;This is the assembler source for the 2View function ReadIntoBitmap() ; ;Parameters: ; a0.l - The destination bitmap's PLANEPTR structure ; a1.l - The source buffer ; a2.l - The pointer to the IFFParse structure ; ; d0.l - The length of the source buffer ; d1.l - The number of bytes per bitmap row ; d2.w - The number of rows in the bitmap ; d3.b - The number of bitplanes in the bitmap ; d4.b - 0 if the source isn't compressed, 1 if it is ; d5.b - 1 if there's masking, 0 if not ; ;Returns: ; Nothing ; ;Bugs: ; Doesn't check ReadChunkBytes() return value xref _LVOCopyMem xref _LVOReadChunkBytes xref _DOSBase xref _IFFParseBase xref _SysBase xref _trashBuf xref _storage xdef _ReadIntoBitmapAsm SECTION "program",code _ReadIntoBitmapAsm: nop nop nop move.l 4(a7),planePtr move.l 8(a7),srcStart ;Store start of buffer move.l 12(a7),iff ;Store the IFFParse struct pointer move.l 16(a7),(sourceBufSize) move.l 20(a7),bytesInRow move.l 24(a7),d0 ;Masking move.w d0,Height move.l 28(a7),d0 lsl.b #2,d0 move.b d0,Depth move.l 32(a7),d0 move.b d0,comp move.l 36(a7),d0 movem.l a2/a4-a6/d2-d4/d7,-(a7) movea.l srcStart,a2 ;Create the current source buf ptr adda.l (sourceBufSize),a2 movea.l a2,a5 ;Create the end-of-source ptr moveq.l #0,d2 clr.l byteOffset move.b Depth,d3 tst.b d0 ;Check masking beq storeMask subq.b #4,d3 ;Store the mask plane number storeMask: move.b d3,maskPlaneNum clr.w curRow ;Clear the current row variable tst.b comp ;Test the compression flag beq uncompressed ;If 0 no compression nextRow: moveq.l #0,d4 ;Start of bitplane loop nextPlane: cmp.b maskPlaneNum,d4 ;If it isn't the mask plane... bne getBitplane ;Get the destination bitmap pointer movea.l _trashBuf,a4 ;Else, get a pointer to a bit bucket bra getBytes getBitplane: movea.l planePtr,a0 movea.l 0(a0,d4),a4 adda.l byteOffset,a4 move.l a4,d7 add.l bytesInRow,d7 ;Create the end-of-row pointer getBytes: cmpa.l a2,a5 bne checkCompType bsr refillSrcBuffer bmi error checkCompType: moveq.l #0,d2 move.b (a2)+,d2 ;Get the current byte cmp.b #128,d2 beq getBytes ;Check for a NOP cmp.b #0,d2 ;Check to see if the byte specifies blt fillMem ;a fill... addq.b #1,d2 ;We need to copy d2+1 bytes move.l a5,d3 ;Check to see if the source buffer sub.l a2,d3 ;contains all the bytes we need to cmp.l d2,d3 ;copy bpl copyAll ;If so, copy them ;Otherwise, copy the number of bytes available movea.l a2,a0 movea.l a4,a1 move.l d3,d0 movea.l _SysBase,a6 jsr _LVOCopyMem(a6) ;Add the number of bytes copied to the destination pointer adda.l d3,a4 sub.b d3,d2 ;Determine how many bytes are left ;to copy bsr refillSrcBuffer bmi error ;Copy a given number of bytes from the source to destination copyAll: movea.l a2,a0 ;Setup for CopyMem() movea.l a4,a1 move.l d2,d0 movea.l _SysBase,a6 jsr _LVOCopyMem(a6) adda.l d2,a4 ;Update destination pointer adda.l d2,a2 ;Update source pointer bra nextCompByte fillMem: neg.b d2 cmpa.l a5,a2 ;See if source buffer is empty bne getFillByte bsr refillSrcBuffer bmi error getFillByte: move.b (a2)+,d0 ;Get the fill byte doFill: move.b d0,(a4)+ ;Do the fill dbra d2,doFill nextCompByte: cmp.l a4,d7 ;Check to see if we've written the bne getBytes ;entire row bra checkLoop ;If so, get the next row checkLoop: ;Check to see if we're done with all the planes in this row addq.b #4,d4 ;Increment the plane counter cmp.b Depth,d4 ;Compare to the # of planes bne nextPlane ;If not equal, get next plane in row setupNextRow: move.l byteOffset,d0 ;Update byte-offset value add.l bytesInRow,d0 move.l d0,byteOffset addq #1,curRow ;Increment the row counter move.w curRow,d0 ;Check to see if we've run through cmp.w Height,d0 ;all the rows bne nextRow ;If not, get the next row bra done ;Transfer a row (uncompressed) uncompressed: nextURow: moveq.l #0,d4 ;Start of bitplane loop nextUPlane: cmp.b maskPlaneNum,d4 ;If it isn't the mask plane... bne getUBitplane ;Get the destination bitmap pointer adda.l bytesInRow,a2 ;Else, skip past the mask plane bra setupNextRow ;And go on to the next row getUBitplane: movea.l planePtr,a0 movea.l 0(a0,d4),a4 adda.l byteOffset,a4 move.l a4,d7 add.l bytesInRow,d7 ;Create the end-of-row pointer getUBytes: cmpa.l a2,a5 bge moveBytes bsr refillSrcBuffer bmi error moveBytes: move.l a5,d2 ;Check to see if all the bytes we need sub.l a2,d2 ;are in the source buffer cmp.l bytesInRow,d2 bge noCompXfer move.l d2,d0 ;Setup registers movea.l a2,a0 movea.l a4,a1 movea.l _SysBase,a6 jsr _LVOCopyMem(a6) adda.l d2,a4 ;Update destination pointer move.l bytesInRow,d0 sub.l d2,d0 move.l d0,d2 bsr refillSrcBuffer bmi error bra xfer_nc ;Transfer the rest noCompXfer: ;Setup to transfer all the bytes in the row move.l bytesInRow,d2 ;row xfer_nc: movea.l a2,a0 ;Transfer the given number of bytes movea.l a4,a1 move.l d2,d0 movea.l _SysBase,a6 jsr _LVOCopyMem(a6) adda.l d2,a2 ;Update the src pointer ;Check to see if we're done with all the planes in this row addq.b #4,d4 ;Increment the plane counter cmp.b Depth,d4 ;Compare to the # of planes bne nextUPlane ;If not equal, get next plane in row setupNextURow: move.l byteOffset,d0 ;Update byte-offset value add.l bytesInRow,d0 move.l d0,byteOffset addq #1,curRow ;Increment the row counter move.w curRow,d0 ;Check to see if we've run through cmp.w Height,d0 ;all the rows bne nextURow ;If not, get the next row done: moveq.l #0,d0 bra return error: moveq.l #0,d0 return: ;Restore registers movem.l (a7)+,a2/a4-a6/d2-d4/d7 rts ;And we're done refillSrcBuffer: movea.l iff,a0 movea.l srcStart,a1 movea.l a1,a2 move.l sourceBufSize,d0 movea.l _IFFParseBase,a6 jsr _LVOReadChunkBytes(a6) movea.l a2,a5 adda.l d0,a5 tst.l d0 rts SECTION "data",data CNOP 0,4 planePtr: dc.l 0 srcStart: dc.l 0 bytesInRow: dc.l 0 byteOffset: dc.l 0 iff: dc.l 0 sourceBufSize: dc.l 0 Height: dc.l 0 curRow: dc.w 0 plane: dc.b 0 maskPlaneNum: dc.b 0 Depth: dc.b 0 comp: dc.b 0 END