NOLIST *--------------------------------------------------------------------------- * Program WriteBitMap * Author Eduard Pech, The New Power Generation * Compiler NCode 1.2 * Version $0.99\alpha.00a$ not yet functional [npg] * Date 14-Jun-92 * Version $0.99\alpha.00b$ fully functional [npg] * Date 15-Jun-92 * Version $0.99\alpha.00c$ [npg] * Date 16-Jun-92 * Version $0.99\alpha.01a$ [npg] * Date 16-Jun-92 * Version $0.99\alpha.01b$ [npg] * Date 22-Jun-92 * Version $0.99\beta.00a$ [npg] * Date 15-Jul-92 * History $0.99\alpha.00a$ * Me idiot. Listen (and don't repeat): * (1) I used _scratch_ registers as parameters. Of course * they've been modified with the third instruction... * (2) I wrote: "WriteByteLen EQU *-WriteByteLen" instead * of "WriteByteLen EQU *-WriteByteTxt". Of course DOS * tried to write out 4 GB onto my 105 MB Quantum... * This "errors" have been discovered on 15-Jun-92. They * have been removed. (It only took about 20 hours of real * time!?!) But then I also discovered a "real" error: * (3) In conjuntion with the "EndOfImage" function the * flags have not been set/tested correctly. I will be * working on this right now (can't take very long, I * hope). * $0.99\alpha.00b$ * Eliminated all errors from the last version. Rewrote the * "EndOfImage" function. Discovered that in any case the * maximum screen size is being used to determine the size * of the output. I'll try to fix this by passing the actual * width and height of the picture/brush. Well, but I tried. * The problem is, I think, that I can't get the "real" size * of the image from the module IFF Support. * $0.99\alpha.00c$ * Discovered how IFF Support stores information about the * image. So I was able to add a "modulo" functionality: * Images not using the whole screen width should be treated * correctly. But I have no possibility to check this out. * And I suspect IFF Support of not expanding such an image * to the full screen width (filling the screen up with 0 * bytes), so the whole probably won't work (but at least * I tried, and it's not my fault). Started commenting the * source code. Finished comments at 0:58, 16-Jun-92. * $0.99\alpha.01a$ * This versions now contains _dangerous_ code. I included * an error handler that notices any error in writing to * the output file, but does stack manipulation which is * _very_ specialized for this program. So, don't try to * change it unless you _really_ know what you do. The * procedure now returns TRUE if no error occured, else * FALSE. Beside this, _LVO's were introduced with this * version. * $0.99\alpha.01b$ * Inserted the command "eor.b #$FF,d0" in "MirrorByte" to * get a reversed bitmap output. This is, because a cleared * bit will be displayed white and v.~v. with "xsetroot". * $0.99\beta.00a$ * After several hard weeks of trial and error I finally * found the "erroneous" piece of code. Instead of adding * only one byte to the bitmap pointer in A2, I always added * eight bytes at a time, probably "thinking" in pixels as * I coded this part. So now no more borders will be created * for pictures that are not a multiple of sixteen pixels * wide. Introduced EQUR directives. *--------------------------------------------------------------------------- XDEF WriteBitMap _LVOFWrite EQU -330 _LVOOpenLibrary EQU -552 _LVOCloseLibrary EQU -414 TRUE EQU -1 FALSE EQU 0 BitPlane EQUR A4 ; register contents must not be changed File EQUR A5 ; register contents must not be changed ImageWidth EQUR D6 ; register contents may change ImageHeight EQUR D7 ; register contents may change HexTabPtr EQUR A3 LFCounter EQUR D5 PointerToX EQUR D6 PointerToY EQUR D7 ; D0-D4/A0-A1 are scratch registers WriteBitMap ; initialization part of WriteBitMap subq.w #1,ImageWidth ; normalize Image.width lsr.w #3,ImageWidth addq.w #1,ImageWidth lsl.w #3,ImageWidth move.w ImageWidth,width ; ((Image.width + 1) DIV 8 + 1) * 8 move.w ImageHeight,height ; Image.height and.w #$000F,ImageWidth lsr.b #3,ImageWidth ext.l ImageWidth move.l ImageWidth,modulo ; Image.width MOD 16 bra.s WBMMain ; branch into main part GetFirstByte ; get the first byte of bitplane moveq #0,PointerToX ; PointerToX := 0 moveq #0,PointerToY ; PointerToY := 0 GetNextByte ; get the next byte of bitplane move.b (BitPlane)+,d0 ; D0 == byte := (BitPlane)+ addq.w #8,PointerToX ; PointerToX := PointerToX + 8 (pixels) cmp.w width,PointerToX ; IF PointerToX >= Image.width bcs.s GNBRet moveq #0,PointerToX ; THEN PointerToX := 0 addq.w #1,PointerToY ; INC (PointerToY,1) add.l modulo,BitPlane ; BitPlane := BitPlane + Image.width MOD 16 GNBRet rts ; back to future... MirrorByte ; mirrors the byte in D0, changes D0-D2 moveq #7,d2 ; loop counter (=> 8 loops) MBLoop ; REPEAT lsr.b #1,d0 ; shift out right bit roxl.b #1,d1 ; shift in from right dbra d2,MBLoop ; UNTIL loop counter == 0 move.b d1,d0 ; return mirrored byte in D0 eor.b #$FF,d0 ; invert it, too rts ; back to back... WBMMain ; main part of WriteBitMap movem.l d1-d7/a0-a6,-(SP) ; save used registers _except_ D0 move.l (4).w,a6 ; get Exec.Base lea dosname,a1 moveq #37,d0 jsr _LVOOpenLibrary(a6) ; Exec.OpenLibrary (dos.library,37) move.l d0,a6 ; no errors due to usage in Oberon already lea HexTab,HexTabPtr ; HexTabPtr := POINTER TO HexTab bsr.s GetFirstByte ; get the first byte of bitplane bsr.s MirrorByte ; transform it, mirror the bits bsr.s WriteByte ; output this new byte moveq #1,LFCounter ; LFCounter := 1 WBMLoop bsr.s EndOfImage ; WHILE ~EndOfImage bne.s WBMDone bsr.s WriteComma ; DO output a comma addq.b #1,LFCounter ; increase LF counter cmp.b #12,LFCounter ; IF LF counter > 12 bls.s WBMMark bsr.s WriteLn ; THEN output a LF moveq #1,LFCounter ; set LF counter to 1 WBMMark bsr.s GetNextByte ; get the next byte of bitplane bsr.s MirrorByte ; mirror its bits bsr.s WriteByte ; output the byte bra.s WBMLoop ; END (* WHILE *) WBMDone move.l #TRUE,-(SP) ; everything was alright here (will go to D0) WBMRet move.l a6,a1 move.l (4).w,a6 ; get Exec.Base jsr _LVOCloseLibrary(a6) ; Exec.CloseLibrary (dos.library) movem.l (SP)+,d0-d7/a0-a6 ; restore used registers _and_ RETURN result rts ; back up... EndOfImage ; checks for end of image cmp.w height,PointerToY ; IF PointerToY >= Image.height bcs.s EOIFalse EOITrue moveq #TRUE,d0 ; THEN RETURN TRUE bra.s EOIRet EOIFalse moveq #FALSE,d0 ; ELSE RETURN FALSE EOIRet rts ; back to life... DoOutput ; output handler move.l File,d1 ; Dos.FileHandlePtr moveq #1,d4 ; number of blocks jsr _LVOFWrite(a6) ; Dos.FWrite cmp.l #1,d0 ; IF blocks_written # blocks_sent == 1 beq.s DORet move.l #FALSE,(SP) ; THEN overwrite return address with FALSE bra.s WBMRet ; terminate WriteBitMap procedure DORet rts ; back to reality... WriteLn ; output a LF move.l #WriteLnTxt,d2 ; POINTER TO Block move.l #WriteLnLen,d3 ; SYSTEM.SIZE (Block) bra.s DoOutput ; branch into output handler WriteComma ; output a comma move.l #WriteCommaTxt,d2 ; POINTER TO Block move.l #WriteCommaLen,d3 ; SYSTEM.SIZE (Block) bra.s DoOutput ; branch into output handler WriteByte ; output a byte ror.l #4,d0 ; save last 4 bits and.w #$000f,d0 ; transform first nibble to hexadecimal move.b 0(HexTabPtr,d0.w),WriteByteTxt+3 ; cipher and store it rol.l #4,d0 ; get back the lower nibble and.w #$000f,d0 ; do the same transformation and move.b 0(HexTabPtr,d0.w),WriteByteTxt+4 ; store it, too move.l #WriteByteTxt,d2 ; POINTER TO Block move.l #WriteByteLen,d3 ; SYSTEM.SIZE (Block) bra.s DoOutput ; branch into output handler SECTION Daten,DATA ; data section dosname ; name of dos.library DC.B "dos.library",0 WriteLnTxt ; text for LF's DC.B 10," " WriteLnLen EQU *-WriteLnTxt WriteCommaTxt ; text for commas to be written DC.B "," WriteCommaLen EQU *-WriteCommaTxt WriteByteTxt ; text for hexadecimal byte output DC.B " 0x00" WriteByteLen EQU *-WriteByteTxt HexTab ; table of hexadecimal ciphers DC.B "0123456789abcdef" SECTION Puffer,BSS ; buffer section width ; Image.width DS.W 1 height ; Image.height DS.W 1 modulo ; Image.width MOD 16 DS.L 1 END