
+    jmp = NEXT
+end)
+
+#### VM loop ####
+jmp = NEXT
+function runVM()
+    while true
+        callPrim(jmp)
     end
 end