High Resolution Graphics10.1 Introduction In the high resolution mode, all 16 bits of each font cell word are displayed. The screen buffer is filled with pointers to successive cells in dynamic RAM and the programmer must manipulate the contents of dynamic RAM to create the required display. To set up a hi-res screen, there are 3 steps which must be performed.
The starting address of the hi-res screen must be on a 32 byte boundary (ie. an address that is divisible by 32). This is because the lower 4 address bits are used by the CRT controller to address the 16 words of the font cell. The hi-res screen must be contained completely in the upper or lower 64K segment of the first 128K block of memory (0 - 1FFFFh). As CP/M loads into the top of memory and loads programs directly below itself, a convenient place for a hi-res screen is directly above the operating system character table at location 2C00h (see Memory Allocation Map of CP/M system, section 1.6.2). This area can also be used under MS-DOS except that this area above the character table must be claimed by the user. This is because the programs are loaded directly above the character table under MS-DOS. It is therefore necessary for the user to include a 40,000 byte buffer at the start of the software. It is also necessary for the user to ensure that the start of the buffer lies on a 32 byte boundary. This can be done by loading the ES segment register contents and ensuring that it is divisible by 32 with no remainder. The following routine clears 40,000 bytes starting at location 2C00h.
10.3 Setting the Screen Buffer Pointers We have defined our high resolution screen to start at address 2C00h and so our first pointer must be 2C00h divided by 32. (ie. the word in screen RAM represents the upper 11 bits of address to dynamic RAM; the CRT controller supplies the lower 4 bits). This means the screen pointers should start at 0160h. Incrementing this number by one translates to an increment in the address of 16 (ie. one complete cell). The following routine fills the screen buffer with pointers to our high resolution screen. Note we only fill 25 rows x 50 columns = 1250 bytes of the 4096 bytes available in the buffer.
10.4 Reprogramming the 6845 CRT Controller In order to derive the correct timing from the display circuit, 16 of the internal registers should be reloaded. The correct data for both the text and high resolution modes are shown on page 99 of the Hardware Reference Manual. The following routine transfers the 16 bytes of data in the table to the 16 internal registers of the CRT controller.
10.5 Examples 10.5.1 Microsoft MACRO-86 Assembly Language This assembly-language routine demonstrates two things, one, interfacing an assembly-language routine to the MS-Basic interpreter and two, using the high-resolution graphics from MS-Basic.
When Basic calls an assembly-language routine it pushes the return address and the value of its CS onto the stack, then enters the called routine. This routine must save any other segment registers it intends using.
code segment assume cs:code,ds:code ; Written by Greg Johnstone and Keith Rea ; ; ; 16-9-83 ; ; Program HI-RES ; ; ; Assemble this program as follows ; ; MACRO86 HI-RES; ; LINK HI-RES; ; ; Link will produce a warning - 'No stack segment', ignore it. Link ; produces a file HI-RES.EXE which will not run. You must produce a ; .COM file as follows: ; ; DEBUG HI-RES.EXE ; N HI-RES.COM ; W ; Q ; ; The resulting program HI-RES.COM will run ; buf_st equ 190h ; offset to hi-res buffer scrn_rm equ 0f000h ; segment address of screen RAM count equ 1250 ; no. of cell locations in hi-res mode crt equ 0e800h ; segment address of CRT controller bdos equ 21h ; MS-DOS function call boot equ 00h ; exit to MS-DOS function. conout equ 02h ; console output function. cr equ 0dh ; carriage return lf equ 0ah ; line feed esc equ 1bh ; escape org 100h loader proc near start: call main ; find out where routine loaded in RAM ; ; Exit and remain resident ; mov dx,offset top+1 ; Set DX to the top of part to remain .. int 27h ; .. resident then quit. loader endp basic proc far ; Set screen RAM pointers to font RAM work area init: push es ; save segment registers used by Basic .. push ds mov ax,cs ; ..and point DS to current CS mov ds,ax mov bx,scrn_rm ; point to screen ram mov es,bx mov bx,0 mov cx,count ; counter for 1250 cells mov ax,hi_res ; starting address of pointers .. shr ax,1 ; .. = RAM address/2 init1: mov es:[bx],ax ; store font pointer inc bx ; address next word and put .. inc bx inc ax ; .. next font cell loop init1 ; set CRT controller for high resolution mov bx,crt ; point to CRT controller mov es,bx mov bx,0 mov si,1 mov cx,offset data ; point to register string mov dl,0 init2: mov al,dl ; set address register AR inc dl ; address next register mov es:[bx],al xchg bx,cx ; point to data mov al,[bx] ; get data byte xchg bx,cx inc cx ; address next byte mov es:[bx+si],al ; set register cmp dl,11h ; last register? jnz init2 ; no, address next register pop ds ; restore Basic's segment registers pop es ret data: db 3ah,32h,34h,0c9h,19h,06h,19h db 19h,03h,0eh,20h,0fh,20h,0,0,0 enddata: org buf_st ; start graphics buffer on 16 .. ; .. byte boundary. Initialise to 0 ; reserve extra 16 bytes just in case .. buff: db 40016 dup(0) ; .. it falls on an odd boundary. hi_res: dw 0 ; segment address of hi-res RAM top: ; routine up to here needs to stay in RAM. basic endp load2 proc near ; Now we have to figure out where we are in memory and tell everyone ; about it. main: call msprnt ; Print the following message db esc,'E','HI-RES ver. 1.0',cr,lf db cr,lf,'Hi-res graphics interface for MS-Basic interpreter' db cr,lf,cr,lf db 'Include the following statements in your program',cr,lf,cr,lf db ' 10 DEF SEG=&H',0 ; ; get the segment address ; mov ax,cs ; Get the contents of CS register .. call hexprnt ; .. convert to hex and print it call msprnt ; print next message db cr,lf db ' 20 HI.RES=&H',0 ; ; get the entry point for Basic ; mov ax,offset init ; Get offset of the start of the .. call hexprnt ; .. routine and print it. call msprnt db cr,lf db ' 30 CALL HI.RES' db cr,lf db 'The hi-res screen starts at segment address &H',0 ; ; now lets find where we put the hi-res screen ; mov ax,cs ; point to CS add ax,buf_st/16 ; add offset to start of hi-res ram test al,1 ; check if on 32-byte boundary. Segment .. jz main1 ; .. address should be even if it is. inc ax ; if odd, make it even .. main1: mov hi_res,ax ; .. and save it. call hexprnt call msprnt db cr,lf,'Use DEF SEG to point to this location in memory and' db cr,lf,'start POKEing data into hi-res RAM',cr,lf,0 ret ; ; subroutine MSPRINT - print bytes following the CALL till zero ; msprnt: pop bp ; get message starting address mov al,cs:[bp] ; get byte pointed to by bp inc bp ; next byte push bp and al,al ; is the byte equal to 0 ? jnz msprnt1 ; no: print it ret ; yes: end of string msprnt1: mov dl,al ; console output routine mov ah,conout int bdos jmp msprnt ; ; subroutine HEXPRNT - convert a byte to hex and print it ; hexprnt: push ax xchg ah,al call hexprnt1 pop ax call hexprnt1 ret hexprnt1: mov dl,al ; save the byte and al,0fh ; get lower nibble mov cl,04h ; then the upper nibble sar dl,cl and dl,0fh cmp dl,09h ; if less than 10 then get the .. jg hexprnt2 ; .. ASCII value of the numeric digit add dl,30h mov hi_byte,dl jmp hexprnt3 hexprnt2: add dl,37h ; else get the ASCII value of the .. mov hi_byte,dl ; .. alpha digit hexprnt3: cmp al,09h ; repeat for upper nibble jg hexprnt4 add al,30h mov lo_byte,al jmp hexprnt5 hexprnt4: add al,37h mov lo_byte,al hexprnt5: mov dl,hi_byte ; print the hex. bytes, one at a time mov ah,conout int bdos mov dl,lo_byte mov ah,conout int bdos ret lo_byte db '0' ; hex value of lower nibble (in ASCII) hi_byte db '0' ; hex value of upper nibble (in ASCII) load2 endp code ends end start10.5.2 Microsoft MS-BASIC Interpreter This program calls the routine given in section 10.5.1. 100 ROUTINE=&H2C8 'Segment address of HI-RES 110 SCREEN=&H2E2 'Segment address of hi-res screen 120 PRINT CHR$(27);"z" 'Clear screen 130 PRINT CHR$(27);"x5" 140 DEF SEG=ROUTINE 'Point to start of HI-RES segment 150 HI.RES=&H108 'Offset to HI-RES 160 CALL HI.RES 'Initialise hi-res screen 170 GOSUB 250 'Throw some data in it 180 A$="" 'Hang about till someone presses a key 190 WHILE A$="" 200 A$=INKEY$ 210 WEND 220 PRINT CHR$(27);"z" 'Put screen back into character mode 230 END 'And that's it folks 240 ' 250 DEF SEG=SCREEN 'Point to start of hi-res screen 260 FOR I=0 TO 31 STEP 2'Start filling hi-res RAM, a word at a time 270 READ HI,LO 'Remember that the screen displays bit 0 first 280 POKE I,LO: POKE I+1,HI 290 NEXT 300 RETURN 310 'This data prints the letter G in the top left corner 315 ' of hi-res screen 320 DATA 255,255,128,1,128,1,128,1,0,1,0,1,0,1,0,1 330 DATA 0,1,255,1,128,1,128,1,128,1,128,1,128,1,255,255 10.6 Printer Configuration Tables in the Grafix Kernel
; Printer configuration tables for Grafix ver.
; 1.2. To get addresses for Grafix ver. 1.3 add
; 10h to each address.
;
; The printer configuration tables contain the
; following information.
;
; prttyp - printer algorithm type. Currently,
; all printers use the same algorithm,
; which is defined as type 1. This is
; the sequence of events:
; 1) send initialisation string
; (initstr)
; 2) send beginning of line string
; (bolstr)
; 3) send graphics string 1 (grstr1)
; 4) send count of graphics
; characters
; 5) send graphics string 2 (grstr2)
; 6) send graphics characters
; 7) send end of line string (eolstr)
; 8) if more data, go to 2
; 9) send final string (finalstr)
;
; grcnt_typ - graphics character count type.
; There are currently 3 count types
; implemented. 1 = 2 hex bytes sent
; as count.
; 2 = 3 ASCII numeric characters
; sent as count
; 3 = no count is sent
;
; eneedles - the number of needles used in the
; print head to print graphics
; characters. This is positive if
; the top dot is the least
; significant bit of the data sent,
; negative if it is the most
; significant bit.
;
; rtmin - the minimum number of characters that
; will be printed on a line. If the user
; data contains fewer characters, the
; remainder sent will be blank (spaces).
= 0000 nul equ 0
= 0002 stx equ 2
= 0003 etx equ 3
= 000A lf equ 10
= 000D cr equ 13
= 000E so equ 14
= 001B escape equ 27
= 0020 space equ 32
= 00FF end_tblf equ 0ffh ;end of table
;flag
= 000A tbl_entry_lgth equ 10 ;maximum table
;string length
;----------------------------------------------
;-- Epson MX80/MX100 Configuration Data --
;----------------------------------------------
= 3B41 epson_tbl equ $
3B41 01 ep_prttyp db 1 ;epson algorithm typ
3B42 01 ep_grcnt_typ db 1 ;epson format of
;graphics bytes
3B43 0008 ep_eneedles dw 8 ;Epson num of scan
;lines/printed line
3B45 0000 ep_rtmin dw 0 ;epson min line
;length to print
3B47 04 0A 1B 41 08 ep_initstr db 4,lf,escape,'A',8;epson
;init string
3B4C 02 1B 32 ep_finalstr db 2,escape,'2' ;epson
;final string
3B4F 00 00 ep_bolstr db 0,nul ;epson beginning
;of line string
3B51 02 0D 0A ep_eolstr db 2,cr,lf ;epson end
;of line string
3B54 02 1B 4C ep_grstr1 db 2,escape,'L' ;epson
;graphics mode
3B57 00 00 ep_grstr2 db 0,nul ;epson
;graphics mode
3B59 FF ep_endf db end_tblf ;end of
;table flag
;-----------------------------------------------
;-- Tally Configuration Data --
;-----------------------------------------------
= 3B5A tally_tbl equ $
3B5A 01 t_prttyp db 1 ;tally
;algorithm type
3B5B 01 t_grcnt_typ db 1 ;tally
;format of graphics
;bytes
3B5C FFF8 t_eneedles dw -8 ;tally num
;of scan lines/printed
;lines
3B5E 00C8 t_rtmin dw 200 ;tally min
;line length to
;print
3B60 00 00 t_initstr db 0,nul ;tally init
;string
3B62 00 00 t_finalstr db 0,nul ;tally
;final string
3B64 00 00 t_bolstr db 0,nul ;tally beg
;of line string
3B66 02 0D 0A t_eolstr db 2,cr,lf ;tally end
;of line string
3B69 02 1B 4C t_grstr1 db 2,escape,'L' ;tally
;graphics mode
3B6C 01 20 t_grstr2 db 1,space ;tally
;graphics mode
3B6E FF t_endf db end_tblf ;table end
;flag
;----------------------------------------------
;-- C. Itoh Configuration Data --
;----------------------------------------------
= 3B6F citoh_tbl equ $
3B6F 01 c_prttyp db 1 ;c.itoh
;algorithm type
3B70 02 c_grcnt_typ db 2 ;c.itoh
;format of graphics
;bytes
3B71 FFF8 c_eneedles dw -8 ;c.itoh num
;of scan lines/printed
;line
3B73 0000 c_rtmin dw 0 ;c.itoh
;line length to
;print
3B75 08 1B 45 1B 54 31 c_initstr db 8,escape,'E',escape,'T16',cr,lf
36 0D 0A ;c.itoh init string
3B7E 04 1B 4E 1B 41 c_finalstr db 4,escape,'N',escape,'A'
;c.itoh final string
3B83 00 00 c_bolstr db 0,nul ;c.itoh beg
;of line string
3B85 02 0D 0A c_eolstr db 2,cr,lf ;c.itoh end
;of line string
3B88 03 1B 53 30 c_grstr1 db 3,escape,'S0';c.itoh
;graphics mode
3B8C 00 00 c_grstr2 db 0,nul ;c.itoh
;graphics mode
3B8E FF c_endf db end_tblf ;table end
;flag
;----------------------------------------------
;-- Okidata Configuration Data --
;----------------------------------------------
;
; The Okidata printer has a 7 dot graphics head
; instead of 8 dots. Since our characters are
; 10x16, the Okidata is programmed to print the
; dots out in 4 rows of 4 dots each (instead of
; 2 rows of 7 dots, with 2 dots left over). This
; allows the program to use the same algorithm
; type for the Okidata as it uses for the other
; printers. However, it is slower since it
; requires 4 passes for every line of characters
; instead of two passes.
= 3B8F okidata_tbl equ $
3B8F 01 ok_prttyp db 1 ;okidata
;algorithm type
3B90 03 ok_grcnt_typ db 3 ;okidata
;format of graphics
;bytes
3B91 FFF9 ok_eneedles dw -7 ;okidata
;num of scan
;lines/printed line
3B93 0001 ok_rtmin dw 1 ;okidata
;line length to
;print
3B95 01 1D ok_initstr db 1,29 ;okidata
;init string - 12
;chars/inch
3B97 02 03 02 ok_finalstr db 2,etx,stx ;okidata
;final string
3B9A 00 00 ok_bolstr db 0,nul ;okidata
;beg of line string
3B9C 02 03 0E ok_eolstr db 2,etx,so ;okidata
;end of line string
3B9F 01 03 ok_grstr1 db 1,etx ;okidata
;graphics mode
3BA1 00 00 ok_grstr2 db 0,nul ;okidata
;graphics mode
3BA3 FF ok_endf db end_tblf ;table end
;flag
10.7 Patching the Grafix Kernel for the MT-180 Printer
A>DEBUG GRAFIX.COM DEBUG-86 VERSION 1.07 >d3b00 0473:3B00 2E A0 3F 0E 2E 08 06 1A-0B C3 00 00 00 00 00 00 . ?......C...... 0473:3B10 0A 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................ 0473:3B20 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................ 0473:3B30 00 00 00 00 32 00 00 00-00 00 00 00 00 00 00 00 ....2........... 0473:3B40 00 01 01 08 00 00 00 04-0A 1B 41 08 02 1B 32 00 ..........A...2. 0473:3B50 00 02 0D 0A 02 1B 4C 00-00 FF 01 01 F8 FF C8 00 ......L.....x.H. 0473:3B60 00 00 00 00 00 00 02 0D-0A 02 1B 4C 01 20 FF 01 ...........L.... 0473:3B70 02 F8 FF 00 00 08 1B 45-1B 54 31 36 0D 0A 04 1B .x.....E.T16.... >e3b5c 0473:3B5C F8.08 FF.00 C8.00 00. 0473:3B60 00.01 00.0D 00.01 00.0C 00. 00. 02. OD. 0473:3B68 OA. O2.03 1B. 4C.25 01.34 20.00 FF.00 01.FF >d3b00 0473:3B00 2E A0 3F 0E 2E 08 06 1A-0B C3 00 00 00 00 00 00 . ?......C...... 0473:3B10 0A 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................ 0473:3B20 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................ 0473:3B30 00 00 00 00 32 00 00 00-00 00 00 00 00 00 00 00 ....2........... 0473:3B40 00 01 01 08 00 00 00 04-0A 1B 41 08 02 1B 32 00 ..........A...2. 0473:3B50 00 02 0D 0A 02 1B 4C 00-00 FF 01 01 08 00 00 00 ......L......... 0473:3B60 01 0D 01 0C 00 00 02 0D-0A 03 1B 25 34 00 00 FF ...........%4... 0473:3B70 02 F8 FF 00 00 08 1B 45-1B 54 31 36 0D 0A 04 1B .x.....E.T16.... >ngr180.com >w Writing 5409 bytes >q A> Procedure for modifying GRAFIX Ver 1.2 to work with the Tally MT180 printer. This modifies the MT140 driver to use MT180 escape codes. To invoke the new version for BUSIGRAF, for example, type: GR180 $S1C3PS <cr> NOTE that this modification clobbers the ability of GRAFIX to operate the C.ITOH printer, so you should keep your original copy of GRAFIX in case you wish to use a C.ITOH at a later date. This modification also prints a Formfeed after the graphics dump is finished. If you do not want this feature then change bytes 3B62 and 3B63 to 00. To patch Grafix Ver 1.3, add 10h to each of the above addresses. That is, start changing bytes at location 3B6C. 10.8 Character PrintingOne of the Sirius 1's most useful graphics features seems to be greatly overlooked: its ability to do character graphics printing. If you design a keyboard file using Keygen that has special non-ASCII characters, and you try printing a document in the standard fashion, you will find that these special characters will not be printed. Suppose, for instance, that you have loaded the future character set (FUTURE.CHR) into your system from the Graphics Toolkit. All the characters displayed on the CRT are in the future type, but when you try printing the file, you will find that the printed characters are once again the standard ASCII type. To remedy this, you must use the CHRPRINT.EXE file, also found on the Graphics Toolkit. CHRPRINT.EXE causes documents to be printed in the same style in which they appear on the screen. This utility will work with any file, as long as the file has been saved in a standard ASCII format; thus, any file created with EDLIN, PMATE, BENCHMARK or WORDSTAR (using non-document mode), or any file just copied from the screen to a file, can be printed with a dot matrix printer in any number of character styles and scripts.To call up CHRPRINT, type: CHRPRINT filename <cr> A>ren chrprint.exe temp A>debug temp DEBUG-86 version 1.07 >d06c0 0473:06C0 02 0D 0A 02 1B 4C 00 00-46 01 01 F8 FF C8 00 00 .....L..F..x.H.. 0473:06D0 00 00 00 00 00 02 0D 0A-02 1B 4C 01 20 46 01 02 ..........L. F.. 0473:06E0 F8 FF 00 00 08 1B 45 1B-54 31 36 0D 0A 04 1B 4E x.....E.T16....N 0473:06F0 1B 41 00 00 02 0D 0A 03-1B 53 30 00 00 46 01 03 .A.......SO..F.. 0473:0700 FC FF 00 00 03 1D 0D 0A-07 1B 25 39 00 1E 0D 0A |.........%9.... 0473:0710 00 00 08 03 02 1B 25 39-08 0D 0A 01 03 00 00 46 ......%9.......F 0473:0720 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................ 0473:0730 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................ >e06b 0473:06CB F8.08 FF.00 C8.00 00. 00.01 0473:06D0 00.0d 00.01 00.0c 00. 00. 02. 0D. 0A. 0473:06D8 02.03 1B. 4C.25 01.34 20.00 46.00 01.46 02.01 0473:06E0 f8.02 >w Writing 0980 bytes >q A>ren temp chrprint.exe N.B. This fix probably clobbers other printer drivers so keep a spare copy of the original. |
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