Virtual Reality Homebrewer's Handbook/vr.iso/vr386/pwrglvio.asm

Assembly Source File | 1996-03-19 | 6KB | 332 lines

    TITLE    GLOVEDEL - Powerglove timing and i/o support
    NAME    GLOVEDEL

    ; SPECIAL VERSION FOR COMBO GLOVE/SEGA DRIVER PORTS
    ; rewritten 20/12/93

    COMMENT    $

/*
 This code is part of the VR-386 project, created by Dave Stampe.
 VR-386 is a desendent of REND386, created by Dave Stampe and
 Bernie Roehl.  Almost all the code has been rewritten by Dave
 Stampre for VR-386.

 Copyright (c) 1994 by Dave Stampe:
 May be freely used to write software for release into the public domain
 or for educational use; all commercial endeavours MUST contact Dave Stampe
 ([e-mail]) for permission to incorporate any part of
 this software or source code into their products!  Usually there is no
 charge for under 50-100 items for low-cost or shareware products, and terms
 are reasonable.  Any royalties are used for development, so equipment is
 often acceptable payment.

 ATTRIBUTION:  If you use any part of this source code or the libraries
 in your projects, you must give attribution to VR-386 and Dave Stampe,
 and any other authors in your documentation, source code, and at startup
 of your program.  Let's keep the freeware ball rolling!

 DEVELOPMENT: VR-386 is a effort to develop the process started by
 REND386, improving programmer access by rewriting the code and supplying
 a standard API.  If you write improvements, add new functions rather
 than rewriting current functions.  This will make it possible to
 include you improved code in the next API release.  YOU can help advance
 VR-386.  Comments on the API are welcome.

 CONTACT: [e-mail]
*/

Algorithms, assembler by Dave Stampe, 22/12/93

        $

        .MODEL large
        .386

        .DATA

extrn   _counts_per_tick      ; MUST contain value programmed into timer

EXTRN    _glove_in_port        ; GLOVE INTERFACE SPECS
EXTRN    _glove_out_port         ; SET UP IN C CODE

EXTRN    _glove_none_mask
EXTRN    _glove_data_mask
EXTRN    _glove_latch_mask
EXTRN    _glove_clock_mask
EXTRN    _glove_clock_latch

EXTRN    _glove_bit_delay

EXTRN    _port_image
EXTRN     _glove_write_mask


    .CODE devices


READ_TIMER     MACRO    ; result will be in ax
    pushf
    cli
    mov    al,00h            ;/* read PC timer */
    out    043h,al
    nop
    nop
    in    al,040h
    mov    ah,al
    nop
    nop
    in    al,040h
    xchg    al,ah
    popf
    ENDM

WRITE_TIMER     MACRO    ; write from BX
    pushf
    cli
    mov    al,34h
    out    43h,al    ; prepare for write
    xor    al,al
    nop
    mov    al,bl
    out    40h,al
    nop
    mov    al,bh
    out    40h,al
    popf
    ENDM



; bit delay macro for byte read, line toggle

bitdelay macro
    local _localloop
    mov    cx,_glove_bit_delay
_localloop:
    in    al,41h
    loop    _localloop
endm



 ;
 ; int timed_glove_delay(int count);  /* returns time in 1.1925 MHZ ticks */
 ;                                    /* to perform <count> delay steps   */

        PUBLIC    _timed_glove_delay

count equ [bp+6]

_timed_glove_delay    proc    far

    push    bp
    mov    bp,sp
    push    cx
    push    dx
    pushf

    mov    bx,0        ; reset timer for no ovf
    WRITE_TIMER             ; this changes timing by factor of 2?

    cli
    READ_TIMER
    mov    bx,ax

    mov    cx,count
caloop: in      al,40h        ; do delay
    loop    caloop

    READ_TIMER
    sub    ax,bx           ; assumes default, count rollover at 65536
    neg    ax

    push    ax
    mov    bx,_counts_per_tick    ; restore timer
    WRITE_TIMER
    pop    ax

    popf
    pop    dx
    pop    cx
    mov    sp,bp
    pop    bp
    ret

_timed_glove_delay    endp


 ;
 ; int glove_delay(int count);    /* performs <count> delay steps   */
 ;

        PUBLIC    _glove_delay

count equ [bp+6]

_glove_delay    proc    far

    push    bp
    mov    bp,sp
    push    cx
    push    dx
    mov    cx,count

gdel:    in    al,41h
    loop    gdel

    pop    dx
    pop    cx
    mov    sp,bp
    pop    bp
    ret

_glove_delay    endp



 ;
 ; int get_glove_byte();    /* reads a byte from glove */
 ;

        PUBLIC    _get_glove_byte

_get_glove_byte    proc    far

    push    bp
    mov    bp,sp
    push    si
    push    cx
    push    dx

    mov    dx,_glove_out_port
    mov    si,_glove_in_port

    mov    ax,_glove_clock_mask    ; preset lines
    pushf
    cli
    mov    ah,BYTE PTR _glove_write_mask
    not    ah
    and    ah,BYTE PTR _port_image
    or    al,ah
    mov    BYTE PTR _port_image,al
    out    dx,al                   ; output data
    popf
    bitdelay

    mov    ax,_glove_clock_latch
    pushf
    cli
    mov    ah,BYTE PTR _glove_write_mask
    not    ah
    and    ah,BYTE PTR _port_image
    or    al,ah
    mov    BYTE PTR _port_image,al
    out    dx,al                   ; output data
    popf
    bitdelay

    mov    ax,_glove_clock_mask
    pushf
    cli
    mov    ah,BYTE PTR _glove_write_mask
    not    ah
    and    ah,BYTE PTR _port_image
    or    al,ah
    mov    BYTE PTR _port_image,al
    out    dx,al                   ; output data
    popf
    bitdelay

    mov    bx,8000h                ; clear accumulator

bitloop:
    xchg    si,dx                   ; add bit to accumulator
    in    al,dx
    xchg    si,dx
    test    al,BYTE PTR _glove_data_mask
    jz    z0
    or    bl,bh
z0:                                     ; next bit
    shr    bh,1
    jz    endbyte

    mov    ax,_glove_none_mask     ; pulse clock line
    pushf
    cli
    mov    ah,BYTE PTR _glove_write_mask
    not    ah
    and    ah,BYTE PTR _port_image
    or    al,ah
    mov    BYTE PTR _port_image,al
    out    dx,al                   ; output data
    popf
    bitdelay

    mov    ax,_glove_clock_mask
    pushf
    cli
    mov    ah,BYTE PTR _glove_write_mask
    not    ah
    and    ah,BYTE PTR _port_image
    or    al,ah
    mov    BYTE PTR _port_image,al
    out    dx,al                   ; output data
    popf
    bitdelay
    jmp    bitloop

endbyte:
    mov    ax,bx
    xor    ah,ah
    pop    dx
    pop    cx
    pop    si
    mov    sp,bp
    pop    bp
    ret

_get_glove_byte    endp


 ;
 ; void set_glove_bits(int data);   /* sets glove clock, data lines */
 ;                                  /* and does a bit delay         */

        PUBLIC    _set_glove_bits

bits equ [bp+6]

_set_glove_bits    proc    far

    push    bp
    mov    bp,sp
    push    dx
    mov    dx,_glove_out_port
    mov    ax,bits

    pushf
    cli
    and    al,BYTE PTR _glove_write_mask
    mov    ah,BYTE PTR _glove_write_mask
    not    ah
    and    ah,BYTE PTR _port_image
    or    al,ah
    mov    BYTE PTR _port_image,al
    out    dx,al                   ; output data
    popf

    push    cx
    bitdelay
    pop    cx

    pop    dx
    mov    sp,bp
    pop    bp
    ret

_set_glove_bits    endp

        end