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Topic       : TOS - The Operating System
Author      : 
Version     : tos.hyp (December 19, 2008)
Subject     : Programmieren/Atari
Nodes       : 3010
Index Size  : 93790
HCP-Version : 5
Compiled on : Atari
@charset    : atarist
@lang       : 
@default    : Title
@help       : 
@options    : +g -i -s +x +zz -t4
@width      : 70
View Ref-File6.12  Bit block transfer                                           TOS

 Name:         »Bit block transfer«

 Line-A number: $A007

 Syntax:       See 'Bindings for bit_blt'

 Description:  This Line-A function copies between a rectangular 
               source and destination block. For this the source area 
               can be combined with a raster. Source and destination 
               can be combined with one of 16 possible logical 
               operations. This function also serves as the basis for 
               the Line-A functions Text block transfer and Copy 
               raster form.

               For the parameters a structure of the type BITBLT has 
               to be filled and passed in register A6.

               The following logical combinations are available:

                Operation  Function 
                    0      D' = 0          Destination is background colour 
                    1      D' = S & D 
                    2      D' = S &  D 
                    3      D' = S 
                    4      D' =  S & D 
                    5      D' = D 
                    6      D' = S ^ D 
                    7      D' = S | D 
                    8      D' =  (S | D) 
                    9      D' =  (S ^ D) 
                   10      D' =  D 
                   11      D' = S |  D 
                   12      D' =  S 
                   13      D' =  S | D 
                   14      D' =   (S & D) 
                   15      D' = 1          Destination is foreground colour 

               D' is the destination after the combination, S and D 
               are the source and destination before the combination. 
               & is the logical AND combination, | is OR, ^ is the 
               exclusive OR (XOR) combination, ! is a NOT inversion.

 Return value: The function does not have a return value.

 Availability: All TOS versions.

 See Also:     Binding   Text block transfer   Copy raster form