qf/asm.qf

array ops 2 allot
array optypes 2 allot
var currop
: op1 ops @ ;
: op2 ops 1 + @ ;

0 const OP_NONE
1 const OP_REG8
2 const OP_REG16
3 const OP_SREG
4 const OP_IMM
5 const OP_INDIRECT

: op! ( op type ) currop @ >r optypes r@ + ! ops r@ + ! 1 r> + currop ! ;

: mkreg makedo , does> @ swap makedo , , does> dup @ swap 1 + @ op! ;
OP_REG8 mkreg reg8
OP_REG16 mkreg reg16
OP_SREG mkreg sreg
OP_INDIRECT mkreg ireg
0 reg16 ax 0 reg8 al 4 reg8 ah
1 reg16 cx 1 reg8 cl 5 reg8 ch
2 reg16 dx 2 reg8 dl 6 reg8 dh
3 reg16 bx 3 reg8 bl 7 reg8 bh
4 reg16 sp 5 reg16 bp 6 reg16 si 7 reg16 di
0 sreg es 1 sreg cs 2 sreg ss 3 sreg ds
0 ireg [ax] 1 ireg [cx] 2 ireg [dx] 3 ireg [bx]
5 ireg [bp] 6 ireg [si] 7 ireg [di]

: # OP_IMM op! ;

&h80 const LBL_REL
var lblfixup var currlbl

: currlbl-head currlbl @ 1 + ;
: mk-lbl-fixpoint
  here currlbl-head @ , tell , lblfixup @ , currlbl-head ! ;

: tell>addr &h100 + ;

: :> makedo tell , 0 , does> 0 # currlbl ! ;
: fixlabel.rel currlbl @ @ tell - &hff & tell 1 - seek outb! ;
: fixlabel.addr currlbl @ @ tell>addr tell 2 - seek outw! ;
: fixlabel ( fixtype -- ) if fixlabel.rel else fixlabel.addr then ;
: fixpoint.seek ( p -- ) 1 + @ seek ;
: fixpoint.fix ( p -- ) 2 + @ fixlabel ;
: fixpoint ( p -- next ) dup fixpoint.seek dup fixpoint.fix @ ;

: fix.fixpoints currlbl-head @ begin dup while fixpoint repeat drop ;

: assembled ( success -- ) 
  currlbl @ and if 
    lblfixup @ fixlabel 
    mk-lbl-fixpoint 
  then 0 currop ! 0 lblfixup ! 0 currlbl ! ;

: update.label tell currlbl @ ! ;
: <: update.label tell fix.fixpoints seek 0 assembled ;

: read-impl ( p -- next cp optypes )
  dup @ swap
  dup 1 + @ swap
  2 + ;

: match-impl ( optypes opcount -- b )
  begin dup 0 > while 
      1 - 2dup + @ over optypes + @ != 
      if drop drop 0 ret then
  repeat drop drop 1 ;


: inst ( opcount|lblfixup -- ) makedo dup &h7f & , 0 , &h80 & , does>
  dup 2 + @ lblfixup !
  dup @ currop @ != if 0 message yelp ret then
  1 + @ begin dup while 
    read-impl currop @ match-impl
    if execute drop 1 assembled ret else drop then 
  repeat drop 1 message yelp 0 assembled ;

: inst-nextimpl do.data 1 + ;
: inst-opcount do.data @ ;

: impl ( [optype...] cp cpinst -- )
  here >r >r ( r: impl inst )
  r@ inst-nextimpl @ , ,
  r@ inst-opcount begin dup while 1 - swap , repeat drop
  r> inst-nextimpl r> swap ! ;

: int &hcd outb! outb! 1 assembled ;
2 inst mov
2 inst movb

OP_IMM OP_REG16 :noname &hb8 op1 + outb! op2 outw! ; ' mov impl
OP_IMM OP_REG8 :noname &hb0 op1 + outb! op2 outb! ; ' movb impl
: :+r anondo >r , OP_REG16 r> does> @ op1 + outb! ;
: :+sreg anondo >r , OP_SREG r> does> @ op1 8 * + outb! ;
: modrm ( mod rm reg ) 8 * | swap 64 * | outb! ;
2 inst add
OP_REG16 OP_REG16 :noname &h01 outb! &h03 op1 op2 modrm ; ' add impl
OP_IMM OP_REG8 :noname &h80 outb! 3 op1 0 modrm op2 outb! ; ' add impl
2 inst xor
OP_REG16 OP_REG16 :noname &h31 outb! &h03 op1 op2 modrm ; ' xor impl
2 inst cmp
OP_IMM OP_REG16 :noname &h81 outb! 3 op1 0 modrm op2 outw! ; ' cmp impl

1 inst div
OP_REG16 :noname &hf7 outb! &h03 op1 &h06 modrm ; ' div impl

1 inst push
&h06 :+sreg ' push impl
&h50 :+r ' push impl
1 inst pop
&h07 :+sreg ' pop impl
&h58 :+r ' pop impl
1 inst dec 
&h48 :+r ' dec impl
1 inst inc
&h40 :+r ' inc impl

1 inst jmp
OP_INDIRECT :noname &hff outb! 0 op1 4 modrm ; ' jmp impl
OP_REG16 :noname &hff outb! 3 op1 4 modrm ; ' jmp impl

: :jumprel here >r 1 LBL_REL | inst 
  :| anondo >r , OP_IMM r> does> @ outb! op1 outb! |; execute
  r> impl ;

&h77 :jumprel ja
&h73 :jumprel jae
&h72 :jumprel jb
&h76 :jumprel jbe
&h74 :jumprel je
&h7f :jumprel jg
&h7d :jumprel jge
&h7c :jumprel jl
&h7e :jumprel jle
&h75 :jumprel jne
&h74 :jumprel jz

: .EXIT ax &h4c00 | # mov &h21 int ;
: d" begin in@ dup [ in@ " lit ] != while outb! repeat drop ;