ProfitPress Mega CDROM2 …eeware (MSDOS)(1992)(Eng)/ProfitPress-MegaCDROM2.B6I/MISC/NETWORK/PCBRI120.ZIP/MEMORY.INC

Text File | 1991-02-19 | 6.0 KB | 174 lines

;;******************************************************************************
;;                         memory.inc      memory.inc
;;******************************************************************************
;;
;;  Copyright (C) 1990 Vance Morrison
;;
;;
;; Permission to view, compile, and modify for LOCAL (intra-organization)
;; USE ONLY is hereby granted, provided that this copyright and permission
;; notice appear on all copies.  Any other use by permission only.
;;
;; Vance Morrison makes no representations about the suitability
;; of this software for any purpose.  It is provided "as is" without expressed
;; or implied warranty.  See the copywrite notice file for complete details.
;;
;;******************************************************************************
;;
;; In order to do fast 16 bit transfers between cards with shared memory
;; we need to tell each card that it can use all 16 bits.  Unforunately,
;; we can't leave this on all the time (because this bit is shared among
;; hardward that may want it unasserted).  Thus before each transfer, the
;; source and destination card need to be places in 16 bit mode.
;;
;; Because in PCroute determining the destination card is difficult, and
;; since it is unlikely that there will be configurations with a mix
;; of 8 and 16 bit shared memory cards, we take a simplified view.
;; Namely if any 8 bit shared memory boards exist, everyone does 8 bit
;; transfers all the time.  If all boards are 16 bit, then before any copy,
;; all cards are placed in 16 bit mode.   ZZ

;; of networking cards is not transparent (at least not with the WD8013EBT).
;; because of this, we need to toggle 16bit mode when it is necessary
;; (it is also necessary to do this with interupts disabled, which also
;; requires special processing).  memory.inc provides functions that allow
;; this toggling to be done automatically.
;;
;;******************************************************************************
;;
;; functions provided by this module are
;;
;;   MEM_DECLARE_16BIT on_macro, off_macro
;;   MEM_DECLARE_8BIT
;;   MEM_DECLARE_NEED_INTS lantency
;;   MEM_COPY_in_CX_SI_DI_ES_out_SI_DI_const_AX_BX_DX_BP_ES
;;
;;******************************************************************************

mem_num_16bit = 0
mem_num_8bit = 0
mem_min_latency = -1


;;******************************************************************************
;;  MEM_DECLARE_16BIT declares the fact that a 16 bit shared memory card
;;  exists in the system.  'on_macro' turns 16 bit mode on for that card`
;;  'off_macro' turns it off.  Interfaces that use main memory for buffering
;;  need not be declared.  Note that on and off macros CAN ONLY MODIFY
;;  THE AX AND DX REGISTERS

MEM_DECLARE_16BIT MACRO on_macro, off_macro

    mem_num_16bit = mem_num_16bit + 1

    HELPER MACRO num
        mem_16bit_&&num&&_on  equ <on_macro>
        mem_16bit_&&num&&_off equ <off_macro>
    ENDM

    HELPER %mem_num_16bit
ENDM


;;******************************************************************************
;; MEM_DECLARE_NEED_INTS declares the fact that there is an interface
;; that uses interupts that need to be serviced quickly, so interupts
;; cannot remain disabled for long times.  'lantency' is the worst case
;; latency required measured in usec.  For example a SLIP line at 19.2K
;; baud requires that interupts be serviced in 500 us.
;;

MEM_DECLARE_NEED_INTS MACRO latency
    if mem_min_latency gt latency       ;; take the minimum
        mem_min_latency = latency
    endif
ENDM


;;******************************************************************************
;;  MEM_DECLARE_8BIT declares the fact that a 8 bit shared memory card
;;  exists in the system.   In this implementation, this means don't ever
;;  use 16 bit mode at all.

MEM_DECLARE_8BIT MACRO
    mem_num_8bit = 1
ENDM


;;******************************************************************************
;; MEM_COPY_in_CX_SI_DI_ES_out_SI_DI does the copy operation.  It requires
;; that SI and DI are EVEN.   This function is esentially a 'rep movsw'
;; with added functionality that enables 16bit bus transfers if possible.
;;

MEM_COPY_in_CX_SI_DI_ES_out_SI_DI_const_AX_BX_DX_BP_ES MACRO
    local copy_loop, done

    inc CX
    shr CX, 1
    if (mem_num_8bit eq 0) and (mem_num_16bit gt 0)
        push AX
        push DX
        if mem_min_latency lt 0
            cli
            MEM_ALL_16BIT_ON_const_BX_CX_BP_SI_DI_ES
            rep
            movsw
            MEM_ALL_16BIT_OFF_const_BX_CX_BP_SI_DI_ES
            sti
        else
                ;; really should copy in pieces, but I don't have
                ;; the time to code it.  for now we just give up
                ;; on 16 bit access
            rep
            movsw
        endif
        pop DX
        pop AX
    else
        rep
        movsw
    endif
ENDM


;;****************************************************************************
;; These macros call the stored on_macro and off_macro respectively

MEM_ALL_16BIT_ON_const_BX_CX_BP_SI_DI_ES MACRO
    irp idx,<1,2,3,4,5,6,7,8>
    if idx le mem_num_16bit
        MEM_16BIT_ON_const_BX_CX_BP_SI_DI_ES idx
    endif
    endm
ENDM

;;****************************************************************************

MEM_ALL_16BIT_OFF_const_BX_CX_BP_SI_DI_ES MACRO
    irp idx,<1,2,3,4,5,6,7,8>
    if idx le mem_num_16bit
        MEM_16BIT_OFF_const_BX_CX_BP_SI_DI_ES idx
    endif
    endm
ENDM

;;****************************************************************************
MEM_16BIT_ON_const_BX_CX_BP_SI_DI_ES MACRO num
    HELPER MACRO name
        name
    ENDM

    HELPER %mem_16bit_&num&_on
ENDM

;;****************************************************************************
MEM_16BIT_OFF_const_BX_CX_BP_SI_DI_ES MACRO num
    HELPER MACRO name
        name
    ENDM

    HELPER %mem_16bit_&num&_off
ENDM