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Assembly Source File | 1993-06-19 | 55.7 KB | 1,686 lines

; ; MODEX.ASM - A Complete Mode X Library ; ; By Matt Pritchard ; With considerable input from Michael Abrash ; ; The following information is donated to the public domain in ; the hopes that save other programmers much frustration. ; ; If you do use this code in a product, it would be nice if ; you include a line like 'Mode X routine by Matt Pritchard' ; in the credits. ' ; .MODEL Medium, Basic .286 PAGE 255, 132 ; ==== MACROS ==== OUT_16 MACRO Register, Value MOV DX, Register ; Select Register MOV AX, Value ; Get Out Value OUT DX, AX ; Set Register(s) ENDM OUT_8 MACRO Register, Value MOV DX, Register ; Select Register MOV AL, Value ; Get Out Value OUT DX, AL ; Set Register ENDM ; ==== General Constants ==== False EQU 0 True EQU -1 b EQU BYTE PTR w EQU WORD PTR d EQU DWORD PTR ; ==== VGA Register Values ==== VGA_Segment EQU 0A000H ; Vga Memory Segment ATTRIB_Ctrl EQU 03C0H ; VGA Attribute Controller GC_Index EQU 03CEH ; VGA Graphics Controller SC_Index EQU 03C4H ; VGA Sequencer Controller SC_Data EQU 03C5H ; VGA Sequencer Data Port CRTC_Index EQU 03D4H ; VGA CRT Controller CRTC_Data EQU 03D5H ; VGA CRT Controller Data MISC_OUTPUT EQU 03C2H ; VGA Misc Register INPUT_1 EQU 03DAH ; Input Status #1 Register DAC_WRITE_ADDR EQU 03C8H ; VGA DAC Write Addr Register DAC_READ_ADDR EQU 03C7H ; VGA DAC Read Addr Register PEL_DATA_REG EQU 03C9H ; VGA DAC/PEL data Register R/W MAP_MASK EQU 02 ; Map Register # READ_MAP EQU 04 ; Read Map Register # MAP_MASK_PLANE1 EQU 0102h ; Map Register + Plane 1 START_DISP_HI EQU 0Ch ; CRTC Index: Display Start Addr Hi START_DISP_LO EQU 0Dh ; CRTC Index: Display Start Addr Lo PLANE_BITS EQU 03h ; Bits 0-1 of Xpos = Plane # ALL_PLANES EQU 0Fh ; All Bit Planes Selected ALL_PLANES_ON EQU 0F02h ; Map Register + All Bit Planes CHAIN4_OFF EQU 0604h ; Chain 4 mode Off ASYNC_RESET EQU 0100h ; (A)synchronous Reset SEQU_RESTART EQU 0300h ; Sequencer Restart ; Constants Specific for these routines NUM_MODES EQU 8 ; # of Mode X Variations ; Specific Mode Data Table format... M_MiscR EQU 0 ; Value of MISC_OUTPUT register M_Pages EQU 1 ; Maximum Possible # of pages M_XSize EQU 2 ; X Size Displayed on screen M_YSize EQU 4 ; Y Size Displayed on screen M_XMax EQU 6 ; Maximum Possible X Size M_YMax EQU 8 ; Maximum Possible Y Size M_CRTC EQU 10 ; Table of CRTC register values ; ==== DGROUP STORAGE NEEDED (36 BYTES) ===== .DATA? SCREEN_WIDTH DW 0 ; Width of a line in Bytes SCREEN_WIDTHx4 DW 0 ; Width of a line in Pixels SCREEN_HEIGHT DW 0 ; Veritcal Height in Pixels LAST_PAGE DW 0 ; # of Display Pages PAGE_ADDR DW 0, 0, 0, 0 ; Offsets to start of each page PAGE_SIZE DW 0 ; Size of Page in Addr Bytes DISPLAY_PAGE DW 0 ; Page # currently displayed ACTIVE_PAGE DW 0 ; Page # currently active CURRENT_PAGE DW 0 ; Offset of current Page CURRENT_SEGMENT DW 0 ; Segment of VGA memory CURRENT_XOFFSET DW 0 ; Current Display X Offset CURRENT_YOFFSET DW 0 ; Current Display Y Offset CURRENT_MOFFSET DW 0 ; Current Start Offset MAX_XOFFSET DW 0 ; Current Display X Offset MAX_YOFFSET DW 0 ; Current Display Y Offset .CODE ; Data Tables, Put in Code Segement for Easy Access ; (Like when all the other Segment Registers are in ; use!!) and reduced DGROUP requirements... LEFT_CLIP_MASK DB 0FH, 0EH, 0CH, 08H RIGHT_CLIP_MASK DB 01H, 03H, 07H, 0FH MODE_TABLE: DW OFFSET MODE_320x200, OFFSET MODE_320x400 DW OFFSET MODE_360x200, OFFSET MODE_360x400 DW OFFSET MODE_320x240, OFFSET MODE_320x480 DW OFFSET MODE_360x240, OFFSET MODE_360x480 MODE_320x200: ; Data for 320 by 200 Pixels DB 063h ; 400 scan Lines & 25 Mhz Clock DB 4 ; Maximum of 4 Pages DW 320, 200 ; Displayed Pixels (X,Y) DW 1302, 816 ; Max Possible X and Y Sizes ;CRTC Setup Data.... DW 00014H ; Dword Mode off DW 0E317H ; turn on Byte Mode DW 00000h ; End of CRTC Data for 320x200 MODE_320x400: ; Data for 320 by 400 Pixels DB 063h ; 400 scan Lines & 25 Mhz Clock DB 2 ; Maximum of 2 Pages DW 320, 400 ; Displayed Pixels X,Y DW 648, 816 ; Max Possible X and Y Sizes ;CRTC Setup Data.... DW 04009H ; Cell Heigth (1 Scan Line) DW 00014H ; Dword Mode off DW 0E317H ; turn on Byte Mode DW 00000h ; End of CRTC Data for 320x400 MODE_360x240: ; Data for 360 by 240 Pixels DB 0E7h ; 480 scan Lines & 28 Mhz Clock DB 3 ; Maximum of 3 Pages DW 360, 240 ; Displayed Pixels X,Y DW 1092, 728 ; Max Possible X and Y Sizes ;CRTC Setup Data.... DW 06B00H ; Horz total DW 05901H ; Horz Displayed DW 05A02H ; Start Horz Blanking DW 08E03H ; End Horz Blanking DW 05E04H ; Start H Sync DW 08A05H ; End H Sync DW 00D06H ; Vertical Total DW 03E07H ; Overflow DW 04109H ; Cell Heigth (2 Scan Lines) DW 0EA10H ; V Sync Start DW 0AC11H ; V Sync End/Prot Cr0 Cr7 DW 0DF12H ; Vertical Displayed DW 00014H ; Dword Mode off DW 0E715H ; V Blank Start DW 00616H ; V Blank End DW 0E317H ; turn on Byte Mode DW 00000h ; End of CRTC Data for 360x240 MODE_360x480: ; Data for 360 by 480 Pixels DB 0E7h ; 480 scan Lines & 28 Mhz Clock DB 1 ; Only 1 Page Possible DW 360, 480 ; Displayed Pixels X,Y DW 544, 728 ; Max Possible X and Y Sizes ;CRTC Setup Data.... DW 06B00H ; Horz total DW 05901H ; Horz Displayed DW 05A02H ; Start Horz Blanking DW 08E03H ; End Horz Blanking DW 05E04H ; Start H Sync DW 08A05H ; End H Sync DW 00D06H ; Vertical Total DW 03E07H ; Overflow DW 04009H ; Cell Heigth (1 Scan Line) DW 0EA10H ; V Sync Start DW 0AC11H ; V Sync End/Prot Cr0 Cr7 DW 0DF12H ; Vertical Displayed DW 00014H ; Dword Mode off DW 0E715H ; V Blank Start DW 00616H ; V Blank End DW 0E317H ; turn on Byte Mode DW 00000h ; End of CRTC Data for 360x480 MODE_320x240: ; Data for 320 by 240 Pixels DB 0E3h ; 480 scan Lines & 25 Mhz Clock DB 3 ; Maximum of 3 Pages DW 320, 240 ; Displayed Pixels X,Y DW 1088, 818 ; Max Possible X and Y Sizes DW 00D06H ; Vertical Total DW 03E07H ; Overflow DW 04109H ; Cell Heigth (2 Scan Lines) DW 0EA10H ; V Sync Start DW 0AC11H ; V Sync End/Prot Cr0 Cr7 DW 0DF12H ; Vertical Displayed DW 00014H ; Dword Mode off DW 0E715H ; V Blank Start DW 00616H ; V Blank End DW 0E317H ; turn on Byte Mode DW 00000h ; End of CRTC Data for 320x240 MODE_320x480: ; Data for 320 by 480 Pixels DB 0E3h ; 480 scan Lines & 25 Mhz Clock DB 1 ; Only 1 Page Possible DW 320, 480 ; Displayed Pixels X,Y DW 540, 818 ; Max Possible X and Y Sizes DW 00D06H ; Vertical Total DW 03E07H ; Overflow DW 04009H ; Cell Heigth (1 Scan Line) DW 0EA10H ; V Sync Start DW 0AC11H ; V Sync End/Prot Cr0 Cr7 DW 0DF12H ; Vertical Displayed DW 00014H ; Dword Mode off DW 0E715H ; V Blank Start DW 00616H ; V Blank End DW 0E317H ; turn on Byte Mode DW 00000h ; End of CRTC Data for 320x480 MODE_360x200: ; Data for 360 by 200 Pixels DB 067h ; 400 scan Lines & 28 Mhz Clock DB 3 ; Maximum of 3 Pages DW 360, 200 ; Displayed Pixels (X,Y) DW 1302, 728 ; Max Possible X and Y Sizes ;CRTC Setup Data.... DW 06B00H ; Horz total DW 05901H ; Horz Displayed DW 05A02H ; Start Horz Blanking DW 08E03H ; End Horz Blanking DW 05E04H ; Start H Sync DW 08A05H ; End H Sync DW 00014H ; Dword Mode off DW 0E317H ; turn on Byte Mode DW 00000h ; End of CRTC Data for 360x200 MODE_360x400: ; Data for 360 by 400 Pixels DB 067h ; 400 scan Lines & 28 Mhz Clock DB 1 ; Maximum of 1 Pages DW 360, 400 ; Displayed Pixels X,Y DW 648, 816 ; Max Possible X and Y Sizes ;CRTC Setup Data.... DW 06B00H ; Horz total DW 05901H ; Horz Displayed DW 05A02H ; Start Horz Blanking DW 08E03H ; End Horz Blanking DW 05E04H ; Start H Sync DW 08A05H ; End H Sync DW 04009H ; Cell Heigth (1 Scan Line) DW 00014H ; Dword Mode off DW 0E317H ; turn on Byte Mode DW 00000h ; End of CRTC Data for 360x400 ; ===== ACTUAL ASSEMBLY CODE ===== ;====================================================== ;SET_VGA_MODEX%(ModeType%, MaxXPos%, MaxYpos%, Pages%) ;====================================================== ; ; Sets Up the specified version of Mode X. Allows for ; the setup of multiple video pages, and a virtual ; screen which can be larger than the displayed screen ; (which can then be scrolled a pixel at a time) ; ; INPUT PARAMETERS: ; ; ModeType% - The Desired Version of 256 Color Mode X ; ; 0 = 320 x 200, 4 Pages max, 1.2:1 Aspect Ratio ; 1 = 320 x 400, 2 Pages max, 2.4:1 Aspect Ratio ; 2 = 360 x 200, 3 Pages max, 1.35:1 Aspect Ratio ; 3 = 360 x 400, 1 Page max, 2.7:1 Aspect Ratio ; 4 = 320 x 240, 3 Pages max, 1:1 Aspect Ratio ; 5 = 320 x 480, 1 Page max, 2:1 Aspect Ratio ; 6 = 360 x 240, 3 Pages max, 1.125:1 Aspect Ratio ; 7 = 360 x 480, 1 Page max, 2.25:1 Aspect Ratio ; ; MaxXpos = The Desired Virtual Screen Width ; MaxYpos = The Desired Virtual Screen Height ; Pages% = The Desired # of Video Pages ; ; RETURNS in AX: 0 (= Failure) or ffff (= Success) ; SVM_STACK STRUC DW ?,?,?,? ;DI,SI,DS,BP DD ? ;Caller SVM_Pages DW ? SVM_Ysize DW ? SVM_Xsize DW ? SVM_Mode DW ? SVM_STACK ENDS PUBLIC SET_VGA_MODEX SET_VGA_MODEX PROC FAR PUSH BP ; Preserve Important PUSH DS ; Register Values PUSH SI PUSH DI MOV BP,SP ; Set up Stack Frame ;Check Legality of Mode Request.... MOV BX, [BP].SVM_Mode ; Get Requested Mode # CMP BX, NUM_MODES ; Is it 0..7? JAE SVM_BadModeSetup ; If Not, Error out SHL BX, 1 ; Scale BX MOV SI, w CS:MODE_TABLE[BX] ; CS:SI -> Mode Info PUSH SI ; Save for later use ;Check # of Requested Display Pages MOV CX, [Bp].SVM_Pages ; Get # of Requested Pages CMP CX, CS:[SI].M_Pages ; Check # Pages for mode JA SVM_BadModeSetup ; Report Error if too Many OR CX, CX ; # Pages = 0? JE SVM_BadModeSetup ; Report Error if 0 ;Check Validity of X Size AND [BP].SVM_XSize, 0FFF8h ;X size Mod 8 Must = 0 MOV AX, [BP].SVM_XSize ; Get Logical Screen Width CMP AX, CS:[SI].M_XSize ; Check against Displayed X JB SVM_BadModeSetup ; Report Error if too small CMP AX, CS:[SI].M_XMax ; Check against Max X JA SVM_BadModeSetup ; Report Error if too big ;Check Validity of Y Size MOV BX, [BP].SVM_YSize ; Get Logical Screen Height CMP BX, CS:[SI].M_YSize ; Check against Displayed Y JB SVM_BadModeSetup ; Report Error if too small CMP BX, CS:[SI].M_YMax ; Check against Max Y JA SVM_BadModeSetup ; Report Error if too big ;Enough memory to Fit it all? SHR AX, 2 ;# of Bytes:Line = XSize/4 MUL BX ;# Bytes/Page = AX/4 * BX JO SVM_BadModeSetup ;Exit if Page Size > 256K MUL CX ;Total Mem = PageSize * Pages JNO SVM_Continue ;Exit if Total Size > 256K SVM_BadModeSetup: XOR AX, AX ; Return Value = False JMP SVM_Exit ; Normal Exit SVM_Continue: MOV AX, 13H ; Start with Mode 13H INT 10H ; Let BIOS Set Mode OUT_16 SC_INDEX, CHAIN4_OFF ; Disable Chain 4 Mode OUT_16 SC_INDEX, ASYNC_RESET ; (A)synchronous Reset MOV DX, MISC_OUTPUT ; VGA Misc Register MOV AL, CS:[SI].M_MiscR ; Get New Timing/Size Value OUT DX, AL ; Set VGA Misc Register OUT_16 SC_INDEX, SEQU_RESTART ; Restart Sequencer ... MOV DX, CRTC_INDEX ; Vga crtc Registers MOV AL, 11H ; Vert Retrace End Register OUT DX, AL ; Load Current Value INC DX ; Point to Data IN AL, DX ; Get Value, Bit 7 = Protect AND AL, 7FH ; Mask out Write Protect OUT DX, AL ; And send it back MOV DX, CRTC_INDEX ; Vga Crtc Registers ADD SI, M_CRTC ; SI -> CRTC Parameter Data SVM_Setup_CRTC: MOV AX, CS:[SI] ; Get CRTC Data from Table ADD SI, 2 ; Advance Pointer OR AX, AX ; At End of Data Table? JZ SVM_Set_Data ; If so, Exit Loop OUT DX, AX ; Reprogram VGA CRTC reg JMP SVM_Setup_CRTC ; Process Next Table Entry SVM_Set_Data: XOR AX, AX ; AX = 0 MOV DISPLAY_PAGE, AX ; Display Page = 0 MOV ACTIVE_PAGE, AX ; Active Page = 0 MOV CURRENT_PAGE, AX ; Current Page (Offset) = 0 MOV CURRENT_XOFFSET, AX ; Horz Scroll Index = 0 MOV CURRENT_YOFFSET, AX ; Vert Scroll Index = 0 MOV CURRENT_MOFFSET, AX ; Memory Scroll Index = 0 MOV AX, VGA_SEGMENT ; Segment for VGA memory MOV CURRENT_SEGMENT, AX ; Save for Future LES's ;Set Logical Screen Width, X Scroll and Our Data POP SI ; Get Saved Ptr to Mode Info MOV AX, [Bp].SVM_Xsize ; Get Display Width MOV CX, AX ; CX = Logical Width SUB CX, CS:[SI].M_XSize ; CX = Max X Scroll Value MOV MAX_XOFFSET, CX ; Set Maximum X Scroll MOV SCREEN_WIDTHx4, AX ; Save Width in Pixels SHR AX, 2 ; Bytes = Pixels / 4 MOV SCREEN_WIDTH, AX ; Save Width in Pixels SHR AX, 1 ; Offset Value = Bytes / 2 MOV AH, 13h ; CRTC Offset Register Index XCHG AL, AH ; Switch format for OUT OUT DX, AX ; Set VGA CRTC Offset Reg ;Setup Data table, Y Scroll, Misc for Other Routines MOV AX, [Bp].SVM_Ysize ; Get Logical Screen Hieght MOV CX, AX ; CX = Logical Height SUB BX, CS:[SI].M_YSize ; CX = Max Y Scroll Value MOV MAX_YOFFSET, CX ; Set Maximum Y Scroll MOV SCREEN_HEIGHT, AX ; Save Hight in Pixels MUL SCREEN_WIDTH ; AX = Page Size in Bytes, MOV PAGE_SIZE, AX ; Save Page Size MOV CX, [Bp].SVM_Pages ; Get # of Pages MOV LAST_PAGE, CX ; Save # of Pages MOV BX, 0 ; Page # = 0 MOV DX, BX ; Page 0 Offset = 0 SVM_Set_Pages: MOV PAGE_ADDR[BX], DX ; Set Page #(BX) Offset ADD BX, 2 ; Page#++ ADD DX, AX ; Compute Addr of Next Page LOOP SVM_Set_Pages ; Loop until Done ;Clear VGA Memory OUT_16 SC_INDEX, ALL_PLANES_ON ; Select All Planes LES DI, d CURRENT_PAGE ; Point to Start of VGA memory XOR AX, AX ; AX = 0 CLD ; Block Xfer Forwards MOV CX, 8000H ; 32K * 4 * 2 = 256K REP STOSW ; Clear dat memory! MOV AX, True ; Return Success Code SVM_EXIT: POP DI ; Restore Saved Registers POP SI POP DS POP BP RET 8 ;We are Done.. Outa here SET_VGA_MODEX ENDP ;================== ;SET_MODEX% (Mode%) ;================== ; ; Quickie Mode Set - Sets Up Mode X to Default Configuration ; ; INPUT PARAMETERS: ; ; ModeType% - The Desired Version of 256 Color Mode X ; ; (0 to 7 - See Chart under SET_VGA_MODEX) ; ; RETURNS in AX: 0 (= Failure) or ffff (= Success) ; SM_STACK STRUC DW ? ;BP DD ? ;Caller SM_Mode DW ? SM_STACK ENDS PUBLIC SET_MODEX SET_MODEX PROC FAR PUSH BP ; Preserve Important MOV BP,SP ; Set up Stack Frame XOR AX, AX ; Assume Failure MOV BX, [BP].SM_Mode ; Get Desired Mode # CMP BX, NUM_MODES ; Is it 0..7? JAE @SX_Exit ; If Not, don't Bother PUSH BX ; Push Mode Parameter SHL BX, 1 ; Scale BX MOV SI, w CS:MODE_TABLE[BX] ;CS:SI -> Mode Info MOV AX, CS:[SI].M_XSize ; Get Default X Size PUSH AX ; Push X Size Parameter MOV AX, CS:[SI].M_Ysize ; Get Default Y size PUSH AX ; Push Y Size Parameter MOV AL, CS:[SI].M_Pages ; Get Default # of Pages MOV AH, 0 ; Hi Byte = 0 PUSH AX ; Push # Pages CALL FAR PTR SET_VGA_MODEX ; Set up Mode X! @SX_Exit: POP BP ; Restore Register RET 2 ; We are Done.. Outa here SET_MODEX ENDP ;============================ ;CLEAR_VGA_SCREEN (ColorNum%) ;============================ ; ; Clears the currently active display page to ; all the color #ColorNum ; CVS_STACK STRUC DW ?,? ;DI, BP DD ? ;Caller CVS_COLOR DB ?,? ;Color to Set Screen to CVS_STACK ENDS PUBLIC CLEAR_VGA_SCREEN CLEAR_VGA_SCREEN PROC FAR PUSH BP ; Preserve Registers PUSH DI MOV BP, SP ; Set up Stack Frame OUT_16 SC_INDEX, ALL_PLANES_ON ; Select All Planes LES DI, d CURRENT_PAGE ; Point to Active VGA Page MOV AL, [BP].CVS_COLOR ; Get Color MOV AH, AL ; Copy for Word Write CLD ; Block fill Forwards MOV CX, PAGE_SIZE ; Get Size of Page SHR CX, 1 ; Divied by 2 for Words REP STOSW ; Block Fill VGA memory POP DI ; Restore Saved Registers POP BP RET 2 ;We are Done.. Outa here CLEAR_VGA_SCREEN ENDP ;=================================== ;SET_POINT (Xpos%, Ypos%, ColorNum%) ;=================================== ; ; Sets a single Pixel at (Xpos, Ypos) on the active ; Display Page to color #ColorNum ; SP_STACK STRUC DW ? ;BP DD ? ;Caller SETP_Color DB ?,? SETP_Ypos DW ? SETP_Xpos DW ? SP_STACK ENDS PUBLIC SET_POINT SET_POINT PROC FAR PUSH BP ; Preserve Registers MOV BP, SP ; Set up Stack Frame LES DI, d CURRENT_PAGE ; Point to Active VGA Page MOV AX, [BP].SETP_Ypos ; Get Line # of Pixel MUL SCREEN_WIDTH ; Get Offset to Start of Line MOV BX, [BP].SETP_Xpos ; Get Xpos MOV CX, BX SHR BX, 2 ; X offset (Bytes) = Xpos/4 ADD BX, AX ; Offset = Width*Ypos + Xpos/4 MOV AX, MAP_MASK_PLANE1 ; Map Mask & Plane Select Register AND CL, PLANE_BITS ; Get Plane Bits SHL AH, CL ; Get Plane Select Value MOV DX, SC_Index ; Setup to select plane OUT DX, AX ; Select Plane... MOV AL,[BP].SETP_Color ; Get Pixel Color MOV ES:[DI+BX], AL ; Draw Pixel POP BP ; Restore Saved Registers RET 6 ; Exit and Clean up Stack SET_POINT ENDP ;========================== ;READ_POINT% (Xpos%, Ypos%) ;========================== ; ; Returns the color of a pixel from the Active Display Page ; ; RETURNS: AX = Color of Pixel at (Xpos, Ypos) ; RP_STACK STRUC DW ? ;Bp DD ? ;Caller RP_Ypos DW ? RP_Xpos DW ? RP_STACK ENDS PUBLIC READ_POINT READ_POINT PROC FAR PUSH BP ; Preserve Registers MOV BP, SP ; Set up Stack Frame LES DI, d CURRENT_PAGE ; Point to Active VGA Page MOV AX, [Bp].RP_Ypos ; Get Line # of Pixel MUL SCREEN_WIDTH ; Get Offset to Start of Line MOV BX, [BP].RP_Xpos ; Get Xpos MOV CX, BX SHR BX, 2 ; X offset (Bytes) = Xpos/4 ADD BX, AX ; Offset = Width*Ypos + Xpos/4 MOV AL, READ_MAP ; GC Read Mask Register MOV AH, CL ; Get Xpos AND AH, PLANE_BITS ; & mask out Plane # MOV DX, GC_INDEX ; Setup to select Read Mask OUT DX, AX ; Select Read Plane... XOR AX, AX ; Clear Return Value MOV AL, ES:[DI+BX] ; Get Color of Pixel POP BP ; Restore Saved Registers RET 4 ; Exit and Clean up Stack READ_POINT ENDP ;====================================================== ;FILL_BLOCK (Xpos1%, Ypos1%, Xpos2%, Ypos2%, ColorNum%) ;====================================================== ; ; Fills a block on the current display Page from Point ; (Xpos1, Ypos1) to Point (Xpos2, Ypos2) in Color #ColorNum ; FB_STACK STRUC DW ?,?,?,? ; DS, DI, SI, BP DD ? ; Caller FB_Color DB ?,? ; Fill Color FB_Ypos2 DW ? ; Lower Right Pixel FB_Xpos2 DW ? ; FB_Ypos1 DW ? ; Upper Left Pixel FB_Xpos1 DW ? ; FB_STACK ENDS PUBLIC FILL_BLOCK FILL_BLOCK PROC FAR PUSH BP ; Save Registers PUSH SI PUSH DI PUSH DS MOV BP, SP ; Set up Stack Frame LES DI, d CURRENT_PAGE ; Point to Active VGA Page CLD ; Direction Flag = Forward OUT_8 SC_INDEX, MAP_MASK ; Set up for Plane Select ; Validate Pixel Coordinates ; If necessary, Swap so X1 <= X2, Y1 <= Y2 MOV AX, [BP].FB_Ypos1 ; AX = Y1 is Y1< Y2? MOV BX, [BP].FB_Ypos2 ; BX = Y2 CMP AX, BX JLE @FB_NOSWAP1 MOV [BP].FB_Ypos1, BX ; Swap Y1 and Y2 and save Y1 XCHG AX, BX ; on stack for future use @FB_NOSWAP1: SUB BX, AX ; Get Y width INC BX ; Add 1 to avoid 0 value MOV [BP].FB_Ypos2, BX ; Save in Ypos2 MUL SCREEN_WIDTH ; Mul Y1 by Bytes per Line ADD DI, AX ; DI = Start of Line Y1 MOV AX, [BP].FB_Xpos1 ; Check X1 <= X2 MOV BX, [BP].FB_Xpos2 ; CMP AX, BX JLE @FB_NOSWAP2 ; Skip Ahead if Ok MOV [BP].FB_Xpos2, AX ; Swap X1 AND X2 and save X2 XCHG AX, BX ; on stack for future use ; All our Input Values are in order, Now determine ; How many full "bands" 4 pixels wide (aligned) there ; are, and if there are partial bands (<4 pixels) on ; the left and right edges. @FB_NOSWAP2: MOV DX, AX ; DX = X1 (Pixel Position) SHR DX, 2 ; DX/4 = Bytes into Line ADD DI, DX ; DI = Addr of Upper-Left Corner MOV CX, BX ; CX = X2 (Pixel Position) SHR CX, 2 ; CX/4 = Bytes into Line CMP DX, CX ; Start and end in same band? JNE @FB_NORMAL ; if not, check for l & r edges JMP @FB_ONE_BAND_ONLY ; if so, then special processing @FB_NORMAL: SUB CX, DX ; CX = # bands -1 MOV SI, AX ; SI = PLANE#(X1) AND SI, PLANE_BITS ; if Left edge is aligned then .. JZ @FB_LEFT_PLANE_FLUSH ; no special processing.. ; Draw "Left Edge" vertical strip of 1-3 pixels... OUT_8 SC_Data, LEFT_CLIP_MASK[SI] ; Set Left Edge Plane Mask MOV SI, DI ; SI = Copy of Start Addr (UL) MOV DX, [BP].FB_Ypos2 ; Get # of Lines to draw MOV AL, [BP].FB_Color ; Get Fill Color MOV BX, SCREEN_WIDTH ; Get Vertical increment Value @FB_LEFT_LOOP: MOV ES:[SI], AL ; Fill in Left Edge Pixels ADD SI, BX ; Point to Next Line (Below) DEC DX ; Lines to go-- JZ @FB_LEFT_CONT ; Exit loop if all Lines Drawn MOV ES:[SI], AL ; Fill in Left Edge Pixels ADD SI, BX ; Point to Next Line (Below) DEC DX ; Lines to go-- JNZ @FB_LEFT_LOOP ; loop until left strip is drawn @FB_LEFT_CONT: INC DI ; Point to Middle (or Right) Block DEC CX ; Reset CX insted of JMP @FB_RIGHT @FB_LEFT_PLANE_FLUSH: INC CX ; Add in Left band to middle block ;DI = Addr of 1st middle Pixel (band) to fill ;CX = # of Bands to fill -1 @FB_RIGHT: MOV SI, [BP].FB_Xpos2 ; Get Xpos2 AND SI, PLANE_BITS ; Get Plane values CMP SI, 0003 ; Plane = 3? JE @FB_RIGHT_EDGE_FLUSH ; Hey, add to middle ; Draw "Right Edge" vertical strip of 1-3 pixels... OUT_8 SC_Data, RIGHT_CLIP_MASK[SI] ; Set Right Edge Plane Mask MOV SI, DI ; Get Addr of Left Edge ADD SI, CX ; Add Width-1 (Bands) DEC SI ; To point to top of Right Edge MOV DX, [BP].FB_Ypos2 ; Get # of Lines to draw MOV AL, [BP].FB_Color ; Get Fill Color MOV BX, SCREEN_WIDTH ; Get Vertical increment Value @FB_RIGHT_LOOP: MOV ES:[SI], AL ; Fill in Right Edge Pixels ADD SI, BX ; Point to Next Line (Below) DEC DX ; Lines to go-- JZ @FB_RIGHT_CONT ; Exit loop if all Lines Drawn MOV ES:[SI], AL ; Fill in Right Edge Pixels ADD SI, BX ; Point to Next Line (Below) DEC DX ; Lines to go-- JNZ @FB_RIGHT_LOOP ; loop until left strip is drawn @FB_RIGHT_CONT: DEC CX ; Minus 1 for Middle bands JCXZ @FB_EXIT ; Uh.. no Middle bands... @FB_RIGHT_EDGE_FLUSH: ;DI = Addr of Upper Left block to fill ;CX = # of Bands to fill in (width) OUT_8 SC_Data, 0FH ; Write to All Planes MOV DX, SCREEN_WIDTH ; DX = DI Incrament SUB DX, CX ; = Screen_Width-# Planes Filled MOV BX, CX ; BX = Quick Refill for CX MOV SI, [BP].FB_Ypos2 ; SI = # of Line to Fill MOV AL, [BP].FB_Color ; Get Fill Color @FB_MIDDLE_LOOP: REP STOSB ; Fill in entire line MOV CX, BX ; Recharge CX (Line Width) ADD DI, DX ; Point to start of Next Line DEC SI ; Lines to go-- JNZ @FB_MIDDLE_LOOP ; Loop until all lines drawn JMP @FB_EXIT ; Outa here @FB_ONE_BAND_ONLY: MOV SI, AX ; Get Left CLip Mask, Save X1 AND SI, PLANE_BITS ; Mask out Row # MOV AL, LEFT_CLIP_MASK[SI] ; Get Left Edge Mask MOV SI, BX ; Get Right Clip Mask, Save X2 AND SI, PLANE_BITS ; Mask out Row # AND AL, RIGHT_CLIP_MASK[SI] ; Get Right Edge Mask byte MOV DX, SC_Data ; Plane Selection OUT DX, AL ; Clip For Left & Right Masks MOV CX, [BP].FB_Ypos2 ; Get # of Lines to draw MOV AL, [BP].FB_Color ; Get Fill Color MOV BX, SCREEN_WIDTH ; Get Vertical increment Value @FB_ONE_LOOP: MOV ES:[DI], AL ; Fill in Pixels ADD DI, BX ; Point to Next Line (Below) DEC CX ; Lines to go-- JZ @FB_EXIT ; Exit loop if all Lines Drawn MOV ES:[DI], AL ; Fill in Pixels ADD DI, BX ; Point to Next Line (Below) DEC CX ; Lines to go-- JNZ @FB_ONE_LOOP ; loop until left strip is drawn @FB_EXIT: POP DS POP DI POP SI POP BP ; Restore Registers RET 10 ; Exit and Clean up Stack FILL_BLOCK ENDP ;===================================================== ;DRAW_LINE (Xpos1%, Ypos1%, Xpos2%, Ypos2%, ColorNum%) ;===================================================== ; ; Draws a Line from (X1,Y1) to (X2,Y2) in Color #ColorNum ; in VGA Mode X ; DL_STACK STRUC DW ?,?,? ;DI, SI , BP DD ? ;Caller DL_ColorF DB ?,? DL_Ypos2 DW ? DL_Xpos2 DW ? DL_Ypos1 DW ? DL_Xpos1 DW ? DL_STACK ENDS PUBLIC DRAW_LINE DRAW_LINE PROC FAR PUSH BP ; Save Registers PUSH SI PUSH DI MOV BP, SP ; Set up Stack Frame CLD ; Direction Flag = Forward OUT_8 SC_INDEX, MAP_MASK ; Set up for Plane Select MOV CH, [BP].DL_ColorF ; Save Color in CH ;Check Line Type MOV SI, [BP].DL_Xpos1 ; AX = X1 is X1< X2? MOV DI, [BP].DL_Xpos2 ; DX = X2 CMP SI, DI ; Is X1 < X2 JE @DL_VLINE ; If X1=X2, Draw Vertical Line JL @DL_NOSWAP1 ; If X1 < X2, don't swap XCHG SI, DI ; X2 IS > X1, SO SWAP THEM @DL_NOSWAP1: ; SI = X1, DI = X2 MOV AX, [BP].DL_Ypos1 ; AX = Y1 is Y1 <> Y2? CMP AX, [BP].DL_Ypos2 ; Y1 = Y2? JE @DL_HORZ ; If so, Draw a Horizontal Line JMP @DL_BREZHAM ; Diagonal line... go do it... ; This Code draws a Horizontal Line in Mode X where: ; SI = X1, DI = X2, and AX = Y1/Y2 @DL_HORZ: MUL SCREEN_WIDTH ; Offset = Ypos * Screen_Width MOV DX, AX ; CX = Line offste into Page MOV AX, SI ; Get Left Edge CLip Mask, Save X1 AND SI, PLANE_BITS ; Mask out Row # MOV BL, LEFT_CLIP_MASK[SI] ; Get Left Edge Mask MOV CX, DI ; Get Right Edge Clip Mask, Save X2 AND DI, PLANE_BITS ; Mask out Row # MOV BH, RIGHT_CLIP_MASK[DI] ; Get Right Edge Mask byte SHR AX, 2 ; Get X1 Byte # (=X1/4) SHR CX, 2 ; Get X2 Byte # (=X2/4) LES DI, d CURRENT_PAGE ; Point to Active VGA Page ADD DI, DX ; Point to Start of Line ADD DI, AX ; Point to Pixel X1 SUB CX, AX ; CX = # Of Bands (-1) to set JNZ @DL_LONGLN ; If longer than one segment, go ahead AND BL, BH ; otherwise, megre clip masks @DL_LONGLN: OUT_8 SC_Data, BL ; Set the Left Clip Mask MOV AL, [BP].DL_ColorF ; Get Line Color MOV BL, AL ; BL = Copy of Line Color STOSB ; Set Left (1-4) Pixels JCXZ @DL_EXIT ; Done if only one Line Segment DEC CX ; CX = # of Middle Segemnts JZ @DL_XRSEG ; If no middle segments.... ;Draw Middle Segments MOV AL, ALL_PLANES ; Write to ALL Planes OUT DX, AL ; Select Planes MOV AL, BL ; Get Color from BL REP STOSB ; Draw Middle (4 Pixel) Segements @DL_XRSEG: MOV AL, BH ; Get Right Clip Mask OUT DX, AL ; Select Planes MOV AL, BL ; Get Color Value STOSB ; Draw Right (1-4) Pixels JMP SHORT @DL_EXIT ; We Are Done... ; This Code Draws A Vertical Line. On entry: ; CH = Line Color, SI & DI = X1 @DL_VLINE: MOV AX, [BP].DL_Ypos1 ; AX = Y1 MOV SI, [BP].DL_Ypos2 ; SI = Y2 CMP AX, SI ; Is Y1 < Y2? JLE @DL_NOSWAP2 ; if so, Don't Swap them XCHG AX, SI ; Ok, NOW Y1 < Y2 @DL_NOSWAP2: SUB SI, AX ; SI = Line Heigth (Y2-Y1+1) INC SI ; AX = Y1, DI = X1, Get offset into Page into AX MUL SCREEN_WIDTH ; Offset = Y1 (AX) * Screen Width MOV DX, DI ; Copy Xpos into DX SHR DI, 2 ; DI = Xpos/4 ADD AX, DI ; DI = Xpos/4 + ScreenWidth * Y1 LES DI, d CURRENT_PAGE ; Point to Active VGA Page ADD DI, AX ; Point to Pixel X1, Y1 ;Select Plane MOV CL, DL ; CL = Save X1 AND CL, PLANE_BITS ; Get X1 MOD 4 (Plane #) MOV AX, MAP_MASK_PLANE1 ; Code to set Plane #1 SHL AH, CL ; Change to Correct Plane # MOV DX, SC_Index ; Set VGA Sequencer OUT DX, AX ; Select Plane! MOV AL, CH ; Get Saved Color MOV BX, SCREEN_WIDTH ; Get Offset to Advance Line By @DL_VLoop: MOV ES:[DI], AL ; Draw Single Pixel ADD DI, BX ; Point to Next Line DEC SI ; Lines to draw-- JNZ @DL_VLoop ; Loop until Done @DL_EXIT: JMP @DL_EXIT2 ; Done! ; This code Draws a diagonal line in Mode X @DL_BREZHAM: LES DI, d CURRENT_PAGE ; Point to Active VGA Page MOV AX, [BP].DL_Ypos1 ; get y1 value MOV BX, [BP].DL_Ypos2 ; get y2 value MOV CX, [BP].DL_Xpos1 ; Get Starting Xpos CMP BX, AX ; Y2-Y1 is? JNC @DL_DeltaYOK ; if Y2>=Y1 then goto... XCHG BX, AX ; Swap em... MOV CX, [BP].DL_Xpos2 ; Get New Starting Xpos @DL_DeltaYOK: MUL SCREEN_WIDTH ; Offset = SCREEN_WIDTH * Y1 ADD DI, AX ; DI -> Start of Line Y1 on Page MOV AX, CX ; AX = Xpos (X1) SHR AX, 2 ; /4 = Byte Offset into Line ADD DI, AX ; DI = Starting pos (X1,Y1) MOV AL, 11h ; Staring Mask AND CL, PLANE_BITS ; Get Plane # SHL AL, CL ; and shift into placE MOV AH, [BP].DL_ColorF ; Color in Hi Bytes PUSH AX ; Save Mask,Color... MOV DX, SC_Index MOV AH, AL ; Plane # in AH MOV AL, MAP_MASK ; Select Plane Register OUT DX, AX ; Select initial plane MOV AX, [BP].DL_Xpos1 ; get x1 value MOV BX, [BP].DL_Ypos1 ; get y1 value MOV CX, [BP].DL_Xpos2 ; get x2 value MOV DX, [BP].DL_Ypos2 ; get y2 value MOV BP, SCREEN_WIDTH ; Use BP for Line width to ; to avoid extra memory access SUB DX, BX ; figure delta_y JNC @DL_DeltaYOK2 ; jump if y2>=y1 ADD BX, DX ; put y2 into y1 NEG DX ; abs(Delta_y) XCHG AX, CX ; and exchange x1 and x2 @DL_DeltaYOK2: MOV BX, 08000H ; seed for fraction accumulator SUB CX, AX ; figure delta_x JC @DL_DrawLeft ; if negitive, go left JMP @DL_DrawRight ; Draw Line that slopes right @DL_DrawLeft: NEG CX ; abs(Delta_X) CMP CX, DX ; is X < Delta_Y? JB @DL_SteepLeft ; yes, so go do steep line (Delta_Y iterations) ; Draw a Shallow line to the left in Mode X @DL_ShallowLeft: XOR AX, AX ; zero low word of Delta_y * 10000h SUB AX, DX ; DX:AX <- DX * 0FFFFh SBB DX, 0 DIV CX ; divide by Delta_X MOV SI, BX ; Si = Acculmulator MOV BX, AX ; Bx = Addor POP AX ; Get Color, Bit mask MOV DX, SC_Data ; Sequence controller data register INC CX ; Inc Delta_X so we can unroll loop ; Loop (x2) to Draw Pixels, Move Left, and Maybe Down... @DL_SLLLoop: MOV ES:[DI], AH ; set first pixel, plane data set up DEC CX ; count down Delta_X JZ @DL_SLLExit ; Exit if done.. ADD SI, BX ; add numerator to accumulator JNC @DL_SLLL2nc ; move down on carry ADD DI, BP ; Move Down one line... @DL_SLLL2nc: DEC DI ; Left one addr ROR AL, 1 ; Move Left one plane CMP AL, 87h ; Skipped around?, if AL <88 then Carry set ADC DI, 0 ; Adjust Address: DI = Di + Carry, ie. plane = OUT DX, AL ; Set up New Bit Plane mask MOV ES:[DI], AH ; set pixel ADD SI, BX ; add numerator to accumulator, JNC @DL_SLLL3nc ; move down on carry ADD DI, BP ; Move Down one line... @DL_SLLL3nc: ; Now move left a pixel... DEC DI ; Left one addr ROR AL, 1 ; Move Left one plane CMP AL, 87h ; Skipped around?, if AL <88 then Carry set ADC DI, 0 ; Adjust Address: DI = Di + Carry, ie. plane = OUT DX, AL ; Set up New Bit Plane mask DEC CX ; count down Delta_X JNZ @DL_SLLLoop ; loop till done @DL_SLLExit: JMP @DL_EXIT2 ; and exit ; Draw a steep line to the left in Mode X @DL_SteepLeft: XOR AX, AX ; zero low word of Delta_y * 10000h XCHG DX, CX ; Delta_Y switched with Delta_x DIV CX ; divide by Delta_Y MOV SI, BX ; Si = Acculmulator MOV BX, AX ; Bx = Addor POP AX ; Get Color, Bit mask MOV DX, SC_Data ; Sequence controller data register INC CX ; Inc Delta_Y so we can unroll loop ; Loop (x2) to Draw Pixels, Move Down, and Maybe left @DL_STLLoop: MOV ES:[DI], AH ; set first pixel DEC CX ; Count Down Delta_Y JZ @DL_STLExit ; Exit if done ADD SI, BX ; add numerator to accumulator JNC @DL_STLnc2 ; No carry, just move down! ; Move Left DEC DI ; Left one addr ROR AL, 1 ; Move Left one plane CMP AL, 87h ; Skipped around?, if AL <88 then Carry set ADC DI, 0 ; Adjust Address: DI = Di + Carry, ie. plane = OUT DX, AL ; Set up New Bit Plane mask @DL_STLnc2: ADD DI, BP ; advance to next line. MOV ES:[DI], AH ; set pixel ADD SI, BX ; add numerator to accumulator JNC @DL_STLnc3 ; No carry, just move down! ;Move Left DEC DI ; Left one addr ROR AL, 1 ; Move Left one plane CMP AL, 87h ; Skipped around?, if AL <88 then Carry set ADC DI, 0 ; Adjust Address: DI = Di + Carry, ie. plane = OUT DX, AL ; Set up New Bit Plane mask @DL_STLnc3: ADD DI, BP ; advance to next line. DEC CX ; count down Delta_Y JNZ @DL_STLLoop ; loop till done @DL_STLExit: JMP @DL_EXIT2 ; and exit ; Draw A line that goes to the Right... @DL_DrawRight: CMP CX, DX ; is X < Delta_Y? JB @DL_SteepRight ; yes, so go do steep line (Delta_Y iterations) ; Draw a Shallow line to the Right in Mode X @DL_ShallowRight: XOR AX, AX ; zero low word of Delta_y * 10000h SUB AX, DX ; DX:AX <- DX * 0FFFFh SBB DX, 0 DIV CX ; divide by Delta_X MOV SI, BX ; Si = Acculmulator MOV BX, AX ; Bx = Addor POP AX ; Get Color, Bit mask MOV DX, SC_Data ; Sequence controller data register INC CX ; Inc Delta_X so we can unroll loop ; Loop (x2) to Draw Pixels, Move Right, and Maybe Down... @DL_SLRLoop: MOV ES:[DI], AH ; set first pixel, mask already set up DEC CX ; count down Delta_X JZ @DL_SLRExit ; Exit if done.. ADD SI, BX ; add numerator to accumulator JNC @DL_SLR2nc ; don't move down if carry not set.... ADD DI, BP ; Move Down one line... @DL_SLR2nc: ; Now move right a pixel... ROL AL, 1 ; Move Right one plane CMP AL, 12h ; Skipped around?, if AL >12 then Carry not set ADC DI, 0 ; Adjust Address: DI = Di + Carry, ie. plane = OUT DX, AL ; Set up New Bit Plane mask MOV ES:[DI], AH ; set pixel ADD SI, BX ; add numerator to accumulator JNC @DL_SLR3nc ; don't move down if carry not set.... ADD DI, BP ; Move Down one line... @DL_SLR3nc: ROL AL, 1 ; Move Right one plane CMP AL, 12h ; Skipped around?, if AL >12 then Carry not set ADC DI, 0 ; Adjust Address: DI = Di + Carry, ie. plane = OUT DX, AL ; Set up New Bit Plane mask DEC CX ; count down Delta_X JNZ @DL_SLRLoop ; loop till done @DL_SLRExit: JMP @DL_EXIT2 ; and exit ; Draw a Shallow line to the Right in Mode X @DL_SteepRight: XOR AX, AX ; zero low word of Delta_y * 10000h XCHG DX, CX ; Delta_Y switched with Delta_x DIV CX ; divide by Delta_Y MOV SI, BX ; Si = Acculmulator MOV BX, AX ; Bx = Addor POP AX ; Get Color, Bit mask MOV DX, SC_Data ; Sequence controller data register INC CX ; Inc Delta_Y so we can unroll loop ; Loop (x2) to Draw Pixels, Move Down, and Maybe Right @STRLoop: MOV ES:[DI], AH ; set first pixel, mask already set up... DEC CX ; count down Delta_Y JZ @DL_EXIT2 ; Exit if Finished ADD SI, BX ; add numerator to accumulator JNC @STRnc2 ; if no carry then just go down... ROL AL, 1 ; Move Right one plane CMP AL, 12h ; Skipped around?, if AL >12 then Carry not set ADC DI, 0 ; Adjust Address: DI = Di + Carry, ie. plane = OUT DX, AL ; Set up New Bit Plane mask @STRnc2: ADD DI, BP ; advance to next line. MOV ES:[DI], AH ; set pixel ADD SI, BX ; add numerator to accumulator JNC @STRnc3 ; if no carry then just go down... ROL AL, 1 ; Move Right one plane CMP AL, 12h ; Skipped around?, if AL >12 then Carry not set ADC DI, 0 ; Adjust Address: DI = Di + Carry, ie. plane = OUT DX, AL ; Set up New Bit Plane mask @STRnc3: ADD DI, BP ; advance to next line. DEC CX ; count down Delta_Y JNZ @STRLoop ; loop till done @DL_EXIT2: POP DI POP SI POP BP ; Restore BP, SI, & DI RET 10 ; Exit and Clean up Stack DRAW_LINE ENDP ;========================= ;SET_ACTIVE_PAGE (PageNo%) ;========================= ; ;Sets the Video Page to be used for future drawing ; SAP_STACK STRUC DW ? ;BP DD ? ;Caller SAP_Page DW ? ;Page # for Drawing SAP_STACK ENDS PUBLIC SET_ACTIVE_PAGE SET_ACTIVE_PAGE PROC FAR PUSH BP ; Preserve Registers MOV BP, SP ; Set up Stack Frame MOV BX, [BP].SAP_Page ; Get Desired Page # CMP BX, LAST_PAGE ; Is Page # Valid? JAE @SAP_Exit ; IF Not, Do Nothing MOV ACTIVE_PAGE, BX ; Set Active Page # SHL BX, 1 ; Scale Page # to Word MOV AX, PAGE_ADDR[BX] ; Get offset to Page MOV CURRENT_PAGE, AX ; And set for future LES's @SAP_Exit: POP BP ; Restore Registers RET 2 ; We are Done.. Outa here SET_ACTIVE_PAGE ENDP ;================ ;GET_ACTIVE_PAGE% ;================ ; ; Returns the Video Page # currently used for Drawing ; ; RETURNS: AX = Current Video Page used for Drawing ; PUBLIC GET_ACTIVE_PAGE GET_ACTIVE_PAGE PROC FAR MOV AX, ACTIVE_PAGE ; Get Active Page # RET ; We are Done.. Outa here GET_ACTIVE_PAGE ENDP ;========================== ;SET_DISPLAY_PAGE (PageNo%) ;========================== ; ;Sets the Video Page to be displayed on the screen ; SDP_STACK STRUC DW ? ;BP DD ? ;Caller SDP_Page DW ? ;Page # to Display... SDP_STACK ENDS PUBLIC SET_DISPLAY_PAGE SET_DISPLAY_PAGE PROC FAR PUSH BP ; Preserve Registers MOV BP, SP ; Set up Stack Frame MOV BX, [BP].SDP_Page ; Get Desired Page # CMP BX, LAST_PAGE ; Is Page # Valid? JAE @SDP_Exit ; IF Not, Do Nothing MOV DISPLAY_PAGE, BX ; Set Display Page # SHL BX, 1 ; Scale Page # to Word MOV CX, PAGE_ADDR[BX] ; Get offset in memory to Page ADD CX, CURRENT_MOFFSET ; Adjust for any scrolling MOV DX, CRTC_Index ; We Change the VGA Sequencer MOV AL, START_DISP_LO ; Display Start Low Register MOV AH, CL ; Low 8 Bits of Start Addr OUT DX, AX ; Set Display Addr Low MOV AL, START_DISP_HI ; Display Start High Register MOV AH, CH ; High 8 Bits of Start Addr OUT DX, AX ; Set Display Addr High @SDP_Exit: POP BP ; Restore Registers RET 2 ; We are Done.. Outa here SET_DISPLAY_PAGE ENDP ;================= ;GET_DISPLAY_PAGE% ;================= ; ; Returns the Video Page # currently be displayed on the screen ; ; RETURNS: AX = Current Display Page ; PUBLIC GET_DISPLAY_PAGE GET_DISPLAY_PAGE PROC FAR MOV AX, DISPLAY_PAGE ; Get Display Page # RET ; We are Done.. Outa here GET_DISPLAY_PAGE ENDP ;================================================= ;SET_DAC_REGISTER (Register%, Red%, Green%, Blue%) ;================================================= ; ; Sets a single (RGB) Vga Palette Register ; to the specified Reg, Green & Blue Values ; SDR_STACK STRUC DW ? ; BP DD ? ; Caller SDR_Blue DB ?,? ; Blue Data Value SDR_Green DB ?,? ; Green Data Value SDR_Red DB ?,? ; Red Data Value SDR_Register DB ?,? ; Palette Register # SDR_STACK ENDS PUBLIC SET_DAC_REGISTER SET_DAC_REGISTER PROC FAR PUSH BP ; Save Bp MOV BP, SP ; Set up Stack Frame ; Select which DAC Register to modify OUT_8 DAC_WRITE_ADDR, [BP].SDR_Register MOV DX, PEL_DATA_REG ; Dac Data Register MOV AL, [Bp].SDR_Red ; Get Red Intensity OUT DX, AL ; Set it MOV AL, [Bp].SDR_Green ; Get Green Intensity OUT DX, AL ; Set it MOV AL, [Bp].SDR_Blue ; Get Blue Intensity OUT DX, AL ; Set it POP BP ; Restore Registers RET 8 ; Exit & Clean Up Stack SET_DAC_REGISTER ENDP ;==================================================== ;GET_DAC_REGISTER (Register%, &Red%, &Green%, &Blue%) ;==================================================== ; ; Gets the RGB Values of a single Vga Palette Register ; ; INPUT: Red%, Green% & Blue% are offsets into DGROUP ; that point to 16 bit integers that will hold ; the returned red, green, and blue values ; GDR_STACK STRUC DW ? ; BP DD ? ; Caller GDR_Blue DW ? ; Addr of Blue Data Value in DS GDR_Green DW ? ; Addr of Green Data Value in DS GDR_Red DW ? ; Addr of Red Data Value in DS GDR_Register DB ?,? ; Palette Register # GDR_STACK ENDS PUBLIC GET_DAC_REGISTER GET_DAC_REGISTER PROC FAR PUSH BP ; Save Bp MOV BP, SP ; Set up Stack Frame ; Select which DAC Register to read in OUT_8 DAC_READ_ADDR, [BP].GDR_Register MOV DX, PEL_DATA_REG ; Dac Data Register XOR AX, AX ; Clear AX IN AL, DX ; Read Red Value MOV BX, [Bp].GDR_Red ; Get Address of Red% MOV [BX], AX ; *Red% = AX IN AL, DX ; Read Green Value MOV BX, [Bp].GDR_Green ; Get Address of Green% MOV [BX], AX ; *Green% = AX IN AL, DX ; Read Blue Value MOV BX, [Bp].GDR_Blue ; Get Address of Blue% MOV [BX], AX ; *Blue% = AX POP BP ; Restore Registers RET 8 ; Exit & Clean Up Stack GET_DAC_REGISTER ENDP ;========================= ;SET_WINDOW (Xpos%, Ypos%) ;========================= ; ; Since a Logical Screen can be larger than the Physical ; Screen, Scrolling is possible. This routine sets the ; Upper Left Corner of the Screen to the specified Pixel. ; ; Xpos & Ypos = Coordinates of the Pixel to put in the ; upper left corner of the screen ; SW_STACK STRUC DW ? ;BP DD ? ;Caller SW_Ypos DW ? SW_Xpos DW ? SW_STACK ENDS PUBLIC SET_WINDOW SET_WINDOW PROC FAR PUSH BP ; Preserve Registers MOV BP, SP ; Set up Stack Frame ; Check if our Scroll Offsets are Valid MOV AX, [BP].SW_Ypos ; Get Desired Y Offset CMP AX, MAX_YOFFSET ; Is it Within Limitss? JA @SW_Exit ; if not, exit MOV BX, [BP].SW_Xpos ; Get Desired X Offset CMP BX, MAX_XOFFSET ; Is it Within Limitss? JA @SW_Exit ; if not, exit ; Compute proper Display start address to use MUL SCREEN_WIDTH ; AX = YOffset * Line Width MOV CX, BX ; CX = Copy of X Offset SHR BX, 2 ; BX / 4 = Bytes into Line ADD AX, BX ; AX = Offset of Upper Left Pixel MOV CURRENT_MOFFSET, AX ; Save Offset Info MOV BX, DISPLAY_PAGE ; Get Display Page # SHL BX, 1 ; Scale Page # to Word ADD AX, PAGE_ADDR[BX] ; Get offset in VGA to Page MOV BX, AX ; BX = Desired Display Start MOV DX, INPUT_1 ; Input Status #1 Register ; Wait for a Vertical Retrace to smooth out the scroll @SW_WAIT: IN AL, DX ; Get VGA stauts JMP $+2 ; Delay (why?) AND AL, 8 ; Bit 3 Gone Hi Yet? JZ @SW_WAIT ; If Not, wait for it CLI ; Don't Interrupt this! ; Set the Start Display Address to the New window MOV DX, CRTC_Index ; We Change the VGA Sequencer MOV AL, START_DISP_LO ; Display Start Low Register MOV AH, BL ; Low 8 Bits of Start Addr OUT DX, AX ; Set Display Addr Low MOV AL, START_DISP_HI ; Display Start High Register MOV AH, BH ; High 8 Bits of Start Addr OUT DX, AX ; Set Display Addr High ; Now Set the Horizontal Pixel Pan values MOV DX, INPUT_1 ; Input Status #1 Register IN AL, DX ; Reset Attrib Flip/Flop OUT_8 ATTRIB_Ctrl, 33h ; Select Pixel Pan Register MOV AL, CL ; Get Low Bits of X Offset AND AL, 03 ; Get # of Pixels to Pan (0-3) SHL AL, 1 ; Shift for 256 Color Mode OUT DX, AX ; Fine tune the display! STI ; Ok, Now you CAN interrupt @SW_Exit: POP BP ; Restore Saved Registers RET 4 ; Exit and Clean up Stack SET_WINDOW ENDP END