; Copyright (C) 2026 Paul Carver Harrison

microcode length 512
microcode width 36
microcode padding left
microcode target vhex
microcode output ucode.hex

mapping length 64
mapping target vhex
mapping output umap.hex

field md 1 0 read=0,write=1
field mssrc 1 0 ucode=0,rma=1
field ms 2 0 nop=0,word=1,hword=2,byte=3
field rwe 1 0
field rma 2 0 pcp=0,dsp=1,rsp=2,tmp=3
field rd 3 imm pcp=0,dsp=1,rsp=2,tmp=3,mdr=4,tos=5,acc=6,imm=7
field rs2 2 imm mdr=0,tos=1,acc=2,imm=3
field rs1 3 imm pcp=0,dsp=1,rsp=2,tmp=3,mdr=4,tos=5,acc=6,imm=7
field aluop 4 0 a,not,add,sub,sgt,slt,gt,lt,and,or,xor,lsl,asr,mul,sextb,sexth
field alusrc 1 0 ucode=0,rma=1
field cci 1 0
field cce 1 0
field seqsrc 1 0 imm=0,map=1
field seqop 2 0 step=0,jump=1,retn=2,call=3
field imm 9 0

sub fetch 000h
    ; fetch instruction and increment pcp. jump to instruction
    rma=pcp,md=read,ms=byte
    rwe,aluop=add,rd=pcp,rs1=pcp,imm=1,seqop=jump,seqsrc=map
end

sub aluop1
    rwe,alusrc=rma,rd=tos,rs1=tos,rs2=tos,seqop=retn
end

sub aluop2
    rwe,aluop=a,rd=tmp,rs1=mdr
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,alusrc=rma,rma=tmp,rd=tos,rs1=tos,rs2=mdr,seqop=retn
end

sub aluopi
    rwe,aluop=a,rd=tmp,rs1=mdr
    rma=pcp,md=read,ms=byte,rwe,aluop=add,rd=pcp,rs1=pcp,imm=1
    rwe,alusrc=rma,rma=tmp,rd=tos,rs1=tos,rs2=mdr,seqop=retn
end

sub pushdb
    ; *(++((word *)dsp)) = tos
    rwe,aluop=add,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=mdr,rs1=tos
    rma=dsp,md=write,ms=word

    ; tos = *pcp++
    rma=pcp,md=read,ms=byte,rwe,aluop=add,rd=pcp,rs1=pcp,imm=1
    rwe,aluop=a,rd=tos,rs1=mdr,seqop=retn
end

sub pushdhu
    ; *(++((word *)dsp)) = tos
    rwe,aluop=add,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=mdr,rs1=tos
    rma=dsp,md=write,ms=word

    ; read half-word into tos
    rma=pcp,md=read,ms=byte,rwe,aluop=add,rd=pcp,rs1=pcp,imm=1
    rwe,aluop=lsl,rd=tos,rs1=mdr,imm=8
    rma=pcp,md=read,ms=byte,rwe,aluop=add,rd=pcp,rs1=pcp,imm=1
    rwe,aluop=or,rd=tos,rs1=tos,rs2=mdr,seqop=retn
end

sub pushdwu
    ; *(++((word *)dsp)) = tos
    rwe,aluop=add,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=mdr,rs1=tos
    rma=dsp,md=write,ms=word

    ; read word into tos
    ; 0
    rma=pcp,md=read,ms=byte,rwe,aluop=add,rd=pcp,rs1=pcp,imm=1
    rwe,aluop=lsl,rd=tos,rs1=mdr,imm=8
    ; 1
    rma=pcp,md=read,ms=byte,rwe,aluop=add,rd=pcp,rs1=pcp,imm=1
    rwe,aluop=or,rd=tos,rs1=tos,rs2=mdr
    rwe,aluop=lsl,rd=tos,rs1=mdr,imm=8
    ; 2
    rma=pcp,md=read,ms=byte,rwe,aluop=add,rd=pcp,rs1=pcp,imm=1
    rwe,aluop=or,rd=tos,rs1=tos,rs2=mdr
    rwe,aluop=lsl,rd=tos,rs1=mdr,imm=8
    ; 3
    rma=pcp,md=read,ms=byte,rwe,aluop=add,rd=pcp,rs1=pcp,imm=1
    rwe,aluop=or,rd=tos,rs1=tos,rs2=mdr,seqop=retn
end

sub pushdha
    seqop=retn
end

sub pushdwa
    seqop=retn
end

sub swap
    rma=dsp,md=read,ms=word
    rd=acc,rs1=mdr,rwe,aluop=a
    rd=mdr,rs1=tos,rwe,aluop=a
    rma=dsp,md=write,ms=word
    rd=tos,rs1=acc,rwe,aluop=a,seqop=retn
end

sub dup
    rwe,aluop=add,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=mdr,rs1=tos
    rma=dsp,md=write,ms=word,seqop=retn
end

sub drop
    ; tos = *(((word *)dsp)--)
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=tos,rs1=mdr,seqop=retn
end

; fetch word from memory and store on data stack
sub fetchdw
    ; tmp = tos
    rwe,aluop=a,rd=tmp,rs1=tos
    ; mdr = *(word *)tmp
    rma=tmp,md=read,ms=word
    ; tos = mdr
    rwe,aluop=a,rd=tos,rs1=mdr,seqop=retn
end

; fetch byte from memory and store on data stack
sub fetchdb
    rwe,aluop=a,rd=tmp,rs1=tos
    rma=tmp,md=read,ms=byte
    rwe,aluop=a,rd=tos,rs1=mdr,seqop=retn
end

; fetch word from memory and store on return stack
sub fetchrw
    ; mdr = *(word *)tos; rsp -= 4
    rwe,aluop=a,rd=tmp,rs1=tos
    rma=tmp,md=read,ms=word,rwe,aluop=sub,rd=rsp,rs1=rsp,imm=4
    
    ; push onto return stack
    rma=rsp,md=write,ms=word

    ; pop off data stack into TOS
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=tos,rs1=mdr,seqop=retn
end

; fetch byte from memory and store on return stack
sub fetchrb
    ; mdr = *(byte *)tos; rsp -= 4
    rwe,aluop=a,rd=tmp,rs1=tos
    rma=tmp,md=read,ms=byte,rwe,aluop=sub,rd=rsp,rs1=rsp,imm=4
    
    ; push onto return stack
    rma=rsp,md=write,ms=word

    ; pop off data stack into TOS
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=tos,rs1=mdr,seqop=retn
end

sub storedw
    ; mdr = *(word *)tos; dsp -= 4
    rwe,aluop=a,rd=tmp,rs1=tos
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rma=tmp,md=write,ms=word
    
    ; pop off data stack into TOS
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=tos,rs1=mdr,seqop=retn
end

sub storedb
    ; mdr = *(word *)tos; dsp -= 4
    rwe,aluop=a,rd=tmp,rs1=tos
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rma=tmp,md=write,ms=byte
    
    ; pop off data stack into TOS
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=tos,rs1=mdr,seqop=retn
end

sub rtod
    ; push TOS onto data stack
    rwe,aluop=add,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=mdr,rs1=tos
    rma=dsp,md=write,ms=word

    ; pop top of return stack into TOS
    rma=rsp,md=read,ms=word,rwe,aluop=add,rd=rsp,rs1=rsp,imm=4
    rwe,aluop=a,rd=tos,rs1=mdr,seqop=retn    
end

sub dtor
    ; push TOS onto return stack
    rwe,aluop=sub,rd=rsp,rs1=rsp,imm=4
    rwe,aluop=a,rd=mdr,rs1=tos
    rma=rsp,md=write,ms=word

    ; pop top of data stack into TOS
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=tos,rs1=mdr,seqop=retn
end

sub pstoredw
    seqop=retn
end

sub pstoredb
    seqop=retn
end

sub jump
    ; transfer TOS to PCP
    rwe,aluop=a,rd=pcp,rs1=tos

    ; pop top of data stack into TOS
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=tos,rs1=mdr,seqop=retn
end

sub jumpz
    ; ACC = NOS = value to check
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=acc,rs1=mdr
    
    ; TMP = TOS = branch address
    rwe,aluop=a,rd=tmp,rs1=tos
    
    ; pop top of data stack into TOS
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=tos,rs1=mdr
    
    ; If not zero, next ISA instruction
    aluop=a,rs1=acc,cce=1,cci=1,seqop=retn

    ; If zero, jump to address in TMP
    rwe,aluop=a,rd=pcp,rs1=tmp,seqop=retn
end

sub jumpnz
    ; ACC = NOS = value to check
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=acc,rs1=mdr
    
    ; TMP = TOS = branch address
    rwe,aluop=a,rd=tmp,rs1=tos
    
    ; pop top of data stack into TOS
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=tos,rs1=mdr
    
    ; If zero, next ISA instruction
    aluop=a,rs1=acc,cce=1,cci=0,seqop=retn

    ; If not zero, jump to address in TMP
    rwe,aluop=a,rd=pcp,rs1=tmp,seqop=retn
end

sub call
    ; push PCP onto return stack
    rwe,aluop=sub,rd=rsp,rs1=rsp,imm=4
    rwe,aluop=a,rd=mdr,rs1=pcp
    rma=rsp,md=write,ms=word

    ; PCP = TOS
    rwe,aluop=a,rd=pcp,rs1=tos

    ; pop top of data stack into TOS
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=tos,rs1=mdr,seqop=retn
end

sub callz
    ; ACC = NOS = value to check
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=acc,rs1=mdr
    
    ; TMP = TOS = branch address
    rwe,aluop=a,rd=tmp,rs1=tos
    
    ; pop top of data stack into TOS
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=tos,rs1=mdr
    
    ; If not zero, next ISA instruction
    aluop=a,rs1=acc,cce=1,cci=1,seqop=retn

    ; push PCP onto return stack
    rwe,aluop=sub,rd=rsp,rs1=rsp,imm=4
    rwe,aluop=a,rd=mdr,rs1=pcp
    rma=rsp,md=write,ms=word

    ; If zero, jump to address in TMP
    rwe,aluop=a,rd=pcp,rs1=tmp,seqop=retn
end

sub callnz
    ; ACC = NOS = value to check
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=acc,rs1=mdr
    
    ; TMP = TOS = branch address
    rwe,aluop=a,rd=tmp,rs1=tos
    
    ; pop top of data stack into TOS
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=tos,rs1=mdr
    
    ; If zero, next ISA instruction
    aluop=a,rs1=acc,cce=1,cci=0,seqop=retn

    ; push PCP onto return stack
    rwe,aluop=sub,rd=rsp,rs1=rsp,imm=4
    rwe,aluop=a,rd=mdr,rs1=pcp
    rma=rsp,md=write,ms=word

    ; If not zero, jump to address in TMP
    rwe,aluop=a,rd=pcp,rs1=tmp,seqop=retn
end

sub ret
    rma=rsp,md=read,ms=word,rwe,aluop=add,rd=rsp,rs1=rsp,imm=4
    rwe,aluop=a,rd=pcp,rs1=mdr,seqop=retn
end

sub retz
    ; ACC = TOS = value to check
    rwe,aluop=a,rd=acc,rs1=tos

    ; pop top of data stack into TOS
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=tos,rs1=mdr

    ; If not zero, next ISA instruction
    aluop=a,rs1=acc,cce=1,cci=1,seqop=retn

    ; return
    rma=rsp,md=read,ms=word,rwe,aluop=add,rd=rsp,rs1=rsp,imm=4
    rwe,aluop=a,rd=pcp,rs1=mdr,seqop=retn
end

sub retnz
    ; ACC = TOS = value to check
    rwe,aluop=a,rd=acc,rs1=tos

    ; pop top of data stack into TOS
    rma=dsp,md=read,ms=word,rwe,aluop=sub,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=tos,rs1=mdr

    ; If zero, next ISA instruction
    aluop=a,rs1=acc,cce=1,cci=0,seqop=retn

    ; return
    rma=rsp,md=read,ms=word,rwe,aluop=add,rd=rsp,rs1=rsp,imm=4
    rwe,aluop=a,rd=pcp,rs1=mdr,seqop=retn
end

sub over
    rwe,aluop=add,rd=dsp,rs1=dsp,imm=4
    rwe,aluop=a,rd=mdr,rs1=tos
    rma=dsp,md=write,ms=word,rwe,aluop=sub,rd=tmp,rs1=dsp,imm=4
    rma=tmp,md=read,ms=word
    rwe,aluop=a,rd=tos,rs1=mdr,seqop=retn
end

sub repeatri
    rma=rsp,md=read,ms=word
    rwe,aluop=sub,rd=mdr,rs1=mdr,imm=1
    aluop=a,rs1=mdr,cce,seqop=jump,imm=1E0h
    rma=rsp,md=write,ms=word
    rma=pcp,md=read,ms=byte,rwe,aluop=add,rd=pcp,rs1=pcp,imm=1
    rwe,aluop=sextb,rd=mdr,rs1=mdr
    rwe,aluop=add,rd=pcp,rs1=pcp,rs2=mdr,seqop=retn
end

sub rot
    seqop=call,imm=dtor
    seqop=call,imm=swap
    seqop=call,imm=rtod
    seqop=call,imm=swap
    seqop=retn

sub nop
    seqop=retn
end

sub repeatri_ret 1EEh
    rma=pcp,md=read,ms=byte,rwe,aluop=sub,rd=rsp,rs1=rsp,imm=4
    rwe,aluop=add,rd=pcp,rs1=pcp,imm=1,seqop=retn
end

sub init 1F8h
     ; nop required on startup
     imm=0
     
     ; data stack starts at 4000h and grows up
     rwe,aluop=a,rd=dsp,imm=40h
     rwe,aluop=lsl,rd=dsp,rs1=dsp,imm=8

     ; return stack starts at 4400h and grows down
     rwe,aluop=a,rd=rsp,imm=44h
     rwe,aluop=lsl,rd=rsp,rs1=rsp,imm=8

     ; init done
     seqop=retn
end

map aluop1*4,aluop2*4,aluopi*4,swap,dup,drop,over,fetchdw,fetchdb,fetchrw,fetchrb,storedw,storedb,pstoredw,pstoredb,rtod,dtor,jump,jumpz,jumpnz,call,callz,callnz,ret,retz,retnz,pushdb,pushdhu,pushdwu,pushdha,pushdwa,repeatri