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Assembly Source File | 1989-03-31 | 20.8 KB | 747 lines

page 60,126 ; Name vidirec0 -- Read or write rectangle directly from or to ; video adapter ; ; Synopsis ercode = vidirec0(ppfrom,ppto,num_rows,row_length, ; scn_width,attr,option,gap); ; ; int ercode Error code: 1 if option is unknown, ; 0 if okay. ; const char far * const *ppfrom ; Pointer to far char pointer containing ; address of source buffer ; char far **ppto Pointer to far char pointer containing ; address of destination buffer ; int num_rows Number of rows in the rectangle ; int row_length Width of the rectangle (in columns) ; int scn_width Twice the screen width (80 or 160 bytes) ; int attr Foreground and background attributes ; (only used for certain options) ; int option Style and direction of I/O; also ; whether interference is to be prevented. ; See discussion and table below. ; unsigned gap Character cells between successive rows ; of data buffer in memory (ignored for ; some option values.) ; ; Description This function reads or writes a rectangular buffer ; directly from or to the video memory on an IBM ; Color/Graphics Adapter, Monochrome Adapter, or ; compatible adapter. It can do so with attention to the ; horizontal and vertical retrace intervals for maximum ; throughput without interference. The characters are ; transferred row by row. ; ; The buffer addresses are stored in far char pointers ; pointed to by ppfrom and ppto. Either or both of these ; may point to physical locations in video memory, ; depending on the value of option. ; ; Several styles of I/O are available. They are selected ; by the value of option. Bit 15 of option, if set, ; indicates that the transfer is to be performed without ; regard to interference. The remaining bits of option ; form an integer which should be selected from the ; following table: ; ; Option Description ; ------ ----------- ; 0 Write characters to the screen without attributes. ; *ppfrom points to a buffer of characters. ; (Same as option 13 with gap == 0.) ; 1 Write characters to the screen with attributes. ; *ppfrom points to a buffer of (char,attr) pairs. ; (Same as option 14 with gap == 0.) ; 2 Write characters to the screen with constant ; attribute specified by attr. ; *ppfrom points to a buffer of characters. ; (Same as option 15 with gap == 0.) ; 3 Fill screen rectangle with constant char & attr. ; *ppfrom points to the character. ; Attr specifies the attribute. ; 4 Fill screen rectangle with constant attribute ; without altering characters displayed. ; ppfrom is ignored. ; 5 Read characters from screen without attributes. ; **ppto is filled with the characters. (Note ; that no trailing NUL is added.) ; (Same as option 16 with gap == 0.) ; 6 Read characters from screen with attributes. ; **ppto is filled with (char,attr) pairs. ; (Same as option 17 with gap == 0.) ; 7 Copy window (with attributes) upward or directly ; leftward on same display page. ; 8 Copy window (without attributes) upward or ; directly leftward on same display page. ; 9 Copy window (with attributes) downward or ; directly rightward on same display page. ; 10 Copy window (without attributes) downward or ; directly rightward on same display page. ; 11 Copy window (with attributes) to non-overlapping ; window or to another display page. ; 12 Copy window (without attributes) to non- ; overlapping window or to another display page. ; ; Note: The preceding options all ignore "gap". ; ; 13 Write characters to the screen without attributes. ; *ppfrom points to a buffer of characters whose ; rows are separated by "gap" bytes. ; 14 Write characters to the screen with attributes. ; *ppfrom points to a buffer of (char,attr) pairs ; whose rows are separated by "gap" pairs. ; 15 Write characters to the screen with constant ; attribute specified by attr. ; *ppfrom points to a buffer of characters whose ; rows are separated by "gap" bytes. ; 16 Read characters from screen without attributes. ; **ppto is filled with the characters. (Note ; that no trailing NUL is added.) The rows of ; **ppto are separated by "gap" bytes. ; 17 Read characters from screen with attributes. ; **ppto is filled with (char,attr) pairs. The ; rows of **ppto are separated by "gap" pairs. ; ; Beware: None of the arguments is checked for ; correctness (except that option is checked for ; out-of-range values)! ; ; If bit 15 of option is clear (indicating protection ; against interference), interrupts will be left enabled ; when this procedure exits. ; ; Returns ercode Error code: 1 if option is unknown, ; 0 if okay. ; **ppto Data in destination buffer ; ; Version 6.00 (C)Copyright Blaise Computing Inc. 1986-1989 ; video_status_port equ 3DAh include beginasm.mac beginMod utamove ; Symbols to aid in referencing arguments on stack ; (Some of these items are also used as local variables.): a equ 0 b equ a + sizeDPointer c equ b + sizeDPointer d equ c + 2 e equ d + 2 f equ e + 2 g equ f + 2 h equ g + 2 ppfrom equ [bp + stkoff + a] ppto equ [bp + stkoff + b] num_rows equ byte ptr [bp + stkoff + c] row_length equ byte ptr [bp + stkoff + d] scn_width equ word ptr [bp + stkoff + e] attr equ byte ptr [bp + stkoff + f] option equ word ptr [bp + stkoff + g] gap equ word ptr [bp + stkoff + h] ; Format of the table entry for one option: option_entry struc do_setup dw ? ; Address of setup_proc. do_slow dw ? ; Address of slow_proc. do_fast dw ? ; Address of fast_proc. do_newrow dw ? ; Address of newrow_proc. dirflag db ? ; Direction: down or up. option_entry ends ; Macro to wait until the beginning of a horizontal ; retrace interval. On exit, interrupts are off. await_horiz_retrace macro local await_display_on,await_display_off sti nop await_display_on: in al,dx shr al,1 jc await_display_on cli await_display_off: in al,dx shr al,1 jnc await_display_off endm ; Here are macros to define procedures for each style of I/O as ; specified by "option". ; ; Each style of I/O requires four procedures: ; (1) a specialized setup procedure ("setup_proc") (which may ; do nothing) ; (2) a procedure ("slow_proc") to do the entire read or write ; while avoiding video interference; ; (3) a procedure ("fast_proc") to do the entire read or write ; without regard to interference (i.e., as fast as possible); ; (4) a procedure ("newrow_proc") to adjust address registers ; (SI and/or DI) and the column counter (CX) for a new row ; of the rectangle. ; These four procedures will be addressed through table "option_table" ; defined below. ; Since these procedures must therefore be highly regular in form, ; the following macros aid in defining the beginning and end of ; each. begin_setup_proc macro o_name ;; Define beginning of setup procedure o_name&_setup_proc proc near endm end_setup_proc macro o_name ;; Define end of setup procedure ret o_name&_setup_proc endp endm ; On entry to each slow_proc, ; ; BX = address of option_table entry; ; CX = number of cells in one row; ; DX = I/O address of video status port. ; ; Also, usually ; DS:SI = address of first source byte; ; ES:DI = address of first target byte. ; ; Additional entry conditions are satisfied ; by the setup_proc. begin_slow_proc macro o_name,save_bx_flag o_name&_slow_proc proc near ifidn <save_bx_flag>,<save_bx> push bx ;; Some options must use BX as ;; additional storage space, so ;; save BX if requested. endif o_name&_single_loop: ;; Begin loop that transfers one ;; character cell. endm end_slow_proc macro o_name,save_bx_flag local done loop o_name&_single_loop ;; Transfer one more cell ;; in this row. sti ifidn <save_bx_flag>,<save_bx> pop bx ;; Restore BX if it was used for ;; temporary data. endif dec num_rows jz done call cs:[bx].do_newrow ;; Use BX to invoke ;; proper newrow_proc. jmp short o_name&_slow_proc ;; Do next row. done: ret ;; Done. o_name&_slow_proc endp endm ; Each fast_proc has the same entry ; conditions as slow_proc. begin_fast_proc macro o_name o_name&_fast_proc proc near endm end_fast_proc macro o_name local done dec num_rows jz done call cs:[bx].do_newrow ;; Use BX to invoke ;; proper newrow_proc. jmp short o_name&_fast_proc done: ret o_name&_fast_proc endp endm ; Each newrow_proc assumes CH == 0. begin_newrow_proc macro o_name o_name&_newrow_proc proc near mov cl,row_length endm end_newrow_proc macro o_name ret o_name&_newrow_proc endp endm ; ************************************************************* ; ********* DEFINE FOUR PROCEDURES FOR EACH OPTION ********** ; ************************************************************* ; ; (Note: many of these definitions just refer to others using "equ".) beginCseg vidirec0 ; W_CHARS: Write characters to the screen without attributes. begin_setup_proc w_chars ; No setup needed. end_setup_proc w_chars begin_slow_proc w_chars await_horiz_retrace movsb inc di end_slow_proc w_chars begin_fast_proc w_chars w_chars_fast_loop: movsb inc di loop w_chars_fast_loop end_fast_proc w_chars begin_newrow_proc w_chars sub di,cx sub di,cx add di,scn_width end_newrow_proc w_chars ; W_CHAR_ATTRS: Write characters & attributes to the screen. w_char_attrs_setup_proc equ w_chars_setup_proc ; No setup needed. begin_slow_proc w_char_attrs,save_bx lodsw ; Insufficient time for a mov bx,ax ; whole "movsw", so do the job await_horiz_retrace ; by a "lodsw" plus a "stosw". mov ax,bx stosw end_slow_proc w_char_attrs,save_bx begin_fast_proc w_char_attrs rep movsw end_fast_proc w_char_attrs w_char_attrs_newrow_proc equ w_chars_newrow_proc ; CONST_ATTR: Write characters to screen with constant attribute ; specified in AH. begin_setup_proc const_attr mov ah,attr end_setup_proc const_attr begin_slow_proc const_attr,save_bx lodsb ; Insufficient time for "lodsb" mov bl,al ; plus "stosw", so do the job await_horiz_retrace ; in halves. mov al,bl stosw end_slow_proc const_attr,save_bx begin_fast_proc const_attr const_attr_fast_loop: lodsb stosw loop const_attr_fast_loop end_fast_proc const_attr const_attr_newrow_proc equ w_chars_newrow_proc ; CONST_CHAR_ATTR: Fill rectangle with constant character ; and attribute (stored in SI). begin_setup_proc const_char_attr mov ah,attr mov al,[si] mov si,ax ; Keep char & attr in SI for the loop end_setup_proc const_char_attr begin_slow_proc const_char_attr await_horiz_retrace mov ax,si stosw end_slow_proc const_char_attr begin_fast_proc const_char_attr mov ax,si rep stosw end_fast_proc const_char_attr const_char_attr_newrow_proc equ w_chars_newrow_proc ; CONST_ATTR_ONLY: Change attribute on rectangle to value ; stored in AH. begin_setup_proc const_attr_only mov ah,attr end_setup_proc const_attr_only begin_slow_proc const_attr_only await_horiz_retrace inc di mov al,ah stosb end_slow_proc const_attr_only begin_fast_proc const_attr_only mov al,ah const_attr_only_fast_loop: inc di stosb loop const_attr_only_fast_loop end_fast_proc const_attr_only const_attr_only_newrow_proc equ w_chars_newrow_proc ; R_CHARS: Read only characters from screen. r_chars_setup_proc equ w_chars_setup_proc ; No setup needed. begin_slow_proc r_chars await_horiz_retrace movsb inc si end_slow_proc r_chars begin_fast_proc r_chars r_chars_fast_loop: movsb inc si loop r_chars_fast_loop end_fast_proc r_chars begin_newrow_proc r_chars sub si,cx sub si,cx add si,scn_width end_newrow_proc r_chars ; R_CHAR_ATTRS: Read characters & attributes from screen. r_char_attrs_setup_proc equ w_chars_setup_proc ; No setup needed. begin_slow_proc r_char_attrs await_horiz_retrace movsw end_slow_proc r_char_attrs r_char_attrs_fast_proc equ w_char_attrs_fast_proc r_char_attrs_newrow_proc equ r_chars_newrow_proc ; UP_CHAR_ATTRS: Copy characters & attributes upward on the screen ; or directly to the left. Start at upper left ; corner of rectangle. up_char_attrs_setup_proc equ w_chars_setup_proc ; No setup needed. begin_slow_proc up_char_attrs,save_bx await_horiz_retrace lodsw ; Insufficient time for a mov bx,ax ; whole "movsw", so do the job await_horiz_retrace ; by a "lodsw" plus a "stosw". mov ax,bx stosw end_slow_proc up_char_attrs,save_bx up_char_attrs_fast_proc equ w_char_attrs_fast_proc begin_newrow_proc up_char_attrs sub si,cx sub si,cx add si,scn_width sub di,cx sub di,cx add di,scn_width end_newrow_proc up_char_attrs ; UP_CHARS: Copy only characters upward on the screen ; or directly to the left. Start at upper left ; corner of rectangle. up_chars_setup_proc equ w_chars_setup_proc ; No setup needed. begin_slow_proc up_chars await_horiz_retrace movsb inc si inc di end_slow_proc up_chars begin_fast_proc up_chars up_chars_fast_loop: movsb inc si inc di loop up_chars_fast_loop end_fast_proc up_chars up_chars_newrow_proc equ up_char_attrs_newrow_proc ; DOWN_CHAR_ATTRS: Copy characters & attributes downward on the screen ; or directly to the right. Start at lower right ; corner of rectangle. begin_setup_proc down_char_attrs mov al,num_rows ; Adjust SI and DI to point dec al ; at the last character in the mov cx,scn_width ; rectangle instead of the first. mul cl mov cl,row_length mov ch,0 dec cx add cx,cx add ax,cx add si,ax add di,ax end_setup_proc down_char_attrs down_char_attrs_slow_proc equ up_char_attrs_slow_proc down_char_attrs_fast_proc equ up_char_attrs_fast_proc begin_newrow_proc down_char_attrs add si,cx add si,cx sub si,scn_width add di,cx add di,cx sub di,scn_width end_newrow_proc down_char_attrs ; DOWN_CHARS: Copy only characters downward on the screen ; or directly to the right. Start at lower right ; corner of rectangle. down_chars_setup_proc equ down_char_attrs_setup_proc begin_slow_proc down_chars await_horiz_retrace movsb dec si dec di end_slow_proc down_chars begin_fast_proc down_chars down_chars_fast_loop: movsb dec si dec di loop down_chars_fast_loop end_fast_proc down_chars down_chars_newrow_proc equ down_char_attrs_newrow_proc ; W_CHARS_GAP: Write characters to the screen without attributes. w_chars_gap_setup_proc equ w_chars_setup_proc ; No setup needed. w_chars_gap_slow_proc equ w_chars_slow_proc w_chars_gap_fast_proc equ w_chars_fast_proc begin_newrow_proc w_chars_gap sub di,cx sub di,cx add di,scn_width add si,gap end_newrow_proc w_chars_gap ; W_CHAR_ATTRS_GAP: Write characters & attributes to the screen. w_char_attrs_gap_setup_proc equ w_char_attrs_setup_proc ; No setup needed. w_char_attrs_gap_slow_proc equ w_char_attrs_slow_proc w_char_attrs_gap_fast_proc equ w_char_attrs_fast_proc begin_newrow_proc w_char_attrs_gap sub di,cx sub di,cx add di,scn_width add si,gap add si,gap end_newrow_proc w_char_attrs_gap ; CONST_ATTR_GAP: Write characters to screen with constant attribute ; specified in AH. const_attr_gap_setup_proc equ const_attr_setup_proc const_attr_gap_slow_proc equ const_attr_slow_proc const_attr_gap_fast_proc equ const_attr_fast_proc const_attr_gap_newrow_proc equ w_chars_gap_newrow_proc ; R_CHARS_GAP: Read only characters from screen. r_chars_gap_setup_proc equ r_chars_setup_proc ; No setup needed. r_chars_gap_slow_proc equ r_chars_slow_proc r_chars_gap_fast_proc equ r_chars_fast_proc begin_newrow_proc r_chars_gap sub si,cx sub si,cx add si,scn_width add di,gap end_newrow_proc r_chars_gap ; R_CHAR_ATTRS_GAP: Read characters & attributes from screen. r_char_attrs_gap_setup_proc equ r_char_attrs_setup_proc ; No setup needed. r_char_attrs_gap_slow_proc equ r_char_attrs_slow_proc r_char_attrs_gap_fast_proc equ r_char_attrs_fast_proc begin_newrow_proc r_char_attrs_gap sub si,cx sub si,cx add si,scn_width add di,gap add di,gap end_newrow_proc r_char_attrs_gap ; ******************************************************************* ; ********** DEFINE THE TABLE OF OPTION INFORMATION ************** ; ******************************************************************* ; Values for dirflag: down equ 1 ; Decreasing addresses (up the screen) up equ 0 ; Increasing addresses (down the screen) ; Macro to create one table entry: o_e macro o_name,dir option_entry <o_name&_setup_proc,o_name&_slow_proc,o_name&_fast_proc,o_name&_newrow_proc,dir> endm ; The table itself follows. It's part of the code segment. option_table: o_e w_chars,up ; 0 end_of_first label option_entry o_e w_char_attrs,up ; 1 o_e const_attr,up ; 2 o_e const_char_attr,up ; 3 o_e const_attr_only,up ; 4 o_e r_chars,up ; 5 o_e r_char_attrs,up ; 6 o_e up_char_attrs,up ; 7 o_e up_chars,up ; 8 o_e down_char_attrs,down ; 9 o_e down_chars,down ; 10 o_e up_char_attrs,up ; 11 o_e up_chars,up ; 12 o_e w_chars_gap,up ; 13 o_e w_char_attrs_gap,up ; 14 o_e const_attr_gap,up ; 15 o_e r_chars_gap,up ; 16 o_e r_char_attrs_gap,up ; 17 ; (Note that options 11 and 12 just ; refer to the procedures used by options ; 7 and 8, respectively, because the ; same algorithms suffice.) end_of_table label option_entry size_of_entry equ end_of_first - option_table table_length equ (end_of_table - option_table)/size_of_entry ; ******************************************************************** ; ********************** BEGIN THE ACTUAL CODE ******************* ; ******************************************************************** beginProc vidirec0 push bp ; Save the frame pointer mov bp,sp push di push si push ds push es mov ax,option mov dx,ax ; Spare copy of raw option and ax,7fffh ; Ignore bit 15 of option. cmp ax,table_length ; Check for option value beyond table. jb option_ok bad_option: mov ax,1 ; Invalid option jmp short exit option_ok: mov cl,size_of_entry ; Convert option value into address mul cl ; of proper table entry. jc bad_option add ax,offset option_table mov option,ax ; Save address of table entry. mov bx,ax ; Set DF according to dirflag value cmp cs:[bx].dirflag,down; in table. je downward cld jmp short have_set_direction downward: std have_set_direction: if LONGDATA lds bx,dword ptr ppto assume ds:nothing else mov bx,ppto endif les di,[bx] ; Put target address into ES:DI. assume es:nothing if LONGDATA lds bx,dword ptr ppfrom assume ds:nothing else mov bx,ppfrom endif lds si,[bx] ; Put source address into DS:SI. assume ds:nothing mov bx,option call cs:[bx].do_setup ; Do specialized portion ; of setup. ; Complete the setup. mov cl,row_length mov ch,0 test dh,80h mov dx,video_status_port jnz no_waiting call cs:[bx].do_slow ; Invoke slow_proc. jmp short done no_waiting: call cs:[bx].do_fast ; Invoke fast_proc. done: xor ax,ax ; Successful completion exit: sti pop es pop ds pop si pop di cld pop bp ; Get the original frame pointer. ret endProc vidirec0 endCseg vidirec0 endMod vidirec0 end