Chip 1994 February

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Assembly Source File | 1993-10-08 | 36.2 KB | 1,445 lines

include defs.asm ; Copyright, 1988-1993, Russell Nelson, Crynwr Software ; This program is free software; you can redistribute it and/or modify ; it under the terms of the GNU General Public License as published by ; the Free Software Foundation, version 1. ; ; This program is distributed in the hope that it will be useful, ; but WITHOUT ANY WARRANTY; without even the implied warranty of ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ; GNU General Public License for more details. ; ; You should have received a copy of the GNU General Public License ; along with this program; if not, write to the Free Software ; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. code segment word public assume cs:code, ds:code public phd_environ org 2ch phd_environ dw ? public phd_dioa org 80h phd_dioa label byte org 100h start: jmp start_1 extrn start_1: near db "PK" extrn branding_msg: byte dw branding_msg even ;put the stack on a word boundary. dw 128 dup(?) ;128 words of stack. our_stack label byte extrn int_no: byte public entry_point, sys_features, flagbyte, is_186, is_286, is_386 entry_point db ?,?,?,? ; interrupt to communicate. sys_features db 0 ; 2h = MC 40h = 2nd 8259 is_186 db 0 ;=0 if 808[68], =1 if 80[123]86. is_286 db 0 ;=0 if 80[1]8[68], =1 if 80[234]86. is_386 db 0 ;=0 if 80[12]8[68], =1 if 80[34]86. flagbyte db 0 original_mask db 0 ;=0 if interrupt was originally on. even functions label word dw f_not_implemented ;0 dw f_driver_info ;1 dw f_access_type ;2 dw f_release_type ;3 dw f_send_pkt ;4 dw f_terminate ;5 dw f_get_address ;6 dw f_reset_interface ;7 dw f_stop ;8 dw f_not_implemented ;9 dw f_get_parameters ;10 dw f_not_implemented ;11 dw f_as_send_pkt ;12 dw f_drop_pkt ;13 dw f_not_implemented ;14 dw f_not_implemented ;15 dw f_not_implemented ;16 dw f_not_implemented ;17 dw f_not_implemented ;18 dw f_not_implemented ;19 dw f_set_rcv_mode ;20 dw f_get_rcv_mode ;21 dw f_set_multicast_list ;22 dw f_get_multicast_list ;23 dw f_get_statistics ;24 dw f_set_address ;25 ;external data supplied by device-dependent module: extrn driver_class: byte extrn driver_type: byte extrn driver_name: byte extrn driver_function: byte extrn parameter_list: byte extrn rcv_modes: word ;count of modes followed by mode handles. ;external code supplied by device-dependent module: extrn send_pkt: near extrn as_send_pkt: near extrn drop_pkt: near extrn set_address: near extrn terminate: near extrn reset_interface: near extrn xmit: near extrn recv: near extrn etopen: near extrn set_multicast_list: near extrn timer_isr: near per_handle struc in_use db 0 ;non-zero if this handle is in use. packet_type db MAX_P_LEN dup(0);associated packet type. packet_type_len dw 0 ;associated packet type length. receiver dd 0 ;receiver handler. receiver_sig db 8 dup(?) ;signature at the receiver handler. class db ? ;interface class per_handle ends handles per_handle MAX_HANDLE dup(<>) end_handles label byte public multicast_count, multicast_addrs, multicast_broad multicast_count dw 0 ;count of stored multicast addresses. multicast_broad db 0ffh,0ffh,0ffh,0ffh,0ffh,0ffh ; entry for broadcast multicast_addrs db MAX_MULTICAST*EADDR_LEN dup(?) ;the device-dependent code reads the board's address from ROM in the ;initialization code. public address_len, rom_address, my_address address_len dw EADDR_LEN ;default to Ethernet. rom_address db MAX_ADDR_LEN dup(?) ;our address in ROM. my_address db MAX_ADDR_LEN dup(?) ;our current address. rcv_mode_num dw 3 free_handle dw 0 ; temp, a handle not in use found_handle dw 0 ; temp, handle for our packet receive_ptr dd 0 ; the pkt receive service routine public send_head, send_tail send_head dd 0 ; head of transmit queue send_tail dd 0 ; tail of transmit queue statistics_list label dword packets_in dw ?,? packets_out dw ?,? bytes_in dw ?,? bytes_out dw ?,? errors_in dw ?,? errors_out dw ?,? packets_dropped dw ?,? ;dropped due to no type handler. savespss label dword savesp dw ? ;saved during the stack swap. savess dw ? their_recv_isr dd 0 ; original owner of board int their_timer dd 0 ; ; The following structure is used to access the registers pushed by the ; packet driver interrupt handler. Don't change this structure without also ; changing the "bytes" structure given below. ; regs struc ; stack offsets of incoming regs _ES dw ? _DS dw ? _BP dw ? _DI dw ? _SI dw ? _DX dw ? _CX dw ? _BX dw ? _AX dw ? _IP dw ? _CS dw ? _F dw ? ; flags, Carry flag is bit 0 regs ends ; ; bits in the _F register. ; CY equ 0001h EI equ 0200h ; ; This structure is a bytewise version of the "regs" structure above. ; bytes struc ; stack offsets of incoming regs dw ? ; es, ds, bp, di, si are 16 bits dw ? dw ? dw ? dw ? _DL db ? _DH db ? _CL db ? _CH db ? _BL db ? _BH db ? _AL db ? _AH db ? bytes ends public their_isr their_isr dd 0 ; original owner of pkt driver int public our_isr our_isr: jmp short our_isr_0 ;the required signature. nop db 'PKT DRVR',0 our_isr_open: push ax ; save lots of registers push bx push cx push dx push si push di push bp push ds push es call etopen ; init the card jc our_isr_no_init mov si,offset rom_address ;copy their original address to movseg es,ds mov di,offset my_address ; their current address. mov cx,MAX_ADDR_LEN/2 rep movsw cmp rcv_modes+2[3*2],0 ;does mode 3 exist? stc ;make sure we generate an error! je our_isr_no_init ;no. call rcv_modes+2[3*2] ; call it. clc our_isr_no_init: pop es ; restore lots of registers pop ds pop bp pop di pop si pop dx pop cx pop bx pop ax mov dh,CANT_RESET ; (actually can't initialize) jc our_isr_error or flagbyte,CALLED_ETOPEN ; remember this fact jmp short our_isr_cont our_isr_0: assume ds:nothing push ax push bx push cx push dx push si push di push bp push ds push es cld mov bx,cs ;set up ds. mov ds,bx assume ds:code mov bp,sp ;we use bp to access the original regs. and _F[bp],not CY ;start by clearing the carry flag. if 0 test _F[bp],EI ;were interrupt on? jz our_isr_ei ;no, don't turn them back on. sti ;yes, turn them back on. our_isr_ei: endif test flagbyte,CALLED_ETOPEN ; have we initialized the card? jz our_isr_open ; no our_isr_cont: mov bl,ah ;jump to the correct function. xor bh,bh cmp bx,25 ;only twenty five functions right now. ja f_bad_command add bx,bx ;*2 ; ; The functions are called with all the original registers except ; BX, DH, and BP. They do not need to preserve any of them. If the ; function returns with cy clear, all is well. Otherwise dh=error number. ; call functions[bx] assume ds:nothing jc our_isr_error our_isr_return: pop es pop ds pop bp pop di pop si pop dx pop cx pop bx pop ax iret our_isr_error: assume ds:nothing mov bp,sp ;we use bp to access the original regs. mov _DH[bp],dh or _F[bp],CY ;return their carry flag. jmp short our_isr_return f_bad_command: assume ds:code extrn bad_command_intercept: near mov bx,_BX[bp] call bad_command_intercept mov _BX[bp],bx mov _DX[bp],dx jnc our_isr_return jmp our_isr_error public re_enable_interrupts re_enable_interrupts: ; Possibly re-enable interrupts. We put this here so that other routines ; don't need to know how we put things on the stack. test _F[bp], EI ; Were interrupts enabled on pkt driver entry? je re_enable_interrupts_1 ; No. sti ; Yes, re-enable interrupts now. re_enable_interrupts_1: ret f_not_implemented: mov dh,BAD_COMMAND stc ret f_driver_info: ; As of 1.08, the handle is optional, so we no longer verify it. ; call verify_handle cmp _AL[bp],0ffh ; correct calling convention? jne f_driver_info_1 ; ne = incorrect, fail ;For enhanced PD, if they call cmp _BX[bp],offset handles ;with a handle, give them the ;class they think it is jb default_handle cmp _BX[bp],offset end_handles ;otherwise default to first class jae default_handle mov bx, _BX[bp] cmp [bx].in_use,0 ;if it's not in use, it's bad. je default_handle mov al, [bx].class mov _CH[bp], al jmp short got_handle default_handle: mov al,driver_class mov _CH[bp],al got_handle: mov _BX[bp],majver ;version mov al,driver_type cbw mov _DX[bp],ax mov _CL[bp],0 ;number zero. mov _DS[bp],ds ; point to our name in their ds:si mov _SI[bp],offset driver_name mov al,driver_function mov _AL[bp],al clc ret f_driver_info_1: stc ret f_set_rcv_mode: call verify_handle cmp cx,rcv_mode_num ;are we already using that mode? je f_set_rcv_mode_4 ;yes, no need to check anything. mov dx,bx ;remember our handle. call count_handles ;is ours the only open handle? cmp cl,1 jne f_set_rcv_mode_1 ;no, don't change the receive mode. mov cx,_CX[bp] ;get the desired receive mode. cmp cx,rcv_modes ;do they have this many modes? jae f_set_rcv_mode_1 ;no - must be a bad mode for us. mov bx,cx add bx,bx ;we're accessing words, not bytes. mov ax,rcv_modes[bx]+2 ;get the handler for this mode. or ax,ax ;do they have one? je f_set_rcv_mode_1 ;no - must be a bad mode for us. mov rcv_mode_num,cx ;yes - remember the number and call ax ; call it. f_set_rcv_mode_4: clc ret f_set_rcv_mode_1: mov dh,BAD_MODE stc ret f_get_rcv_mode: call verify_handle mov ax,rcv_mode_num ;return the current receive mode. mov _AX[bp],ax clc ret f_set_multicast_list: ;following instruction not needed because cx hasn't been changed. ; mov cx,_CX[bp] ;Tell them how much room they have. ;verify that they supplied an even number of EADDR's. mov ax,cx xor dx,dx mov bx,EADDR_LEN div bx or dx,dx ;zero remainder? jne f_set_multicast_list_2 ;no, we don't have an even number of ; addresses. cmp ax,MAX_MULTICAST ;is this too many? ja f_set_multicast_list_3 ;yes - return NO_SPACE f_set_multicast_list_1: mov multicast_count,ax ;remember the number of addresses. movseg es,cs mov di,offset multicast_addrs push ds mov ds,_ES[bp] ; get ds:si -> new list. mov si,_DI[bp] push cx rep movsb pop cx pop ds mov si,offset multicast_addrs call set_multicast_list ret f_set_multicast_list_2: mov dh,BAD_ADDRESS stc ret f_set_multicast_list_3: mov dh,NO_SPACE stc ret f_get_multicast_list: mov _ES[bp],ds ;return what we have remembered. mov _DI[bp],offset multicast_addrs mov ax,EADDR_LEN ;multiply the count by the length. mul multicast_count mov _CX[bp],ax ;because they want total bytes. clc ret f_get_statistics: call verify_handle ;just in case. mov _DS[bp],ds mov _SI[bp],offset statistics_list clc ret access_type_class: mov dh,NO_CLASS stc ret access_type_type: mov dh,NO_TYPE stc ret access_type_number: mov dh,NO_NUMBER stc ret access_type_bad: mov dh,BAD_TYPE stc ret ;register caller of pkt TYPE f_access_type: mov bx, offset driver_class access_type_9: mov al, [bx] ;get the next class. inc bx or al,al ;end of the list? je access_type_class ;class failed (story of my life) cmp _AL[bp],al ;our class? jne access_type_9 ;no, try again access_type_1: cmp _BX[bp],-1 ;generic type? je access_type_2 ;yes. mov al,driver_type cbw cmp _BX[bp],ax ;our type? jne access_type_type ;no. access_type_2: cmp _DL[bp],0 ;generic number? je access_type_3 cmp _DL[bp],1 ;our number? jne access_type_number access_type_3: cmp _CX[bp],MAX_P_LEN ;is the type length too long? ja access_type_bad ;yes - can't be ours. ; now we do two things--look for an open handle, and check the existing ; handles to see if they're replicating a packet type. mov free_handle,0 ;remember no free handle yet. mov bx,offset handles access_type_4: cmp [bx].in_use,0 ;is this handle in use? je access_type_5 ;no - don't check the type. mov al, _AL[bp] ;is this handle the same class as cmp al, [bx].class ; they're want? jne short access_type_6 mov es,_DS[bp] ;get a pointer to their type mov di,_SI[bp] ; from their ds:si to our es:di mov cx,_CX[bp] ;get the minimum of their length ; and our length. As currently ; implemented, only one receiver ; gets the packets, so we have to ; ensure that the shortest prefix ; is unique. cmp cx,[bx].packet_type_len ;Are we less specific than they are? jb access_type_8 ;no. mov cx,[bx].packet_type_len ;yes - use their count. access_type_8: lea si,[bx].packet_type or cx,cx ; pass-all TYPE? (zero TYPE length) jne access_type_7 ; ne = no mov bx,offset handles+(MAX_HANDLE-1)*(size per_handle) jmp short access_type_5 ; put pass-all last access_type_7: repe cmpsb jne short access_type_6 ;go look at the next one. access_type_inuse: mov dh,TYPE_INUSE ;a handle has been assigned for TYPE stc ;and we can't assign another ret access_type_5: ;handle is not in use cmp free_handle,0 ;found a free handle yet? jne access_type_6 ;yes. mov free_handle,bx ;remember a free handle access_type_6: add bx,(size per_handle) ;go to the next handle. cmp bx,offset end_handles ;examined all handles? jb access_type_4 ;no, continue. mov bx,free_handle ;did we find a free handle? or bx,bx je access_type_space ;no - return error. mov [bx].in_use,1 ;remember that we're using it. mov ax,_DI[bp] ;remember the receiver type. mov [bx].receiver.offs,ax mov ax,_ES[bp] mov [bx].receiver.segm,ax push ds mov ax,ds mov es,ax mov ds,_DS[bp] ;remember their type. mov si,_SI[bp] mov cx,_CX[bp] mov es:[bx].packet_type_len,cx ; remember the TYPE length lea di,[bx].packet_type rep movsb lds si,es:[bx].receiver ;copy the first 8 bytes lea di,[bx].receiver_sig ; to the receiver signature. mov cx,8/2 rep movsw pop ds mov al, _AL[bp] mov [bx].class, al mov _AX[bp],bx ;return the handle to them. clc ret access_type_space: mov dh,NO_SPACE stc ret f_release_type: call verify_handle ;mark this handle as being unused. mov [bx].in_use,0 call count_handles ;All handles gone now? cmp cl,0 jne f_release_type_1 ;no, don't change the receive mode. if 0 cmp rcv_modes+2[3*2],0 ;does mode 3 exist? je f_release_type_1 ;no. mov rcv_mode_num,3 ;yes - remember the number and call rcv_modes+2[3*2] ; call it. endif f_release_type_1: clc ret f_send_pkt: ;ds:si -> buffer, cx = length ; XXX Should re-enable interrupts here, but some drivers are broken. ; Possibly re-enable interrupts. ; test _F[bp], EI ; Were interrupts enabled on pkt driver entry? ; je f_send_pkt_1 ; No. ; sti ; Yes, re-enable interrupts now. ;f_send_pkt_1: ;following two instructions not needed because si and cx haven't been changed. ; mov si,_SI[bp] ; mov cx,_CX[bp] ; count of bytes in the packet. add2 packets_out,1 add2 bytes_out,cx ;add up the received bytes. mov ds,_DS[bp] ; address of buffer from caller's ds. assume ds:nothing, es:nothing ; If -n option take Ethernet encapsulated Novell IPX packets (from BYU's ; PDSHELL) and change them to be IEEE 802.3 encapsulated. EPROT_OFF equ EADDR_LEN*2 test cs:flagbyte,N_OPTION jnz f_send_pkt_2 call send_pkt ret f_send_pkt_2: cmp ds:[si].EPROT_OFF,3781h ; if not Novell (prot 8137) jne f_send_pkt_3 ; don't tread on it push ax ; get scratch reg mov ax,[si].EPROT_OFF+4 ; get len xchg ah,al inc ax ; make even (rounding up) and al,0feh xchg ah,al mov ds:[si].EPROT_OFF,ax ; save in prot field pop ax ; restore old contents f_send_pkt_3: call send_pkt ret assume ds:code f_as_send_pkt: ;es:di -> iocb. test driver_function,4 ; is this a high-performance driver? je f_as_send_pkt_2 ; no. ; Possibly re-enable interrupts. test _F[bp], EI ; Were interrupts enabled on pkt driver entry? je f_as_send_pkt_1 ; No. sti ; Yes, re-enable interrupts now. f_as_send_pkt_1: push ds ; set up proper ds for the buffer lds si,es:[di].buffer ; ds:si -> buffer assume ds:nothing mov cx,es:[di].len ; cx = length add2 packets_out,1 add2 bytes_out,cx ; add up the received bytes. ;ds:si -> buffer, cx = length, es:di -> iocb. call as_send_pkt pop ds assume ds:code ret f_as_send_pkt_2: mov dh, BAD_COMMAND ; return an error. stc ret f_drop_pkt: ; es:di -> iocb. test driver_function,4 ; is this a high-performance driver? je f_as_send_pkt_2 ; no. push ds ; Preserve ds mov si,offset send_head ; Get head offset dp_loop: mov ax,ds:[si] ; Get offset mov dx,ds:[si+2] ; Get segment mov bx,ax or bx,dx ; End of list? je dp_endlist ; Yes cmp ax,di ; Offsets equal? jne dp_getnext ; No mov bx,es cmp dx,bx ; Segments equal? jne dp_getnext ; No call drop_pkt ; Pass to driver les di,es:[di].next ; Get next segment:offset mov ds:[si],di ; Set next offset mov ds:[si+2],es ; Set next segment pop ds ; Restore ds clc ret dp_getnext: mov ds,dx ; Get next segment mov si,ax ; Get next iocb offset lea si,ds:[si].next ; Get next iocb next ptr offset jmp dp_loop ; Try again dp_endlist: pop ds ; Restore ds mov dh,BAD_IOCB ; Return error stc ; Set carry ret f_terminate: call verify_handle ; must have a handle mov [bx].in_use,0 ; mark handle as free call count_handles ; all handles gone? or cl,cl jne f_terminate_4 ; no, can't exit completely ; ; Now disable interrupts ; mov al,int_no or al,al ;are they using a hardware interrupt? je f_terminate_no_irq ;no. cmp original_mask,0 ;was it enabled? je f_terminate_no_mask ;yes, don't mask it now. call maskint f_terminate_no_mask: ; ; Now return the interrupt to their handler. ; mov ah,25h ;get the old interrupt into es:bx mov al,int_no add al,8 cmp al,8+8 ;is it a slave 8259 interrupt? jb f_terminate_3 ;no. add al,70h - (8+8) ;map it to the real interrupt. f_terminate_3: push ds lds dx,their_recv_isr int 21h pop ds f_terminate_no_irq: cmp their_timer.segm,0 ;did we hook the timer interrupt? je f_terminate_no_timer mov ax,2508h ;restore the timer interrupt. push ds lds dx,their_timer int 21h pop ds f_terminate_no_timer: call terminate ;terminate the hardware. mov al,entry_point ;release our_isr. mov ah,25h push ds lds dx,their_isr int 21h pop ds ; ; Now free our memory ; movseg es,cs mov ah,49h int 21h clc ret f_terminate_4: mov dh, CANT_TERMINATE stc ret f_get_address: ; call verify_handle ; mov es,_ES[bp] ; get new one ; mov di,_DI[bp] ; get pointer, es:di is ready ; mov cx,_CX[bp] ;Tell them how much room they have. cmp cx,address_len ;is there enough room for our address? jb get_address_space ;no. mov cx,address_len ;yes - get our address length. mov _CX[bp],cx ;Tell them how long our address is. mov si,offset my_address ;copy it into their area. rep movsb clc ret get_address_space: mov dh,NO_SPACE stc ret f_set_address: call count_handles cmp cl,1 ;more than one handle in use? ja f_set_address_inuse ;yes - we can't set the address mov cx,_CX[bp] ;get the desired address length. cmp ch,0 cmp cl,parameter_list[3] ;is it the right length? ja f_set_address_too_long ;no. mov ds,_ES[bp] ; set new one assume ds:nothing mov si,_DI[bp] ; set pointer, ds:si is ready mov ax,cs mov es,ax mov di,offset my_address rep movsb mov ds,ax ;restore ds. assume ds:code mov cx,_CX[bp] ;get the desired address length. mov si,offset my_address call set_address jc f_set_address_err ;Did it work? mov cl,parameter_list[3] xor ch,ch mov _CX[bp],cx ;yes - return our address length. clc ret f_set_address_inuse: mov dh,CANT_SET stc ret f_set_address_too_long: mov dh,NO_SPACE stc ret f_set_address_err: ;we get here with cy set - leave it set. mov si,offset rom_address ;we can't set the address, restore mov di,offset my_address ; to original. mov cx,MAX_ADDR_LEN/2 rep movsw ret f_reset_interface: call verify_handle call reset_interface clc ret ; Stop the packet driver doing upcalls. Also a following terminate will ; always succed (no in use handles any longer). f_stop: mov bx,offset handles f_stop_2: mov [bx].in_use,0 add bx,(size per_handle) ; next handle cmp bx,offset end_handles jb f_stop_2 clc ret f_get_parameters: ;strictly speaking, this function only works for high-performance drivers. test driver_function,4 ;is this a high-performance driver? jne f_get_parameters_1 ;yes. mov dh,BAD_COMMAND ;no - return an error. stc ret f_get_parameters_1: mov _ES[bp],cs mov _DI[bp],offset parameter_list clc ret count_handles: ;exit with cl = number of handles currently in use. mov bx,offset handles mov cl,0 ;number of handles in use. count_handles_1: add cl,[bx].in_use ;is this handle in use? add bx,(size per_handle) ;go to the next handle. cmp bx,offset end_handles jb count_handles_1 ret verify_handle: ;Ensure that their handle is real. If it isn't, we pop off our return ;address, and return to *their* return address with cy set. mov bx,_BX[bp] ;get the handle they gave us cmp bx,offset handles jb verify_handle_bad ;no - must be bad. cmp bx,offset end_handles jae verify_handle_bad ;no - must be bad. cmp [bx].in_use,1 ;if it's not in use, it's bad. jne verify_handle_bad ret verify_handle_bad: mov dh,BAD_HANDLE add sp,2 ;pop off our return address. stc ret public set_recv_isr set_recv_isr: mov ah,35h ;get the old interrupt into es:bx mov al,int_no ; board's interrupt vector or al,al je set_isr_no_irq add al,8 cmp al,8+8 ;is it a slave 8259 interrupt? jb set_recv_isr_1 ;no. add al,70h - 8 - 8 ;map it to the real interrupt. set_recv_isr_1: int 21h mov their_recv_isr.offs,bx ;remember the old seg:off. mov their_recv_isr.segm,es mov ah,25h ;now set our recv interrupt. mov dx,offset recv_isr int 21h cmp byte ptr timer_isr,0cfh ;is there just an iret at their handler? je set_isr_no_timer ;yes, don't bother hooking the timer. mov ax,3508h ;get the old interrupt into es:bx int 21h mov their_timer.offs,bx ;remember the old seg:off. mov their_timer.segm,es mov ah,25h ;now set our recv interrupt. mov dx,offset timer_isr int 21h set_isr_no_timer: mov al,int_no ; Now enable interrupts call unmaskint mov original_mask,al set_isr_no_irq: ret public count_in_err count_in_err: assume ds:nothing add2 errors_in,1 ret public count_out_err count_out_err: assume ds:nothing add2 errors_out,1 ret recv_isr_frame struc recv_isr_ds dw ? recv_isr_dx dw ? recv_isr_ax dw ? recv_isr_ip dw ? recv_isr_cs dw ? recv_isr_f dw ? recv_isr_frame ends ; ; I have had a problem with some hardware which under extreme LAN loading ; conditions will re-enter the recv_isr. Since the 8259 interrupts for ; the card are masked off, and the card's interrupt mask register is ; cleared (in 8390.asm at least) disabling the card from interrupting, this ; is clearly a hardware problem. Due to the low frequencey of occurance, and ; extreme conditions under which this happens, it is not lilely to be fixed ; in hardware any time soon, plus retrofitting of hardware in the field will ; not happen. To protect the driver from the adverse effects of this I am ; adding a simple re-entrancy trap here. - gft - 910617 ; in_recv_isr db 0 ; flag to trap re-entrancy recv_isr: cmp in_recv_isr, 0 jne recv_iret mov in_recv_isr, 1 ; I realize this re-entrancy trap is not perfect, you could be re-entered ; anytime before the above instruction. However since the stacks have not ; been swapped re-entrancy here will only appear to be a spurious interrupt. ; - gft - 910617 ; In order to achieve back-to-back packet transmissions, we handle the ; latency-critical portion of transmit interrupts first. The xmit ; interrupt routine should only start the next transmission, but do ; no other work. It may only touch ax and dx (the only register necessary ; for doing "out" instructions) unless it first pushes any other registers ; itself. push ax push dx call xmit ; Now switch stacks, push remaining registers, and do remaining interrupt work. push ds mov ax,cs ;ds = cs. mov ds,ax assume ds:code mov savesp,sp mov savess,ss mov ss,ax mov sp,offset our_stack cld push bx push cx push si push di push bp push es ; The following comment is wrong in that we now do a specific EOI command, ; and because we don't enable interrupts (even though we should). ; Chips & Technologies 8259 clone chip seems to be very broken. If you ; send it a Non Specific EOI command, it clears all In Service Register ; bits instead of just the one with the highest priority (as the Intel ; chip does and clones should do). This bug causes our interrupt ; routine to be reentered if: 1. we reenable processor interrupts; ; 2. we reenable device interrupts; 3. a timer or other higher priority ; device interrupt now comes in; 4. the new interrupting device uses ; a Non Specific EOI; 5. our device interrupts again. Because of ; this bug, we now completely mask our interrupts around the call ; to "recv", the real device interrupt handler. This allows us ; to send an EOI instruction to the 8259 early, before we actually ; reenable device interrupts. Since the interrupt is masked, we ; are still guaranteed not to get another interrupt from our device ; until the interrupt handler returns. This has another benefit: ; we now no longer prevent other devices from interrupting while our ; interrupt handler is running. This is especially useful if we have ; other (multiple) packet drivers trying to do low-latency transmits. mov al,int_no ; Disable further device interrupts call maskint ; The following is from Bill Rust, <wjr@ftp.com> ; this code dismisses the interrupt at the 8259. if the interrupt number ; is > 8 then it requires fondling two PICs instead of just one. mov al, int_no ; get hardware int # cmp al, 8 ; see if its on secondary PIC jg recv_isr_4 add al, 60h ; make specific EOI dismissal out 20h, al jmp recv_isr_3 ; all done recv_isr_4: add al,60h - 8 ; make specific EOI (# between 9 & 15). out 0a0h,al ; Secondary 8259 (PC/AT only) mov al,62h ; Acknowledge on primary 8259. out 20h,al recv_isr_3: ; sti ; Interrupts are now completely safe call recv cli ;interrupts *must* be off between ;here and the stack restore, because ;if we have one of our interrupts ;pending, we would trash our stack. mov al,int_no ; Now reenable device interrupts call unmaskint pop es pop bp pop di pop si pop cx pop bx mov ss,savess mov sp,savesp pop ds assume ds:nothing pop dx pop ax mov in_recv_isr, 0 ; clear the re-entrancy flag - gft - 901617 recv_iret: iret recv_exiting_flag db 0 ;nonzero if recv_exiting will be run. recv_exiting_addr dd ? public schedule_exiting schedule_exiting: ;call this routine to schedule a subroutine that gets run after the ;recv_isr. This is done by stuffing routine's address in place ;of the recv_isr iret's address. This routine should push the flags when it ;is entered, and should jump to recv_exiting_exit to leave. ;enter with ax = address of routine to run. cmp recv_exiting_flag,0 ;is it already scheduled? jne schedule_exiting_1 ;yes, don't do it again! inc recv_exiting_flag ;set the flag. les di,savespss ;make es:di -> their stack. xchg ax,es:[di].recv_isr_ip ;stuff our routine's address in, mov recv_exiting_addr.offs,ax ;and save the original address. mov ax,cs xchg ax,es:[di].recv_isr_cs mov recv_exiting_addr.segm,ax schedule_exiting_1: ret public recv_exiting_exit recv_exiting_exit: ;recv_exiting jumps here to exit, after pushing the flags. cli ;protect the following semaphore. mov recv_exiting_flag,0 push recv_exiting_addr.segm push recv_exiting_addr.offs iret public maskint maskint: or al,al ;are they using a hardware interrupt? je maskint_1 ;no, don't mask off the timer! assume ds:code mov dx,21h ;assume the master 8259. cmp al,8 ;using the slave 8259 on an AT? jb mask_not_irq2 mov dx,0a1h ;go disable it on slave 8259 sub al,8 mask_not_irq2: mov cl,al in al,dx ;disable them on the correct 8259. mov ah,1 ;set the bit. shl ah,cl or al,ah ; ; 500ns Stall required here, per INTEL documentation for eisa machines ; - gft - 910617 ; push ax in al,61h ; 1.5 - 3 uS should be plenty in al,61h in al,61h pop ax out dx,al maskint_1: ret public unmaskint unmaskint: ;exit with cl = 0 if the interrupt had been enabled. assume ds:code mov dx,21h ;assume the master 8259. mov cl,al cmp cl,8 ;using the slave 8259 on an AT? jb unmask_not_irq2 ;no in al,dx ;get master mask push ax in al,61h ;wait lots of time. in al,61h in al,61h pop ax and al,not (1 shl 2) ; and clear slave cascade bit in mask out dx,al ;set new master mask (enable slave int) ; ; 500ns Stall required here, per INTEL documentation for eisa machines ; - gft - 910617 ; push ax in al,61h ; 1.5 - 3 uS should be plenty in al,61h in al,61h pop ax mov dx,0a1h ;go enable int on slave 8259 sub cl,8 unmask_not_irq2: in al,dx ;enable interrupts on the correct 8259. mov ah,1 ;clear the bit. shl ah,cl mov cl,al ;remember the original mask. and cl,ah not ah and al,ah ; ; 500ns Stall required here, per INTEL documentation for eisa machines ; - gft - 910617 ; push ax in al,61h ; 1.5 - 3 uS should be plenty in al,61h in al,61h pop ax out dx,al ret public recv_locate recv_locate: ;called when we want to determine what to do with a received packet. ;enter with es:di -> packet type, dl = packet class. ;exit with cy if the packet is not desired, or nc if we know its type. assume ds:code, es:nothing ; If -n option take IEEE 802.3 encapsulated packets that could be Novell IPX ; and make them Ethernet encapsulated Novell IPX packets (for PDSHELL). test flagbyte,N_OPTION jz not_n_op ; Make IEEE 802.3-like packets that could be Novell IPX into BlueBook class ; Novell type 8137 packets. cmp dl,IEEE8023 ;Is this an IEEE 802.3 packet? jne recv_not_802_3 ;no cmp word ptr es:[di],0ffffh ;if this word not ffff jne recv_not_8137 ; then not Novell sub di,2 ; back it up to the 8137 word. mov es:[di],3781h ; fake as Novell protocol (8137) mov dl,BLUEBOOK jmp short recv_not_8137 recv_not_802_3: ; Convert incoming Ethernet type 8137 IPX packets to type 8138, as with -n in ; effect we can't send type 8137, and it will only confuse Netware. cmp dl,BLUEBOOK ;Is this a BLUEBOOK packet? jne recv_not_8137 ;no, don't change it. cmp word ptr es:[di],3781h ;Is it an 8137 packet? jne recv_not_8137 ;no, don't change it. mov es:[di],word ptr 3881h ;yes, mung it slightly. recv_not_8137: not_n_op: mov bx,offset handles recv_find_1: cmp [bx].in_use,0 ;is this handle in use? je recv_find_2 ;no - don't check the type. mov ax,[bx].receiver.offs ;do they have a receiver? or ax,[bx].receiver.segm je recv_find_2 ;no - they're not serious about it. ;per request by the UK people, we match on IEEE 802.3 classes, then types. ;for all others, we match on type, then class. This lets their software work ;without breaking BLUEBOOK type length=0 clients. cmp [bx].class,IEEE8023 ;is this an IEEE 802.3 handle jne recv_find_7 ;no. cmp dl,IEEE8023 ;is the packet also IEEE 802.3? jne recv_find_2 ;no, give up on it now. recv_find_7: mov cx,[bx].packet_type_len ;compare the packets. lea si,[bx].packet_type jcxz recv_find_3 ;if cx is zero, they want them all. cmp [bx].class, dl ;is this the right class? jne recv_find_2 ;no- don't bother push di repe cmpsb pop di je recv_find_3 ;we've got it! recv_find_2: add bx,(size per_handle) ;go to the next handle. cmp bx,offset end_handles jb recv_find_1 add2 packets_dropped,1 ;count it as dropped. stc ret recv_find_3: mov found_handle,bx ;remember what our handle was. clc ret public recv_find, recv_found recv_find: ;called when we want to determine what to do with a received packet. ;enter with cx = packet length, es:di -> packet type, dl = packet class. ;exit with es:di = 0 if the packet is not desired, or es:di -> packet buffer ; to be filled by the driver. assume ds:code, es:nothing push cx ;preserve packet length. call recv_locate ;search for the packet type. pop cx jc recv_find_5 ;we didn't find it -- discard it. ; recv_found: ;called to do the first upcall. ;exit with es:di = 0 if the packet is not desired, or es:di -> packet buffer ; to be filled by the driver. add2 packets_in,1 add2 bytes_in,cx ;add up the received bytes. mov bx,found_handle les di,[bx].receiver ;remember the receiver upcall. mov receive_ptr.offs,di mov receive_ptr.segm,es test flagbyte,W_OPTION ;did they select the Windows option? je recv_find_6 ;no, don't check for the upcall. ; does the receiver signature match whats currently in memory? if not, ; jump to fake return push si push cx lea si,[bx].receiver_sig mov cx,8/2 repe cmpsw pop cx pop si je recv_find_6 recv_find_5: xor di,di ;"return" a null pointer. mov es,di ret recv_find_6: mov ax,0 ;allocate request. stc ;with stc, flags must be an odd number push ax ; save a number that cant be flags pushf ;save flags in case iret used. call receive_ptr ;ask the client for a buffer. ; on return, flags should be at top of stack. if an IRET has been used, ; then 0 will be at the top of the stack pop bx cmp bx,0 je recv_find_4 ;0 is at top of stack add sp,2 recv_find_4: ret public recv_copy recv_copy: ;called after we have copied the packet into the buffer. ;enter with ds:si ->the packet, cx = length of the packet. ;preserve bx. assume ds:nothing, es:nothing push bx mov bx,found_handle mov ax,1 ;store request. clc ;with clc, flags must be an even number push ax ; save a number that can't be flags pushf ;save flags incase iret used. call receive_ptr ;ask the client for a buffer. pop bx cmp bx,1 ;if this is a 1, IRET was used. je recv_copy_1 pop bx recv_copy_1: pop bx ret public send_queue send_queue: ; Queue an iocb. ; Enter with es:di -> iocb, interrupts disabled. ; Destroys ds:si. assume ds:nothing, es:nothing mov es:[di].next.offs,0 ; Zero next offset mov es:[di].next.segm,0 ; Zero next segment mov si,send_head.offs ; Queue empty? or si,send_head.segm jnz sq_notempty ; No mov send_head.offs,di ; Set head offset mov send_head.segm,es ; Set head segment jmp sq_settail sq_notempty: ; Queue is not empty lds si,send_tail ; Get tail segment:offset mov ds:[si].next.offs,di ; Set next offset mov ds:[si].next.segm,es ; Set next segment sq_settail: mov send_tail.offs,di ; Set tail offset mov send_tail.segm,es ; Set tail segment ret public send_dequeue send_dequeue: ; Dequeue an iocb and possibly call its upcall. ; Enter with device or processor interrupts disabled, ah = return code. ; Exits with es:di -> iocb; destroys ds:si, ax, bx, cx, dx, bp. assume ds:nothing, es:nothing les di,send_head ; Get head segment:offset lds si,es:[di].next ; Get next segment:offset mov send_head.offs, si ; Set head offset mov send_head.segm, ds ; Set head segment or es:flags[di], DONE ; Mark done mov es:ret_code[di], ah ; Set retcode test es:[di].flags,CALLME ; Does he want an upcall? je send_dequeue_1 ; No. push es ; Push iocb segment push di ; and offset clc ; Clear carry. mov ax,1 ; Push a number that cant be flags. push ax pushf ; Save flags in case iret used. call es:[di].upcall ; Call the client. pop ax ; Pop first word. cmp ax,1 ; If this is a 1, IRET was used. je send_dequeue_2 ; Far return used. add sp,2 ; Pop flags. send_dequeue_2: pop di ; Pop iocb segment pop es ; and offset send_dequeue_1: ret code ends end start