338 lines
7.7 KiB
Fennel
338 lines
7.7 KiB
Fennel
(local lume (require "lib.lume"))
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(local {: lo : hi} (require "lib.util"))
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(fn inc16-stk [l h]
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[:block
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[:inc l :x]
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[:bne :done]
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[:inc h :x]
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:done])
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(fn inc16 [l h]
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[:block
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[:inc l]
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[:bne :done]
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[:inc h]
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:done
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])
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(fn dec16 [l h]
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[:block
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[:lda l]
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[:bne :declow]
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[:dec h]
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:declow
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[:dec l]])
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(fn add16 [l h]
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[:block
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[:clc]
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[:adc l]
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[:sta l]
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[:bcc :go]
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[:inc h]
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:go
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])
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(fn mk-vm [prg options]
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(local code1 (prg:org 0xc00))
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(fn prg.dat-parser.vm [bytecodes]
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(local block (prg:new-block))
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(each [_ bytecode (ipairs (lume.slice bytecodes 2))]
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(if
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(= (type bytecode) :number)
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(prg:parse-dats block [[:ref :lit] [:dw bytecode]])
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(= (type bytecode) :string)
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(prg:parse-dats block [[:ref bytecode]])
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(= (type bytecode) :table)
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(prg:parse-dats block [bytecode])
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(error (.. "VM can't parse " (fv bytecode)))))
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block)
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(local vm {
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:IP :0x60
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:IPH :0x61
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:W :0x62
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:WH :0x63
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:ROFF :0x64
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:TOP :0x80
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:TOPH :0x81
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:ST1 :0x7e
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:ST1H :0x7f
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:ST2 :0x7c
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:ST2H :0x7d
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:RSTACK :0x6000
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:code code1
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:ret (fn [self] [:jmp :next])
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:reserve (fn [self] [:block [:inx] [:inx]])
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:push
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(fn [self v]
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(local l (bit.band v 0xff))
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(local h (bit.band (bit.rshift v 8) 0xff))
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[:block (self:reserve)
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[:lda l]
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[:sta self.TOP :x]
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[:lda h]
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[:sta self.TOPH :x]
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])
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:drop (fn [self] [:block [:dex] [:dex]])
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:def
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(fn [self name ...]
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(code1:append name [:flatten ...] (self:ret)))
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:word
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(fn [self name ...]
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(code1:append name [:jsr :subroutine] [:vm ...] [:vm :ret]))
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:inline
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(fn [self ...]
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[:block [:jsr :subroutine] [:vm ...] [:vm :restore]])
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:asm
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(fn [self ...]
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[:block [:vm :native] [:block ...] [:jsr :interpret]])
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})
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(code1:append :next
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[:ldy 0]
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[:lda [vm.IP] :y] [:sta vm.W]
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(inc16 vm.IP vm.IPH)
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[:lda [vm.IP] :y] [:sta vm.WH]
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(inc16 vm.IP vm.IPH)
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; [:lda vm.WH]
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; [:jsr mon.hexout]
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; [:lda vm.W]
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; [:jsr mon.hexout]
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; [:lda (achar " ")]
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; [:jsr mon.putchar]
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[:jmp [vm.W]])
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(code1:append :reset
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[:lda #(lo ($1:lookup-addr :quit))]
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[:sta vm.IP]
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[:lda #(hi ($1:lookup-addr :quit))]
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[:sta vm.IPH]
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[:lda 0]
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[:sta vm.ROFF]
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[:ldx 0xfe]
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[:rts])
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(vm:def
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:subroutine ; usage: [jsr :subroutine] followed by bytecode
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[:ldy vm.ROFF]
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[:lda vm.IP] [:sta vm.RSTACK :y] [:iny]
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[:lda vm.IPH] [:sta vm.RSTACK :y] [:iny]
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[:sty vm.ROFF]
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:interpret ; usage: [jsr :interpret] followed by bytecode
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[:pla] [:sta vm.IP] [:pla] [:sta vm.IPH]
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(inc16 vm.IP vm.IPH))
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(vm:def :ret
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[:ldy vm.ROFF]
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[:dey] [:lda vm.RSTACK :y] [:sta vm.IPH]
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[:dey] [:lda vm.RSTACK :y] [:sta vm.IP]
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[:sty vm.ROFF])
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(code1:append :native [:jmp [vm.IP]])
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(code1:append :quit [:rts])
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(code1:append :restore
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[:lda vm.IP] [:sta vm.W]
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[:lda vm.IPH] [:sta vm.WH]
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[:ldy vm.ROFF]
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[:dey] [:lda vm.RSTACK :y] [:sta vm.IPH]
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[:dey] [:lda vm.RSTACK :y] [:sta vm.IP]
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[:sty vm.ROFF]
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[:jmp [vm.W]])
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(vm:def :drop (vm:drop))
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(vm:def :dup
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(vm:reserve)
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[:lda vm.ST1H :x]
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[:sta vm.TOPH :x]
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[:lda vm.ST1 :x]
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[:sta vm.TOP :x])
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(vm:def :swap
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[:lda vm.TOP :x]
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[:ldy vm.ST1 :x]
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[:sty vm.TOP :x]
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[:sta vm.ST1 :x]
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[:lda vm.TOPH :x]
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[:ldy vm.ST1H :x]
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[:sty vm.TOPH :x]
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[:sta vm.ST1H :x])
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(vm:def :over
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(vm:reserve)
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[:lda vm.ST2H :x]
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[:sta vm.TOPH :x]
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[:lda vm.ST2 :x]
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[:sta vm.TOP :x])
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(vm:word :2dup :over :over)
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(vm:def :>rot ; (a b c -- c a b)
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[:lda vm.TOP :x] ; a: c (a b c)
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[:ldy vm.ST2 :x] ; y: a (a b c)
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[:sta vm.ST2 :x] ; a: c (c b c)
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[:lda vm.ST1 :x] ; a: b (c b c)
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[:sta vm.TOP :x] ; a: b (c b b)
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[:sty vm.ST1 :x] ; y: a (c a b)
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[:lda vm.TOPH :x] ; a: c (a b c)
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[:ldy vm.ST2H :x] ; y: a (a b c)
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[:sta vm.ST2H :x] ; a: c (c b c)
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[:lda vm.ST1H :x] ; a: b (c b c)
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[:sta vm.TOPH :x] ; a: b (c b b)
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[:sty vm.ST1H :x] ; y: a (c a b)
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)
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(vm:def :<rot ; (a b c -- b c a)
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[:lda vm.TOP :x] ; a: c (a b c)
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[:ldy vm.ST1 :x] ; y: b (a b c)
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[:sta vm.ST1 :x] ; a: c (a c c)
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[:lda vm.ST2 :x] ; a: a (a c c)
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[:sta vm.TOP :x] ; a: a (a c a)
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[:sty vm.ST2 :x] ; y: b (b c a)
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[:lda vm.TOPH :x] ; a: c (a b c)
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[:ldy vm.ST1H :x] ; y: b (a b c)
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[:sta vm.ST1H :x] ; a: c (a c c)
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[:lda vm.ST2H :x] ; a: a (a c c)
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[:sta vm.TOPH :x] ; a: a (a c a)
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[:sty vm.ST2H :x] ; y: b (b c a)
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)
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(vm:def :get
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[:lda [vm.TOP :x]]
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[:tay]
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(inc16-stk vm.TOP vm.TOPH)
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[:lda [vm.TOP :x]]
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[:sta vm.TOPH :x]
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[:sty vm.TOP :x])
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(vm:def :set ; v p --
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[:lda vm.ST1 :x]
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[:sta [vm.TOP :x]]
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(inc16-stk vm.TOP vm.TOPH)
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[:lda vm.ST1H :x]
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[:sta [vm.TOP :x]]
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(vm:drop) (vm:drop))
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(vm:def :bget ; p -- b
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[:lda [vm.TOP :x]] [:sta vm.TOP :x]
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[:lda 0] [:sta vm.TOPH :x])
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(vm:def :bset ; b p --
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[:lda vm.ST1 :x] [:sta [vm.TOP :x]]
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(vm:drop) (vm:drop))
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(vm:def :lit
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(vm:reserve) [:ldy 0]
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[:lda [vm.IP] :y] [:sta vm.TOP :x]
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(inc16 vm.IP vm.IPH)
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[:lda [vm.IP] :y] [:sta vm.TOPH :x]
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(inc16 vm.IP vm.IPH))
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(vm:def :>r ; v --
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[:ldy vm.ROFF]
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[:lda vm.TOP :x] [:sta vm.RSTACK :y] [:iny]
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[:lda vm.TOPH :x] [:sta vm.RSTACK :y] [:iny]
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[:sty vm.ROFF]
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(vm:drop))
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(vm:def :r> ; -- v
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(vm:reserve)
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[:ldy vm.ROFF]
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[:dey] [:lda vm.RSTACK :y] [:sta vm.TOPH :x]
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[:dey] [:lda vm.RSTACK :y] [:sta vm.TOP :x]
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[:sty vm.ROFF])
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(vm:def :rtop ; -- v
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(vm:reserve)
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[:ldy vm.ROFF]
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[:dey] [:lda vm.RSTACK :y] [:sta vm.TOPH :x]
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[:dey] [:lda vm.RSTACK :y] [:sta vm.TOP :x])
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(vm:def :rdrop
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[:ldy vm.ROFF] [:dey] [:dey] [:sty vm.ROFF])
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(vm:def :bz ; f --
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[:block
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[:lda vm.TOP :x]
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[:bne :skip]
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[:lda vm.TOPH :x]
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[:beq :dojmp]
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:skip
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(vm:drop)
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[:lda 2] (add16 vm.IP vm.IPH) (vm:ret)
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:dojmp (vm:drop)]
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:jmp
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; ugh I don't have enough registers for this; a (one-byte?) relative jump would maybe be better
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[:ldy 0] [:lda [vm.IP] :y] [:sta vm.W]
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[:iny] [:lda [vm.IP] :y] [:sta vm.IPH]
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[:lda vm.W] [:sta vm.IP])
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(fn vm.while [self preamble ...]
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[:block
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:start
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[:vm (table.unpack preamble)]
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[:ref :bz] [:ref :end]
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[:vm ...]
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[:ref :jmp] [:ref :start]
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:end])
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(fn vm.until [self ...]
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[:block :start [:vm ...] [:ref :bz] [:ref :start]])
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(fn vm.for [self ...]
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[:vm :>r (vm:while [:rtop] :r> :dec :>r ...) :rdrop])
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(vm:def :+ ; a b -- c
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[:clc]
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[:lda vm.ST1 :x] [:adc vm.TOP :x] [:sta vm.ST1 :x]
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[:lda vm.ST1H :x] [:adc vm.TOPH :x] [:sta vm.ST1H :x]
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(vm:drop))
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(vm:def :- ; a b -- c
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[:sec]
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[:lda vm.ST1 :x] [:sbc vm.TOP :x] [:sta vm.ST1 :x]
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[:lda vm.ST1H :x] [:sbc vm.TOPH :x] [:sta vm.ST1H :x]
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(vm:drop))
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(vm:def :inc ; a -- a+1
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(inc16-stk vm.TOP vm.TOPH))
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(vm:def :dec ; a -- a-1
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[:block
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[:lda vm.TOP :x]
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[:bne :declow]
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[:dec vm.TOPH :x]
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:declow
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[:dec vm.TOP :x]])
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(vm:def :not ; f - !f
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[:block
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[:lda vm.TOP :x]
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[:bne :zero]
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[:lda vm.TOPH :x]
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[:bne :zero]
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[:lda 0xff] [:sta vm.TOP :x] [:sta vm.TOPH :x] (vm:ret)
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:zero
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[:lda 0] [:sta vm.TOP :x] [:sta vm.TOPH :x]])
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(vm:def := ; a b -- f
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[:block
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[:lda vm.ST1 :x]
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[:cmp vm.TOP :x]
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[:bne :noteq]
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[:lda vm.ST1H :x]
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[:cmp vm.TOP :x]
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[:bne :noteq]
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[:lda 0xff] (vm:drop) [:sta vm.TOP :x] [:sta vm.TOPH :x] (vm:ret)
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:noteq
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[:lda 0] (vm:drop) [:sta vm.TOP :x] [:sta vm.TOPH :x]])
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vm)
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{:new mk-vm}
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