The X-Philes (2nd Revision)/The X-Philes Number 1 (1995).iso/xphiles/hp48_2/star-1_0.tar/chip8.star

Text File | 1991-03-22 | 9KB | 677 lines

;;++
;;
;;   CHIP-8 Macro Definitions for STAR, the Saturn Macro Assembler
;;
;;   Copyright (C) 1990 Roger Ivie
;;   Copyright (C) 1990 Jan Brittenson
;;
;;--

    save list
    list = 0

    if (pass == 1) && !chip8loaded

;;++
;;
;;      This macro package is based on the M80 (Digital Research'
;;   Macro Assembler for the Intel 8080 and Zilog Z80 families of
;;   micro processors) written by:
;;
;;    Roger Ivie
;;    [e-mail] (internet)
;;    35 South 300 West
;;    Logan, Utah 84321
;;
;;
;;      If you have questions regarding the STAR port, or about the
;;   STAR Macro assembler, write to:
;;
;;    Jan Brittenson <[e-mail]>
;;
;;
;;--

; Define symbols for the registers. Note that the scheme assumes that
; data will never be bigger than 12 bits.

    v0=x'0f000
    v1=x'0f001
    v2=x'0f002
    v3=x'0f003
    v4=x'0f004
    v5=x'0f005
    v6=x'0f006
    v7=x'0f007
    v8=x'0f008
    v9=x'0f009
    va=x'0f00a
    vb=x'0f00b
    vc=x'0f00c
    vd=x'0f00d
    ve=x'0f00e
    vf=x'0f00f

    hide    v0
    hide    v1
    hide    v2
    hide    v3
    hide    v4
    hide    v5
    hide    v6
    hide    v7
    hide    v8
    hide    v9
    hide    va
    hide    vb
    hide    vc
    hide    vd
    hide    ve
    hide    vf

    __instrhi=0
    __instrlo=0

    hide    __instrhi
    hide    __instrlo

;-------
;
;    Other-endian DW

    macro __dw value=0

    value = $value
    byte    value >> 8 & 0xff, value & 0xff

    endmacro

    hide    __dw

;-------
;
;    Clear screen:
;
;    CLS

    macro    cls
    __dw    0x00e0
    endmacro

    hide    cls

;-------
;
;    Return from subroutine:
;
;    RET
;    RETURN

    macro    ret
    __dw    0x00ee
    endmacro

    macro    return
    __dw    0x00ee
    endmacro

    hide    ret
    hide    return

;-------
;
;    Jump to location:
;
;    JUMP <addr>
;    JUMP <addr>+V0

    macro    jump dest

    dest=$dest

    if dest >= v0
      __dw    dest & 0x0fff + 0x0b000
    else        ;; Otherwise, it's JUMP <addr>
      __dw    dest + 0x01000
    endif

    endmacro

    hide    jump

;-------
;
;    Call a subroutine:
;
;    CALL <addr>
;

    macro    call  dest

      __dw    $dest + 0x02000

    endmacro

    hide    call

;-------
;
;    Skip if equal:
;
;    SKE Vx,<constant>
;    SKE Vx,Vy

    macro    ske x, y

    x = $x
    y = $y

    if x >= v0    ;; Verify first operand is a register
      if y >= v0    ;; It's SKE Vx,Vy

        __dw ((x & 0xf) << 8) + ((y & 0xf) << 4) + 0x5000
      else
        __dw ((x & 0xf) << 8) + y + 0x3000
      endif
    else
      error The first operand of SKE must be a register, not `$x'
      data.4  0
    endif

    endmacro

    hide    ske

;-------
;
;    Skip if not equal:
;
;    SKNE Vx,<constant>
;    SKNE Vx,Vy

    macro    skne x, y

    x = $x
    y = $y

    if x >= v0    ;; Verify first operand is a register
      if y >= v0    ;; It's SKNE Vx,Vy

        __dw ((x & 0xf) << 8) + ((y & 0xf) << 4) + 0x9000

      else        ;; It's SKNE Vx,<constant>

        __dw ((x & 0xf) << 8) + y + 0x4000
      endif
    else
      error The first operand of SKNE must be a register, not `$x'
      data.4  0
    endif

    endmacro

    hide    skne

;-------
;
;    Register transfer:
;
;    LD Vx,<constant>
;    LD Vx,Vy
;    LD I,<constant>
;    LD Vx,DELAY
;    LD DELAY,Vx
;    LD SOUND,Vx
;    LD BCD,Vx
;    LD @I,Vx
;    LD Vx,@I

    macro    ld dest, src

    if uc^dest == `I'    ;; It's LD I,?
      if ($src) < v0    ;;   Source has to be a constant

        __dw  ($src) + 0xa000
      else
        error I can only be loaded from a constant, not `$src'
        data.4  0
      endif
    else            ;; *1*

    if uc^dest == `DELAY'    ;; It's LD DELAY,?
      if ($src) >= v0    ;;   Source has to be a register

        __dw ($src) & 0xf << 8 + 0xf015
      else
        error DELAY can only be loaded from a register, not `$src'
        data.4  0
      endif
    else            ;; *2*

    if uc^src == `DELAY'    ;; It's LD ?,DELAY
      if ($dest) >= v0    ;;   Destination has to be a register

        __dw  ($dest) & 0xf << 8 + 0xf007
      else
        error Only a register can be loaded from DELAY, not `$src'
        data.4  0
      endif
    else            ;; *3*

    if uc^dest == `SOUND'    ;; It's LD SOUND,?
      if ($src) >= v0    ;;   Source has to be a register

        __dw ($src) & 0xf << 8 + 0xf018
      else
        error SOUND can only be loaded from a register, not `$src'
        data.4  0
      endif
    else            ;; *4*

    if uc^dest == `BCD'    ;; It's LD BCD,?
      if ($src) >= v0    ;; Source has to be a register

        __dw  ($src) & 0xf << 8 + 0xf033
      else
        error BCD can only be loaded from a register, not `$src'
        data.4  0
      endif
    else            ;; *5*

    if uc^dest == `@I'    ;; It's LD @I,?
      if src >= v0        ;; Source has to be a register

        __dw ($src) & 0xf << 8 + 0xf055
      else
        error @I can only be loaded from a register, not `$src'
        data.4  0
      endif
    else            ;; *6*

    if uc^src == `@I'    ;; It's LD ?,@I
      if ($dest) >= v0    ;; Destination as to be a register

        __dw  ($dest) & 0xf << 8 + 0xf065
      else
        error Only a register can be loaded from @I, not `$dest'
        data.4  0
      endif

    else            ;; *7*

;; If we get here, it should be either LD Vx,Vy or LD Vx,<constant>

    dest = $dest
    src = $src

    if dest >= v0        ;; Make certain destination is a register
      if src < v0        ;;   It's LD Vx,<constant>

        __dw dest & 0xf << 8 + src + 0x6000

      else            ;;   It has to be LD Vx,Vy

        __dw dest & 0xf << 8 + (src & 0xf << 4) + 0x8000
      endif
    else
      error Invalid LD instruction
      data.4  0

    endif

    endif
    endif
    endif
    endif
    endif
    endif
    endif

    endmacro

    hide    ld

;-------
;
;    Add two operands:
;
;    ADD Vx,<constant>
;    ADD Vx,Vy
;    ADD I,Vx

    macro    add dest, src

    src  = $src

    if uc^dest == `I'    ;; It's ADD I,Vx
      if src >= v0        ;;   Verify that the source is a register

        __dw src & 0xf << 8 + 0xf01e
      else
        error Only a register can be added to I, not `$src'
        data.4  0
      endif
    else            ;; *1*

;; It has to be either ADD Vx,Vy or ADD Vx,<constant>

    dest = $dest

    if dest >= v0        ;; Verify that the destination is a register
          if src >= v0        ;;   It's ADD Vx,Vy

        __dw dest & 0xf << 8 + (src & 0xf << 4) + 0x8004

      else            ;;   It's ADD Vx,<constant>

        __dw dest & 0xf << 8 + src + 0x7000
      endif
    else
      error Things can be ADDed only to I or to a register, not `$dest'
      data.4  0
    endif

    endif

    endmacro

    hide    add

;-------
;
;    Inclusive or:
;
;    OR Vx,Vy

    macro    or dest,src

    dest = $dest
    src = $src

    if (dest >= v0) && (src >= v0)
      __dw ((dest & 0xf) << 8) + ((src & 0xf) << 4) + 0x8001
    else
      error Both operands must be registers
      data.4  0
    endif

    endmacro

    hide    or

;-------
;
;    Bitwise and:
;
;    AND Vx,Vy

    macro    and dest,src

    dest = $dest
    src = $src

    if (dest >= v0) && (src >= v0)
      __dw ((dest & 0xf) << 8) + ((src & 0xf) << 4) + 0x8002
    else
      error Both operands must be registers
      data.4  0
    endif

    endmacro

    hide    and

;-------
;
;    Bitwise exclusive or:
;
;    XOR Vx,Vy

    macro    xor dest,src

    dest = $dest
    src = $src

    if (dest >= v0) && (src >= v0)

      __dw ((dest & 0xf) << 8) + ((src & 0xf) << 4) + 0x8003
    else
      error Both operands must be registers
      data.4 0
    endif

    endmacro

    hide    xor

;-------
;
;    Subtract:
;
;    SUB Vx,Vy

    macro    sub dest,src

    dest = $dest
    src = $src

    if (dest >= v0) && (src >= v0)
      __dw  ((dest & 0xf) << 8) + ((src & 0xf) << 4) + 0x8005
    else
      error Both operands must be registers
      data.4  0
    endif
    endmacro

    hide    sub

;-------
;
;    Shift right:
;
;    SHR Vx,Vy

    macro    shr dest,src

    dest = $dest
    src = $src

    if (dest >= v0) && (src >= v0)
      __dw  ((dest & 0xf) << 8) + ((src & 0xf) << 4) + 0x8006
    else
      error Both operands must be registers
      data.4  0
    endif
    endmacro

    hide    shr

;-------
;
;    Reverse subtract:
;
;    RSUB Vx,Vy

    macro    rsub dest,src

    dest = $dest
    src = $src

    if (dest >= v0) && (src >= v0)
      __dw  ((dest & 0xf) << 8) + ((src & 0xf) << 4) + 0x8007
    else
      error Both operands must be registers
      data.4  0
    endif

    endmacro

    hide    rsub

;-------
;
;    Shift left:
;
;    SHL Vx,Vy

    macro    shl dest,src

    dest = $dest
    src = $src

    if (dest >= v0) && (src >= v0)
      __dw ((dest & 0xf) << 8) + ((src & 0xf) << 4) + 0x800E
    else
      error Both operands must be registers
      data.4  0
    endif
    endmacro

    hide    shl

;-------
;
;    And constant and random number:
;
;    RANDOM Vx        ; Uses 0FFH for constant
;    RANDOM Vx,<constant>

    macro    random dest,mask=``nil''

    dest = $dest
    mask = $mask

    if dest >= v0
          if mask == `nil'
        __dw ((dest & 0xf) << 8) + 0xc0ff
      else
        __dw ((dest & 0xf) << 8) + mask + 0xc000
      endif
    else
      error First operand must be a register, not `$dest'
      data.4 0
    endif
    endmacro

    hide    random

;-------
;
;    Show sprite:
;
;    SHOW Vx,Vy,N

    macro    show x,y,n

    x = $x
    y = $y
    n = $n

    if (x >= v0) && (y >= v0)
      __DW ((x & 0xf) << 8) + ((y & 0xf) << 4) + (n & 0xf) + 0xd000
    else
      error Coordinates must be registers
      data.4  0
    endif

    endmacro

    hide    show

;-------
;
;    Skip if key pressed:
;
;    SKIFKEY Vx

    macro    skifkey dest

    dest = $dest

    if dest >= v0
      __dw  ((dest & 0xf) << 8) + 0xe09e
    else
      error Destination must be a register
      data.4  0
    endif

    endmacro

    hide    skifkey

;-------
;
;    Skip if key not pressed:
;
;    SKIFNOTKEY Vx

    macro    skifnotkey dest

    dest = $dest

    if dest >= v0
      __dw ((dest & 0xf) << 8) + 0xe0a1
    else
      error Destination must be a register, not `$dest'
      data.4  0
    endif

    endmacro

    hide    skifnotkey

;-------
;
;    Get a keystroke:
;
;    GETKEY Vx

    macro    getkey dest

    dest = $dest

    if dest >= v0
      __dw  ((dest & 0xf) << 8) + 0xf00a
    else
      error Destination must be a register, not `$dest'
      data.4  0
    endif
    endmacro

    hide    getkey

;-------
;
;    Point to character font element:
;
;    CHAR Vx

    macro    char src

    src = $src

    if src >= v0
      __dw  src & 0xf << 8 + 0xf029
    else
      error Source must be a register
      data.4  0
    endif
    endmacro

    hide    char


    chip8loaded = 1
    hide    chip8loaded

    static    0, x'1ff
    floating x'200, x'ffff


    endif

    . = x'200

    hide    list
    restore    list